ABSTRACT
This chapter discusses prospective approaches in drug absorption through skin topical delivery. The skin structure is very complex and composed of three main layers: epidermis, dermis, and hypodermis. Skin penetration of the therapeutic and other active agents involves intercellular, intracellular, and transappendageal routes, resulting in topical delivery to the skin or transdermal delivery into the systemic circulation. The application of nanocarriers to transfer therapeutic agents through the skin offers several benefits: protection from the environment, enhancement of product esthetics, sustained release, follicular targeting, and protection against degradation. Nanocarriers can be classified as lipid- or polymeric- based nanoparticles. Lipid-based nanocarriers can penetrate the skin and break the stratum corneum structure, leading to fluidity and efficient drug transport across the skin. Microemulsions are biphasic dispersions composed of immiscible lipids stabilized by a film of surfactant in conjunction with a cosurfactant. The main advantages of skin drug delivery include minimal invasiveness or noninvasiveness of an application and improved drug pharmacokinetics and drug targeting.
