Co2+ ion penetration at different concentrations across animal models of hu
man skin - five days old rat skin (without hairs) and nine days old rat ski
n (with hairs)- was studied in vitro in vertical diffusion cells. The resul
ts showed that the permeated amounts of Co2+ ions are proportional to its c
oncentration in donor solutions, whereby permeated fractions are higher at
lower concentrations. Results confirmed that the most important barrier aga
inst the penetration of ions is horny layer of the skin.