The angiotensin-converting enzyme (ACE) inhibitor delapril is shown to exist in two conformational isomers, cis and trans, which interconvert around the amide bond. The two conformers were separated by capillary zone electrophoresis (CZE). The experimental conditions, such as buffer parameters (concentration, pH and nature), voltage, temperature and pH of sample solution were optimized. In order to improve selectivity, different organic modifiers were also investigated. The baseline separation of delapril conformers was accomplished within 6.5 min with a buffer consisting of 100 mM ammonium formate with pH of 3; voltage 25 kV; capillary temperature 15°C and sample pH of 1.6 with detection at 214 nm.
A. Ben Amar, M. Abidi, N. Ben Hamida
Angiotensin-converting enzyme inhibitor, delapril, Capillary Zone Electrophoresis, conformer separation