Ammonium Chloride Delayed-Release Tablets

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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Ammonium Chloride Delayed-Release Tablets contain not less than 94.0 percent and not more than 106.0 percent of the labeled amount of NH₄Cl. Ammonium Chloride Delayed-Release Tablets are enteric-coated.

1 Packaging and storage

Preserve in tight containers.

2 Identification

A filtered solution of finely powdered Tablets, equivalent to ammonium chloride solution (1 in 10), responds to the tests for Ammonium 〈191〉 and for Chloride 〈191〉.

Disintegration 〈701〉: 2 hours, determined as directed for Enteric-Coated Tablets.

3 Limit of thiocyanate

Powder and dissolve in water a sufficient number of Tablets to make about 25 mL of ammonium chloride solution (1 in 10), and filter. Acidify 10 mL of the solution with hydrochloric acid, and add a few drops of ferric chloride TS: no reddish orange color is produced.

4 Assay

Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 200 mg of ammonium chloride, to a 500-mL Kjeldahl flask, and add 200 mL of water and 50 mL of sodium hydroxide solution (2 in 5). Immediately connect the flask by means of a distillation trap to a well-cooled condenser, the delivery tube of which dips into 40 mL of boric acid solution (1 in 25) contained in a suitable receiver. Heat to boiling, and distill about 200 mL. Cool the liquid in the receiver, if necessary, then add methyl red TS, and titrate with 0.1 N sulfuric acid VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sulfuric acid is equivalent to 5.349 mg of NH₄Cl.