Development and Validation of a Stability‐Indicating LC Method for the Determination of Empagliflozin‐Related Substances With Sensitivity Profiling and Robustness Assessment Using Analytical Quality by Design Principles

ABSTRACT A robust, accurate, linear, and stability‐indicating liquid chromatography (LC) method equipped with a photodiode array (PDA) detector was developed and validated for the quantitative estimation of empagliflozin (EMP), an antidiabetic agent approved for the treatment of type 2 diabetes mellitus. The method enables the determination of specified known impurities as well as degradation products present in the EMP drug substance. A systematic Quality by Design (QbD) approach was employed to evaluate the method's robustness, ensuring consistent performance under varied analytical conditions. Chromatographic separation was achieved using a Zorbax SB‐C18 column (250 × 4.6 mm, 3.5 µm) with a gradient elution program. The mobile phase consisted of Solvent A (water: acetonitrile, 50:50 v/v) and Solvent B (methanol: water, 90:10 v/v). The optimized chromatographic conditions included a flow rate of 0.7 mL/min, column temperature of 27°C, injection volume of 20 µL, and UV detection at 225 nm. Method validation was performed in accordance with ICH Q2(R2) guidelines. The method demonstrated excellent accuracy, with recovery values ranging from 95.8% to 105.4%, and linearity was observed over a wide concentration range from the limit of quantification (LOQ) to 300% of the target level, with correlation coefficients ( R 2 ) exceeding 0.998 for all identified impurities. Method precision, expressed as relative standard deviation (RSD), was consistently below 5.0%. Forced degradation studies confirmed that EMP is stable under various chemical and physical stress conditions, further supporting the stability‐indicating nature of the developed method.