Solid Lipid Nanoparticles and Nanostructured Lipid Carriers as Topical Delivery Systems for Antioxidants

Abstract

The stratum corneum (SC) is the main barrier to the percutaneous absorption of topically applied drugs. It is a multilayer matrix of hydrophobic and hydrophilic components whose structural integrity is maintained by the presence of modified desmosomes, called corneodesmosomes, which lock the corneocytes together and provide tensile strength for the SC to resist to shearing forces. Nowadays, the use of antioxidants (AOs) has been boosted, from either a prophylactic or a therapeutic point of view. Such trend has been prompt by the discovery of the involvement of free radicals and other reactive oxygen species (ROS) in physiopathological mechanisms of diseases, including infection, inflammation and cancer, either systemically or at a topical level. Human skin is very susceptible to oxidative stress (OS), since it is continuously exposed to exogenous and endogenous factors that contribute to ROS formation and, consequently, to cell/structural modifications that results in skin damage.