Transdermal permeability of estradiol through human skin of different body regions in vitro

Transdermal permeability of estradiol was carried out by using Valia-Chien double-compartment permeation cell for the following 6 skin regions with intact and without stratum corneum: chest, abdomen, hip, upper arm, thigh and back. The estradiol permeation rates and accumulative amounts within 72 h in vitro were examined by HPLC. The results showed that the permeation rates of intact skin from different regions of the body were significantly different (P less than 0.01), and for the skins without stratum corneum over different regions, the permeation rates or the permeation amounts were about 18-55 times higher than that for the intact skin. The results demonstrated that the stratum corneum acts as the rate-limiting barrier in the skin permeation of estradiol, and that the difference in estradiol permeation rates for different skin regions was mainly caused by the different extents of the barrier.