Preparation, Characterization, and Keratinocyte Cell Viability of a β‑Cyclodextrin-Myrcene Complex Intended for Skin Application.

Context: Myrcene has biomedical potential; however, due to its environmental instability and low water solubility, novel approaches, such as inclusion complex formation, can overcome these disadvantages and improve its applicability in cosmetics. Objective: This research investigated the formation of a β-cyclodextrin:myrcene complex using an experimental design approach, followed by physicochemical characterization. The inclusion complex was also evaluated for cytocompatibility in HaCaT keratinocytes for use in skin formulations. Materials and methods: Inclusion complexes were obtained by coprecipitation and optimized using response surface design. The complexes were characterized by FTIR spectroscopy, thermal behavior (TGA and DSC), XRD, and SEM. Cell viability in HaCaT cells was assessed using the MTT assay. Results: The β-cyclodextrin:myrcene complex exhibited a 75.88% inclusion efficacy. FTIR results indicated changes in the band position/intensity consistent with host-guest interactions. Thermal analyses revealed reduced water loss events and the disappearance of the β-CD thermal transition. The X-ray diffraction results suggest a reduction in crystallinity, as indicated by changes in the sample peaks. Scanning electron microscopy data reveal the formation of cubic/rhomboid structures. Cytocompatibility assays demonstrated that free myrcene maintained viability above 70% across most tested concentrations, whereas the formed inclusion complex reduced apparent viability at higher concentrations, consistent with limited aqueous solubility. Conclusions: β-CD effectively entrapped myrcene through coprecipitation, as confirmed by complementary solid-state and thermal analyses. Cytocompatibility results highlighted a reduction in cell viability after the formation of inclusion complexes when compared to myrcene and β-CD controls, possibly due to solubility-related effects. These findings reveal the need for the application of new methods to evaluate the in vitro compatibility and safety of intended skin use.