Bridging the Gap: Eco-Friendly HPLC Analysis of Metformin and Lobeglitazone Sulfate Despite Polarity and Dosage Differences

Abstract

A precise and stability-indicating high-performance liquid chromatographic (HPLC) method was developed and validated for the simultaneous estimation of lobeglitazone sulfate (0.5 mg) and metformin hydrochloride (500 mg) in pharmaceutical formulations. This method effectively addresses the analytical challenge posed by the significantly different dosage strengths and contrasting polarities of lobeglitazone (water insoluble) and metformin (water soluble). Utilizing a Phenomenex Strong Cation Exchange (250 mm × 4.6 mm, 10 μm) column, the method employed a mobile phase of ammonium dihydrogen phosphate (pH 3.0) and a premix of methanol and acetonitrile (80:20), delivered at a flow rate of 1.0 mL/min. The PDA detector was set at 251 nm to monitor eluents, and the column temperature was maintained at 30°C for optimal separation. The method was validated as per ICH guidelines, covering specificity, linearity, accuracy, precision, LOD, LOQ, solution stability, and robustness. Forced degradation studies under various stress conditions (acidic, basic, oxidative, photolytic, and thermal) revealed no significant degradation products. The method was also assessed for greenness using a AGREE tool, achieving a score of 0.68, demonstrating its eco-friendly nature. Overall, this method is suitable for the routine analysis of these drugs in pharmaceutical formulations.