SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Zhang Jack Y. (Last) (First) (Middle) C/O AMPHASTAR PHARMACEUTICALS, INC. 11570 6TH STREET (Street) RANCHO CUCAMONGA CA 91730 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Amphastar Pharmaceuticals, Inc. [ AMPH ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner X Officer (give title below) Other (specify below) CEO & Chief Scientific Officer
	3. Date of Earliest Transaction (Month/Day/Year) 09/13/2017
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

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	09/13/2017		M		176,987	D	$11.53	1,731,937	D
Common Stock	09/13/2017		F		153,882	D	$15.86	1,578,055	D
Common Stock	09/13/2017		M		138,632	D	$11.53	1,197,337	I	See footnote(1)
Common Stock	09/13/2017		F		120,504	D	$15.87	1,076,833	I	See footnote(1)
Common Stock								7,461,594	I	See footnote(2)
Common Stock								5,000	I	See footnote(3)
Common Stock								200,000	I	See footnote(4)

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 Securities Underlying Derivative Security (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: 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)	$11.53	09/13/2017		M			176,987	(5)	09/28/2017	Common Stock	176,987	$0	0	D
Employee Stock Option (right to buy)	$11.53	09/13/2017		M			138,632	(5)	09/28/2017	Common Stock	138,632	$0	0	I	See footnote(1)

1. Name and Address of Reporting Person* Zhang Jack Y. (Last) (First) (Middle) C/O AMPHASTAR PHARMACEUTICALS, INC. 11570 6TH STREET (Street) RANCHO CUCAMONGA CA 91730 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner X Officer (give title below) Other (specify below) CEO & Chief Scientific Officer

1. Name and Address of Reporting Person* Luo Mary Z. (Last) (First) (Middle) C/O AMPHASTAR PHARMACEUTICALS, INC. 11570 6TH STREET (Street) RANCHO CUCAMONGA CA 91730 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner X Officer (give title below) Other (specify below) COO,Chief Scientist & Chairman

Explanation of Responses:

1. The securities are held of record by Mary Z. Luo. The reporting persons are husband and wife.

2. The shares are held of record by APCL, of which the reporting persons are the sole owners.

3. The shares are held of record in an account for the benefit of the reporting persons' son. The reporting persons disclaim beneficial ownership of these shares, and the inclusion of these shares in this report should not be deemed an admission of beneficial ownership of any such shares for purposes of Section 16, or for any other purpose.

4. The shares are held of record by a trust for the benefit of the reporting persons' son. The reporting persons disclaim beneficial ownership of these shares, and the inclusion of these shares in this report should not be deemed an admission of beneficial ownership of any such shares for purposes of Section 16, or for any other purpose.

5. Shares subject to the option are fully vested and immediately exercisable

	/s/ Ken Stupak, by power of attorney for Jack Y. Zhang	09/15/2017
	/s/ Ken Stupak, by power of attorney for Mary Z. Luo	09/15/2017
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
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