Differential pulse polarographic assay of tolmetin sodium capsules

Differential pulse polarography (DPP) is proposed as a direct method for the quantitation of tolmetin sodium in a capsule formulation (Tolectin® — 200 mg as the sodium dihydrate salt). Classical direct-current (DC) polarography has been employed to investigate the nature of the reduction occurring at the surface of the dropping mercury electrode (DME) using acetate buffer of pH 5.0 as the supporting electrolyte. The mean value of the results obtained by DPP expressed as a percentage of the stated amount, and the standard deviation, were found to be 99.87 ± 0.43. The standard addition procedure used to assess the accuracy of the proposed method gave a mean percentage recovery of the total drug of 100.15 ± 0.75%.