Asian Journal of Biomedical and Pharmaceutical Sciences

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Simultaneous Determination of Some Antihypertension Drugs in Their Binary Mixtures by Simple Spectrophotometric Methods

Two simple, accurate and cost effective dual wavelength (Method I) and mean centering of ratio spectra MCR (Method II) spectrophotometric methods are developed and validated for determination of two drug combinations. The first comprises Hydrochlorothiazide (HCZ) and Benazepril Hydrochloride (BZ) and the second comprises HCZ and Candesartan Cilexetil (CAN) in their bulk powder and pharmaceutical tablets. In method (I), two wavelengths were selected for each drug in such a way that the difference in absorbance was zero for the second drug. For BZ/HCZ, mixture (I), BZ had equal absorbance values at 224.2 and 252.9 nm, therefore these two wavelengths were used to determine HCZ. Similarly, 243.8 and 293.8 nm were selected to determine BZ, where HCZ had equal absorbance values. For CAN/HCZ, mixture (II), HCZ is determined at 242.2 and 264.4 nm while CAN is determined at 257.8 and 280 nm. In method (II), absorption spectra of each drug were recorded, divided by suitable divisor and the obtained ratio spectra were mean centered. The concentrations of the proposed drugs were then determined from the calibration curves obtained by measuring amplitudes at 274 and 240.2 nm for HCZ and BZ respectively for mixture (I) and 274 and 240.4 nm for HCZ and CAN respectively for mixture (II). The developed methods were validated according to ICH guidelines demonstrating good accuracy and precision. The results were statistically compared with those obtained by reported methods indicting no significant difference and ability of methods to be used for routine analysis of proposed drugs.

Author(s): Eglal A. Abdelaleema , Ibrahim A. Naguiba, Hala E. Zaazaab and Mohammed E. Drazc