Gallium(III) chelates of mixed phosphonate-carboxylate triazamacrocyclic ligands relevant to nuclear medicine: Structural, stability and in vivo studies

The first protonation constant higher than 14 of triaza macrocyclic ligands with mixed methylene phosphonate/carboxylate pendant arms and the very high thermodynamic stability constant of the Ga3 + chelate of one of them were determined by potentiometry and 69Ga/31P NMR. The 67Ga-labeled chelates animal renal excretion is delayed by negative charge.81