»Propylthiouracil contains not less than 98.0 percent and not more than 100.5 percent of C7H10N2OS, calculated on the dried basis.
Packaging and storage Preserve in well-closed, light-resistant containers.
Identification, Infrared Absorption 197K.
Melting range 741: between 218 and 221.
Loss on drying 731 Dry it 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 specimen being used.
Heavy metals, Method II 231: 0.002%.
Ordinary impurities 466
Test solution: methanol.
Standard solution: methanol.
Application volume: 10 µL.
Eluant: a mixture of toluene, ethyl acetate, and formic acid (50:45:5), in a nonequilibrated chamber.
Assay Weigh accurately about 300 mg of Propylthiouracil, transfer to a 500-mL conical flask, and add 30 mL of water. Add from a buret about 30 mL of 0.1 N sodium hydroxide VS, heat to boiling, and agitate until solution is complete. Wash down any particles on the wall of the flask with a few mL of water, then add about 50 mL of 0.1 N silver nitrate while mixing, and boil gently for 7 minutes. Cool to room temperature, and continue to titrate with 0.1 N sodium hydroxide VS, determining the endpoint potentiometrically, using a glass-calomel electrode system. Each mL of 0.1 N sodium hydroxide is equivalent to 8.512 mg of C7H10N2OS.
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USP32NF27 Page 3434
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.