Computer-based approach to chelation therapy: a theoretical study of some chelating agents for the selective removal of toxic metal ions from plasma.

COMICS is a computer programme for calculating equilibrium concentrations of metal complexes and reactive species in multi-metal-multi-ligand systems. Its usefulness for analysing metal ion equilibria in blood plasma has been improved by including albumin as a ligand. Using this model system the distribution and removal of copper(II) and zinc ions in histidinaemia, lead poisoning and Wilson's disease have been examined. The efficacy of TRIEN in removing excess copper(II) is shown. The use of specific tripeptides such as Gly-Gly-His methyl ester for the selective removal of copper(II) is suggested. A possible chemoprophylaxis of influenza based on complexation of zinc is discussed. Calculations confirm that thiosemicarbazones such as methisazone and 2-acetylpyridine thiosemicarbazone are effective competitors for heavy metal ions under physiological conditions.