Application of LC and HPTLC-densitometry for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide

Two methods are described for the simultaneous determination of benazepril HCl and hydrochlorothiazide in binary mixture, The first method was based on HPTLC separation of the two drugs follow ed by densitometric measurements of their spots at 238 and 275 nm for benazepril HCl and hydrochlorothiazide respectively, The separation was carried out on Merck HPTLC aluminum sheets of silica gel 60 F-254. using ethyl acetatw-methanol-chloroform (10:3:2 v/v) as mobile phase. Second order polynomial equation was used for the regression line in the range 2-20 and 2.5-25 mug/spot for benazepril HCl and hydrochlorothiazide, respectively. The second method was based on HPLC separation of the two drugs on reversed phase, ODS column at ambient temperature using a mobile: phase consisting of acetonitrile and water (35:65 v/v) and adjusting to pH 3.3 with acetic acid, Quantitation was achieved with UV detection at 240 nm based on peak area with linear calibration curves at concentration ranges 10-60 and 12.5-75 mug ml(-1) for benazepril HCl and hydrochlorothiazide, respectively. The two proposed methods were successfully applied to the determination of both drugs in laboratory prepared mixtures and in commercial tablets, No chromatographic interference from the tablets excipients was found, (C) 2001 Elsevier Science B,V. All rights reserved.