Positron emission tomography (PET) is an important molecular imaging modality. To develop new bifunctional chelators for use in more sensitive... Show morePositron emission tomography (PET) is an important molecular imaging modality. To develop new bifunctional chelators for use in more sensitive PET imaging, 64Cu-radiolabeled chelators have been investigated as promising PET agents. We synthesized and evaluated a macrocyclic chelator (NOTA)-based new bifunctional ligands with different coordination groups. New bifunctional chelators were evaluated for their radiolabeling efficiency with 64Cu, and in vitro complex stability of 64Cu-labeled chelators in human serum was also studied. 64Cu-labeled chelators was further evaluated for in vitro complex stability by EDTA challenge as a rigorous test of transchelation. As a result, chelator D, E, 3p-C-NE3TA, and 3p-C-NOTA were indicated as best chelators and have a promise for 64Cu-based PET imaging. Radioimmunotherapy (RIT) is a highly selective modality of cancer treatment and uses a radiolabeled chelator conjugated with monoclonal antibody. Our continued research of developing new RIT agents radiolabeled with 177Lu, different types of a macrocyclic based bifunctional chelators (DOTA, NOTA and NE3TA)- with variation of denticity, macrocyclic cavity, and bimodality were synthesized. Radiolabeling efficiency of chelators and in vitro complex stability of 177Lu-radiolabeled complex in human serum were evaluated. The effects of different pH and TLC solvents were investigated to confirm the best radiolabeling condition of new chelators with 177Lu. Furthermore, complex stability of 177Lu-radiolabeled chelators in a solution with excess EDTA and various metals was evaluated for transchelation. Therefore, the results of radiolabeling, serum stability and EDTA and metal challenge studies indicate that cavity size and ligand x denticity in chelators affected binding affinity to Lu(III) . 3p-C-DETA was identified as the best chelator for further research of RIT agent. M.S. in Chemistry, December 2013 Show less
