Center Composite Design Assisted Optimization of Rp-hplc Method for Simultaneous Estimation of Linagliptin and Empagliflozin Using Aqbd Perspective

This study reports the development of a reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous estimation of Linagliptin and Empagliflozin in pharmaceutical dosage forms using a Quality by Design (QbD) approach. In the QbD strategy, a central composite design (CCD) was employed to evaluate the influence of critical method parameters, particularly the composition of the mobile phase and the flow rate. The interaction effects of these parameters on critical responses, including retention time and resolution of Linagliptin and Empagliflozin, were analyzed using three-dimensional response surface plots. These plots helped to establish the optimal chromatographic conditions for the developed method. The proposed method is simple, precise, and accurate for the estimation of Linagliptin and Empagliflozin. Chromatographic separation was achieved using a C18 column (NOVATOZ C18, 250 × 4.6 mm, 5 µm) with gradient elution. The mobile phase consisted of Methanol and Acetonitrile (90:10, v/v) delivered at a flow rate of 1 mL/min. Detection of analytes was performed using a photodiode array (PDA) detector at 225 nm. Linearity was observed over the concentration range of 2.5–12.5 µg/mL for Linagliptin and 5–25 µg/mL for Empagliflozin, with correlation coefficients (r²) of 0.993 and 0.991, respectively. The developed method was successfully applied for the quantitative analysis of Linagliptin and Empagliflozin in pharmaceutical dosage forms.