Interaction between 1,2-dimethyl-3-hydroxypyrid-4-one and europium(III)

The interaction of the clinically used 1,2-dimethyl-3-hydroxypyrid-4-one with trivalent europium Eu(III), was investigated by using potentiometric and spectroscopic methods. The stability constants of the EuLn(3-n)+ complexes determined by spectroscopic and potentiometric measurements were found to be log beta(11) = 6.5 +/- 0.3 and log beta(12) = 12.0 +/- 0.5. However, at pH >= N 5, hydrolysis of the Eu-L complexes starts, resulting in the formation of needle-type, yellow crystals. The low solubility of the Eu-L complexes in the neutral pH range is disadvantageous with respect to the use of deferiprone as chelating agent for decorporation of trivalent f-elements.