In vitro and in vivo comparative studies on chelation of aluminum by some polyaminocarboxylic acids

Since desferrioxamine exhibits toxic effects, the possible use of several other therapeutic agents in acute aluminum intoxication has been investigated in this study. The potential for the chelation of aluminum (Al) by different compounds has been first determined using two in vitro techniques. The formation of stable complexes with Al in an aqueous solution has been evaluated by using pulse polarography. This technique allows the influence of temperature and of calcium (Ca) to be studied for each compound. Certain compounds (HEDTA, DTPA) showed extensive chelation in the presence of Ca2+ at a temperature of 37 +/- 1 degree C. An ultrafiltration technique combined with Al determination by atomic emission spectroscopy (A.E.S.) has allowed the ability of different substances to complex Al that was previously bound to serum proteins, to be estimated. The kinetics of chelation and the minimum efficient concentration have been determined for all of the products studied. The real efficacies of the compounds were studied by in vivo investigations to compare the effectiveness of the best chelating agents (DFO, HEDTA and EDTA) on the distribution and excretion of Al, after repeated i.p. administration to rats. HEDTA shows a chelation potential as widely active as the DFO potential.