QUANTITATIVE DETERMINATION OF FOUR ANGIOTENSIN-II-RECEPTOR ANTAGONISTS IN PRESENCE OF HYDROCHLOROTHIAZIDE BY A GRADIENT TECHNIQUE HPLC IN THEIR PHARMACEUTICAL 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. A gradient HPLC method was developed for the assay of several ARAII in presence of Hydrochlorothiazide. The method was performed by reversed phase high performance liquid chromatography using a mobile phase 0.025M potassium dihydrogen phosphate (pH 6.0): acetonitrile=80:20\% with detection at 220nm on an ACE C18 column (250mmx4.6mm, 5 mu m) at flow rate 1.5mL/min in a gradient manner. The proposed method was validated in terms of linearity, accuracy, precision, and limits of detection and quantitation.