Whole-body distribution of americium in rats for different pathways of intake

Purpose : To compare data on the whole-body distribution of americium-241 (Am-241) in rats following intravenous injection (IV), inhalation, and wound (intramuscular injection, IM). Material and methods : Following exposure, each rat was placed in an individual metabolism cages for the duration of the study, 28 days (d). Urine and feces were collected daily. Tissues and organs were collected and measured. Results : Liver and skeleton were the main sites of deposition for all routes of exposure but the content differed substantially. By 28 d, 2 41 Am content in liver was similar for IV and IM administrations (12 +/- 4% and 14 +/- 5%, respectively), which was 3-fold higher compared to inhalation. Americium-241 content in skeleton was 27% by the end of the IV study; which was 50% higher compared to the IM study and 6-fold higher compared to inhalation. The cumulative excretion in 28 d was 54% for IV (44% by feces and 10% by urine); 38% for IM (34% by feces and 4% by urine); and 84% for inhalation (83% by feces and 1% by urine). Conclusion : Unperturbed rat models for the three routes of administration are the baseline for evaluating the efficacy of chelating agents.