Stability Indicating HPLC Method for Simultaneous Determination of Repaglinide and Metformin Hydrochloride in Pharmaceutical Dosage Form

A simple, specific and accurate stability-indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of Repaglinide and Metformin hydrochloride. An isocratic RPHPLC was achieved on younglin HPLC system using Varian C18 (250 4.6 mm i.d, 5 m particle size) column with the mobile phase containing mixture of acetonitrile: 10mM ammonium acetate(pH 3.0, adjusted with phosphoric acid) (70 : 30, v/v). The flow rate was 1.0ml/min and the eluent was monitored at 230nm. The retention times of Repaglinide and Metformin hydrochloride were found to be 3.1 min and 5.58 min, respectively. Linearity was established for Repaglinide and Metformin hydrochloride in the range of 0.5-3 μg/ml and 200-1200 μg/ml, respectively. The percentage recoveries of Repaglinide and Metformin hydrochloride were found to be in the range of 99.87%±0.7 and 99.89%±0.15 respectively. Both the drugs were subjected to acid, alkali, oxidation, and dry heat degradation. The degradation studies indicated, Repaglinide and Metformin hydrochloride showed degradation in acid, alkaline, H₂O₂, and in dry heat condition. The degradation products of Repaglinide and Metformin hydrochloride were well resolved from the pure drug with significant differences in their retention time values. This method can be successfully employed for simultaneous quantitative analysis of Repaglinide and Metformin hydrochloride in bulk drugs and formulations.