IMPURITY PROFILING METHOD DEVELOPMENT AND VALIDATION FOR METFORMIN HCL AND VILDAGLIPTIN FROM COMBINATION TABLET DOSAGE FORM BY RP-HPLC COUPLED WITH UV/PDA DETECTOR

A precise, accurate, robust method was developed for quantitative estimation of related impurities of Metformin HCL and Vildagliptin from combination tablet dosage form. The mixture of ammonium dihydrogen orthophosphate and octane sulfonic acid sodium salt buffer at pH 4 was used as mobile phase A and mixture of methanol and buffer in the ratio of95:5 used as a mobile phase B. The mobile phase was pumped at 0.8 ml/minutes flow rate through BDS Hypersil C8, 250 x 4.6 mm, 5µ, HPLC column operated at 35°C. All the solutions were injected at 10µl injection volume, and the chromatograms were monitored at 210 nm based on optimum response of impurities and analytes. The % recovery of Metformin HCL, was found 90.4, 92.3, 99.4 and 99.2%, while for Vildagliptin was 90.5, 94.5, 99.6 and 98.3 % from LOQ, 50,100 and 150 % levels respectively. The method was found linear from LOQ to 150% with the correlation coefficients (r2) were 0.998 for Metformin HCL and Vildagliptin. No interference observed from diluent and placebo at the retention time of all known impurities and principle analytes in specificity study and no significantly affected chromatographic pattern for standard, system suitability criteria and sample chromatograms during robustness study, hence the method is specific and robust. The method can be used in quality control laboratories for analysis of related substances from these combination drug products in pharmaceutical industries.