Hygiena 2018, 63(3):76-83 | DOI: 10.21101/hygiena.a1700

Trans-epidermal absorption of polycyclic aromatic hydrocarbons

Andrea Málková¹, Lenka Kotingová¹, Roman Kanďár², Martina Špryncová², Lenka Andrlová², Aleš Bezrouk³, Lenka Borská⁴, Renata Kohlerová⁵, Zdeněk Fiala¹

¹ Univerzita Karlova, Lékařská fakulta v Hradci Králové, Ústav hygieny a preventivního lékařství, Hradec Králové, Česká republika

² Univerzita Pardubice, Fakulta chemicko-technologická, Katedra biologických a biochemických věd, Pardubice, Česká republika

³ Univerzita Karlova, Lékařská fakulta v Hradci Králové, Ústav lékařské biofyziky, Hradec Králové, Česká republika

⁴ Univerzita Karlova, Lékařská fakulta v Hradci Králové, Ústav patologické fyziologie, Hradec Králové, Česká republika

⁵ Univerzita Karlova, Lékařská fakulta v Hradci Králové, Ústav lékařské biochemie, Hradec Králové, Česká republika

Polycyclic aromatic hydrocarbons (PAHs) are a group of significant contaminants in the occupational and living environment. In addition to the inhalation route of exposure in the occupational environment, there is also significant the dermal route of exposure. Existing experimental data on the intensity and rate of penetration of these substances into systemic circulation are still limited. The presented paper is focused on methodological and interpretative issues of trans-epidermal absorption of PAHs in vitro. In this study, we assessed the intensity (Flux) and rate (Lag time) of penetration of naphthalene, phenanthrene, pyrene and benzo[a]pyrene through the epidermal membrane derived from a pig ear. The experiment was performed using static vertical Franz diffusion cells (n = 32) and isopropyl myristate was used as a solvent. Flux (nmol/cm²/hour) reached 95.7 ± 45.5 in the case of naphthalene, 19.5 ± 8.7 of phenanthrene, 4.38 ± 1.98 of pyrene and 0.21 ± 0.08 of benzo[a]pyrene. Lag time (hour) was 0.26 ± 0.17 in the case of naphthalene, 2.12 ± 0.41 of phenanthrene, 3.25 ± 0.50 of pyrene and 11.2 ± 4.08 of benzo[a]pyrene. The Flux value decreased with the molecular weight of PAHs, while the Lag time increased with the molecular weight of PAHs. The amount of PAHs that penetrated through the epidermal membrane in a given time period ranged between 0.24% (benzo[a]pyrene) and 0.84% (phenanthrene) of the applied dose. The penetration of PAHs through the epidermal membrane showed a lower degree of data variability compared to full thickness skin experiments. The results suggest that the use of the epidermal membrane could define more accurately both the estimation of the internal dose of PAHs after dermal exposure and the estimation of the associated health risk within a conservative exposure scenario. However, experiments with using the epidermal membrane are time consuming and experimentally demanding, with no option of an objective control of the integrity of the epidermal membrane, which can lead to costly testing, loss of samples and, finally, an increase in the differences in data values obtained in different laboratories.

Keywords: polycyclic aromatic hydrocarbons (PAH) - dermal absorption, epidermal membrane, experiments

Published: September 30, 2018  Show citation