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U.S. Department of Health and Human Services

CFR - Code of Federal Regulations Title 21

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The information on this page is current as of April 1 2019.

For the most up-to-date version of CFR Title 21, go to the Electronic Code of Federal Regulations (eCFR).

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Help | More About 21CFR
[Code of Federal Regulations]
[Title 21, Volume 5]
[Revised as of April 1, 2019]
[CITE: 21CFR331.20]



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

Sec. 331.20 Determination of percent contribution of active ingredients.

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]

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