RP-HPLC Method Development and Validation for Simultaneous Estimation of Prazosin and Polythiazide in Bulk and Pharmaceutical Dosage Form

A new isocratic RP-HPLC method was developed and validated for simultaneous estimation of Prazosin and Polythiazide in bulk and pharmaceutical dosage form with stability studies as per ICH guidelines. In this method Symmetry C18 column (150mm×4.6mm, 5Pm particle size), Waters Alliance e2695 HPLC system with PDA detector and the mobile phase contained a mixture of 0.01M Potassium dihydrogen orthophosphate buffer (pH adjusted to 3.48 with orthophosphoric acid) and Acetonitrile (50:50, v/v) was used. The flow rate was set to 1mL/min with the responses measured at 265nm. The retention time of Prazosin and Polythiazide was found to be 2.989min and 2.134min respectively with resolution of 5.1. Linearity was established for Prazosin is 25150μg/mL and for Polythiazide is 6.25-37.5μg/mL with correlation coefficients (r2 =0.999). The percentage recoveries for Prazosin are 100.34% and Polythiazide is 100.32% respectively. Prazosin and Polythiazide are more sensitive towards acidic, basic and oxidative degradation condition. The developed method was successfully applied for the quantification of Prazosin and Polythiazide in bulk and pharmaceutical dosage form. KEYWORDS: Prazosin, Polythiazide, RP-HPLC, ICH.