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 *

Zhou Rong
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)
EVP, Production Center
(Last)          (First)          (Middle)

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

6/15/2023
(Street)

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

 
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)
Rule 10b5-1(c) Transaction Indication
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

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 6/15/2023  M  13575 A$14.40 101888 D  
Common Stock 6/15/2023  S  5000 D$51.7893 (1)96888 D  
Common Stock 6/15/2023  M  4631 A$14.95 101519 D  
Common Stock 6/15/2023  M  1171 A$16.19 102690 D  
Common Stock         99668 I See footnote (2)
Common Stock         5000 I See footnote (3)

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
Employee Stock Option (right to buy) $14.40 6/15/2023  M     13575   (4)4/14/2024 Common Stock 13575 $0 4316 D  
Employee Stock Option (right to buy) $14.95 6/15/2023  M     4631   (4)3/26/2025 Common Stock 4631 $0 13893 D  
Employee Stock Option (right to buy) $16.19 6/15/2023  M     1171   (4)6/15/2025 Common Stock 1171 $0 3514 D  

Explanation of Responses:
(1) The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $51.74 to $51.88, 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.
(2) The shares are held of record by the Zhou Family Trust for which the reporting person serves as a trustee.
(3) The shares are held of record by the reporting person's spouse.
(4) Shares subject to the option are fully vested and immediately exercisable.

Reporting Owners
Reporting Owner Name / Address
Relationships
Director10% OwnerOfficerOther
Zhou Rong
C/O AMPHASTAR PHARMACEUTICALS, INC.
11570 6TH STREET
RANCHO CUCAMONGA, CA 91730


EVP, Production Center

Signatures
/s/ Eva Wen, by power of attorney6/20/2023
**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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