Simultaneous determination of losartan potassium and hydrochlorothiazide from tablets and human serum by RP-HPLC

A new, simple, precise, rapid, and accurate RP-HPLC method has been develop ed for the simultaneous determination of losartan potassium and hydrochloro thiazide from tablets and human serum. Chromatography was carried out on a C-18 reversed-phase column using a mixture of 0.01 M KH2PO4: acetonitrile ( 65:35; v/v) adjusted to pH 3.1 with H3PO4 at a flow rate 1.0 mL/min. Detection was realised at 232 mn using a UV detector. Linearity was obtaine d in the concentration range of 25-10000 ng/mL and 50-10000 ng/mL for losar tan potassium and hydrochlorothiazide, respectively. The limit of detection and the limit of quantification of the procedure were found to be 1.02 ng/ mL and 3.39 ng/mL for losartan potassium; 4.49 ng/mL and 14.96 ng/mL for hy drochlorothiazide, respectively. This method was succesfully applied without any interferences to the simult aneous analysis of losartan potassium and hydrochlorothiazide in human seru m and pharmaceutical dosage forms in the presence of each other.