Analytical Quality by Design (AQbD) Driven Development of a Robust Stability-Indicating RP-HPLC Method for the Precision Estimation of Dapagliflozin and Vildagliptin in Combined Fixed-Dose Tablets

Abstract

A simple, accurate, precise, and stability-indicating RP-HPLC method was developed and validated for the simultaneous estimation of Dapagliflozin (DAPA) and Vildagliptin (VILDA) in a combined tablet dosage form using a Quality by Design approach. Method development was carried out systematically by identifying important analytical parameters and optimizing them using the Design of Experiments. Chromatographic separation was achieved using an Inertsil ODS-3 C18 column with phosphate buffer (pH 4.5) and acetonitrile as the mobile phase at a flow rate of 1.0 mL/min. The detection was performed at 210 nm. Vildagliptin and Dapagliflozin were eluted at approximately 2.4 min and 7.7 min, respectively, with good peak shapes and satisfactory resolutions. The developed method was validated according to the ICH guidelines for parameters such as specificity, linearity, accuracy, precision, robustness, limit of detection, and limit of quantification. The method showed good linearity for both drugs, with correlation coefficient values greater than 0.999. The accuracy results were within acceptable limits, and the percentage RSD for precision studies was less than 2%, indicating good reproducibility of the method. Forced degradation studies under acidic, alkaline, oxidative, thermal, photolytic, and humid conditions showed that the method could effectively separate the drugs from their degradation products, proving its stability-indicating nature. Therefore, the proposed RP-HPLC method is simple, reliable, cost-effective, and suitable for routine quality control analysis and stability studies of combined pharmaceutical dosage forms of Dapagliflozin and Vildagliptin.