Form 144 Filer Information UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Form 144

NOTICE OF PROPOSED SALE OF SECURITIES
PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933

Form 144

144: Issuer Information

Name of Issuer
Amphastar Pharmaceuticals, Inc.
SEC File Number
001-36509
Address of Issuer
11570 6th St
Rancho Cucamonga
CALIFORNIA
91730
Phone
9099809484
Name of Person for Whose Account the Securities are To Be Sold
Richard Prins
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer
  1. Director

144: Securities Information


RecordTitle of the Class of Securities To Be SoldName and Address of the BrokerNumber of Shares or Other Units To Be SoldAggregate Market ValueNumber of Shares or Other Units OutstandingApproximate Date of SaleName the Securities Exchange
#1Common stock
UBS Financial Services Inc
1000 Harbor Blvd
3rd Floor
Weehawken
NEW JERSEY
07086
10,000$495,00048,860,00011/13/2023
NASDAQ

144: Securities To Be Sold

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

RecordTitle of the ClassDate you AcquiredNature of Acquisition TransactionName of Person from Whom AcquiredIs this a Gift?Date Donor AcquiredAmount of Securities AcquiredDate of PaymentNature of Payment *
#1Common stock06/07/2022RSU VestingIssuer4,01906/07/2022NA
#2Common stock06/07/2019RSU VestingIssuer3,29506/07/2019NA
#3Common stock06/12/2021RSU VestingIssuer2,68606/12/2021NA


* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

144: Securities Sold During The Past 3 Months

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

RecordName and Address of SellerTitle of Securities SoldDate of SaleAmount of Securities SoldGross Proceeds
#1Richard Prins
590 Hedgerow Ln
Charlottesville
VIRGINIA
22903
Common stock08/15/20234,163$238,884
#2Richard Prins
590 Hedgerow Ln
Charlottesville
VIRGINIA
22903
Common stock08/18/20232,000$104,979

144: Remarks and Signature

Remarks
Date of Notice
11/13/2023

ATTENTION:

The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature
/s/ UBS Financial Services Inc, as attorney-in-fact for Richard Prins

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)