[en] A procedure has been devised to test in vitro the relative effectiveness of chelating agents for the elimination of radiotoxins from specified, in vivo labeled endogenous ligands. The report describes the elimination of ²³⁹Pu from liver homogenates by various chelating agents. The effectivity of a homologous series of polyaminocarboxylic acids (PACA's) was compared to that of certain derivatives containing a straight alkyl group. The effectiveness of these lipophilic PACA's appears to depend on the chain length of the substituent. Lipophilic chelons were more effective in chelating ²³⁹Pu than unsubstituted PACA's. Combination of EDTA or DTPA with a number of oligodentate complexing agents were also tested. With EDTA, the removal of Pu was enhanced by p-aminosalicylic acid (PAS), Desferioxamine B (DFOA) and strongly enhanced by 4,5-Dihydroxy-m-benzenedisulfonic acid (Tiron). Only DFOA showed enhanced removal with DTPA. The different behavior of the mixed ligand treatments can be explained by either formation of binary complexes or action on different biological Pu-pools

[en] A simple method was devised to separate ²²⁴Ra from a source of ²²⁸Th. The procedure involves coprecipitation of ²²⁸Th and Zirconium as the hypophosphate in HCl. ²²⁴Ra was soluble in the acidic medium and was separated from ²²⁸Th by 3 successive centrifugations at 40,000 xg. Initial yield was approximately 40 percent and the separation factor was 10⁵ or better

[en] Polyaminocarboxylic acids derived from diethylenetriamine and triethylenetetramine containing a lipophilic group have been synthesized. Compounds derived from triethylenetetramine were more effective in removing Pu in vitro from liver constituents labeled in vivo than those derived from diethylenetriamine. Alkylated acids showed a greater efficacy than their nonsubstituted counterparts. The greater efficacy was confirmed in a pilot experiment in rats with aged burdens of ²⁴¹Am. The relative effectiveness of a number of structurally related chelons as well as combinations of chelating agents for the removal of ²³⁹Pu and ²⁴¹Am from high molecular weight liver proteins has been reported earlier. The efficacy of a chelating agent for the decorporation of potentially harmful metal ions is dependent on three factors: the affinity of the chelon for the respective metal ion, the ability of the chelon to reach the site of metal deposition in vivo and the toxicity of the agent itself. Present experiments are directed towards the synthesis and testing of agents which have balanced hydrophilic and lipophilic properties