quantitative determination of three angiotensin-ii-receptor antagonists in presence of hydrochlorothiazide by rp-hplc in their tablets preparations

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 c18 column (250 mm × 4.6 mm, 5 μm) 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.