Azelaic acid-willow bark extract-panthenol – Loaded lipid nanocarriers improve the hydration effect and antioxidant action of cosmetic formulations

The classic medication recommended in acne and atopic dermatitis comprises the administration of antibiotics, corticosteroids and topical steroids. To overcome some inconveniences of using synthetic antibiotics, e.g. irritation, inflammation and dryness, this study proposes a biotherapeutic strategy which is based on cosmetic formulations including nanostructured lipid carriers (NLCs) loaded with three actives, azelaic acid (AzA), white willow bark extract (WBE) and panthenol (Ph). The main objective was to obtain non-cytotoxic and hemocompatible NLCs with high entrapment efficiency for all actives, controlled release of these actives and enhanced hydration effect and antioxidant action. The large confinement space of developed NLCs prepared with echium oil has been proved by the appropriate encapsulation efficiencies for AzA, WBE and Ph actives, with values reaching 90 %. The NLC-AzA-WBE- Ph improved the reconstruction of epidermal cells, the cell viability of BJ human fibroblast line being up to 100 % at concentrations up to 62.5 μg/mL. The hemolytic tests revealed the protective effect of the WBE and AzA on the red blood cells; the hemolysis has been drastic reduced, the developed NLC manifesting a nonhemolytic action. The synergism of all actives led to an efficient antioxidant NLCs that inhibits 97 % of short-life radicals and 15 % of ABTS long-life radical cations. The incorporation of NLC-AzA-WBE- -Ph into a Carbopol gel resulted in an advanced cosmetic formulation that assures a high hydration effect. The degree of hydration in the cosmetic formulations ranges up to 84 % in the T-zone for type-III skin (predisposed in acne) and above 80 % in the body region for skin type-II (susceptible in dermatitis). By summarizing, the moisturizing nature of Ph, completed by the antioxidant activity and controlled release behaviour of WBE and AzA, significant enriched the final properties of the NLCs-based cosmetic formulations for a dual use in acne and atopic dermatitis therapy.