Preparation and application of functional hydroxyethyl cellulose hydrogels containing β-cyclodextrin complexes for cosmetic materials

To address the formulation challenges associated with cosmetic active ingredients, including degradation, oxidation, and potential skin irritation, functional supramolecular inclusion complexes were prepared by a coprecipitation method using arbutin, niacinamide, and benzoic acid as guest molecules and β-cyclodextrin (β-CD) as the host. Unlike conventional single-component encapsulation approaches, this study proposes a novel multi-component co-delivery strategy for the simultaneous incorporation of multiple skin-brightening agents and a poorly water-soluble preservative into a single delivery platform. The potential host–guest interactions and complexation behavior were investigated using UV–Vis spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), proton nuclear magnetic resonance ( 1 H NMR) spectroscopy, thermogravimetric analysis (TGA), and field-emission scanning electron microscopy (FE-SEM). The resulting inclusion complexes were subsequently incorporated into a hydroxyethyl cellulose (HEC)-based hydrogel to formulate multifunctional topical lotions. The formulations exhibited weakly acidic pH values of 5.53 and 5.55, within the range generally considered compatible with human skin. Rheological and texture profile analyses demonstrated pseudoplastic (shear-thinning) behavior and appropriate mechanical properties, including hardness, adhesiveness, and cohesiveness, for topical application. Furthermore, disk diffusion assays demonstrated antifungal activity against Candida albicans in the formulations containing the benzoic acid/β-CD inclusion complex. Collectively, these findings demonstrate that the integration of multi-component β-CD inclusion complexes into an HEC hydrogel network yields functional formulations with potential as cosmetic platforms.