Migration of polycyclic aromatic hydrocarbons from a polymer surrogate through the stratum corneum layer of the skin

Konstantin Simon; Lidia Schneider; Gila Oberender; Ralph Pirow; Christoph Hutzler; Andreas Luch; Alexander Roloff

doi:10.1016/j.ecoenv.2023.115113

Migration of polycyclic aromatic hydrocarbons from a polymer surrogate through the stratum corneum layer of the skin

Ecotoxicol Environ Saf. 2023 Jun 12:262:115113. doi: 10.1016/j.ecoenv.2023.115113. Online ahead of print.

Authors

Konstantin Simon¹, Lidia Schneider², Gila Oberender³, Ralph Pirow², Christoph Hutzler², Andreas Luch⁴, Alexander Roloff⁵

Affiliations

¹ German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2-4, 14195 Berlin, Germany. Electronic address: Konstantin.Simon@bfr.bund.de.
² German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany.
³ German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; Berliner Hochschule für Technik (BHT), Luxemburger Str. 10, 13353 Berlin, Germany.
⁴ German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2-4, 14195 Berlin, Germany.
⁵ German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany. Electronic address: Alexander.Roloff@bfr.bund.de.

PMID: 37315362
DOI: 10.1016/j.ecoenv.2023.115113

Abstract

In this study, we determined partition (K_sc/m) and diffusion (D_sc) coefficients of five different polycyclic aromatic hydrocarbons (PAH) migrating from squalane into and through the stratum corneum (s.c.) layer of the skin. Carcinogenic PAH have previously been detected in numerous polymer-based consumer products, especially those dyed with carbon black. Upon dermal contact with these products, PAH may penetrate into and through the viable layers of the skin by passing the s.c. and thus may become bioavailable. Squalane, a frequent ingredient in cosmetics, has also been used as a polymer surrogate matrix in previous studies. K_sc/m and D_sc are relevant parameters for risk assessment because they allow estimating the potential of a substance to become bioavailable upon dermal exposure. We developed an analytical method involving incubation of pigskin with naphthalene, anthracene, pyrene, benzo[a]pyrene and dibenzo[a,h]pyrene in Franz diffusion cell assays under quasi-infinite dose conditions. PAH were subsequently quantified within individual s.c. layers by gas chromatography coupled to tandem mass spectrometry. The resulting PAH depth profiles in the s.c. were fitted to a solution of Fick's second law of diffusion, yielding K_sc/m and D_sc. The decadic logarithm logK_sc/m ranged from -0.43 to +0.69 and showed a trend to higher values for PAH with higher molecular masses. D_sc, on the other hand, was similar for the four higher molecular mass PAH but about 4.6-fold lower than for naphthalene. Moreover, our data suggests that the s.c./viable epidermis boundary layer represents the most relevant barrier for the skin penetration of higher molecular mass PAH. Finally, we empirically derived a mathematical description of the concentration depth profiles that better fits our data. We correlated the resulting parameters to substance specific constants such as the logarithmic octanol-water partition coefficient logP, K_sc/m and the removal rate at the s.c./viable epidermis boundary layer.

Keywords: diffusion; partition; polycyclic aromatic hydrocabons (PAH); skin migration; stratum corneum.