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RP-HPLC and NMR study of cis-trans isomerization of enalaprilat
S Bouabdallah1, H Trabelsi, T Ben Dhia
1Laboratoire National de Contrôle des Médicaments 11bis, rue jebel Lakhdar, Bab Saadoun 1006, Tunis, Tunisia.
Abstract:
The angiotensin converting enzyme inhibitor, enalaprilat can exist in solution as cis and trans conformers which interconvert around the amide bond at room temperature. A HPLC with UV detection was performed to study the influence of various chromatographic operational conditions on both rotamers separation and elution of enalaprilat as a single peak. In addition nuclear overhauser enhancement difference was used for the identification of the conformers. The isomer ratio integrated from the obtained 1H NMR result were 71.5:28.5 and 76:24 at 298 and 279 K, respectively where the trans was the major form.
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