Author(s): M. Mukkanti Eswarudu1, A. Lakshmana Rao2* and K. Vijay3
A simple, novel, sensitive, rapid, precise and accurate high performance liquid chromatography method has been developed and validated for simultaneous determination of Prazosin and Polythiazide in human plasma using Hydrochlorothiazide as internal standard (ISTD).The analytes were extracted from 500 µl aliquots of human plasma sample by direct protein precipitation technique using acetonitrile. Evaluation of content of the drugs were done by employing a mixture of acetonitrile and potassium dihydrogen orthophosphate buffer in ratio of 35: 65 v/v as the mobile phase with a flow rate of 1 ml/min and injection volume of 10µl. Chromatographic separation was accomplished using Zorbax C18, (150×4.6 mm; 5µm) analytical column and the effluents were monitored at 265 nm with PDA detector. The total run time was 8 min with retention time of Prazosin, Polythiazide and Hydrochlorothiazide was 6.598 min, 5.214 min and 3.579 min respectively. Linearity was established at a concentration range of 5.0-500 ng/ml for Prazosin and 2.5-250 ng/ml for Polythiazide. The method was validated as per the US-FDA guidelines and the results were within the acceptance criteria and proposed method was successfully applied for the simultaneous determination of Prazosin and Polythiazide in human plasma.