<SEC-DOCUMENT>0001144204-19-017481.txt : 20190401
<SEC-HEADER>0001144204-19-017481.hdr.sgml : 20190401
<ACCEPTANCE-DATETIME>20190401170100
ACCESSION NUMBER:		0001144204-19-017481
CONFORMED SUBMISSION TYPE:	10-K/A
PUBLIC DOCUMENT COUNT:		4
CONFORMED PERIOD OF REPORT:	20181231
FILED AS OF DATE:		20190401
DATE AS OF CHANGE:		20190401

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Synthetic Biologics, Inc.
		CENTRAL INDEX KEY:			0000894158
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				133808303
		STATE OF INCORPORATION:			NV
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		10-K/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12584
		FILM NUMBER:		19721552

	BUSINESS ADDRESS:	
		STREET 1:		9605 MEDICAL CENTER DRIVE
		STREET 2:		SUITE 270
		CITY:			ROCKVILLE
		STATE:			MD
		ZIP:			20850
		BUSINESS PHONE:		(734) 332-7800

	MAIL ADDRESS:	
		STREET 1:		9605 MEDICAL CENTER DRIVE
		STREET 2:		SUITE 270
		CITY:			ROCKVILLE
		STATE:			MD
		ZIP:			20850

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ADEONA PHARMACEUTICALS, INC.
		DATE OF NAME CHANGE:	20081027

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PIPEX PHARMACEUTICALS, INC.
		DATE OF NAME CHANGE:	20061214

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SHEFFIELD PHARMACEUTICALS INC
		DATE OF NAME CHANGE:	19970730
</SEC-HEADER>
<DOCUMENT>
<TYPE>10-K/A
<SEQUENCE>1
<FILENAME>tv517555_10ka.htm
<DESCRIPTION>FORM 10-K/A
<TEXT>
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<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="margin: 0"></P>

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<P STYLE="margin: 0">&nbsp;</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>UNITED STATES</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SECURITIES AND EXCHANGE COMMISSION</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Washington, DC 20549</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>FORM 10-K/A</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Amendment No. 1</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 0; width: 100%"><TR STYLE="vertical-align: top; text-align: justify">
<TD STYLE="width: 0.25in"></TD><TD STYLE="width: 0.5in; text-align: left"><FONT STYLE="font-family: Wingdings; font-size: 10pt"><B>x</B></FONT></TD><TD STYLE="text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>ANNUAL
REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934</B></FONT></TD>
</TR></TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>For the fiscal year ended December 31,
2018</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>OR</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 0; width: 100%"><TR STYLE="vertical-align: top; text-align: justify">
<TD STYLE="width: 0.25in"></TD><TD STYLE="width: 0.5in; text-align: left"><FONT STYLE="font-family: Wingdings; font-size: 10pt"><B>&#168;</B></FONT></TD><TD STYLE="text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>TRANSITION
REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES ACT OF 1934</B></FONT></TD>
</TR></TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>For the transition period from &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
to &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Commission File Number: 1-12584</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SYNTHETIC BIOLOGICS, INC.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><I>(Exact Name of Registrant as Specified
in Its Charter)</I></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: bottom">
    <TD STYLE="width: 47%; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Nevada</B></FONT></TD>
    <TD STYLE="width: 4%; padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="width: 47%; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>13-3808303</B></FONT></TD></TR>
<TR>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><I>(State or Other Jurisdiction of Incorporation or</I></FONT><BR>
<FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><I>Organization)</I></FONT></TD>
    <TD STYLE="vertical-align: bottom; padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><I>(I.R.S. Employer</I></FONT><BR>
<FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><I>Identification Number)</I></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: bottom">
    <TD STYLE="width: 47%; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>9605 Medical Center Drive, Ste. 270</B></FONT><BR>
<FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Rockville, MD</B></FONT></TD>
    <TD STYLE="width: 4%; padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="width: 47%; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>20850</B></FONT></TD></TR>
<TR>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><I>(Address of Principal Executive Offices)</I></FONT></TD>
    <TD STYLE="vertical-align: bottom; padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><I>(Zip Code)</I></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Registrant&rsquo;s telephone number,
including area code:<BR>
(301) 417-4364</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: bottom">
    <TD STYLE="width: 47%; border-bottom: black 1pt solid; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Securities registered pursuant to Section 12(b) of the Act:</B></FONT></TD>
    <TD STYLE="width: 4%; padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="width: 47%; border-bottom: black 1pt solid; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Name of each exchange on which registered:</B></FONT></TD></TR>
<TR>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Common Stock, $0.001 par value per share</B></FONT></TD>
    <TD STYLE="vertical-align: bottom; padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>NYSE AMERICAN, LLC</B></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Securities registered pursuant to Section
12(g) of the Act:<BR>
<I>None</I></B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Indicate by check mark if the registrant is a well-known seasoned
issuer, as defined in Rule 405 of the Securities Act.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif">Yes
<FONT STYLE="font-family: Wingdings">&#168;</FONT> No </FONT><FONT STYLE="font-family: Wingdings"><B>x</B></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Indicate by check mark if the registrant
is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif">Yes
<FONT STYLE="font-family: Wingdings">&#168;</FONT> No </FONT><FONT STYLE="font-family: Wingdings"><B>x</B></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Indicate by check mark whether the issuer:
(1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding
12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif">Yes
</FONT><FONT STYLE="font-family: Wingdings"><B>x</B></FONT> <FONT STYLE="font-family: Times New Roman, Times, Serif">No <FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Indicate by check mark whether the registrant
has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (section
232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit
such files).</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif">Yes
</FONT><FONT STYLE="font-family: Wingdings"><B>x</B></FONT> <FONT STYLE="font-family: Times New Roman, Times, Serif">No <FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Indicate by check mark if disclosure of
delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of issuer&rsquo;s
knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment
to this Form 10-K. <FONT STYLE="font-family: Wingdings">&#120;</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Indicate by check mark whether the registrant
is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth
company. See the definitions of &ldquo;large accelerated filer, &ldquo;accelerated filer,&rdquo; &ldquo;smaller reporting company&rdquo;
and &ldquo;emerging growth company&rdquo; in Rule 12b-2 of the Exchange Act. (Check one):</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 24%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Large&nbsp;Accelerated&nbsp;Filer</FONT></TD>
    <TD STYLE="width: 1%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="width: 47%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></TD>
    <TD STYLE="width: 1%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="width: 24%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Accelerated&nbsp;Filer</FONT></TD>
    <TD STYLE="width: 1%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="width: 2%; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Non-accelerated&nbsp;Filer</FONT></TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Wingdings; font-size: 10pt"><B>x</B></FONT></TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Smaller&nbsp;Reporting&nbsp;Company</FONT></TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Wingdings; font-size: 10pt"><B>x</B></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Emerging growth company</FONT></TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><FONT STYLE="font-family: Wingdings">&#168;</FONT></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">If an emerging growth company, indicate
by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial
accounting standards provided pursuant to Section 13(a) of the Exchange Act.&nbsp;&nbsp; <FONT STYLE="font-family: Wingdings">&#168;</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Indicate by check mark whether the registrant
is a shell company (as defined in Rule 12b-2 of the Exchange Act).</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif">Yes <FONT STYLE="font-family: Wingdings">&#168;</FONT>
No </FONT><FONT STYLE="font-family: Wingdings"><B>x</B></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">The aggregate market value of the registrant&rsquo;s
common stock held by non-affiliates of the registrant as of June 29, 2018, the last business day of the registrant&rsquo;s recently
completed second quarter, was approximately $27.8 million based on $8.40, the closing price of the registrant&rsquo;s common stock
as reported by the NYSE American on that date.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">As of February 26, 2019, the registrant
had 15,484,411 shares of common stock outstanding.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Documents incorporated by reference: <B>None</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"></P>




<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>EXPLANATORY NOTE</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">This Amendment No. 1 on Form 10-K/A hereby
amends the Registrant's Annual Report on Form 10-K for the fiscal year ended December 31, 2018 (the &ldquo;Original Filing&rdquo;),
which the Registrant filed with the Securities and Exchange Commission on February 27, 2019. This Amendment No. 1 is being filed
solely to correct and replace Exhibit 23.1 to the Original Filing, which inadvertently omitted a reference to the Registrant&rsquo;s
registration statement on Form S-1.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Except as described above, no changes have
been made to the Original Filing and this Amendment No.&nbsp;1 does not modify, amend or update in any way any of the financial
or other information contained in the Original Filing. This Amendment No.&nbsp;1 does not reflect events that may have occurred
subsequent to the Original Filing Date.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Accordingly, this Amendment No.
1 should be read in conjunction with the Original Filing Pursuant to Rule 12b-15 under the Securities Exchange Act of 1934,
as amended, this Amendment No.&nbsp;1 also contains new certifications pursuant to Section&nbsp;302 and Section 906 of the
Sarbanes-Oxley Act of 2002, which are attached hereto.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>PART IV</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>Item 15. Exhibits, Financial Statement Schedules.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">(a) Index to Financial Statements and Exhibits</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">(2) EXHIBITS</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><A HREF="tv517555_ex23-1.htm">Exhibit 23.1 Consent of Independent Registered Public Accounting Firm</A></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><A HREF="tv517555_ex31-1.htm">Exhibit 31.1 Certification of the Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002</A></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><A HREF="tv517555_ex31-1.htm">Exhibit 31.2 Certification of the Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002</A></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><A HREF="tv517555_ex32-1.htm">Exhibit 32.1 Certification of the Chief Executive Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002</A></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><A HREF="tv517555_ex32-1.htm">Exhibit 32.2 Certification of the Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002</A></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">The exhibits listed in the accompanying Index to Exhibits are
filed or incorporated by reference as part of this annual report.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>


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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;&nbsp;&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SIGNATURES</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 23.9pt; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Pursuant to the requirements of Section
13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this Amendment No. 1 to this report to be signed
on its behalf by the undersigned.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 26.9pt; text-align: justify">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD COLSPAN="2" STYLE="padding-right: 1.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">SYNTHETIC BIOLOGICS, INC.</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 55%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="width: 5%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="width: 40%; padding-right: 0.8pt; text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">By:</FONT></TD>
    <TD STYLE="border-bottom: black 1pt solid; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">/s/ Steven A. Shallcross</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Steven A. Shallcross</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Chief Executive Officer, Chief Financial Officer&nbsp;and Director</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">(Principal Executive Officer, Principal Financial Officer and Principal Accounting Officer)</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Date:
    April 1, 2019</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;&nbsp;</P>


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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>PART IV</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 9%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>&nbsp;Item 15.</B></FONT></TD>
    <TD STYLE="width: 91%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B><I>Exhibits and Financial Statement Schedules</I></B></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 86px; padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">(a)(1)</FONT></TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">The following financial statements are included in this Annual Report on Form 10-K for the fiscal years ended December 31, 2018 and 2017.</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">1.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Independent Registered Public Accounting Firm</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">2.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Consolidated Balance Sheets as of December 31, 2018 and 2017</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">3.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Consolidated Statements of Operations for the years ended December 31, 2018 and 2017</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">4.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Consolidated Statements of changes in Stockholders&rsquo; Equity for the years ended December 31, 2018 &nbsp;&nbsp;and 2017</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">5.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Consolidated Statements of Cash Flows for the years ended December 31, 2018 and 2017</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">6.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Notes to Consolidated Financial Statements</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">(a)(2)</FONT></TD>
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">All financial statement schedules have been omitted as the required information is either inapplicable or included in the Consolidated Financial Statements or related notes.</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 86px; text-align: center"><FONT STYLE="font-size: 10pt">(a)(3)</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">The following exhibits are either filed as part of this report or are incorporated herein by reference:</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416116716/v446112_ex1-1.htm"><FONT STYLE="font-size: 10pt">1.1</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416116716/v446112_ex1-1.htm"><FONT STYLE="font-size: 10pt">At Market Issuance Agreement dated August 5, 2016 between Synthetic Biologics, Inc. and FBR Capital Markets &amp; Co. (Incorporated by reference to Exhibit 1.1 of the Registrant&rsquo;s Current Report on Form 8-K filed August 5, 2016, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418025766/tv493213_ex1-1.htm"><FONT STYLE="font-size: 10pt">1.2</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418025766/tv493213_ex1-1.htm"><FONT STYLE="font-size: 10pt">Amendment No. 1 to At The Market Issuance Sales Agreement(Incorporated by reference to Exhibit 1.1 of the Registrant&rsquo;s Current Report on Form 8-K filed May 7, 2016, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418053807/tv504760_ex1-1.htm"><FONT STYLE="font-size: 10pt">1.3&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418053807/tv504760_ex1-1.htm"><FONT STYLE="font-size: 10pt">Underwriting Agreement, dated October 10, 2018, by and between Synthetic Biologics, Inc. and A.G.P./Alliance Global Partners, as representative of the underwriters (Incorporated by reference to Exhibit 1.1 of the Registrant&rsquo;s Current Report on Form 8-K filed October 51, 2018), File No. 001-12584.) </FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000095012401502861/c64437ex3-1.txt"><FONT STYLE="font-size: 10pt">3.1</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000095012401502861/c64437ex3-1.txt"><FONT STYLE="font-size: 10pt">Certificate of Incorporation, as amended&nbsp;(Incorporated by reference to (i) Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed October 16, 2008, File No. 001-12584,&nbsp;&nbsp;(ii) Exhibit 3.1 of the Registrant&rsquo;s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2001 filed August 14, 2001, File No. 001-12584; and (iii) Exhibits 3.1, 4.1 and 4.2 of the Registrant&rsquo;s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 1998 filed August 14, 1998, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex31.htm"><FONT STYLE="font-size: 10pt">3.2</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex31.htm"><FONT STYLE="font-size: 10pt">Articles of Merger (Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed October 19, 2009, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex32.htm"><FONT STYLE="font-size: 10pt">3.3</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex32.htm"><FONT STYLE="font-size: 10pt">Certificate of Merger filed with the Secretary of State of Delaware (Incorporated by reference to Exhibit 3.2 of the Registrant&rsquo;s Current Report on Form 8-K filed October 19, 2009, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex33.htm"><FONT STYLE="font-size: 10pt">3.4</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex33.htm"><FONT STYLE="font-size: 10pt">Articles of Incorporation filed with the Nevada Secretary of State (Incorporated by reference to Exhibit 3.3 of the Registrant&rsquo;s Current Report on Form 8-K filed October 19, 2009, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420411060729/v238878_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.5</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420411060729/v238878_ex3-1.htm"><FONT STYLE="font-size: 10pt">Amended and Restated Bylaws Adopted and Effective October 31, 2011 (Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed November 2, 2011, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412009508/v302955_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.6</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412009508/v302955_ex3-1.htm"><FONT STYLE="font-size: 10pt">Certificate of Amendment to Articles of Incorporation (Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed February 16, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415031962/v411020_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.7</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415031962/v411020_ex3-1.htm"><FONT STYLE="font-size: 10pt">Certificate of Amendment to Certificate of Incorporation. (Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed May 18, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047316/v474831_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.8</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047316/v474831_ex3-1.htm"><FONT STYLE="font-size: 10pt">Certificate of Amendment to Certificate of Incorporation. (Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed September 8, 2017, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.9</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex3-1.htm"><FONT STYLE="font-size: 10pt">Certificate of Designations for Series A Preferred Stock to Certificate of Incorporation (Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed September 12, 2017, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418043710/tv500716_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.10</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418043710/tv500716_ex3-1.htm"><FONT STYLE="font-size: 10pt">Certificate of Change Pursuant to NRS 78. 209(Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed August 13, 2018, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418050928/tv503400_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.11</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418050928/tv503400_ex3-1.htm"><FONT STYLE="font-size: 10pt">Certificate of Amendment to Articles of Incorporation (Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed September 26, 2018, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.12</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex3-1.htm"><FONT STYLE="font-size: 10pt">Certificate of Designations for Series B Preferred Stock to Certificate of Incorporation (Incorporated by reference to Exhibit 3.1 of the Registrant&rsquo;s Current Report on Form 8-K filed October 15, 2018, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex3-1.htm"><FONT STYLE="font-size: 10pt">3.13</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex3-1.htm"><FONT STYLE="font-size: 10pt">Certificate of Amendment to Certificate of Designations for Series B Preferred Stock to Certificate of Incorporation (Incorporated by reference to Exhibit 3.2 of the Registrant&rsquo;s Current Report on Form 8-K filed October 15, 2018, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016308000028/s11-8078_ex41.htm"><FONT STYLE="font-size: 10pt">*4.1</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016308000028/s11-8078_ex41.htm"><FONT STYLE="font-size: 10pt">2001 Stock Incentive Plan (Incorporated by reference to Exhibit 4.1 of the Registrant&rsquo;s Registration Statement on Form S-8 filed January 18, 2008, File No. 333-148764.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016308000028/s11-8078_ex42.htm"><FONT STYLE="font-size: 10pt">*4.2</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016308000028/s11-8078_ex42.htm"><FONT STYLE="font-size: 10pt">2007 Stock Incentive Plan (Incorporated by reference to Exhibit 4.2 of the Registrant&rsquo;s Registration Statement on Form S-8 filed January 18, 2008, File No. 333-148764.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420410063805/v204023_ex4-1.htm"><FONT STYLE="font-size: 10pt">*4.3</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420410063805/v204023_ex4-1.htm"><FONT STYLE="font-size: 10pt">2010 Stock Incentive Plan (Incorporated by reference to Exhibit 4.1 of the Registrant&rsquo;s Registration Statement on Form S-8 filed November 29, 2010, File No. 333-170858.)</FONT></A></TD></TR>
</TABLE>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<!-- Field: Page; Sequence: 4 -->
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<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 86px; text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412058598/v326949_ex10-4.htm"><FONT STYLE="font-size: 10pt">4.4</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412058598/v326949_ex10-4.htm"><FONT STYLE="font-size: 10pt">Form of Warrant to Purchase Common Stock issued to Griffin Securities, Inc. on October 30, 2012 (Incorporated by reference to Exhibit 10.4 of the Registrant&rsquo;s Current Report on Form 8-K filed October 31, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413038075/v348628_ex4-1.htm"><FONT STYLE="font-size: 10pt">4.5</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413038075/v348628_ex4-1.htm"><FONT STYLE="font-size: 10pt">Specimen Stock Certificate (Incorporated by reference to Exhibit 4.1 to the Registrant&rsquo;s Registration Statement on Form S-3 filed on July 3, 2013, File No. 333-189794.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413062332/v360550_ex4-1.htm"><FONT STYLE="font-size: 10pt">4.6</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413062332/v360550_ex4-1.htm"><FONT STYLE="font-size: 10pt">Amended and Restated 2010 Stock Incentive Plan (Incorporated by reference to Exhibit 4.1 to the Registrant&rsquo;s Registration Statement on Form S-8 filed on November 15, 2013, File No. 333-192355.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420414060628/v391133_ex4-1.htm"><FONT STYLE="font-size: 10pt">4.7</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420414060628/v391133_ex4-1.htm"><FONT STYLE="font-size: 10pt">Form of Warrant for Purchasers of Units (Incorporated by reference to Exhibit 4.1 to the Registrant&rsquo;s Current Report on Form 8-K filed on October 10, 2014, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415047653/v414477_ex4-1.htm"><FONT STYLE="font-size: 10pt">*4.8</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415047653/v414477_ex4-1.htm"><FONT STYLE="font-size: 10pt">Synthetic Biologics, Inc. 2010 Stock Incentive Plan, as amended and restated on May 15, 2015. (Incorporated by reference to Exhibit 4.1 to the Registrant&rsquo;s Registration Statement on Form S-8 filed on August 10, 2015, File No. 333-206268.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416122164/v448017_ex4-1.htm"><FONT STYLE="font-size: 10pt">4.9</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416122164/v448017_ex4-1.htm"><FONT STYLE="font-size: 10pt">Synthetic Biologics, Inc. 2010 Stock Incentive Plan, as amended and restated on May 15, 2015. (Incorporated by reference to Exhibit 4.1 to the Registrant&rsquo;s Registration Statement on Form S-8 filed on August 31, 2016, File No. 333-206268.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416134769/v453193_ex4-1.htm"><FONT STYLE="font-size: 10pt">4.10</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416134769/v453193_ex4-1.htm"><FONT STYLE="font-size: 10pt">Form of Series A Warrant to Purchase Common Stock issued November 18, 2016 (Incorporated by reference to Exhibit 4.1 of the Registrant&rsquo;s Current Report on Form 8-K filed on November 15, 2016, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416134769/v453193_ex4-2.htm"><FONT STYLE="font-size: 10pt">4.11</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416134769/v453193_ex4-2.htm"><FONT STYLE="font-size: 10pt">Form of Series B Warrant to Purchase Common Stock issued November 18, 2016 (Incorporated by reference to Exhibit 4.2 of the Registrant&rsquo;s Current Report on Form 8-K filed on November 15, 2016, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416134769/v453193_ex4-3.htm"><FONT STYLE="font-size: 10pt">4.12</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416134769/v453193_ex4-3.htm"><FONT STYLE="font-size: 10pt">Form of Warrant Agreement, dated November 18, 2016 between Synthetic Biologics, Inc. and Corporate Stock Transfer, Inc. (Incorporated by reference to Exhibit 4.3 of the Registrant&rsquo;s Current Report on Form 8-K filed on November 15, 2016, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047318/v474807_ex4-1.htm"><FONT STYLE="font-size: 10pt">*4.13</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047318/v474807_ex4-1.htm"><FONT STYLE="font-size: 10pt">Amended and Restated 2010 Stock Incentive Plan (Incorporated by reference to Exhibit 4.1 to the Registrant&rsquo;s Registration Statement on Form S-8 filed on September 8, 2017, File No. 333-220401.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418026171/tv492231_ex4-1.htm"><FONT STYLE="font-size: 10pt">4.14</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418026171/tv492231_ex4-1.htm"><FONT STYLE="font-size: 10pt">Form of Warrant issued December 26, 2017 to InSite Communications (Incorporated by reference to Exhibit 4.1 of the Registrant&rsquo;s Current Report on Form 10-Q filed May 5, 2018, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047318/v474807_ex4-1.htm"><FONT STYLE="font-size: 10pt">*4.15</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047318/v474807_ex4-1.htm"><FONT STYLE="font-size: 10pt">Amended and Restated 2010 Stock Incentive Plan (Incorporated by reference to Exhibit 4.1 to the Registrant&rsquo;s Registration Statement on Form S-8 filed on October 2, 2018, File No. 333&mdash;227668.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418053807/tv504760_ex4-1.htm"><FONT STYLE="font-size: 10pt">4.16&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418053807/tv504760_ex4-1.htm"><FONT STYLE="font-size: 10pt">&nbsp;Warrant Agency Agreement, dated October 15, 2018, by and between Synthetic Biologics, Inc. and Corporate Stock Transfer, Inc. (including the form of warrant certificate)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016308000571/s11-8675_ex1022.htm"><FONT STYLE="font-size: 10pt">10.1</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016308000571/s11-8675_ex1022.htm"><FONT STYLE="font-size: 10pt">License Agreement between The Regents of the University of California and Epitope Pharmaceuticals, Inc. (Incorporated by reference to Exhibit 10.22 of the Registrant&rsquo;s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2008 filed August 14, 2008, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000095015209000057/k47262exv10w1.htm"><FONT STYLE="font-size: 10pt">*10.2</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000095015209000057/k47262exv10w1.htm"><FONT STYLE="font-size: 10pt">Form of Director/Officer Indemnification Agreement (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed January 6, 2009, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex11.htm"><FONT STYLE="font-size: 10pt">10.3</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex11.htm"><FONT STYLE="font-size: 10pt">Agreement and Plan of Reincorporation Merger (Incorporated by reference to Exhibit 1.1 of the Registrant&rsquo;s Current Report on Form 8-K filed October 19, 2009, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex11.htm"><FONT STYLE="font-size: 10pt">10.4</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016309000007/s22-9415_ex11.htm"><FONT STYLE="font-size: 10pt">Sublicense Agreement between Meda AB, Adeona Pharamaceuticals, Inc. and Pipex Therapeutics, Inc. (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed May 11, 2010, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016310000137/s22-9739_ex102.htm"><FONT STYLE="font-size: 10pt">10.5</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000089016310000137/s22-9739_ex102.htm"><FONT STYLE="font-size: 10pt">Non-Disturbance Agreement among Pipex Therapeutics, Inc., Mclean Hospital Corp and Meda AB (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed May 11, 2010, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420411019139/v216123_ex10-21.htm"><FONT STYLE="font-size: 10pt">10.6</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420411019139/v216123_ex10-21.htm"><FONT STYLE="font-size: 10pt">McLean Hospital Corporation Exclusive License Agreement (Incorporated by reference to Exhibit 10.21 of the Registrant&rsquo;s Annual Report on Form 10-K filed March 31, 2011, File No. 001-12584.)</FONT></A></TD></TR>
</TABLE>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

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<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 86px; text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420411066263/v241347_ex10-2.htm"><FONT STYLE="font-size: 10pt">10.7</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420411066263/v241347_ex10-2.htm"><FONT STYLE="font-size: 10pt">Stock Purchase Agreement with Intrexon Corporation (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed November 21, 2011, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420411066263/v241347_ex10-3.htm"><FONT STYLE="font-size: 10pt">10.8</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420411066263/v241347_ex10-3.htm"><FONT STYLE="font-size: 10pt">Registration Rights Agreement with Intrexon Corporation (Incorporated by reference to Exhibit 10.3 of the Registrant&rsquo;s Current Report on Form 8-K filed November 21, 2011, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412006057/v301320_ex10-1.htm"><FONT STYLE="font-size: 10pt">*10.9</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412006057/v301320_ex10-1.htm"><FONT STYLE="font-size: 10pt">Employment Agreement with Jeffrey Riley (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed February 6, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412043904/v320664_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.10</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412043904/v320664_ex10-1.htm"><FONT STYLE="font-size: 10pt">Exclusive Channel Collaboration Agreement with Intrexon Corporation (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed August 9, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412043904/v320664_ex10-2.htm"><FONT STYLE="font-size: 10pt">10.11</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412043904/v320664_ex10-2.htm"><FONT STYLE="font-size: 10pt">Stock Purchase Agreement with Intrexon Corporation (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed August 9, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412043904/v320664_ex10-3.htm"><FONT STYLE="font-size: 10pt">10.12</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412043904/v320664_ex10-3.htm"><FONT STYLE="font-size: 10pt">First Amendment to Registration Rights Agreement between Synthetic Biologics, Inc. and Intrexon Corporation (Incorporated by reference to Exhibit 10.3 of the Registrant&rsquo;s Current Report on Form 8-K filed August 9, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412058598/v326949_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.13</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412058598/v326949_ex10-1.htm"><FONT STYLE="font-size: 10pt">Stock Purchase Agreement dated October 25, 2012 with investors (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed October 31, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412058598/v326949_ex10-2.htm"><FONT STYLE="font-size: 10pt">10.14</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412058598/v326949_ex10-2.htm"><FONT STYLE="font-size: 10pt">Registration Rights Agreement dated October 25, 2012 with investors (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed October 31, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412058598/v326949_ex10-3.htm"><FONT STYLE="font-size: 10pt">10.15</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412058598/v326949_ex10-3.htm"><FONT STYLE="font-size: 10pt">Joinder Agreement by and among Synthetic Biologics, Inc., NRM VII Holdings I, LLC and Intrexon Corporation (Incorporated by reference to Exhibit 10.3 of the Registrant&rsquo;s Current Report on Form 8-K filed October 31, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412069077/v330545_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.16</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412069077/v330545_ex10-1.htm"><FONT STYLE="font-size: 10pt">Patent License Agreement dated December 19, 2012 between Synthetic Biologics, Inc. and The University of Texas at Austin (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed December 21, 2012, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412069077/v330545_ex10-2.htm"><FONT STYLE="font-size: 10pt">10.17&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420412069077/v330545_ex10-2.htm"><FONT STYLE="font-size: 10pt">Sponsored Research Agreement dated December 19, 2012 between Synthetic Biologics, Inc. and The University of Texas at Austin (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed December 21, 2012, File No. 001-12584.)</FONT></A></TD></TR>
</TABLE>


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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 86px; text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-45.htm"><FONT STYLE="font-size: 10pt">10.18</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-45.htm"><FONT STYLE="font-size: 10pt">Exclusive License Agreement with The Regents of The University of California (Incorporated by reference to Exhibit 10.45 of the Registrant&rsquo;s Annual Report on Form 10-K filed April 16, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-46.htm"><FONT STYLE="font-size: 10pt">10.19</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-46.htm"><FONT STYLE="font-size: 10pt">First Amendment to Exclusive License Agreement with The Regents of The University of California (Incorporated by reference to Exhibit 10.46 of the Registrant&rsquo;s Annual Report on Form 10-K filed April 16, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-47.htm"><FONT STYLE="font-size: 10pt">10.20</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-47.htm"><FONT STYLE="font-size: 10pt">Second Amendment to Exclusive License Agreement with The Regents of The University of California (Incorporated by reference to Exhibit 10.47 of the Registrant&rsquo;s Annual Report on Form 10-K filed April 16, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-48.htm"><FONT STYLE="font-size: 10pt">10.21</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-48.htm"><FONT STYLE="font-size: 10pt">Third Amendment to Exclusive License Agreement with The Regents of The University of California (Incorporated by reference to Exhibit 10.48 of the Registrant&rsquo;s Annual Report on Form 10-K filed April 16, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-49.htm"><FONT STYLE="font-size: 10pt">10.22</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413022048/v337358_ex10-49.htm"><FONT STYLE="font-size: 10pt">Fourth Amendment to Exclusive License Agreement with The Regents of The University of California (Incorporated by reference to Exhibit 10.49 of the Registrant&rsquo;s Annual Report on Form 10-K filed April 16, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.23</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-1.htm"><FONT STYLE="font-size: 10pt">Exclusive License Agreement between Synthetic Biologics, Inc., Synthetic Biomics, Inc. and Cedars-Sinai Medical Center dated December 5, 2013 (Incorporated by reference to Exhibit 10.1 to the Registrant&rsquo;s Current Report on Form 8-K filed on December 10, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-2.htm"><FONT STYLE="font-size: 10pt">10.24</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-2.htm"><FONT STYLE="font-size: 10pt">Exclusive Option Agreement between Synthetic Biologics, Inc., Synthetic Biomics, Inc. and Cedars-Sinai Medical Center dated December 5, 2013 (Incorporated by reference to Exhibit 10.2 to the Registrant&rsquo;s Current Report on Form 8-K filed on December 10, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-3.htm"><FONT STYLE="font-size: 10pt">10.25</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-3.htm"><FONT STYLE="font-size: 10pt">Stock Purchase Agreement between Synthetic Biologics, Inc., Synthetic Biomics, Inc. and Cedars-Sinai Medical Center dated December 5, 2013(Incorporated by reference to Exhibit 10.3 to the Registrant&rsquo;s Current Report on Form 8-K filed on December 10, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-4.htm"><FONT STYLE="font-size: 10pt">10.26</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-4.htm"><FONT STYLE="font-size: 10pt">Stock Purchase Agreement between Synthetic Biologics, Inc., Synthetic Biomics, Inc. and Mark Pimentel dated December 5, 2013 (Incorporated by reference to Exhibit 10.4 to the Registrant&rsquo;s Current Report on Form 8-K filed on December 10, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-5.htm"><FONT STYLE="font-size: 10pt">10.27</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420413066566/v362603_ex10-5.htm"><FONT STYLE="font-size: 10pt">Stock Purchase Agreement between Synthetic Biologics, Inc., Synthetic Biomics, Inc. and Cedars-Sinai Medical Center dated December 5, 2013 (Incorporated by reference to Exhibit 10.5 to the Registrant&rsquo;s Current Report on Form 8-K filed on December 10, 2013, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420414019505/v372138_ex10-49.htm"><FONT STYLE="font-size: 10pt">10.28</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420414019505/v372138_ex10-49.htm"><FONT STYLE="font-size: 10pt">First Amendment to Exclusive License Agreement. (Incorporated by reference to Exhibit 10.49 of the Registrant&rsquo;s Annual Report on Form 10-K for the year ended December 31, 2013 filed March 31, 2014, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415017251/v404847_ex10-1.htm"><FONT STYLE="font-size: 10pt">*10.29</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415017251/v404847_ex10-1.htm"><FONT STYLE="font-size: 10pt">Employment Agreement, dated March 18, 2015, by and between Jeffrey Riley and the Company. (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed on March 19, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415017251/v404847_ex10-2.htm"><FONT STYLE="font-size: 10pt">*10.30</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415017251/v404847_ex10-2.htm"><FONT STYLE="font-size: 10pt">Employment Agreement, dated March 18, 2015, by and between C. Evan Ballantyne and the Company. (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed on March 19, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415022349/v406688_def14a.htm"><FONT STYLE="font-size: 10pt">10.31</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415022349/v406688_def14a.htm"><FONT STYLE="font-size: 10pt">Amended and Restated 2010 Stock Incentive Plan. (Incorporated by reference to Exhibit B to the Definitive Proxy Statement filed on April 13, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415027137/v408591_ex10-1.htm"><FONT STYLE="font-size: 10pt">*10.32</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415027137/v408591_ex10-1.htm"><FONT STYLE="font-size: 10pt">Employment Agreement, dated April 28, 2015, by and between Stephen A. Shallcross and the Company. (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed on May 4, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415027137/v408591_ex10-2.htm"><FONT STYLE="font-size: 10pt">*10.33</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415027137/v408591_ex10-2.htm"><FONT STYLE="font-size: 10pt">Severance Agreement, dated April 29, 2015, by and between C. Evan Ballantyne and the Company. (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed on May 4, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415041693/v415129_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.34</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415041693/v415129_ex10-1.htm"><FONT STYLE="font-size: 10pt">Fifth Amendment to the Exclusive License Agreement with The Regents of The University of California, dated July 25, 2014. (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed on July 9, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415041693/v415129_ex10-2.htm"><FONT STYLE="font-size: 10pt">10.35</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415041693/v415129_ex10-2.htm"><FONT STYLE="font-size: 10pt">Sixth Amendment to the Exclusive License Agreement with The Regents of The University of California, dated July 8, 2015. (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed on July 9, 2015, File No. 001-12584.)</FONT></A></TD></TR>
</TABLE>


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<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 86px; text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415041693/v415129_ex10-3.htm"><FONT STYLE="font-size: 10pt">10.36</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415041693/v415129_ex10-3.htm"><FONT STYLE="font-size: 10pt">Clinical Trial Agreement between Putney Drug Corp. and The Regents of The University of California, dated April 29, 2010. (Incorporated by reference to Exhibit 10.3 of the Registrant&rsquo;s Current Report on Form 8-K filed on July 9, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415041693/v415129_ex10-4.htm"><FONT STYLE="font-size: 10pt">10.37</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415041693/v415129_ex10-4.htm"><FONT STYLE="font-size: 10pt">Amendment to the Clinical Trial Agreement between Putney Drug Corp. and The Regents of The University of California, dated July 8, 2015. (Incorporated by reference to Exhibit 10.4 of the Registrant&rsquo;s Current Report on Form 8-K filed on July 9, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415047499/v417666_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.38</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415047499/v417666_ex10-1.htm"><FONT STYLE="font-size: 10pt">Exclusive Channel Collaboration Agreement by and between Synthetic Biologics, Inc. and Intrexon Corporation dated as of August 10, 2015**. (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed on August 10, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415047499/v417666_ex10-2.htm"><FONT STYLE="font-size: 10pt">10.39</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415047499/v417666_ex10-2.htm"><FONT STYLE="font-size: 10pt">Stock Issuance Agreement by and between Synthetic Biologics, Inc., and Intrexon Corporation, dated August 10, 2015. (Incorporated by reference to Exhibit 10.2 to the Registrant&rsquo;s Current Report on Form 8-K filed on August 10, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415047499/v417666_ex10-3.htm"><FONT STYLE="font-size: 10pt">10.40</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415047499/v417666_ex10-3.htm"><FONT STYLE="font-size: 10pt">Second Amendment to the Registration Rights Agreement by and between Synthetic Biologics, Inc. and Intrexon Corporation, dated as of August 10, 2015. (Incorporated by reference to Exhibit 10.3 of the Registrant&rsquo;s Current Report on Form 8-K filed August 10, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415053643/v419703_ex10-5.htm"><FONT STYLE="font-size: 10pt">10.41</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415053643/v419703_ex10-5.htm"><FONT STYLE="font-size: 10pt">Amendment, dated August 29, 2015, to the Stock Purchase Agreement, dated December 3, 2013, by and among Synthetic Biologics, Inc., Synthetic Biomics, Inc. and Mark Pimentel, M.D. (Incorporated by reference to Exhibit 10.5 of the Registrant&rsquo;s Current Report on Form 8-K filed September 3, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415063126/v423087_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.42</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415063126/v423087_ex10-1.htm"><FONT STYLE="font-size: 10pt">Third Amendment to the License Agreement between Synthetic Biologics, Inc., Synthetic Biomics, Inc. and Cedar-Sinai Medical Center, dated September 4, 2015. (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Quarterly Report on Form 10-Q for the quarter ended September 30, 2015 filed November 5, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415070350/v426642_ex10-1.htm"><FONT STYLE="font-size: 10pt">*10.43</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415070350/v426642_ex10-1.htm"><FONT STYLE="font-size: 10pt">Amendment to Employment Agreement by and between Synthetic Biologics, Inc. and Jeffrey Riley, dated as of December 4, 2015. (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed December 10, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415070350/v426642_ex10-2.htm"><FONT STYLE="font-size: 10pt">*10.44</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420415070350/v426642_ex10-2.htm"><FONT STYLE="font-size: 10pt">Form of Stock Option Agreement. (Incorporated by reference to Exhibit 10.2 of the Registrant&rsquo;s Current Report on Form 8-K filed December 10, 2015, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416137730/v454252_ex1-1.htm"><FONT STYLE="font-size: 10pt">*10.45</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420416137730/v454252_ex1-1.htm"><FONT STYLE="font-size: 10pt">Amendment to Employment Agreement by and between Synthetic Biologics, Inc. and Steven A. Shallcross, dated as of December 1, 2016. (Incorporated by reference to Exhibit 1.1 of the Registrant&rsquo;s Current Report on Form 8-K filed December 2, 2016, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417002809/v457071_ex10-1.htm"><FONT STYLE="font-size: 10pt">*10.46</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417002809/v457071_ex10-1.htm"><FONT STYLE="font-size: 10pt">Employment Agreement by and between Synthetic Biologics, Inc. and Joseph Sliman dated as of January 17, 2017 (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed January 19, 2017, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417012545/v459847_ex10-58.htm"><FONT STYLE="font-size: 10pt">*10.47</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417012545/v459847_ex10-58.htm"><FONT STYLE="font-size: 10pt">Employment Agreement by and between Synthetic Biologics, Inc. and Jeffrey Riley dated as of February 27, 2017.</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.48</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex10-1.htm"><FONT STYLE="font-size: 10pt">Share Purchase Agreement dated as of September 11, 2017 between Synthetic Biologics, Inc. and MSD Credit Opportunity Master Fund, L.P. (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed September 12, 2017, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417030853/v468238_ex10-1.htm"><FONT STYLE="font-size: 10pt">*10.49</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417030853/v468238_ex10-1.htm"><FONT STYLE="font-size: 10pt">Amendment to Employment Agreement dated May 31,2017 between Synthetic Biologics, Inc. and Steven A. Shallcross (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed June 2, 2017, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417062794/tv480950_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.50</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417062794/tv480950_ex10-1.htm"><FONT STYLE="font-size: 10pt">Separation Agreement dated December 5, 2017 between Synthetic Biologics, Inc. and Jeffrey Riley (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed December 7, 2017, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417064821/tv481856_ex10-1.htm"><FONT STYLE="font-size: 10pt">*10.51</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417064821/tv481856_ex10-1.htm"><FONT STYLE="font-size: 10pt">Amendment to Employment Agreement dated December 20,2017 between Synthetic Biologics, Inc. and Steven A. Shallcross (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed December 21, 2017, File No. 001-12584.)</FONT></A></TD></TR>
</TABLE>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 86px; text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex4-1.htm"><FONT STYLE="font-size: 10pt">10.52</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420417047548/v474946_ex4-1.htm"><FONT STYLE="font-size: 10pt">Registration Rights Agreement dated as of September 11, 2017 between Synthetic Biologics, Inc. and MSD Credit Opportunity Master Fund, L.P. (Incorporated by reference to Exhibit 4.1 of the Registrant&rsquo;s Current Report on Form 8-K filed on September 12, 2017, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418010286/tv485536_ex10-53.htm"><FONT STYLE="font-size: 10pt">10.53</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418010286/tv485536_ex10-53.htm"><FONT STYLE="font-size: 10pt">Fourth Amendment to Exclusive License Agreement entered into February 16, 2017 between Synthetic Biologics, Inc. and Cedars-Sinai Medical Center. (Incorporated by reference to Exhibit 10.53 of the Registrant&rsquo;s Annual Report on Form 10-K filed on February 22, 2018, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418010286/tv485536_ex10-54.htm"><FONT STYLE="font-size: 10pt">10.54</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418010286/tv485536_ex10-54.htm"><FONT STYLE="font-size: 10pt">Fifth Amendment dated August 22, 2017 to Sponsored Research Agreement dated December 19, 2012 between Synthetic Biologics, Inc. and The University of Texas at Austin(Incorporated by reference to Exhibit 10.54 of the Registrant&rsquo;s Annual Report on Form 10-K filed on February 22, 2018, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418048214/tv502397_ex10-1.htm"><FONT STYLE="font-size: 10pt">10.55</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418048214/tv502397_ex10-1.htm"><FONT STYLE="font-size: 10pt">Stock Purchase Agreement entered into as of September 5, 2018 by and among Synthetic Biologics, Inc., Synthetic Biomics, Inc., and Cedars-Sinai Medical Center(Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed on September 6, 2018, File No. 001-12584.)</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418063398/tv508585_ex10-1.htm"><FONT STYLE="font-size: 10pt">*10.56&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420418063398/tv508585_ex10-1.htm"><FONT STYLE="font-size: 10pt">Employment Agreement between Synthetic Biologics, Inc. and Steven A. Shallcross dated as of December 6, 2018 (Incorporated by reference to Exhibit 10.1 of the Registrant&rsquo;s Current Report on Form 8-K filed on December 6, 2018), File No. 001-12584.&nbsp;</FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420419010592/tv513906_ex21.htm"><FONT STYLE="font-size: 10pt">21</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="http://www.sec.gov/Archives/edgar/data/894158/000114420419010592/tv513906_ex21.htm"><FONT STYLE="font-size: 10pt">List
    of Subsidiaries <SUP>(2)</SUP></FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="tv517555_ex23-1.htm"><FONT STYLE="font-size: 10pt">23.1&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="tv517555_ex23-1.htm"><FONT STYLE="font-size: 10pt">Consent of Independent Registered Public Accounting Firm (BDO USA, LLP) <SUP>(1)</SUP></FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="tv517555_ex31-1.htm"><FONT STYLE="font-size: 10pt">31.1&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="tv517555_ex31-1.htm"><FONT STYLE="font-size: 10pt">Certification of Steven A. Shallcross, Chief Executive Officer, pursuant to Rule 13a-14(a)/15d-14(a) <SUP>(1)</SUP></FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="tv517555_ex31-1.htm"><FONT STYLE="font-size: 10pt">31.2&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="tv517555_ex31-1.htm"><FONT STYLE="font-size: 10pt">Certification of Steven A. Shallcross, Chief Financial Officer pursuant to Rule 13a-14(a)/15d-14(a) <SUP>(1)</SUP></FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="tv517555_ex32-1.htm"><FONT STYLE="font-size: 10pt">32.1&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="tv517555_ex32-1.htm"><FONT STYLE="font-size: 10pt">Certification of Steven A. Shallcross, Chief Executive Officer pursuant to Section 1350 of the Sarbanes-Oxley Act of 2002 <SUP>(1)</SUP></FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><A HREF="tv517555_ex32-1.htm"><FONT STYLE="font-size: 10pt">32.2&nbsp;</FONT></A></TD>
    <TD STYLE="text-align: justify"><A HREF="tv517555_ex32-1.htm"><FONT STYLE="font-size: 10pt">Certification of Steven A. Shallcross, Chief Financial Officer pursuant to Section 1350 of the Sarbanes-Oxley Act of 2002 <SUP>(1)</SUP></FONT></A></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-size: 10pt">101.INS</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">XBRL Instance Document <SUP></SUP></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-size: 10pt">101.SCH</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">XBRL Taxonomy Extension Schema Document <SUP></SUP></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-size: 10pt">101.CAL</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">XBRL Taxonomy Extension Calculation Linkbase Document <SUP></SUP></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-size: 10pt">101.DEF</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">XBRL Taxonomy Extension Definition Linkbase Document <SUP></SUP></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-size: 10pt">101.LAB</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">XBRL Taxonomy Extension Label Linkbase Document <SUP></SUP></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-size: 10pt">101.PRE&nbsp;</FONT></TD>
    <TD STYLE="text-align: justify"><FONT STYLE="font-size: 10pt">XBRL Taxonomy Extension Presentation Linkbase Document <SUP></SUP></FONT></TD></TR>
</TABLE>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 1%">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>(1)</B></FONT></TD>
    <TD STYLE="width: 96%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Filed herewith.</B></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>(2)</B></FONT></TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Previously
    filed.</B></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 1%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>*</B></FONT></TD>
    <TD STYLE="width: 96%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Management contract or compensatory plan or arrangement required to be identified pursuant to Item 15(a)(3) of this report.</B></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>**</B></FONT></TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Confidential treatment has been requested as to certain portions of this exhibit pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.</B></FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;&nbsp;</P>


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<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>2
<FILENAME>tv517555_ex23-1.htm
<DESCRIPTION>EXHIBIT 23.1
<TEXT>
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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right"><B>Exhibit 23.1</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B><U>Consent of Independent Registered
Public Accounting Firm</U></B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Synthetic Biologics, Inc.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Rockville, MD</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; color: fuchsia">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">We hereby consent to the incorporation
by reference in the Registration Statements on Form S-1 (No. 333-227400), Form S-3 (Nos. 333-180562, 333-188219, 333-156973, 333-206267,
333-207327, 333-203323, 333-226500 and 333-224728) and Form S-8 (Nos. 333-192355, 333-170858, 333-148764, 333-206268, 333-213388,
333-220401 and 333-227668) of Synthetic Biologics, Inc. of our report dated February 27, 2019 relating to the consolidated financial
statements, which appears in this Form 10-K.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 28%; border-bottom: black 1pt solid; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">/s/ BDO USA, LLP</FONT></TD>
    <TD STYLE="width: 72%; padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">BDO USA, LLP</FONT></TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">McLean, Virginia</FONT></TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">April 1, 2019</FONT></TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;&nbsp;</P>


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<DOCUMENT>
<TYPE>EX-31.1
<SEQUENCE>3
<FILENAME>tv517555_ex31-1.htm
<DESCRIPTION>EXHIBIT 31.1
<TEXT>
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<BODY STYLE="font: 10pt Times New Roman, Times, Serif">

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right"><B>Exhibits 31.1 and 31.2</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>CERTIFICATION OF PRINCIPAL EXECUTIVE
OFFICER AND PRINCIPAL FINANCIAL OFFICER</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>PURSUANT TO RULE 13a-14 OR RULE 15d-14
OF THE SECURITIES EXCHANGE ACT OF 1934,</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>AS ADOPTED PURSUANT TO SECTION 302 OF
THE SARBANES-OXLEY ACT OF 2002</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">I, Steven A. Shallcross, certify that:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 3%">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">1.</FONT></TD>
    <TD STYLE="width: 94%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">I have reviewed this Annual Report on Form 10-K/A (Amendment No. 1 to Annual Report on Form 10-K for the fiscal year ended December 31, 2018) of Synthetic Biologics, Inc.;</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 3%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">2.</FONT></TD>
    <TD STYLE="width: 94%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 3%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">3.</FONT></TD>
    <TD STYLE="width: 94%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 3%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">4.</FONT></TD>
    <TD STYLE="width: 94%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">The registrant&rsquo;s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 6%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">a)</FONT></TD>
    <TD STYLE="width: 91%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.75in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 6%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">b)</FONT></TD>
    <TD STYLE="width: 91%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.75in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 6%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">c)</FONT></TD>
    <TD STYLE="width: 91%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Evaluated the effectiveness of the registrant&rsquo;s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.75in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 6%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">d)</FONT></TD>
    <TD STYLE="width: 91%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Disclosed in this report any change in the registrant&rsquo;s internal control over financial reporting that occurred during the registrant&rsquo;s most recent fiscal quarter (the registrant&rsquo;s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant&rsquo;s internal control over financial reporting; and</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 3%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">5.</FONT></TD>
    <TD STYLE="width: 94%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">The registrant&rsquo;s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant&rsquo;s auditors and the audit committee of the registrant&rsquo;s board of directors (or persons performing the equivalent functions):</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 6%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">a)</FONT></TD>
    <TD STYLE="width: 91%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant&rsquo;s ability to record, process, summarize and report financial information; and</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-align: justify; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 6%; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">b)</FONT></TD>
    <TD STYLE="width: 91%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant&rsquo;s internal control over financial reporting.</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">April 1,
    2019</FONT></TD>
    <TD STYLE="vertical-align: bottom; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">By:</FONT></TD>
    <TD COLSPAN="2" STYLE="vertical-align: top; border-bottom: black 1pt solid; padding-right: 1.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">/s/ Steven A. Shallcross</FONT></TD></TR>
<TR>
    <TD STYLE="vertical-align: top; width: 53%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="vertical-align: bottom; width: 5%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="vertical-align: top; width: 6%; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Name:</FONT></TD>
    <TD STYLE="vertical-align: top; width: 36%; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Steven A. Shallcross</FONT></TD></TR>
<TR>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="vertical-align: bottom; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Title:</FONT></TD>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">Chief Executive Officer, Chief Financial Officer</FONT></TD></TR>
<TR>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="vertical-align: bottom; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="vertical-align: top; padding-right: 0.8pt"><FONT STYLE="font: 10pt Times New Roman, Times, Serif">(Principal Executive Officer and Principal Financial Officer)</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right">&nbsp;</P>




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<DOCUMENT>
<TYPE>EX-32.1
<SEQUENCE>4
<FILENAME>tv517555_ex32-1.htm
<DESCRIPTION>EXHIBIT 32.1
<TEXT>
<HTML>
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</HEAD>
<BODY STYLE="font: 10pt Times New Roman, Times, Serif">

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right"><B>Exhibits 32.1 and 32.2</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>CERTIFICATION OF PRINCIPAL EXECUTIVE
OFFICER AND PRINCIPAL FINANCIAL OFFICER</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>PURSUANT TO 18 U.S.C. SECTION 1350, AS
ADOPTED PURSUANT TO</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SECTION 906 OF THE SARBANES-OXLEY ACT
OF 2002</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Pursuant to 18 U.S.C. &sect;1350, as created
by Section 906 of the Sarbanes-Oxley Act of 2002, the undersigned officer of Synthetic Biologics, Inc. (the &ldquo;Registrant&rdquo;)
hereby certifies, to such officer&rsquo;s knowledge, that:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 26.9pt; text-align: justify">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 3%; font-size: 10pt">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">(1)</FONT></TD>
    <TD STYLE="width: 94%; padding-right: 0.8pt; text-align: justify; font-size: 10pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">the accompanying Annual Report on Form 10-K/A (Amendment No. 1 to Annual Report on Form 10-K for the fiscal year ended December 31, 2018) of the Registrant for the year ended December 31, 2018 (the &ldquo;Report&rdquo;) fully complies with the requirements of Section 13(a) or Section 15(d), as applicable, of the Securities Exchange Act of 1934, as amended; and</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-indent: -0.25in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 3%">&nbsp;</TD>
    <TD STYLE="width: 3%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">(2)</FONT></TD>
    <TD STYLE="width: 94%; padding-right: 0.8pt; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">Date: April 1, 2019</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">By:</FONT></TD>
    <TD COLSPAN="2" STYLE="border-bottom: black 1pt solid; padding-right: 1.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">/s/ Steven A. Shallcross</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 52%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="width: 5%; padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="width: 6%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Name:</FONT></TD>
    <TD STYLE="width: 37%; padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Steven A. Shallcross</FONT></TD></TR>
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    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Title:</FONT></TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Chief Executive Officer, Chief Financial Officer</FONT></TD></TR>
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    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt">&nbsp;</TD>
    <TD STYLE="padding-right: 0.8pt"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">(Principal Executive Officer and Principal Financial Officer)</FONT></TD></TR>
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