Establishment of a Sensitive and Stability-Indicating RP-HPLC Protocol for Co-Quantification of Empagliflozin and Sitagliptin

Aim/Background: To develop a stability-indicating RP-HPLC method for simultaneous quantification of Empagliflozin (EMPA) and Sitagliptin (SITA) in a synthetic mixture for quality control and stability studies. Materials and Methods: Separation used a C18 column with phosphate buffer-methanol-acetonitrile (40:20:40,%v/v/v) at 1.0 mL/min, detected at 224 nm. Validation per ICH Q2(R1) assessed linearity, precision, accuracy, specificity, and robustness. Stress tests included acidic, alkaline, oxidative, thermal, and photolytic conditions. Results: EMPA (2.8 min) and SITA (3.7 min) showed linearity (R² >0.99) over 20-120 µg/mL (EMPA) and 200-1200 µg/mL (SITA), with %RSD < 2% and recovery 99-102%. Detection limits were 1.8 µg/ mL (EMPA) and 4.7 µg/mL (SITA). Stress tests revealed moderate EMPA degradation (acidic/ alkaline) and high SITA degradation (thermal/photolytic), with distinct degradation peaks. This precise, accurate RP-HPLC method is stability-indicating and suitable for routine quality control and stability analysis of EMPA-SITA mixtures per ICH guidelines. Conclusion: The developed RP-HPLC method is precise, accurate, and reliable for simultaneous estimation of EMPA and SITA. Its stability-indicating nature ensures suitability for routine quality control and stability studies of Synthetic Mixture.