21 C.F.R. § 331.20 Determination of percent contribution of active ingredients.
Title 21 - Food and Drugs
To determine the percent contribution of an antacid active ingredient, place an accurately weighed amount of the antacid active ingredient equal to the amount present in a unit dose of the product into a 250-milliliter (mL) beaker. If wetting is desired, add not more than 5 mL of alcohol (neutralized to an apparent pH of 3.5), and mix to wet the sample thoroughly. Add 70 mL of water, and mix on a magnetic stirrer at 300 ±30 r.p.m. for 1 minute. Analyze the acid neutralizing capacity of the sample according to the procedure provided in the United States Pharmacopeia 23/National Formulary 18 and calculate the percent contribution of the antacid active ingredient in the total product as follows: Percent contribution =(Total mEq. Antacid Active Ingredient×100)/(Total mEq. Antacid Product). [61 FR 4823, Feb. 8, 1996]
Title 21: Food and Drugs
PART 331—ANTACID PRODUCTS FOR OVER-THE-COUNTER (OTC) HUMAN USE
Subpart C—Testing Procedures
§ 331.20 Determination of percent contribution of active ingredients.