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Sulindac
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C20H17FO3S 356.41

1H-Indene-3-acetic acid, 5-fluoro-2-methyl-1-[[4-(methylsulfinyl)phenyl]methylene]-, (Z)-.
cis-5-Fluoro-2-methyl-1-[(p-methylsulfinyl)benzylidene]indene-3-acetic acid [38194-50-2].
» Sulindac contains not less than 99.0 percent and not more than 101.0 percent of C20H17FO3S, calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
Identification—
Solution: 15 µg per mL.
Medium: hydrochloric acid in methanol (1 in 120).
Absorptivities at 284 nm, calculated on the dried basis, do not differ by more than 3.0%.
Loss on drying 731— Dry it in vacuum at 100 for 2 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Heavy metals, Method II 231: 0.001%.
Chromatographic purity—
Standard preparation— Prepare a solution of USP Sulindac RS in methanol having a concentration of 25 mg per mL (Solution A). Prepare a second solution by diluting 1.0 volume of Solution A with methanol to obtain 250 volumes of solution (Solution B).
Test preparation— Prepare a solution of the sample in methanol having a concentration of 25 mg per mL.
System suitability— From the chromatograms obtained as directed under Procedure, estimate the intensity of the origin spot, if any, in the chromatogram of Solution A. The system is satisfactory if any spot observed at the origin is less intense than that obtained from the principal spot in the chromatogram of 2 µL of Solution B.
Procedure— Apply 4-µL portions of Solution A and the Test preparation and 2-, 4-, 6-, 8-, and 10-µL portions of Solution B to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of a mixture of ethyl acetate and glacial acetic acid (97:3) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, allow the solvent to evaporate, and examine the plate under short-wavelength UV light: the chromatograms show principal spots at about the same RF value. Estimate the levels of any additional spots observed in the chromatogram of the Test preparation by comparison with the spots in the series of chromatograms of Solution B: the sum of the levels is not greater than that of the principal spot obtained from the 10-µL portion of Solution B (1%).
Organic volatile impurities, Method V 467: meets the requirements except that the limit for chloroform is 500 ppm.
Solvent— Use dimethyl sulfoxide.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay— Dissolve about 700 mg of Sulindac, accurately weighed, in about 80 mL of methanol, and titrate with 0.1 N sodium hydroxide VS, determining the endpoint potentiometrically, using a glass-calomel electrode system (see Titrimetry 541). During the titration, and just prior to reaching the endpoint, wash down the walls of the titration vessel with small amounts of methanol. Each mL of 0.1 N sodium hydroxide is equivalent to 35.64 mg of C20H17FO3S.
Auxiliary Information— Staff Liaison : Clydewyn M. Anthony, Ph.D., Scientist
Expert Committee : (MDCCA05) Monograph Development-Cough Cold and Analgesics
USP29–NF24 Page 2045
Phone Number : 1-301-816-8139