Derivative Spectrophotometric and HPLC Validated Methods for Simultaneous Determination of Metformin and Glibenclamide in Combined Dosage Form

The aim of the present Study was to develop a simple and rapid method for determination of metformin (MET) and glibenclamide (GLB) ) in Pharmaceutical dosage form. A high-performance liquid chromatographic, fist and second derivative spectrophotometric methods used for the simultaneous determination of MET and GLB. The first derivative amplitudes at 236 nm and 275.7 nm were selected for the assay of MET and GLB, respectively. Calibration curves were established at 5–120 μg/ml-1 for and 1–20 μg/ml-1, with limits of detection of 0.21μg/ml-1 and 0.29 μg/ml-1 and limits of quantification of 0.64μg/ml-1 and 0.89 μg/mL-1 for MET and GLB, respectively. The second derivative amplitudes at 244.6 nm and 229 nm were selected for the assay of MET and GLB, respectively. Calibration curves were established at 5–120 μg/ml-1 for and 1–20 μg/ml-1, with limits of detection of 0.46 μg/ml-1 and 0.30 μg/ml-1 and limits of quantification of 0.1.41μg/ml-1 and 0.91 μg/ ml-1 for MET and GLB, respectively. In the HPLC method separation was performed by using C18 reversed phase column and a mobile phase of acetonitrile: 0.05 M KH2PO4 (60:40v/v) adjusted by phosphoric acid to pH 3, at flow rate of 1 ml/min and the detection wavelength were 210 nm and 238 nm ,the retention time was found to be 3.145 and 7.792 min, linearity over the concentration ranges of 5–75 μm/ml-1 and 2-45 μg/ml-1, with limits of detection of 0.64 μm/l-1 and 0.02 μg/ml-1 and limits of quantification of 1.95 μg/l-1 and 0.07 μg/ml-1 for MET and GLB, respectively. The methods were also applied for the determination of MET and GLB in the presence of their degradation products formed under variety of stress conditions. Proposed methods were validated for precision, accuracy, linearity range, robustness and ruggedness.