Mathematical development and in vivo safety and efficacy studies of a topical formulation containing Actinidia arguta leaves extract

Abstract

Climate changes, coupled to environmental protection issues, have attracted increasing attention from consumers in the last decade, leading to the re-use and valorisation of food by-products. Actinidia arguta leaves arise as an example, being discarded in high amounts during kiwiberry production. The leaves are characterized by high levels of polyphenols with strong antioxidant/antiradical capacity. In our last studies we proved, by 3D in vitro models and in vivo assays, that A. arguta leaves extract is safe and non-irritant for skin application. The aim of this study was to develop and optimize a topical formulation with A. arguta leaves extract and evaluate its in vivo safety and moisture efficacy in human healthy volunteers. The formulation was developed by a mathematical model, namely Response Surface Methodology, and the independent variables studied were the amount of carbomer (X1, %), glycerin (X2, %) and decyl oleate (X3, %), while the dependent variables were pH (Y1), viscosity (Y2), and particle size (Y3). According to the Box–Behnken design, the optimal formulation was composed by 0.329% of carbomer, 15% of glycerin and 13.796% of decyl oleate. The stability studies demonstrated that the formulation does not suffer modifications along time. Besides that, the in vivo studies performed in human volunteers proved the absence of irritation or allergic reactions as well as the improvement of the skin hydration.