Delivery systems for cosmetics - From manufacturing to the skin of natural antioxidants

Delivery systems are extensively used in cosmetic products. This literature review describes some of the delivery systems used in the cosmetic industry, some general considerations about their presence and incorporation in cosmetic formulations, as well as their skin interactions. This review also covers the manufacturing process of a cosmetic cream formulation, including basic ingredients, natural antioxidants in particular. In addition, future perspectives, recent concerns, and further work regarding the cosmetic industry are also described. Natural antioxidants present health benefits such as anti-ageing, anti-inflammatory, anti-carcinogenic, and anti-microbial properties that potentiate their use in cosmetic products. Furthermore, they can also be used as preservatives since they avoid the lipid oxidation that usually occurs in cosmetic products. However, antioxidants may have stability issues and difficulties in crossing the transdermal barrier. Delivery systems can be used to protect sensitive active ingredients from degradation and to grant a target and controlled release. Several types of delivery systems (e.g. liposomes, niosomes, transfersomes, lipid nanoparticles, polymeric microparticles and nanoparticles) have been used in cosmetic formulations. The use of delivery systems may improve the penetration of the antioxidant. Skin interaction with the different delivery systems depends mostly on their size, flexibility and composition. Moreover, delivery systems should be easily incorporated in the cosmetic formulation leading to a final uniform and sensorially attractive product for the costumer. New concerns about environmental impact or animal welfare are emerging with respect to the cosmetic development, manufacturing and quality control. Delivery systems used in the cosmetic industry, their skin interactions and production were covered. The manufacturing of cream formulations with delivery systems, as well as product testing were also presented, with illustrative studies along the text. Recent trends and work on the field of cosmetics and delivery systems were explored. [Display omitted] •Natural antioxidants can be used both as preservatives and as active ingredients.•Delivery systems can be used to overcome some limitations of natural antioxidants.•Skin interaction may depend on the delivery system size, elasticity and composition.•Integration of delivery systems in a cream should assure the stability of both.•Environmental or animal welfare