Synthesis and stability of the [ 45 Ti]Ti-DOTA complex: en route towards aza-macrocyclic 45 Ti-based radiopharmaceuticals.

We report the use of DOTA as a chelator for titanium. The resulting complex is fully characterised and in vitro stability studies reveal its high kinetic inertness against transmetallation and transchelation. The radiolabeling of DOTA with 45 Ti, via a guaiacol-based liquid-liquid extraction method, leads to a high radiochemical conversion up to 98%.