ABSTRACT
Chemical delivery/absorption into and through the skin is important in both
dermato-pharmacology and dermato-toxicology. The human stratum corneum
is the first layer of the skin, and constitutes a rate-limiting barrier to the transport
of most chemicals across the skin (Blank, 1965). Chemicals must first partition
into the stratum corneum before entering the deeper layers of the skin, the
epidermis and the dermis, to reach the vascular system. Chemical partitioning
proceeds much faster than complete diffusion through the whole stratum
corneum, and the process quickly reaches equilibrium (Scheuplein and
Bronaugh, 1985). In addition to binding within the stratum corneum, a
chemical can also be retained within the stratum corneum as a reservoir (Zatz,
1993). Thus, understanding the process of chemical partitioning into the
stratum corneum becomes important in developing an insight into its barrier
properties and transport mechanisms.
