C12H14N4O2S 278.33

Benzenesulfonamide, 4-amino-N-(4,6-dimethyl-2-pyrimidinyl)-.
N1-(4,6-Dimethyl-2-pyrimidinyl)sulfanilamide [57-68-1].

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

USP Reference standards 11— USP Sulfamethazine RS.

Clarity and color of solution— Dissolve 1.0 g in a mixture of 20 mL of water and 5 mL of 1 N sodium hydroxide: the solution is clear and not more deeply colored than pale yellow.

Identification—

Melting range 741: between 197 and 200.

Acidity— Digest 3.0 g with 150 mL of carbon dioxide-free water at 70 for about 5 minutes, stirring occasionally to maintain suspension of the test specimen. Cool the mixture rapidly in an ice bath to 20 ± 0.5, with mechanical stirring. Filter immediately, with vacuum, omitting washing of the solid but drying it thoroughly by suction. Add 2 drops of thymolphthalein TS to 25.0 mL of the filtrate, and titrate with 0.1 N sodium hydroxide VS. To a second 25.0-mL portion of the filtrate add 10 mL of hydrochloric acid. Cool the mixture to 15, and titrate with 0.1 M sodium nitrite VS as directed under Nitrite Titration 451: the volume of 0.1 N sodium hydroxide consumed does not exceed the volume of 0.1 M sodium nitrite consumed by more than 0.5 mL.

Loss on drying 731— Dry about 1 g, accurately weighed, at 105 for 2 hours: it loses not more than 0.5% of its weight.

Residue on ignition 281: not more than 0.1%.

Selenium 291: 0.003%, a 200-mg test specimen being used.

Heavy metals, Method II 231: 0.002%.

Ordinary impurities 466—

Residual solvents 467: meets the requirements.

Assay— Proceed with Sulfamethazine as directed under Nitrite Titration 451. Each mL of 0.1 M sodium nitrite is equivalent to 27.83 mg of C12H14N4O2S.

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

USP29–NF24 Page 2031

Phone Number : 1-301-816-8394