ABSTRACT
The presence of an efficient physical barrier-stratum corneum, the outermost layer of the epidermis-impairs the optimal permeation
and penetration of a substance across the skin. Many strategies are
being researched to improve the delivery of substances to the viable
layers of the epidermis as well as the dermis and blood circulation,
after topical administration. This chapter reviews the skin structure
and its possible pathways for penetration and permeation, as well
as the most relevant alternatives regarding chemical and physical
methods to modify drug transport across the skin, with a focus on
the role of composite nanoparticles based on lipids and/or polymers
in this process. To comprehend and validate experimental research,
a brief review about the available in vitro and in vivo methods to determine drug transport across skin is also included.
