Simultaneous Estimation of Pioglitazone Hydrochloride and Metformin Hydrochloride using UV Spectroscopic Method

Two new UV-spectrophotometric methods have been developed for simultaneous estimation of Pioglitazone hydrochloride and Metformin hydrochloride in tablets. The first method was based on application of vierodt’s method which involves the formation and solving of simultaneous equations at 225nm and 237nm, as absorbance maxima of Pioglitazone hydrochloride and Metformin hydrochloride, respectively. The second method employed was absorption correction method which involves direct estimation of pioglitazone hydrochloride at 267 nm, as at this wavelength Metformin hydrochloride has zero absorbance and shows no interference. For estimation of Metformin hydrochloride, corrected absorbance was calculated at 237.0 nm due to the interference of Pioglitazone hydrochloride at this wavelength. Calibration curves were linear with correlation coefficient between 0.999 over the concentration range of 6-14 μg/mL and 1-5 μg/mL for both the drugs. The mean percent recovery was found in the range of 99.41-99.80 and 100.36-100.52 for vierodt’s method and 99.18-99.80 and 99.64-99.92 for absorption correction method, for pioglitazone hydrochloride and Metformin hydrochloride, respectively. The results of analysis were validated statistically. The proposed methods are simple, rapid, accurate, precise and economical and can be used successfully in the quality control of pharmaceutical formulations and routine laboratory analysis.