C12H14N4O4S 310.33

Benzenesulfonamide,4-amino-N-(5,6-dimethoxy-4-pyrimidinyl)-.
N1-(5,6-Dimethoxy-4-pyrimidinyl)sulfanilamide [2447-57-6].

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

USP Reference standardsá11ñ— USP Sulfadoxine RS.

Identification—

Melting range á741ñ: between 197and 200.

Loss on drying á731ñ— Dry it at 105for 4hours:it loses not more than 0.5%of its weight.

Residue on ignition á281ñ: not more than 0.1%.

Heavy metals,Method IIá231ñ: 0.002%.

Chromatographic purity— Prepare a solution in a mixture of alcohol and ammonium hydroxide (9:1)having a concentration of about 20mg per mL.Prepare a Standard solution of USP Sulfadoxine RShaving a concentration of about 0.10mg per mLin a mixture of alcohol and ammonium hydroxide (9:1).Separately apply 10µLeach of the test solution and the Standard solution to a suitable chromatographic plate (see Chromatography á621ñ)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 1in 10solution of sulfuric acid in alcohol,and expose to nitrous fumes generated by adding 7Msulfuric acid dropwise to a solution containing 10%sodium nitrite and 3%potassium iodide.Dry the plate in a current of warm air for 15minutes,and spray with a 1in 200solution 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 á451ñ.Each mLof 0.1Msodium nitrite is equivalent to 31.03mg of C12H14N4O4S.

Expert Committee:(PA7)Pharmaceutical Analysis 7

USP28–NF23Page 1825

Phone Number:1-301-816-8394