An enantioselective study of β-cyclodextrin and ionic liquid-β-cyclodextrin towards propranolol enantiomers by molecular dynamic simulations.

Abstract

In this study, the enantioselectivity of β-cyclodextrin and its derivatives towards propranolol enantiomers are investigated by molecular dynamic (MD) simulations. β-cyclodextrin (β-CD) have previously been shown to be able to recognize propranolol (PRP) enantiomers. To improve upon the enantioselectivity of β-cyclodextrin, we propose the use of an ionic-liquid-modified-β-cyclodextrin (β-CD-IL). β-CD-IL was found to be able to complex R and S propranolol enantiomers with differing binding energies. The molecular docking study reveals that the ionic liquid chain attached to the β-CD molecule has significant interaction with propranolol. The formation of the most stable complex occurred between (S)-β-CD-IL and (S)-propranolol with an energy of -5.80 kcal/mol. This is attributed to the formation of a hydrogen bond between the oxygen of the propranolol and the hydrogen on the primary rim of the (S)-β-CD-IL cavity. This interaction is not detected in other complexes. The root mean-squared fluctuation (RMSF) value indicates that the NH group is the most flexible molecular fragment, followed by the aromatic group. Also of note, the formation of a complex between pristine β-CD and (S)-propranolol is the least favorable.