BIOANALYTICAL METHOD DEVELOPMENT AND VALIDATION FOR SIMULTANEOUS DETERMINATION OF LINAGLIPTIN AND METFORMIN DRUGS IN HUMAN PLASMA BY RP-HPLC METHOD

A simple, rapid, precise and accurate high performance liquid chromatography method was developed for simultaneous determination of linagliptin and metformin in human plasma. The analytes were extracted by protein precipitation technique and chromatograph using a mobile phase consisting of acetonitrile and 0.01M di-potassium hydrogen phosphate buffer in ratio of 75: 25 and adjusting pH 7.0 with orthophosphoric acid using Grace vyadyec genesis CN (150 x 4.6 mm, 4 mu m) column. The flow rate 1.0 mL min(-1) and UV detection at 237 nm was employed. The retention time for linagliptin and metformin and internal standard (phenformin) was 4.95, 15.41 min and 11.06 min respectively. Linearity for linagliptin and metformin was found to be in the range of 1-32 ng/mL for both drugs respectively. The method was validated as per the USFDA guidelines and the results were within the acceptance criteria for selectivity, sensitivity, linearity, precision, accuracy, recovery stability of solution, stability of solution in plasma and dilution integrity.