Diethyldithiocarbamate in treatment of acute cadmium poisoning

An insoluble complex was synthesized by the reaction of sodium diethyldithiocarbamate trihydrate (DDTC) with CdCl2 X 2.5 H2O (Cd). Elemental analyses of the product yielded a percent composition of each element which was consistent with the postulated structure of two mole equivalents of (DDTC)- and one mole equivalent of Cd++. The DDTC formed a complex with 11 other metal ions tested, but not with Ca++ or Mg++. The complex with Cd was highly insoluble in water, 0.1 N HCl, 0.1 N NaOH, human serum, and carbon tetrachloride, but it was soluble in pure dimethyl sulfoxide. The DDTC protected mice from a greater than LD100 dose of Cd. This protective effect was more pronounced when DDTC treatment was delayed at least 30 min after i.p. administration of Cd. More than 98 percent of mice treated with 500 mg per kg of DDTC 30 min to five hrs after Cd administration survived, and 50 percent survived when treatment wad delayed for eight hrs. Administration of DDTC prior to or immediately after Cd gave less protection. The lowest (DDTC)-/Cd++ molar dose ratio which resulted in 100 percent survival following the otherwise lethal dose of Cd was 7.6, which was less than four times the theoretical stoichiometric molar ratio for formation of the complex. The LD50 of the complex in mice wa approximately 650 mg per kg of the i.p. route, indicative of a low degree of dissociation in vivo.