In the past few years, gallium-68 has demonstrated significant potential as a radioisotope for positron emission tomography (PET), and the optimization of chelators for gallium coordination is a major goal in the development of radiopharmaceuticals. Methylaminotriazacyclononane trimethylphosphinate (MA-NOTMP), a new C-functionalized triazacyclononane derivative with phosphinate pendant arms, presents excellent coordination properties for (68) Ga (low ligand concentration, labelling at low pH even at room temperature). A "ready-to-be-grafted" bifunctional chelating agent (p-NCS-Bz-MA-NOTMP) was prepared to allow (68) Ga labelling of sensitive biological vectors. Conjugation to a bombesin(7-14) derivative was performed, and preliminary in vitro experiments demonstrated the potential of MA-NOTMP in the development of radiopharmaceuticals. This new chelator is therefore of major interest for labelling sensitive biomolecules, and further in vivo experiments will soon be performed.
Keywords: bombesin; gallium; phosphinates; radiolabelling; triazacyclononane.
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