Inclusion Complexes of Sunscreen Agents withβ-Cyclodextrin: Spectroscopic and Molecular Modeling Studies

Abstract

The inclusion complexes of selected sunscreen agents, namely, oxybenzone (Oxy), octocrylene (Oct), and ethylhexyl-methoxycinnamate (Cin) withβ-cyclodextrin (β-CD) were studied by UV-Vis spectroscopy, differential scanning calorimetry (DSC),13C NMR techniques, and molecular mechanics (MM) calculations and modeling. Molecular modeling (MM) study of the entire process of the formation of 1 : 1 stoichiometry sunscreen agent/β-cyclodextrin structures has been used to contribute to the understanding and rationalization of the experimental results. Molecular mechanics calculations, together with13C NMR measurements, for the complex withβ-CD have been used to describe details of the structural, energetic, and dynamic features of host-guest complex. Accurate structures of CD inclusion complexes have been derived from molecular mechanics (MM) calculations and modeling. The photodegradation reaction of the sunscreen agents' molecules in lotion was explored using UV-Vis spectroscopy. It has been demonstrated that the photostability of these selected sunscreen agents has been enhanced upon forming inclusion complexes withβ-CD in lotion. The results of this study demonstrate thatβ-CD can be utilized as photostabilizer additive for enhancing the photostability of the selected sunscreen agents' molecules.