Rp-HPLC Method Development and Validation for the Simultaneous Estimation of Metformin, Empagliflozin and Linagliptin in Its Bulk and Combined Tablet Doseage Form

A simple, precise, accurate, and stability-indicating reverse phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous estimation of Metformin (MET), Empagliflozin (EMP), and Linagliptin (LIN) in bulk drugs and combined tablet dosage forms. Chromatographic separation was achieved using a C18 column with a mobile phase consisting of phosphate buffer and methanol in an optimized ratio, delivered at a suitable flow rate, and detection was carried out using a UV/PDA detector. The method provided well-resolved peaks with satisfactory retention times, good peak symmetry, and acceptable system suitability parameters. The proposed method was validated according to ICH guidelines for parameters including accuracy, precision, linearity, range, specificity, robustness, limit of detection (LOD), and limit of quantification (LOQ). Linearity was observed over the selected concentration ranges for all three drugs with correlation coefficients greater than 0.99. Accuracy studies showed percentage recoveries within acceptable limits, indicating the reliability of the method. Precision studies demonstrated low %RSD values, confirming repeatability and intermediate precision. The method was found to be robust against small deliberate variations in chromatographic conditions. Forced degradation studies under acidic, alkaline, oxidative, thermal, and photolytic conditions confirmed that the method is stability-indicating, as degradation products did not interfere with the analyte peaks. The developed RP-HPLC method is suitable for routine quality control analysis and stability testing of MET, EMP, and LIN in pharmaceutical formulations.