<SEC-DOCUMENT>0001104659-24-036270.txt : 20240319
<SEC-HEADER>0001104659-24-036270.hdr.sgml : 20240319
<ACCEPTANCE-DATETIME>20240319185531
ACCESSION NUMBER:		0001104659-24-036270
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20240315
FILED AS OF DATE:		20240319
DATE AS OF CHANGE:		20240319

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Luo Mary Z.
		CENTRAL INDEX KEY:			0001611156
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36509
		FILM NUMBER:		24765658

	MAIL ADDRESS:	
		STREET 1:		11570 6TH STREET
		CITY:			RANCHO CUCAMONGA
		STATE:			CA
		ZIP:			91730

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Zhang Jack Y.
		CENTRAL INDEX KEY:			0001611157
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36509
		FILM NUMBER:		24765659

	MAIL ADDRESS:	
		STREET 1:		11570 6TH STREET
		CITY:			RANCHO CUCAMONGA
		STATE:			CA
		ZIP:			91730

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Amphastar Pharmaceuticals, Inc.
		CENTRAL INDEX KEY:			0001297184
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				330702205
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		11570 SIXTH STREET
		CITY:			RANCHO CUCAMONGA
		STATE:			CA
		ZIP:			91730
		BUSINESS PHONE:		909-980-9484

	MAIL ADDRESS:	
		STREET 1:		11570 SIXTH STREET
		CITY:			RANCHO CUCAMONGA
		STATE:			CA
		ZIP:			91730
</SEC-HEADER>
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        <issuerName>Amphastar Pharmaceuticals, Inc.</issuerName>
        <issuerTradingSymbol>AMPH</issuerTradingSymbol>
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            <rptOwnerName>Zhang Jack Y.</rptOwnerName>
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            <rptOwnerState>CA</rptOwnerState>
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            <rptOwnerName>Luo Mary Z.</rptOwnerName>
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                <transactionAcquiredDisposedCode>
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                <directOrIndirectOwnership>
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                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
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            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
                <value>2024-03-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
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                <transactionFormType>4</transactionFormType>
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                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>202658</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.05</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
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            </transactionAmounts>
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                    <value>1236808</value>
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            </postTransactionAmounts>
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                    <footnoteId id="F2"/>
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                <directOrIndirectOwnership>
                    <value>I</value>
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                    <value>See footnote</value>
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                <value>2024-03-15</value>
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    <footnotes>
        <footnote id="F1">Consists of 399,187 shares withheld to pay the exercise price and withholding taxes incurred in connection with the exercise of 622,046 options and 9,534 shares withheld to satisfy the reporting person's tax liability in connection with the vesting of restricted stock units, or RSUs.</footnote>
        <footnote id="F2">The reported shares were withheld to satisfy the reporting person's tax liability in connection with the vesting of RSUs.</footnote>
        <footnote id="F3">The securities are held of record by Mary Z. Luo. The reporting persons are husband and wife.</footnote>
        <footnote id="F4">Consists of 198,640 shares withheld to pay the exercise price and withholding taxes incurred in connection with the option exercise and 4,018 shares withheld to satisfy the reporting person's tax liability in connection with the vesting of RSUs.</footnote>
        <footnote id="F5">The shares are held of record by Applied Physics &amp; Chemistry Laboratories, Inc., of which the reporting persons and The Bill Luobei Zhang 2004 Irrevocable Trust are the sole owners.</footnote>
        <footnote id="F6">Shares subject to the option are fully vested and immediately exercisable.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Eva Wen, by power of attorney for Jack Y. Zhang</signatureName>
        <signatureDate>2024-03-19</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Eva Wen, by power of attorney for Mary Z. Luo</signatureName>
        <signatureDate>2024-03-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</SEC-DOCUMENT>
