Spectrophotometric determination of benazepril hydrochloride and hydrochlorothiazide in binary mixture using second derivative, second derivative of the ratio spectra and chemometric methods

Different spectrophotometric methods are presented for the simultaneous det ermination of benazepril hydrochloride and hydrochlorothiazide in pharmaceu tical tablets. The first method depends on second derivative (D-2) ultravio let spectrophotometry, with zero crossing and peak to base measurement. The second derivative amplitudes at 214.8 and 227.4 nm were selected for the a ssay of benazepril hydrochloride and hydrochlorothiazide. respectively. The second method depends on second derivative of the ratio spectra by measure ment of the amplitudes at 241.2 and 273.2 nm for benazepril hydrochloride a nd hydrochlorothiazide respectively. Chemometric methods, classical least s quares and principal component regression, were applied to analyze the mixt ure. Both the chemometric methods were applied to the zero and first order spectra of the mixture. The proposed methods were successfully applied for the determination of the two drugs in laboratory prepared mixtures and in c ommerical tablets. (C) 2001 Elsevier Science B.V. All rights reserved.