In vitro model for decontamination of human skin: Formaldehyde

Decontamination of a chemical from skin is often an emergency measure. This study utilized an in vitro model to compare the decontamination capacity of three model decontaminant solutions (tap water, isotonic saline, and hypertonic saline). Human cadaver skin was dosed (approximately 0.25 μg on 3 cm2 per skin) with radio-labeled [14C]-formaldehyde. After a defined exposure time (1, 3, and 30 min post-dosing, respectively), the surface skin was washed three times (4 ml per time) with each solution. After washing, the skin was stripped with tape discs twice. Lastly, the wash solutions, strippings, receptor fluid, and remainder of skin were liquid scintillation analyzer counted to determine the amounts of formaldehyde. Additionally, an evaporation test at different exposure times (1 min, 3 min, 15 min, 30 min, and 60 min, respectively) was conducted to monitor formaldehyde % evaporation. There were no statistical differences among these groups except isotonic saline, at 3 min post-exposure (in wash solutions), showed a significantly difference (p < 0.05) when compared to tap water. Formaldehyde % evaporation increased linearly with extending application times, and were 7.7%, 13.6%, 19.7%, 24.4%, and 35.9% (1 min, 3 min, 15 min, 30 min, and 60 min, respectively). This data suggests that isotonic saline may be effective in removing formaldehyde from skin. However, results from this model need validation in vivo. The model may provide a facile and robust method of accelerating knowledge of decontamination mechanism and lead to enhanced efficacy.