Aminobenzoic Acid Topical Solution
» Aminobenzoic Acid Topical Solution contains, in each mL, not less than 45 mg and not more than 55 mg of aminobenzoic acid (C7H7NO2).
Packaging and storage— Preserve in tight, light-resistant containers.
A: To 1 mL of Topical Solution add 1 mL of 1 N sodium hydroxide, and add, in the order named, 0.5 mL of potassium iodide TS, 0.5 mL of 3 N hydrochloric acid, and 0.5 mL of sodium hypochlorite TS: a brown precipitate is formed.
B: To 1 mL of Topical Solution add 2 mL of 3 N hydrochloric acid, and cool to about 10. Add 1 mL of sodium nitrite solution (1 in 100), then add a solution prepared by mixing 50 mg of 2-naphthol with 3 mL of sodium hydroxide solution (1 in 10): a red color is produced.
Specific gravity 841: not less than 0.895 and not more than 0.905.
Alcohol content 611: between 65% and 75% of C2H5OH.
Assay— Transfer 5 mL of Topical Solution, accurately measured, to a suitable open vessel, evaporate on a steam bath to dryness, and proceed as directed under Nitrite Titration 451, beginning with “Add 20 mL of hydrochloric acid.” Each mL of 0.1 M sodium nitrite is equivalent to 13.71 mg of C7H7NO2.
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Topic/Question Contact Expert Committee
Monograph Feiwen Mao, M.S.
Senior Scientific Liaison
(SM32010) Monographs - Small Molecules 3
USP35–NF30 Page 2167