Topical delivery of antioxidants.

Reactive oxygen species (ROS) and free radicals have been implicated in a number of diseases and disorders, and the skin, for its localization, is exposed to a large number of environmental threats. Free radical scavengers and antioxidants have thus been proposed as protective or therapeutic agents against ROS-mediated injuries. Oral treatment with several antioxidants has been reported to provide skin protection against deleterious effects of ultraviolet radiation. Topical delivery of antioxidants has increasingly gained interest and development, especially by offering better targeting to the upper skin layer. However, the topical delivery of antioxidants for dermal action is a challenging research field since the molecules are, in general, susceptible to degradation. The search for a new delivery system that, simultaneously, preserves the antioxidant stability and enhances its deposition on the skin, opened a new chapter in drug delivery design. Nanocarriers have been successful in enhancing the clinical efficiency of several drugs. More recent approaches in modulating through the skin delivery led to the development of specialized nanoparticulated systems. The first part of this article presents a review of the potential of antioxidants as pharmacological agents in ROS related diseases, with a special focus on oxidative stress implicated skin pathologies: ROS formation and natural protection against ROS toxicity, ROS-mediated skin damage and skin protection by antioxidants. In the second part of this work, we present reported formulation strategies for dermal delivery of antioxidants focusing on the nanoparticulated systems developed in recent years.