Inclusion complexes of sunscreen agents with β-cyclodextrin: Spectroscopic and molecular modeling studies

The inclusion complexes of selected sunscreen agents, namely, oxybenzone (Oxy), octocrylene (Oct), and ethylhexyl-methoxycinnamate (Cin) with β-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 with ¹³C NMR measurements, for the complex with β-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 with β-CD in lotion. The results of this study demonstrate that β-CD can be utilized as photostabilizer additive for enhancing the photostability of the selected sunscreen agents' molecules.