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
                                                                                  
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
                      

1. Name and Address of Reporting Person *

Zhang Jack Y.
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
(Last)          (First)          (Middle)

C/O AMPHASTAR PHARMACEUTICALS, INC., 11570 6TH STREET
3. Date of Earliest Transaction (MM/DD/YYYY)

2/10/2021
(Street)

RANCHO CUCAMONGA, CA 91730
(City)        (State)        (Zip)
4. If Amendment, Date Original Filed (MM/DD/YYYY)

 
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. Trans. Date 2A. Deemed Execution Date, if any 3. Trans. 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 2/10/2021  S(1)  15747 D$18.7556 (2)6891246 I See footnote (3)
Common Stock 2/11/2021  S(1)  19823 D$19.0629 (4)6871423 I See footnote (3)
Common Stock 2/12/2021  S(1)  13277 D$18.9442 (5)6858146 I See footnote (3)
Common Stock         2246988 D  
Common Stock         1449961 I See footnote (6)
Common Stock         5000 I See footnote (7)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security3. Trans. Date3A. Deemed Execution Date, if any4. Trans. Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
6. Date Exercisable and Expiration Date7. 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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares

Explanation of Responses:
(1) The sales reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 12, 2020.
(2) The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.48 to $18.97, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2), (4) and (5).
(3) The shares are held of record by Applied Physics & Chemistry Laboratories, Inc., of which the reporting persons and The Bill Luobei Zhang 2004 Irrevocable Trust (the "BLZ Trust") are the sole owners.
(4) The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.805 to $19.19, inclusive.
(5) The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.85 to $19.18, inclusive.
(6) The securities are held of record by Mary Z. Luo. The reporting persons are husband and wife.
(7) 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.

Reporting Owners
Reporting Owner Name / Address
Relationships
Director10% OwnerOfficerOther
Zhang Jack Y.
C/O AMPHASTAR PHARMACEUTICALS, INC.
11570 6TH STREET
RANCHO CUCAMONGA, CA 91730
XXCEO & Chief Scientific Officer
Luo Mary Z.
C/O AMPHASTAR PHARMACEUTICALS, INC.
11570 6TH STREET
RANCHO CUCAMONGA, CA 91730
XXCOO, Chief Scientist & Chairma
Applied Physics & Chemistry Laboratories, Inc.
C/O AMPHASTAR PHARMACEUTICALS, INC.
11570 6TH STREET
RANCHO CUCAMONGA, CA 91730

X


Signatures
/s/ William J. Peters, by power of attorney for Jack Y. Zhang2/12/2021
**Signature of Reporting PersonDate

/s/ William J. Peters, by power of attorney for Mary Z. Luo2/12/2021
**Signature of Reporting PersonDate

/s/ William J. Peters, by power of attorney for Jack Y. Zhang, principal and owner of Applied Physics & Chemistry Laboratories, Inc.2/12/2021
**Signature of Reporting PersonDate


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).
Note:File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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