FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Purchase Marilyn J.   2. Issuer Name and Ticker or Trading Symbol Amphastar Pharmaceuticals, Inc. [AMPH] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Corp. Exec. VP of Operations (Last) (First) (Middle) C/O AMPHASTAR PHARMACEUTICALS, INC., 11570 6TH STREET 3. Date of Earliest Transaction (Month/Day/Year) 07/07/2014 (Street) RANCHO CUCAMONGA, CA 91730 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 07/07/2014   F   1,239 (1) D $ 8.75 31,375 (2) D   Common Stock 10/03/2014   F   519 (1) D $ 11.41 30,856 D   Common Stock 03/26/2015   A   14,046 (3) A $ 0 44,902 D   Common Stock               16,044 (4) I See footnote (5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Employee Stock Option (right to buy)

$ 14.95

03/26/2015

A

42,054

(6)

03/26/2025

Common Stock

42,054

$ 0

42,054

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Purchase Marilyn J. C/O AMPHASTAR PHARMACEUTICALS, INC. 11570 6TH STREET RANCHO CUCAMONGA, CA 91730			Corp. Exec. VP of Operations

Signatures

/s/ Ken Stupak, by power of attorney		03/27/2015
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	The reported securities were withheld to satisfy the Reporting Person's tax liability in connection with the vesting of deferred stock units (DSUs).
(2)	Excludes 16,044 shares previously reported as held directly.
(3)	The reported securities are represented by DSUs which vest in four equal annual installments beginning on March 26, 2016.
(4)	All of the reported shares were previously reported as held directly.
(5)	The shares are held directly by the Purchase Family Trust for which the Reporting Person serves as co-trustee.
(6)	Shares subject to the option vest in four equal annual installments beginning on March 26, 2016.

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