Evaluation of In Vitro Skin Permeation of Enzymatically Synthesized Phloridzin Acetates from Emulsions and Liposomes Dispersed in Gel

This work aims to evaluate the effect of cosmetic formulations on the skin permeation of phloridzin acetates, therefore in vitro transdermal delivery of these bioactive compounds across Strat-M membrane is investigated. The formulations tested are gel emulsion, oil in water emulsion (O/W emulsion), gel in oil emulsion, liquid crystal emulsion, and liposomes dispersed in gel. The release of esters from the O/W emulsion is diffusion-controlled (n = 0.5), while release kinetics from gel-based formulations depends on coupled diffusion and polymer relaxations effect (0.5 < n < 1). The highest values of effective diffusion coefficient are obtained after release from O/W emulsion (24.64 × 10−10 m2 min−1 for phloridzin acetate and 6.55 × 10−10 m2 min−1 for phloridzin diacetate). The lag phase lasting from 1 h (gel emulsion) to 5 h (liquid crystal emulsion) indicates that esters permeation is significantly affected by the formulation used. Formulations in which the water is continuous phase are the most appropriate carrier system for transdermal delivery of phloridzin esters. Additionally, liposomes are successfully applied as carrier systems for the controlled release of esters, although it should be noted that liposomes without cholesterol show remarkable stability (ζ = −43 mV) and homogeneity (polydispersity index = 0.198). Practical application: Phloridzin is a flavonoid glycoside that possesses many beneficial activities such as antioxidant, UV-protecting, and anti-inflammatory activity, so the use of this flavonoid and its derivatives in numerous cosmetic and pharmaceutical formulations seems very attractive. Results obtained in this study give a comprehensive insight into the release mechanism of phloridzin acetates from emulsions and liposomes, enable the selection of optimum cosmetic formulations depending on the application, and provide significant scientific contribution in the field of topical administration of bioactive flavonoid derivatives.