Dermal absorption of polycyclic aromatic hydrocarbons in the blood-perfused pig ear

Urinary 1-OH-pyrene, a metabolite of pyrene, is a sensitive biological marker for dermal absorption of pyrene in man. In order to determine whether this metabolite is a reliable biomarker of cutaneous absorption of other polycyclic aromatic hydrocarbons (PAHs), the blood-perfused pig ear model was used to compare the dermal absorption flux of pyrene with nine other PAHs after coal tar application. Cumulative absorption of PAHs into the perfusion blood, 200 min after application of an overdose of coal tar, ranged between 830 pmol cm-2 for phenanthrene to less than 4 pmol cm-2 for benzo[b]fluoroanthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[ah]anthracene and indeno[123-cd]pyrene. The results of this study show that when pyrene is used as a marker compound for PAH absorption through pig skin, the cumulative absorption of PAHs with a lower molecular weight will be underestimated: fluorene, tenfold; phenanthrene, 12-fold; anthracene and fluoranthene, ca. twofold. The percutaneous absorption of PAHs with a higher molecular weight than pyrene will be overestimated: e.g. benzo[a]pyrene, sevenfold; indeno [123-cd]pyrene, ca. 100-fold. It is likely that this conclusion is also valid for dermal PAH absorption in man.