Stability-Indicating RP-HPLC Method for Simultaneous Determination of Metformin Hydrochloride and Vildagliptin in Tablet and Biological Samples

Abstract

The present work aimed to develop and validate a simple, rapid, sensitive, accurate, and precise method for simultaneous determination of metformin hydrochloride and vildagliptin in tablet and biological samples. Isocratic elution of both the analytes was performed at 35 °C by injecting 20 μL into Thermo Hypersil ODS C18 column (5 μm, 4.6 mm× 250 mm), while the flow rate was set to 0.8 mL/min. The mobile phase comprised of methanol, acetonitrile, and phosphate buffer (5:30:65, v/v, pH 3.5), and wavelength was selected at 212 nm. The overall run time per sample was 7.0 min with a retention time of 3.36 and 5.41 min for metformin hydrochloride and vildagliptin, respectively. The calibration curve was linear from 10-140 μg/mL for metformin and 1-14 μg/mL for vildagliptin with a coefficient of determination (R2) ≤ 0.9919, while repeatability and reproducibility (expressed as relative standard deviation) were lower than 1.13 and 0.97%, respectively. Force degradation studies indicated a complete separation of the analytes in the presence of their degradation products providing a high degree of method specificity. The proposed reversed-phase high-performance liquid chromatography (RP-HPLC) method was demonstrated to be simple and rapid for the determination of metformin hydrochloride and vildagliptin in commercially available tablet and biological samples providing recoveries ranged between 100.13-100.29%.