[Code of Federal Regulations] [Title 21, Volume 5] [Revised as of April 1, 2001] From the U.S. Government Printing Office via GPO Access [CITE: 21CFR331.21] [Page 221] TITLE 21--FOOD AND DRUGS CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES--Continued PART 331--ANTACID PRODUCTS FOR OVER-THE-COUNTER (OTC) HUMAN USE--Table of Contents Subpart C--Testing Procedures Sec. 331.21 Test modifications. The formulation or mode of administration of certain products may require a modification of the United States Pharmacopeia 23/National Formulary 18 acid neutralizing capacity test. Any proposed modification and the data to support it shall be submitted as a petition under the rules established in Sec. 10.30 of this chapter. All information submitted will be subject to the disclosure rules in part 20 of this chapter. [61 FR 4823, Feb. 8, 1996]