Sulfinpyrazone Tablets

General Notices

Action and use

Uricosuric.

Definition

Sulfinpyrazone Tablets contain Sulfinpyrazone. They are coated.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of sulfinpyrazone, C23H20N2O3S

92.5 to 107.5% of the stated amount.

Identification

Extract a quantity of the powdered tablets containing 0.2 g of Sulfinpyrazone with chloroform, filter and evaporate the filtrate to dryness on a water bath. The residue complies with the following tests.

A. The light absorption, Appendix II B, in the range 230 to 350 nm of a 0.002% w/v solution in 0.01m sodium hydroxide exhibits a maximum only at 260 nm.
B. Dissolve 10 mg in 3 mL of acetone and add 0.05 mL of iron(iii) chloride solution R2 and 3 mL of water. A red colour is produced.

Related substances

Carry out the method for thin-layer chromatography, Appendix III A, using as the coating substance a suitable silica gel containing a fluorescent indicator with an optimal intensity at 254 nm (Merck silica gel 60 F254 plates are suitable) and a mixture of 20 volumes of glacial acetic acid and 80 volumes of chloroform as the mobile phase. Place the plate in a tank containing a beaker of glacial acetic acid and allow it to stand for 10 minutes. Heat the plate at 60° for 40 minutes, cool and pass a current of nitrogen over the plate for 10 minutes. Apply separately to the plate, under an atmosphere of nitrogen, 2 µL of each of the following solutions. For solution (1) shake a quantity of the powdered tablets containing 0.2 g of Sulfinpyrazone with 10 mL of chloroform, filter and use the filtrate. For solution (2) dilute 2 volumes of solution (1) to 100 volumes with acetone and dilute 1 volume of the resulting solution to 10 volumes with acetone. For solution (3) dissolve 10 mg of 1,2-diphenyl-4-(2-phenylsulfonylethyl)pyrazolidine-3,5-dione EPCRS (impurity A) in 10 mL of acetone. For solution (4) dilute 5 volumes of solution (3) to 10 volumes with acetone. For solution (5) dissolve 10 mg of 1,2-diphenyl-4-(2-phenylthioethyl)pyrazolidine-3,5 dione EPCRS (impurity B) in 10 mL of acetone. For solution (6) dilute 5 volumes of solution (5) to 10 volumes with acetone. After removal of the plate, allow it to dry in air and examine under ultraviolet light (254 nm). In the chromatogram obtained with solution (1) any spots corresponding to impurity A and impurity B are not more intense than the spots in the chromatograms obtained with solutions (3) and (5) respectively (5% of each), not more than one such spot is more intense than the corresponding spot in the chromatogram obtained with solution (4) or (6) (2.5%) and any other secondary spot is not more intense than the spot in the chromatogram obtained with solution (2) (0.2%).

Assay

Weigh and powder 20 tablets. Stir a quantity of the powder containing 0.5 g of Sulfinpyrazone with 10 mL of petroleum spirit (boiling range, 40° to 60°) for 10 minutes in a glass-stoppered flask. Decant through a sintered-glass filter, wash with two 7-mL quantities of petroleum spirit (boiling range, 40° to 60°) and discard the petroleum spirit. Warm to 80° to remove the solvent and extract the residue with six 20-mL quantities of hot acetone previously neutralised to bromothymol blue solution R3, decanting each solution and filtering through the sintered-glass filter. Titrate the combined extracts with 0.1m sodium hydroxide VS using bromothymol blue solution R3 as indicator. Each mL of 0.1m sodium hydroxide VS is equivalent to 40.45 mg of C23H20N2O3S.