Dermal uptake of nicotine from air and clothing: Experimental verification

The current study aims to elucidate in greater detail the dermal uptake of nicotine from air or from nicotine-exposed clothes, which was demonstrated recently in a preliminary study. Six non-smoking participants were exposed to gaseous nicotine (between 236 and 304 μg/m3) over 5 h while breathing clean air through a hood. Four of the participants wore only shorts and two wore a set of clean clothes. One week later, two of the bare-skinned participants were again exposed in the chamber, but they showered immediately after exposure instead of the following morning. The two participants who wore clean clothes on week one, were now exposed wearing a set of clothes that had been exposed to nicotine. All urine was collected for 84 h after exposure and analysed for nicotine and its metabolites cotinine and 3OH-cotinine. All participants except those wearing fresh clothes excreted substantial amounts of biomarkers, comparable to levels expected from inhalation intake. Uptake for one participant wearing exposed clothes exceeded estimated intake via inhalation by >50%. Excretion continued during the entire urine collection period, indicating that nicotine accumulates in the skin and is released over several days. Absorbed nicotine was significantly lower after showering in one subject, but not the other. Differences in the normalized uptakes and in the excretion patterns were observed among the participants. The observed cotinine half-lives suggest that non-smokers exposed to airborne nicotine may receive a substantial fraction through the dermal pathway. Washing skin and clothes exposed to nicotine may meaningfully decrease exposure. This article is protected by copyright. All rights reserved.