No abstract available

No abstract available

No abstract available

No abstract available

[en] New oxotechnetium complexes of general formula [^99mTc(O)(PNS)(S(CH₂)_nOSiR₃)] (4-6) were synthesized by direct reduction of [^99mTcO₄]^- with stannous chloride, in the presence of the tridentate heterofunctionalized phosphine H₂PNS and of the monodentate silylated thiols [HS(CH₂)_nOSiR₃] (n=2, R=Ph (1); n=3, R=Ph (2); n=3, R=Et (3)). The mixed-ligand rhenium and technetium complexes of general formula [M(O)(PNS)(S(CH₂)_nOH)] (n=2: M=^99mTc, (7), M=Re, (7a); n=3: M=^99mTc, (8), M=Re, (8a)) were also prepared. All the ^99mTc complexes were obtained with high radiochemical purity (>95%), after purification by HPLC, and were characterized by comparison of their HPLC profiles with the ones obtained for the corresponding Re compounds. The silylated compounds 4-6 are stable in phosphate saline buffer (PBS) pH 7.4, rat plasma, human serum and whole blood, and do not bind to plasmatic proteins, and also do not challenge with glutathione. The biological behavior of [^99mTc(O)(PNS)(S(CH₂)_nOH)] (7, 8) and [^99mTc(O)(PNS)(S(CH₂)_nOSiR₃)] (4-6) was studied. The effect of the pH on the cleavage of the O-Si bond in complexes 4-6 was also evaluated

No abstract available

[en] Reduction of perrhenate with stannous chloride at an excess of sodium gluconate in aqueous solution results in formation of rhenium(V) gluconate. The reaction proceeds slowly compared to that of pertechnetate. Aqueous solutions of rhenium(V) gluconate can be prepared down to a concentration level of at least 10 4 mol·^-1 within two hours. The usefulness of rhenium(V) gluconate to serve as a precursor for preparation of oxorhenium(V) complexes as potential radio therapeutic agents is revealed by subsequent ligand exchange reactions carried out with mercaptoacetyldiglycine, 3-thiapentane-dithiol-1,5/butanethiol and with 2-aminobenzenethiol. 5 figs., 14 refs

[en] The coupling of Re- and ^99mTc-MAG₃ complexes with amines and nucleobases was carried out with good yields using O-(benzotriazol-1-yl-)-N,N,N',N'-tetramethyl-uronium-tetrafluoroborate (TBTU), and base in polar aprotic solvents (NMP, DMF, DMSO). The one step reaction followed by simple gel chromatography makes the method well appropriate for preparations at the low no-carrier-added level of technetium-99m. (author)

[en] The formation of β-amyloid deposits is considered a histopathological feature of Alzheimer′s disease (AD). In vivo molecular imaging by means of amyloid-avid radiotracers will allow for an early and conclusive diagnostic of AD. Herein, we describe the radiosynthesis of the radiofluorinated styryl benzoxazole derivative [¹⁸F]-[2-[N-methyl-N-(2′-fluoroethyl)-4′-aminostyryl]benzoxazole] ([¹⁸F]-1) and its pre-clinical evaluation, including metabolic and biodistribution studies in male Wistar rats. The in vivo biological evaluation of [¹⁸F]-1 showed that this new radiotracer has a moderate brain uptake with a slow brain washout and a poor in vivo stability. - Graphical abstract: A New ¹⁸F-Labeled Styryl Benzoxazole Derivative ([¹⁸F]-1) for β-Amyloid Targeting has been synthesized in good radiochemical yield and high radiochemical purity (>99%, both isomers. Biodistribution and metabolism studies of ¹⁸F]-1 in male Wistar rats have shown that this new radiotracer can cross the BBB but has a poor in vivo stability. - Highlights: • Design of a fluorinated styryl benzoxazole derivative for detection of β-amyloid plaques. • Nucleophilic radiofluorination with readily available [¹⁸F]KF. • Metabolism and biodistribution studies of the radiofluorinated styryl benzoxazole derivative