ABSTRACT
Losartan potassium, Valsartan, Telmisartan and Irbesartan are angiotensin-II-receptor antagonists [ARA II] group which used in treatment of hypertension alone or in combination with other drugs mainly Hydrochlorothiazide. RP- HPLC method was developed for the assay of three angiotensin-II-receptor antagonists [ARA-IIs] in presence of Hydrochlorothiazide. The method was performed by reversed phase high performance liquid chromatography using a mobile phase which is consisted of 0.025 M potassium dihydrogen phosphate [pH 6.0]: acetonitrile = 65:35% with detection at 220 nm on an ACE CIS column [250 mm x 4.6 mm, 5 microm] at flow rate 1.5 mL/min in an isocratic manner. The proposed method was validated according to ICH guidline in terms of linearity, accuracy, precision, robustness, limit of detection and limit of quantitation