Equilibrium and Kinetic Properties of Gd(III)AAZTA Complex a Highly Efficient MRI Contrast Agent

Fulvio Uggeri¹, Alessandro Maiocchi¹, Silvio Aime², Erno Brucher³, Zsolt Baranyai³, Attila Benyei³

The heptadentate ligand AAZTA and its derivatives were recently reported to give stable complexes with Gd(III) with superior efficiency as MRI contrast agents. Nevertheless, only preliminary data are available on the coordination behaviour of this interesting ligand. In this work, thermodynamic and kinetic stability data are determined for the complex formation of AAZTA towards Gd(III) ions and other metal ion of interest for this application. The obtained data have shown that near physiological conditions Gd(AAZTA) is significantly more inert than Gd(DTPA)allowing its potentially safe use as contrast agent in MRI.