Development and Validation of Stability-Indicating Methods for the Estimation of Antidiabetic Drugs (Repaglinide and Sitagliptin)

Abstract

The present study aimed to develop and validate a stability-indicating reverse-phase high-performance liquid chromatographic method for simultaneous estimation of Repaglinide and Sitagliptin in pharmaceutical formulations. Chromatographic separation was achieved using a C18 column with an optimized phosphate- buffer/acetonitrile mobile phase under isocratic conditions and ultraviolet/photodiode array detection. The analytical procedure was evaluated for system suitability, specificity, linearity, accuracy, precision, sensitivity, and robustness in accordance with ICH validation principles. Forced degradation studies were performed under acidic, alkaline, oxidative, thermal, and photolytic conditions to establish the stability- indicating capability of the method. The developed procedure showed satisfactory system suitability, with theoretical plate counts above 2000, acceptable tailing factors, and resolution >2.0. Good linearity was obtained for Repaglinide  and Sitagliptin. Recovery studies demonstrated mean recoveries of approximately 99–101% with low percent relative standard deviation values. Forced degradation resulted in measurable degradation while maintaining separation of degradation products from the analyte peaks, with peak purity passing for both drugs. The validated method was therefore found to be suitable for routine quantitative analysis, quality control, andstability testing of Repaglinide and Sitagliptin pharmaceutical formulations.