ABSTRACT
The topical administration route is preferred to the systemic delivery to treat skin disorders as it provides dramatically higher skin-to-plasma ratios, maintaining therapeutically effective drug concentrations in the target organ with relatively less risk of inducing side effects due to high systemic exposure (Herkenne et al. 2008). The skin became popular as a potential site for systemic drug delivery, on the one hand, because of the possibility of avoiding the problems of stomach emptying, pH effects, enzyme deactivation associated with gastrointestinal passage, and hepatic ‘rst-pass metabolism, and, on the other hand, due to its capability to enable input control.
