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
                                                                                  
 OMB APPROVAL
OMB Number: 3235-0287
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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 * PRINS RICHARD K 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                    _____ 10% Owner
_____ Officer (give title below)    _____ Other (specify below)
(Last)         (First)         (Middle)
C/O AMPHASTAR PHARMACEUTICALS, INC., 11570 6TH STREET		 3. Date of Earliest Transaction (MM/DD/YYYY)
8/11/2020
(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) _X _ Form filed by One Reporting Person
___ 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  8/11/2020    S    6000  D $20.3294 (1) 39160  D   

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 Security 3. Trans. Date 3A. Deemed Execution Date, if any 4. 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 Date 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 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

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 $20.32 to $20.39, 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.

Reporting Owners
Reporting Owner Name / Address
Relationships
Director 10% Owner Officer Other
PRINS RICHARD K
C/O AMPHASTAR PHARMACEUTICALS, INC.
11570 6TH STREET
RANCHO CUCAMONGA, CA 91730		 X



Signatures
/s/ Eva Wen, by power of attorney 8/12/2020
**Signature of Reporting Person Date