Determination of benazepril and cilazapril in pharmaceuticals by high performance liquid chromatography

A high performance liquid chromatography method was developed for the specific determination of new angiotensin-converting enzyme inhibitors benazepril and cilazapril in pharmaceutical dosage forms. The proposed method was conducted using a reverse phase technique, UV monitoring at 211 nn and enalapril as an internal standard. The detector response was linear in the range of 10-50 mu g/mL for benazepril and 40-200 mu g/mL, for cilazapril. The drugs were extracted from tablets with methanol. The percentage recoveries ranged from 96.34 to 102.04 and from 103.08 to 107.96 for benazepril and cilazapril, respectively.