Sulfacetamide Sodium
C8H9N2NaO3S·H2O 254.24

Acetamide, N-[(4-aminophenyl)sulfonyl]-, monosodium salt, monohydrate.
N-Sulfanilylacetamide monosodium salt monohydrate [6209-17-2].

Anhydrous 236.23 [127-56-0].
»Sulfacetamide Sodium contains not less than 99.0 percent and not more than 100.5 percent of C8H9N2NaO3S, calculated on the anhydrous basis.
Packaging and storage— Preserve in tight, light-resistant containers.
A: Dissolve about 1 g in 25 mL of water, adjust with 6 N acetic acid to a pH of between 4 and 5, and filter. Wash the precipitate with water, and dry at 105 for 2 hours: the sulfacetamide so obtained melts between 180 and 184.
B: Place about 500 mg of the sulfacetamide obtained in Identification test A in a test tube, and heat gently until it boils: an oily liquid, which has the characteristic odor of acetamide, condenses on the walls of the test tube (distinction from the sublimates of sulfadiazine, sulfamerazine, and sulfamethazine, which are solids at room temperature).
C: The filtrate obtained in Identification test A responds to the tests for Sodium 191.
D: Dissolve about 100 mg in 5 mL of water, and add 5 drops of cupric sulfate TS: a light bluish green precipitate is formed, and it remains unchanged on standing.
E: Dissolve about 500 mg in 10 mL of dilute hydrochloric acid (1 in 10). To about one-half of the solution add 2 mL of trinitrophenol TS: a very heavy flocculent or almost gelatinous precipitate is formed. To the remainder of the solution add 3 drops of formaldehyde TS: a white precipitate is formed, and it changes to orange on standing (distinction from sulfamethoxypyridazine).
pH 791: between 8.0 and 9.5, in a solution (1 in 20).
Water, Method I 921: not more than 8.1%.
Selenium 291: 0.003%, a 200-mg test specimen being used.
Heavy metals— Dissolve 1.0 g in 25 mL of water, and add 5 drops of freshly prepared sodium sulfide TS: any color produced is not darker than that of a control made with 25 mL of water, 2.0 mL of Standard Lead Solution (see Heavy Metals 231), and 5 drops of sodium sulfide TS (0.002%).
Ordinary impurities 466
Test solution: methanol.
Standard solution: methanol.
Eluant: a mixture of ethyl acetate, methanol, and ammonium hydroxide (17:6:5).
Visualization: 1.
Assay— Proceed with Sulfacetamide Sodium as directed under Nitrite Titration 451. Each mL of 0.1 M sodium nitrite is equivalent to 23.62 mg of C8H9N2NaO3S.
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Topic/Question Contact Expert Committee
Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientist
(MDAA05) Monograph Development-Antivirals and Antimicrobials
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3613