Sulfadoxine
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C12H14N4O4S 310.33

Benzenesulfonamide, 4-amino-N-(5,6-dimethoxy-4-pyrimidinyl)-.
N1-(5,6-Dimethoxy-4-pyrimidinyl)sulfanilamide [2447-57-6].
»Sulfadoxine contains not less than 99.0 percent and not more than 101.0 percent of C12H14N4O4S, calculated on the dried basis.
Packaging and storage— Preserve in well-closed, light-resistant containers.
Identification—
Solution: 6 µg per mL.
Medium: 0.1 N sodium hydroxide.
Melting range 741: between 197 and 200.
Loss on drying 731 Dry it at 105 for 4 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Chromatographic purity— Prepare a solution in a mixture of alcohol and ammonium hydroxide (9:1) having a concentration of about 20 mg per mL. Prepare a Standard solution of USP Sulfadoxine RS having a concentration of about 0.10 mg per mL in a mixture of alcohol and ammonium hydroxide (9:1). Separately apply 10 µL each of the test solution and the Standard solution to a suitable chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel. Develop the chromatogram in a solvent system consisting of a mixture of chloroform, methanol, and dimethylformamide (20:2:1) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the chamber, and air-dry. Spray the dried plate with a 1 in 10 solution of sulfuric acid in alcohol, and expose to nitrous fumes generated by adding 7 M sulfuric acid dropwise to a solution containing 10% sodium nitrite and 3% potassium iodide. Dry the plate in a current of warm air for 15 minutes, and spray with a 1 in 200 solution of N-(1-naphthyl)ethylenediamine dihydrochloride in alcohol. No spot in the test solution, other than the principal spot, is greater in size and intensity than the spot obtained from the Standard solution.
Assay— Proceed with Sulfadoxine as directed under Nitrite Titration 451. Each mL of 0.1 M sodium nitrite is equivalent to 31.03 mg of C12H14N4O4S.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientist
1-301-816-8394
(MDAA05) Monograph Development-Antivirals and Antimicrobials
Reference Standards Lili Wang, Technical Services Scientist
1-301-816-8129
RSTech@usp.org
USP32–NF27 Page 3623
Pharmacopeial Forum: Volume No. 34(2) Page 300
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.