A paired comparison between human skin and hairless guinea pig skin in vitro permeability and tag time measurements for 6 industrial chemicals

The purpose of the present study was to measure and compare permeability coefficients (k(p)) and lag times (T) in human skin and hairless guinea pig (HGP) skin. Paired experiments employed heat-separated epidermal membranes from human and HGP sources mounted on static in vitro diffusion cells. Infinite-dose, saturated aqueous solutions of 6 industrial chemicals were used as donors: aniline, benzene, 1,2-dichloroethane, diethyl phthalate, naphthalene, and tetrachloroethylene. No significant differences were found between human and HGP skin for either k(p) or tau for any of these chemicals (p >= .24). HGP vs. human k(p) measurements, and HGP vs. human T measurements, were highly correlated. For k(p') the slope of the linear correlation was close to unity (1.080 +/- 0.182) and the intercept close to 0 (0.015 +/- 4029cm/h), with a correlation coefficient (r(2)) = 0.898. For T, the slope was also close to unity (0.818 +/- 0.030) and the intercept close to 0 (-0.014 +/- 0.023 h), with r(2) = 0.994. These results suggest that HGP skin may serve as an excellent surrogate for human skin in in vitro dermal penetration studies.