Role of the thiazolyl sulphur of ambilhar as an electron donor in metal chelation.

Administration of ambilhar or its N-acetyl derivative to rabbits resulted in a significant increase in urinary iron excretion, due to chelation. Substitution of the sulphur of thiazole by nitrogen abolished its metal chelating power. In vitro three different iron chelates were obtained, containing one or two iron atoms per mole of drug. However, in vivo studies revealed the presence of an ambilhar iron complex in which 6 molecules of the drug were chelated with one iron atom. Reduction is an important factor in the process of metal chelation by the thiazole sulphur of the drug.