Purpose: A simple, sensitive, linear, precise, and accurate method by gradient reversed-phase-high performance liquid chromatography for the simultaneous estimation of metformin (MET), losartan (LOS) and glimepiride (GLI) in bulk and in their combined tablet dosage form was developed and validated.
Methodology: The separation of the three drugs was based on the use of Luna c18 (250 ~ 4.6 mm, i.e. 5 ƒÊm) column in a gradient mode. Mobile phase consisted of Methanol (solvent A) and 0.1% Orthophosphoric acid [OPA] (solvent B) was set with gradient programming for 18 min and was delivered at 1 ml/min flow rate and effluents are achieved with variable wavelength: Photodiode array detector at 284 nm. The retention times of MET, LOS and GLI were found to be 3.11, 7.12 and 13.52mins respectively. The percentage assay of MET, LOS and GLI was found to be 100.5%, 100.5 and 100.4%, respectively. Calibration curves were linear for MET, LOS and GLI at concentration ranges of 30- 450 ng/ml, and 15-225ng/ml and 1-18ng/ml with the regression coefficient of 0.999 for all the three drugs and precise with (% RSD <2). The drug was subjected to various stress conditions of acid and base hydrolysis, oxidation, photolysis, thermal degradation and condition.
Findings: Considerable degradation was found under all stress conditions and the degradation products were well resolved from Metformin (MET),Llosartan (LOS) and Glimepiride (GLI) in the proposed gradient RP-HPLC method.
Conclusion: The method was validated by determining its linearity, accuracy, precision, system suitability and can be employed for routine quality control analysis.
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