ANALYSIS OF ACE-INHIBITORS IN PHARMACEUTICAL DOSAGE FORMS BY DERIVATIVE UV SPECTROSCOPY AND LIQUID-CHROMATOGRAPHY (HPLC)

Derivative UV spectroscopy and high performance liquid chromatography (HPLC) were applied to the determination of angiotensin-converting enz yme (ACE) inhibitors in their pharmaceutical dosage forms. For spectro photometric determinations, the more appropriate derivative order was selected for each drug: ramipril (third-order), benazepril (second-ord er), enalapril maleate (second-order), lisinopril (first- and second-o rder) and quinapril (first-order). Reverse phase HPLC procedures (ODS column) were developed able to provide a single, symmetric peak for ea ch drug; mixtures A-B, where A is 20 mM sodium heptansulphonate (pH 2. 5) and B is acetonitrile-THF (95:5 v/v), proved to be suitable mobile phases to obtain selective separations of the cited ACE inhibitors. At ambient temperature, a low pH value (2.5) was found to be critical to avoid peak splitting and band broadening. (C) 1997 Elsevier Science B .V.