UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A INFORMATION

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE
SECURITIES EXCHANGE ACT OF 1934

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◻Preliminary Proxy Statement

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⌧Definitive Additional Materials

◻Soliciting Material Pursuant to §240.14a-12

AMPHASTAR PHARMACEUTICALS, INC.

(Name of Registrant as Specified In Its Charter)

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