Evaluation of iron-chelating agents in an in vivo system: potential usefulness of EHPG, a powerful iron-chelating drug.

Fifteen compounds with a high affinity to ferric iron have been screened for in vivo iron-chelating efficiency in a rat model. One of the most potent of these drugs was ethylenediamine-N,N'-bis(o-hydroxyphenylglycine) (EHPG). EHPG-induced iron excretion was up to 8 times higher than iron excretion induced by identical doses of desferrioxamine (DF). Studies employing selective radio-iron probes of reticuloendothelial and parenchymal iron stores showed that although EHPG is able to interact with both storage iron compartments, its effect on parenchymal iron is much more pronounced. Unlike DF which has two alternative routes of excretion, EHPG-induced iron excretion is restricted mainly to the gut. Although EHPG seems to be superior to DF in both its chelating efficiency and preferential interaction with hepatic parenchymal iron stores, information on its in vivo toxicity is at present insufficient and it cannot yet be recommended for clinical use.