Abstract

A simple, specific, accurate and precise reverse phase high performance liquid chromatographic method was developed for the simultaneous determination of losartan potassium and hydrochlorthiazide in tablet dosage forms. A Lichrospher 100 C-18, 5 μm column having 20x4.6 mm i.d. in isocratic mode, with mobile phase containing 20 mM KH2PO4 buffer (pH 3): acetonitri1e:tetrahydrofuran in 60:30:10 were used. The flow rate was 1.0 ml/min and effluent was monitored at 215 nm. The retention time of losartan potassium and hydrochlorthiazide were 7.94 min and 3.26 min, respectively. Linearity for losartan potassium and hydrochlorthiazide were in the range of 4-40 μg/ml and 1-10 μg/ml, respectively. Average percentage recoveries obtained for losartan and hydrochlorothiazide were 100.2% and 100.1%, respectively. In vitro evaluation of tablets containing losartan and hydrochlorothiazide was performed by evaluating tablets for thickness, diameter, hardness, tensile strength, disintegration and dissolution. Parameters for dissolution testing (dissolution medium and speed) were optimized. Dissolution testing was performed at 100 rpm in 0.1 N HCI as dissolution medium by paddle method. The proposed method is accurate, precise, specific and rapid for simultaneous estimation of losartan potassium and hydrochlorthiazide in tablets as well as for dissolution testing.