In Vitro and In Vivo Behaviour of 111In Complexes of TTHA, TTHA-Bis(Butylamide) and TTHA-Bis(Glucamide): Stability, Biodistribution and Excretion Studied by Gamma Imaging

Aiming at radiopharmaceutical application, (111)In(3+) complexes of the polyaminocarboxylates TTHA, TTHA-bis(butylamide) and TTHA-bis(glucamide) were investigated. The in vitro stability of (111)In(TTHA)(3-) and (111)In(TTHA-bis(butylamide)(-) was evaluated by measuring the exchange of (111)In(3+) from the complexes to transferrin and the results were compared with those for (111)In(DTPA)(2-). We also performed biodistribution studies of the three (111)In(3+) complexes by gamma-imaging in Wistar rats and by measuring the radioactivity in their organs. TTHA and its derivatives seem to have similar in vivo biodistribution with prevailing renal excretion.