Nuclear magnetic resonance (NMR) spectroscopy of inclusion compounds of tolbutamide and chlorpropamide with .BETA.-cyclodextrin in aqueous solution.

Abstract

A structural study of the inclusion compounds of tolbutamide and chlorpropamide with β-cyclodextrin in aqueous solution was attempted by means of proton nuclear magnetic resonance (1H-NMR) and carbon-13 nuclear magnetic resonance (13C-NMR) experiments. The changes in chemical shift (1H, 13C) and in relaxation times (1H-T1p, 13C-T1) suggested that the drug phenyl moiety was included in the cavity of β-CD mainly by hydrophobic interaction, and that the primary hydroxy side of β-CD was tightly associated with each drug. The binding mechanism and binding sites between the drug molecules and β-CD are discussed in detail.