Preliminary toxicity studies on bis-[βn,n-dimorpholino) ethyl] selenide (mose) a new radioimaging agent

The present study describes the acute toxicity of MOSE, a proposed radioimaging agent for brain scintography. Acute intraperitoneal administration of MOSE in mice revealed an LD50 between 1.35 and 6.25 g/kg, with convulsions preceding death. Intravenous administration of MOSE in rats resulted in an LD50 between 400 and 800 mg/kg, with death also preceded by convulsions. The rabbit was more sensitive to the acute effects of MOSE than the rat. The LD50 for MOSE given i.v. in the rabbit was 80 mg/kg. The predominant toxic sign was convulsions, which immediately preceded death at high doses. At intermediate doses convulsions were elicited, followed by a period of lethargy which gave way to hyperactivity on the following day. Normal appearances were restored within a week. Hematology and blood chemistries were similar to controls, except for increased serum LDH in animals receiving MOSE when sampled two weeks after dosing. Repeated administration of MOSE by the intravenous route in rabbits at a dose rate of 1 mg/kg/da, five days per week for two weeks, resulted in no signs of toxicity. Hematology, clinical chemistry, and histology revealed no changes in animals receiving MOSE when compared to control. It was concluded that barring any unusual susceptibility in man, the proposed diagnostic dose to man is unlikely to precipitate any acute toxic effects.