Capillary electrophoretic and nuclear magnetic resonance studies on the opposite affinity pattern of propranolol enantiomers towards various cyclodextrins

In the present study the migration order of the propranolol enantiomers with various native CDs and neutral and charged CD derivatives was examined in capillary electrophoresis (CE). The reversal of the enantiomer migration order was observed due to sulfation of beta-CD on its primary hydroxy groups. The structures of intermolecular selector-select and temporary diastereomeric associates in solution were elucidated based on 1D rotating frame nuclear Overhauser effect spectroscopy (1D ROESY) experiments. Major structural differences were observed between the propranolol complexes with native beta-CD and heptakis(6-O-sulfo)-beta-CD.