Dermal exposure to methamphetamine hydrochloride contaminated residential surfaces II. Skin surface contact and dermal transfer relationship

This in vitro investigation evaluated [C-14] - d-methamphetamine hydrochloride ([C-14]-meth HCl) transfer from contaminated vinyl tile (non-porous and smooth) and upholstery fabric (rough and loose) to human skin. C-14-Meth HCl transfer rate from vinyl to skin was rapid; a contact duration as brief as 15 s resulted in measurable radioactivity in the skin and receptor fluid samples. In contrast, the transfer from fabric occurred more slowly: the amount of [C-14]-meth HCl that was transferred from dry fabric after 2-h skin contact was one-fifth the amount transferred from vinyl after 5-min contact time. With moistened fabric, the transfer efficiency to skin after 2-h contact was seven times greater than that of dry fabric. While the duration of surface-skin contact appeared to affect the total dermal absorption of [C-14]-meth HCl, it had little effect on the time point of maximum transdermal absorption. [C-14]-meth HCl retained in skin continued to be absorbed after the contaminated material was removed. Mass balance in these studies was approximately 96%. In conclusion, [C-14]-meth HCl penetrates into/through human skin quickly following skin contact with contaminated materials. The porosity of the contact surface and the moisture content appears to alter the degree of transfer and dermal penetration. (C) 2014 Published by Elsevier Ltd.