A Phase Solubility Study on the Chiral Discrimination of Ibuprofen by β-Cyclodextrin Complexes

The effects of chiral discrimination in inclusion complexes formed by native β-cyclodextrin and its substituted form (namely methyl-β-cyclodextrin) with racemate or pure enantiomers of the non-steroidal anti-inflammatory drug ibuprofen have been investigated in water. Stability constants and complexation efficiency have been determined for these host–guest systems with a 1:1 molar ratio from phase solubility profiles, showing that in aqueous solution, methylated cyclodextrin is a better complex agent than native cyclodextrin, with more enhanced effects for the (R)-enantiomer. These results have been validated using NMR technique. In particular, 1H NMR spectra in D2O show a splitting of the signals for the methyl group and the aromatic protons close to the asymmetric centre of the racemate ibuprofen included in cyclodextrin cavity.