Spectral analysis of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical formulations by three chemometric techniques

Three chemometric techniques (classical least squares and inverse least squares and principal component regression) were applied to the spectrophotometric analysis of two pharmaceutical tablet formulations containing hydrochlorothiazide and benazepril hydrochloride in the presence of their overlapping spectra. A training set was randomly prepared by using the different composition mixtures containing 0-22 mug/mL of hydrochlorothiazide and 0-361 mug/mL of benazepril hydrochloride in 0.1 M NaOH. The chemometric calibrations were constructed by using the prepared training set and its measuring the absorbances at 24 points in the spectrum from 220 to 350 mn. The obtained chemometric calibrations were used to the prediction of hydrochlorothiazide and benazepril hydrochloride in samples. The validation of three techniques was realised by analysing the synthetic mixtures of two drugs. The numerical values were computed by means of the "Maple V" software. The results obtained by applying the chemometric techniques to synthetic mixtures and two pharmaceutical preparations containing the title drugs were compared with each other.