Method Development and Validation of a RP-HPLC Method for the Simultaneous Estimation of Metformin and Dapagliflozin in the presence of their Degradation Product

Abstract

A robust and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous estimation of metformin and dapagliflozin in the presence of their degradation products. Chromatographic separation was achieved on a Hypersil C18 column (250x4.6 mm, 5 μm) with an isocratic elution of potassium dihydrogen phosphate buffer (pH 3.0) and methanol (40:60 %v/v) at a flow rate of 1.0 mL/min. Detection was carried out at 255 nm. The method was validated in accordance with ICH guidelines, demonstrating linearity in the range of 5-20 μg/mL for both analytes with correlation coefficients of 0.999. Precision, accuracy, robustness, and specificity were confirmed, with a % RSD of < 2%. Limit of detection (LOD) values were 0.26 μg/mL for metformin and 0.41 μg/mL for dapagliflozin, while limit of quantification (LOQ) values were 0.79 μg/mL and 1.24 μg/mL, respectively. Forced degradation studies were performed under acidic, basic, oxidative, thermal, and photolytic conditions, revealing significant degradation of the drugs under all tested conditions. The method proved to be stability-indicating and can effectively quantify metformin and dapagliflozin even in the presence of their degradation products, making it suitable for stability studies and routine analysis of pharmaceutical formulations