» Sulfabenzamide contains not less than 99.0 percent and not more than 100.5 percent of C13H12N2O3S, calculated on the dried basis.
Packaging and storage Preserve in well-closed, light-resistant containers.
Clarity and color of solution Dissolve 2.0 g in 15 mL of 1 N sodium hydroxide, with warming: a colorless to pale yellow solution having not more than a slight turbidity is produced.
B: To about 100 mg, suspended in 2 mL of water, add 100 mg of sodium bicarbonate: it dissolves with effervescence (distinction from sulfanilamide, sulfapyridine, sulfathiazole, sulfadiazine, and sulfaguanidine).
Melting range, Class I 741: between 180 and 184.
Loss on drying 731 Dry it at 105 for 2 hours: it loses not more than 0.5% of its weight.
Selenium 291: 0.001%, a 300-mg test specimen and 3 mL of Stock Solution being used.
Heavy metals, Method II 231: 0.002%.
Ordinary impurities 466
Test solution: methanol.
Standard solution: methanol.
Eluant: a mixture of chloroform, methanol, and glacial acetic acid (90:5:5).
Assay Transfer about 800 mg of Sulfabenzamide, accurately weighed, to a 125-mL conical flask, and dissolve in 25 mL of dimethylformamide. Add 3 drops of thymol blue TS (prepared with methanol), and titrate with 0.1 N sodium methoxide VS to a blue endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sodium methoxide is equivalent to 27.63 mg of C13H12N2O3S.
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USP32NF27 Page 3612