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 o n HPTLC separation of the two drugs follow ed by densitometric measurements of their spots at 238 and 275 nm for benazepril HCl and hydrochlorothiazid e respectively, The separation was carried out on Merck HPTLC aluminum shee ts 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 reg ression line in the range 2-20 and 2.5-25 mug/spot for benazepril HCl and h ydrochlorothiazide, respectively. The second method was based on HPLC separ ation 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 de tection at 240 nm based on peak area with linear calibration curves at conc entration ranges 10-60 and 12.5-75 mug ml(-1) for benazepril HCl and hydroc hlorothiazide, respectively. The two proposed methods were successfully app lied to the determination of both drugs in laboratory prepared mixtures and in commercial tablets, No chromatographic interference from the tablets ex cipients was found, (C) 2001 Elsevier Science B,V. All rights reserved.