Preparation of Rh-105 labeled monoclonal antibody (MAb B72.3) using aminobenzylpropyleneamineoxime as the bifunctional chelating agent; Comparison toI-131 labeled MAb B72.3

Monoclonal antibody(MAb) B72.3 was labeled with Rh-105 using aminobenzylpro pyleneamineoxime (PnAO-phi-NH2) as the bifunctional chelating agent. Rh-105 -PnAO-phi-NH2 was formed at similar to 80 degrees C at pH 5-6 and purified by extraction into chloroform. The excess unreacted ligand was retained in the aqueous phase by addition of Cu2+ ions by forming a charged complex. Th e amine group on Rh-105 complex was activated and conjugated with MAb at pH 8.5. similar to 90% complexation and 40-60% conjugation were realised. Rad iolabeled antibody was purified by gel filtration. B72.3 MAb was labeled wi th I-131 and used for comparison of biodistribution in normal mice.