Tolmetin Sodium
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C15H14NNaO3·2H2O 315.30

1H-Pyrrole-2-acetic acid,1-methyl-5-(4-methylbenzoyl)-,sodium salt,dihydrate.
Sodium 1-methyl-5-p-toluoylpyrrole-2-acetate dihydrate [64490-92-2].

Anhydrous 279.27 [35711-34-3].
»Tolmetin Sodium contains not less than 98.0percent and not more than 102.0percent of C15H14NNaO3,calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
A: Infrared Absorption á197Kñ.
B: Ultraviolet Absorption á197Uñ
Solution: 10µg per mL.
Medium: pH7phosphate buffer (see Buffer solutionsin the section Reagents,Indicators,and Solutions.)
C: Asolution (1in 20)responds to the tests for Sodium á191ñ.
Loss on drying á731ñ Dry it in vacuum at 60for 4hours:it loses between 10.4%and 12.4%of its weight.
Chromatographic purity— Dissolve 125mg in 10mLof methanol to obtain the Test solution.Dissolve USP Tolmetin Sodium RSin methanol to obtain a Standard solutionhaving a concentration of 12.5mg per mL.Dilute a portion of this Standard solutionquantitatively with methanol to obtain a Diluted standard solutionhaving a concentration of 62.5µg per mL.Apply separate 20-µLportions of the three solutions on the starting line to a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with 0.25-mm layer of chromatographic silica gel mixture.Develop the chromatogram in a solvent system consisting of a mixture of chloroform and glacial acetic acid (95:5)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the chamber,mark the solvent front,air-dry,and view under short-wavelength UVlight:the RFvalue of the principal spot from the Test solutioncorresponds to that from the Standard solution.Any other spot obtained from the Test solutiondoes not exceed in size or intensity the principal spot obtained from the Diluted standard solution(0.5%),and the sum of the total impurities based on a comparison of the intensities of all such other spots with the Diluted standard solutiondoes not exceed 2.0%.
Organic volatile impurities,Method Iá467ñ: meets the requirements.
Assay— Dissolve,by warming,about 300mg of Tolmetin Sodium,accurately weighed,in 150mLof glacial acetic acid.Cool to room temperature,and titrate with 0.1Nperchloric acid VS,determining the endpoint electrometrically.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 27.93mg of C15H14NNaO3.
Auxiliary Information— Staff Liaison:Daniel K.Bempong,Ph.D.,Scientist
Expert Committee:(PA2)Pharmaceutical Analysis 2
USP28–NF23Page 1949
Phone Number:1-301-816-8143