{"data":{"id":"us/21-cfr-331.21","jurisdiction":"us","citation":"21 CFR 331.21","heading":"Test modifications.","body":"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 § 10.30 of this chapter. All information submitted will be subject to the disclosure rules in part 20 of this chapter.","path":["Title 21—Food and Drugs","CHAPTER I—FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES","SUBCHAPTER D—DRUGS FOR HUMAN USE","PART 331—ANTACID PRODUCTS FOR OVER-THE-COUNTER (OTC) HUMAN USE","Subpart C—Testing Procedures"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-21.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:47Z","sha256":"4a848d40eedd9dafb9c8a70b53469e493850d057d815a5571befa2a64b976955","source_id":"us-cfr","stale":true,"prev":"us/21-cfr-331.20","next":"us/21-cfr-331.30"},"notice":"GroundRules: Original legal text. Not legal advice."}