Toxicokinetics of Sulfur Mustard and its Dna-Adducts in the Hairless Guinea Pig

In order to provide a quantitative basis for pretreatment and therapy of intoxications with sulfur mustard (SM) the toxicokinetics of this agent as well as its major DNA-adduct were studied in male hairless guinea pigs for the intravenous, respiratory and percutaneous routes. the study comprised measurement of the concentration-time course of SM in blood and measurement of the concentrations of intact SM and its adduct to guanine in various tissues at several time points after administration of, or exposure to SM. SM was analyzed in blood and tissues by gas chromatography with automated thermodesorption injection and mass-spectrometric detection. DNA-adducts were measured via an immuno-slot-blot method. In contrast with nerve agents of the phosphofluoridate type, SM partitions strongly to various organs, especially the lung, spleen, liver and bone marrow. the respiratory toxicity of SM appears to be local, rather than systemic. Surprisingly, the maximum concentration of SM in blood upon percutaneous exposure to 1 LCt50 (10,000 mg.min.m 3, estimated) is approximately 6-fold higher than that for nose-only exposure to 3 LCt50 (2,400 mg.min.m−3). Pretreatment of hairless guinea pigs with the potential scavengers N-acetyl cysteine or cysteine isopropyl ester did not significantly increase the LCt50-value for nose-only exposure to SM vapor.