In the five years since the first edition of this book was published, there has been an explosion
in new information relating to the nature of dry skin and its treatment. Investigators from various
disciplines, including dermatologists, pharmacists, chemists, biochemists, molecular biologists,
physiologists, pharmacologists, and even psychologists have advanced our knowledge tremendously.
We now understand that the stratum corneum has a surprisingly large number of functions in maintaining
the physiologic stability and homeostasis of the skin and mind.
carriers have different shapes and sizes, and their biogenesis, modality of transport,
and delivery to the final destination are regulated by a multitude of very complex
molecular machineries, which include cytoskeletal elements, signaling complexes, and
lipid modifying enzymes to name a few. A concept that has clearly emerged in the last
decade is that each membrane pathway does not represent a close system, but is fully
integrated with all the other trafficking pathways.
Since this book was first published in 1998, there have been significant advances in
our understanding of the morphology of the skin and the properties that govern the
transport of molecules into and across the three major strata. The multitude of data
that has been generated has allowed the development of predictive models for both
the rate and extent of dermal absorption and has increased our ability to predict the
likelihood of local toxic events subsequent to solute penetration and permeation.