Simultaneous Spectrophotometric Estimation of Candesartan Cilexetil and Hydrochlorothiazidein Tablet Dosage Form

A new simple derivative spectrophotometric method has been developed for the simultaneous determination of Candesartan Cilexetil and Hydrochlorothiazide in tablet dosage forms. Candesartan antagonizes the effect of angiotensin II (vasoconstriction and aldosterone secretion) by blocking the angiotensin II receptor in vascular smooth muscle and the adrenal gland and decrease the blood pressure whereas Hydrochlorothiazide increases chloride, sodium and water excretion by interfering with transport of sodium ions across renal tubular epithelium. And there by show the diuretic action. The first derivative method is based on the measurement of absorbance of one drug at the zero crossing point of another drug. Candesartan Cilexetil and Hydrochlorothiazide were determined at two different wavelengths 222.69 (zero crossing point of Hydrochlorothiazide) and 254.63 nm (zero crossing point of Candesartan Cilexetil) from the derivative spectra respectively. The methods hows linearity over the concentration range 0.5-50 and 0.1-50 µg/ml for Candesartan Cilexetil and Hydrochlorothiazide respectively in phosphate buffer. The proposed method was validated and can be used for routine analysis of combined tablet dosage forms containing Candesartan Cilexetil and Hydrochlorothiazide. Key words: Candesartan Cilexetil, Derivative spectroscopy, Hydrochlorothiazide, Simultaneous determination.