Sulfisoxazole Acetyl
(sul'' fi sox' a zole a seet' il).
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C13H15N3O4S 309.34

Acetamide, N-[(4-aminophenyl)sulfonyl]-N-(3,4-dimethyl-5-isoxazolyl)-.
N-(3,4-Dimethyl-5-isoxazolyl)-N-sulfanilylacetamide [80-74-0].
» Sulfisoxazole Acetyl contains not less than 98.0 percent and not more than 100.5 percent of C13H15N3O4S, calculated on the dried basis.
Packaging and storage— Preserve in tight, light-resistant containers.
USP Reference standards 11
USP Sulfisoxazole Acetyl RS Click to View Structure
B: Ultraviolet Absorption 197U
Solution: 10 µg per mL.
Medium: alcohol.
Absorptivities at 290 nm, calculated on the dried basis, do not differ by more than 3.0%.
Melting range 741: between 192 and 195.
Loss on drying 731 Dry it at 105 for 3 hours: it loses not more than 0.5% of its weight.
Ordinary impurities 466
Test solution: methanol.
Standard solution: methanol.
Eluant: a mixture of toluene and acetone (1:1).
Visualization: 1.
Other requirements— It meets the requirements for Residue on ignition, Selenium, and Heavy metals under Sulfisoxazole.
Assay— Transfer about 1 g of Sulfisoxazole Acetyl, accurately weighed, to a 250-mL beaker. Add 15 mL of glacial acetic acid, swirl to dissolve, then add 25 mL of hydrochloric acid and 80 mL of water. Proceed as directed under Nitrite Titration 451, beginning with “Cool to about 15.” Each mL of 0.1 M sodium nitrite is equivalent to 30.94 mg of C13H15N3O4S.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Leonel M. Santos, Ph.D.
Senior Scientific Liaison
(SM12010) Monographs - Small Molecules 1
Reference Standards RS Technical Services
USP35–NF30 Page 4726