A Medical Research and Evaluation Facility and Studies Supporting the Medical Chemical Defense Program. Task 92-29: Efficacy Assessment of Topical Skin Protectants against Sulfur Mustard Vapors in Hairless Guinea Pigs

The objective of this work was to determine the dose-response relationship between the duration of a topical exposure of sulfur mustard vapors to hairless guinea pigs (HGPs) and the incidence of microblisters observed histologically. The dose-response curve was compared to results of similar work performed at the U.S. Army Medical Research Institute of Chemical Defense (USAMRICD). The effects of ketamine hydrochloride anesthesia on HGP skin reflectance were also examined. The exposure time needed to produce a 50 percent incidence of microblisters in HGP skin exposed to saturated HD vapors was approximately 7.5 min. Comparison with USAMRICD study results indicated that the HGPs used in the present study were more tolerant of HD vapors by approximately 2 min. However, the probit analysis slopes exhibited the same rate of increase in microblisters as a function of HD vapor exposure time. The model was thus validated for use in screening prophylactic and therapeutic treatments against mustard injury. Ketamine hydrochloride anesthesia significantly reduced the baseline (pre-dose) level of red chromaticity on HGP skin test sites.