Evaluation of barrier creams against sulphur mustard. I. In vitro studies using human skin

The purpose of this study was to assess the effectiveness of a range of passive and reactive barrier cream formulations against the chemical warfare agent sulphur mustard (SM) using an in vitro diffusion cell system containing human skin. In general, proprietary formulations were relatively effective under occluded conditions, but ineffective under unoccluded conditions. For example, SM skin absorption rates through occluded control and Stokoderm pre-treated skin were 538 +/- 193 and 200 +/- 51 microg x cm(-2) x h(-1), respectively (p < 0.05). Under unoccluded conditions, control and Stokoderm pre-treated skin absorption rates were 4.41 +/- 1.90 and 36.84 +/- 15.19 microg x cm(-2) x h(-1) (p < 0.05). Novel (perfluorinated) barrier creams were generally more effective under unoccluded conditions; pre-treatment with one formulation led to an 18-fold reduction in skin absorption rate and reduced the total amount of SM penetrated by 95% of the applied dose. Several proprietary formulations also had adverse effects on the effectiveness of the skin decontaminant fuller's earth. The rate (Jss) and total amount (percentage of dose) of SM absorbed through the skin were deemed to be independent parameters of barrier cream performance. These data indicate that (1) perceived conditions of use, (2) compatibility with existing protective equipment and (3) the rate and extent of SM skin absorption must all be taken into account when evaluating barrier creams in vitro.