title: 99mTc(I) scorpionate complexes for brain imaging: synthesis, characterization and biological evaluation.
abstract: The new dihydrobis(azolyl)borate ligand Na[H2B(tim(Me))(3,5-Me2pz)] (L1) was synthesized and used to prepare the complexes fac-[M(κ(3)-H(μ-H)B(tim(Me))(3,5-Me2-pz))(CO)3] (M = Re (4), 99mTc (4a)). L1 and 4 were characterized by common analytical techniques, including X-ray diffraction analysis for 4. The successful synthesis of complex 4a, obtained with high radiochemical purity, has shown for the first time that dihydrobis(azolyl)borate ligands combining 2- mercaptoimidazolyl and pyrazolyl rings are capable of stabilizing the fac-[99mTc(CO)3]+ unit. Complex 4a displays a high in vitro stability, in PBS (pH 7.4), indicating that the B-H...99mTc bond is retained even under physiological conditions. Biodistribution studies in mice have shown that 4a can cross the blood-brain barrier, emerging as a good alternative for the design of radiopharmaceuticals for brain imaging.
authors.affiliation: Unidade de Ciências Químicas e Radiofarmacêuticas, Instituto Tecnológico e Nuclear Estrada Nacional 10, 2686-953 Sacavém, Portugal.
authors.forename: Carolina
authors.initials: C
authors.lastname: Moura
authors.forename: Lurdes
authors.initials: L
authors.lastname: Gano
authors.forename: Isabel C
authors.initials: IC
authors.lastname: Santos
authors.forename: António
authors.initials: A
authors.lastname: Paulo
authors.forename: Isabel
authors.initials: I
authors.lastname: Santos
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism; D001921:Brain / Q000000981:diagnostic imaging*; D004355:Drug Stability; D005260:Female; D051379:Mice; D015609:Organotechnetium Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals