Packaging and storage— Preserve in tight, light-resistant containers.

Identification— The residue obtained by evaporating, on a steam bath, a volume of Topical Solution, equivalent to about 200 mg of benzethonium chloride, responds to the Identification tests under Benzethonium Chloride.

Oxidizing substances— To 5 mL add 0.5 mL of potassium iodide TS and a few drops of 3 N hydrochloric acid: the solution does not acquire a yellow color.

Limit of nitrites— To 1 drop of Topical Solution on a spot plate add 1 drop each of glacial acetic acid, sulfanilic acid in acetic acid (1 in 100), and 1-naphthylamine–acetic acid solution (prepared by boiling 30 mg of 1-naphthylamine in 70 mL of water, decanting the colorless solution from the blue-violet residue, and mixing with 30 mL of glacial acetic acid): no red color develops in the resulting solution within 10 minutes.

Residual solvents 467: meets the requirements.

Assay— Transfer a volume of Topical Solution, equivalent to about 200 mg of benzethonium chloride, to a glass-stoppered flask, and proceed as directed in the Assay under Benzethonium Chloride, beginning with “Add 0.4 mL of bromophenol blue solution (1 in 2000)”.

Expert Committee : (MDAA05) Monograph Development-Antivirals and Antimicrobials

USP29–NF24 Page 248

Phone Number : 1-301-816-8394