Validated stability-indicating RP-HPLC UV method for simultaneous determination of metformin and repaglinide

Abstract

Summary A simple, rapid, precise, and accurate, stability-indicating reversed phase high performance liquid chromatographic method was developed and validated for simultaneous determination of metformin HCl and repaglinide. The chromatographic separation was achieved on YMC Pack AM ODS (5 μm, 250 mm length × 4.6 mm i.d.) column at a detector wavelength of 210 nm, using an isocratic mobile phase consisting of methanol and 10 mM potassium dihydrogen phosphate buffer (pH 2.5) in a ratio of 70:30 v/v at a flow rate of 1 mL min−1. The retention times for metformin and repaglinide were found to be 2.6 and 11.3 min, respectively. The drugs were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Validation of the method was carried out as per International Conference on Harmonization (ICH) guidelines. Linearity was established for metformin and repaglinide in the range of 5–200 μg mL−1 and 1–200 μg mL−1, respectively. The limits of detection were 0.3 μg mL−1 and 0.13 μg mL−1 for metformin and repaglinide, respectively. The method was found to be specific and stability-indicating as no interfering peaks of degradants and excipients were observed. The proposed method is hence suitable for application in quality-control laboratories for quantitative analysis of both the drugs individually and in combination, since it is simple and rapid with good accuracy and precision.