Effect of the chiral discrimination on the vibrational properties of (R)-, (S)- and (R, S)-ibuprofen/methyl-β-cyclodextrin inclusion complexes

Abstract

The effects of chiral discrimination of ibuprofen (IBP) on the complexation process with methyl-β-cyclodextrin (Me-β-CD) were investigated in the solid phase by FTIR-ATR spectroscopy and numerical simulation. The inclusion mechanism was deduced from the temperature-dependent analysis of the vibrational spectra, in the C=O stretching region, of complexes formed by Me-β-CD with the two enantiomeric and the racemic forms of IBP. The mechanism turned out to be enthalpy-driven, with IBP enantiomers giving rise to more stable inclusion complexes with respect to the racemate.

Keywords:

• ibuprofen
• inclusion complex
• FTIR-ATR spectroscopy
• numerical simulation
• chirality