Simultaneous determination of benazepril hydrochloride and hydrochlorothiazide by micro-bore liquid chromatography

A micro-bore liquid chromatographic method was developed for the simultaneo us determination of benazepril hydrochloride and hydrochlorothiazide in pha rmaceutical dosage forms. The use of a BDS C-18 micro-bore analytical colum n, results in substantial reduction in solvent consumption and increased se nsitivity. The mobile phase consisted of a mixture of 0.025 M sodium dihydr ogen phosphate (pH 4.8) and acetonitrile (55:45, v/v), pumped at a flow rat e of 0.40 ml min(-1). Detection was set at 250 nm using an ultraviolet dete ctor. Calibration graphs are linear (r better than 0.9991, n = 5), in conce ntration range 5.0-20.0 mu g ml(-1) for benazepril hydrochloride and 6.2-25 .0 mu g ml(-1) for hydrochlorothiazide. The intra- and interday R.S.D. valu es were < 1.25% (n = 5), while the relative percentage error (E-r) was < 0. 9% (n = 5). The detection limits attained according to IUPAC definition wer e 0.88 and 0.58 mu g ml(-1) for benazepril hydrochloride and hydrochlorothi azide, : respectively. The method was applied in the quality control of com mercial tablets and content uniformity test and proved to be suitable for r apid and reliable quality control. (C) 1999 Elsevier Science B.V. All right s reserved.