Spectroscopic studies for the inclusion complexation of ketoprofen enantiomers with β-cyclodextrin

Asma Obaid; Arniza Khairani Mohd Jamil; Samikannu Prabu; Siti Munirah Saharin; Sharifah Mohamad

doi:10.1016/j.saa.2020.118674

Spectroscopic studies for the inclusion complexation of ketoprofen enantiomers with β-cyclodextrin

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Nov 5:241:118674. doi: 10.1016/j.saa.2020.118674. Epub 2020 Jul 2.

Authors

Asma Obaid¹, Arniza Khairani Mohd Jamil², Samikannu Prabu², Siti Munirah Saharin², Sharifah Mohamad³

Affiliations

¹ Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia; Department of Chemistry, Faculty of Science, Jazan University, Jazan 45142, Saudi Arabia.
² Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
³ Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia; Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia. Electronic address: sharifahm@um.edu.my.

PMID: 32652287
DOI: 10.1016/j.saa.2020.118674

Abstract

Inclusion complexes of R-ketoprofen and S-ketoprofen enantiomers with β-cyclodextrin (β-CD) in aqueous solution were studied using various spectroscopic techniques such as Raman, FTIR, UV and fluorescence. The different relative intensities and characteristic band shifts of the two enantiomers from Raman spectra suggests different interaction when complexed with β-CD. Raman experiments revealed a noticeable diminishing of the CC vibration and ring deformation, which indicate the embedding of ketoprofen inside the β-CD cavity. It's revealed that distinct differences between R- and S-ketoprofen in the presence of β-CD at neutral pH. The stoichiometry ratio and binding constant of the inclusion complexes were calculated using Benesi-Hildebrand plot. Both enantiomers showed stoichiometry ratio of 1:1 inclusion complex with β-CD. The binding constant of R-ketoprofen (4088 M^-1) is higher than S-ketoprofen (2547 M^-1). These values indicated that β-CD formed inclusion complexes more preferentially with R-ketoprofen than S-ketoprofen. Results demonstrated that β-CD can be used as a promising chiral selector for ketoprofen enantiomers.

Keywords: Chiral recognition; Inclusion complexes; Ketoprofen enantiomers; Spectrophotometry; β-Cyclodextrin.