Acute systemic toxicity of pure dimercaprol and trimercaptopropane.

Dimercaprol, free of 1,2,3-trimercaptopropane (TMP), TMP, and mixtures of these two compounds were injected intramuscularly and intraperitoneally into fasted rats and mice, respectively. The LD50 values for dimercaprol and TMP in rats were 87 and 19 mg/kg. The corresponding LD50 values in mice were 90 and 20 mg/kg. The potency ratio of TMP as compared to dimercaprol was 4.5 in both animal groups. Mixtures of pure dimercaprol and TMP, prepared to give 0, 2.5, 5, 10 and 20% TMP, relative to the total amount of dimercaprol and TMP, were injected intramuscularly into rats. A potency ratio of 4.5 was again found. These results indicated that the TMP in dimercaprol did not cause synergistic toxicity. Animal reaction showed that the injection of TMP was much more painful and produced more severe convulsions than injections of dimercaprol.