DEVELOPMENT AND VALIDATION OF A STABILITY-INDICATING RP-HPLC METHOD FOR THE SIMULTANEOUS ESTIMATION OF METFORMIN AND EMPAGLIFLOZIN IN FIXED DOSE COMBINATION TABLETS

Abstract

Metformin and empagliflozin are commonly prescribed together for the management of type 2 diabetes mellitus, and ensuring the quality and stability of their fixed-dose formulations requires reliable analytical approaches. In this study, a simple, robust, and stability-indicating RP-HPLC method was developed and validated for the simultaneous determination of metformin and empagliflozin in bulk and tablet dosage forms. Chromatographic separation was performed on a Shimadzu LC-20 system with PDA detection using a mobile phase of phosphate buffer (pH 3.0) and methanol in a 70:30 (v/v) ratio, delivered isocratically at 1.0 mL/min with detection at 224nm. Validation was carried out in accordance with ICH Q2 (R1) guidelines, covering parameters such as system suitability, linearity, precision, accuracy, sensitivity, robustness, and specificity. The method produced sharp and symmetrical peaks with satisfactory resolution and retention times. A linear relationship was observed across the concentration range of 10–50 µg/mL with correlation coefficients exceeding 0.999. Accuracy was confirmed with recoveries within 98–102%, and precision values for both intra- and inter-day studies were below 2% RSD. The low LOD and LOQ values demonstrated high sensitivity, while forced degradation under acidic, alkaline, oxidative, photolytic, and thermal conditions confirmed the ability of the method to separate the analytes from their degradation products. Overall, the proposed RP-HPLC method is accurate, precise, sensitive, and stability-indicating, offering the benefits of short run time, simple isocratic elution, and cost-effectiveness. These features make it highly suitable for routine assay and stability testing of metformin–empagliflozin formulations in pharmaceutical Industry.