Skin permeation of polycyclic aromatic hydrocarbons: A solvent-based in vitro approach to assess dermal exposures against benzo[a]pyrene and dibenzopyrenes

ABSTRACT

Consumer products with high contents of polycyclic aromatic hydrocarbons (PAHs) were repeatedly identified by market surveillance authorities. Since several of the individual compounds have been identified as genotoxic carcinogens, there might be health risks associated with the usage of these items. It therefore becomes reasonable to argue to reduce PAH contents in consumer products to a level as low as possible. This study presents data on the migration of PAHs from consumer products into aqueous sweat simulant or aqueous ethanol and on its combined migration and penetration into human skin. Product specimens were either submerged in simulant, or placed directly on test skins in Franz cell chambers to simulate dermal contacts. Migration of hexacyclic dibenzopyrenes became detectable by using ethanolic simulant, but not in aqueous sweat simulant. Similarly, migration of the pentacyclic model carcinogen benzo[a]pyrene (B[a]P) into aqueous sweat simulant was significantly lower when compared with human skin or skin models. The results point to a gross underestimation (about two orders of magnitude) when using aqueous sweat simulant instead of human skin for assessing PAH migration. On the other side, the usage of 20% ethanol as simulant revealed good agreement to the actual exposure of human skin against B[a]P migrating out of contaminated products. Our results underline that aqueous sweat simulant is not suitable to study dermal migration of highly lipophilic compounds.

KEYWORDS:

• Benzo[a]pyrene
• dermal exposure
• dibenzopyrenes
• Franz cell
• migration
• skin models

Acknowledgments

The authors would like to thank Barbara Gerding and Karsten Schön for excellent technical assistance and Dr. Christian Witzel for providing human skin from plastic surgery.

Funding

This study was financially supported by internal funding of the German Federal Institute for Risk Assessment (BfR), grants No. 1322-343, 1322-514 and 72-003.