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 developed for the simultaneous determination of losartan potassium and hydrochlorothiazide 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 obtained in the concentration range of 25-10000 ng/mL and 50-10000 ng/mL for losartan 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 hydrochlorothiazide, respectively. This method was succesfully applied without any interferences to the simultaneous analysis of losartan potassium and hydrochlorothiazide in human serum and pharmaceutical dosage forms in the presence of each other.