[en] The nuclear properties and commonly labelling methods of fluorine-18 are described. The synthesis, application and potential promise of many fluorine-18 labelling of amino acids are discussed in detail

[en] It is of great importance to study the preparation of radiopharmaceuticals for brain receptor imaging with PET, among which Fluorine-18 was used as the radionuclide in many of these radiopharmaceuticals. The author reviews the common methods for preparing Fluorine-18 labelled radiopharmaceuticals for brain receptor imaging, with particular emphasis on nucleophilic routes. Some progresses on the preparations of the radiopharmaceuticals classified according to the corresponding receptors were also discussed

[en] The selecting criteria of amino acid suitable for evaluation of brain tumors is introduced. Three methods for ¹⁸F labelling amino acids, namely Balz-Schiemann reaction, electrophilic fluorination and nucleophilic fluorination, are compared. The results show that nucleophilic substitution is the best method for ¹⁸F labelling amino acid

[en] Organostannanes were important precursors which was easy to radioiodinate. N-Succinimidyl-3-(tri-n-butylstannyl) benzoate (STB) was radiolabeled using Iodogen to get radioactive N-Succinimidyl-3-iodobenzoate (S¹²⁵IB) with 96% of high radiochemical yield. The optimization of labeling condition was explored in this study. S¹²⁵IB was stable at room temperature in dark. Cold SIB was prepared as a standard and IR and NMR results were given in this article. (authors)

[en] Objective: To seek for an effective way to acquire radiolabeled vasoactive intestinal peptide (VIP) with excellent in vivo stability. N-succinimidyl-3-iodo-125-benzoate (S¹²⁵IB) came from radioiodination of N-succinimidyl-3-(tri-n-butylstannyl) benzoate (ATE) precursor and then conjugated with VIP to form ¹²⁵IBA-VIP. The labelling procedure was optimized; the in vitro stability and biological activity were evaluated. Methods: 1) Radiolabeling of ATE precursor was achieved with iodogen oxidant and the influential factors were considered in this procedure. The labeling efficiency was determined by thin layer chromatography (TLC) and the purification was carried out by Sep-pak silica gel cartridge. The stability was detected by TLC after 2 h storage in dark at 4 degree C. 2) Conjugation of S¹²⁵ IB and VIP. The labelling efficiency was determined with RP TLC and the purification was carried out with high performance liquid chromatography (HPLC, RP C18 column). Trichloroacetic acid (TCA) precipitation method was applied to evaluate the in vitro stability while the biological activity was determined by cell binding experiments with SGC7901 cell lines. Results: 1) S¹²⁵IB experiments. The radioiodination of ATE was performed well for 5 min at 25 degree C with 10 micrograms of iodogen at suitable mole ratio (3-8:1) of ATE/Na ¹²⁵I, the labelling efficiency was about 96%. The stability was kept well at 4 degree C in dark, no significant decrease of S¹²⁵IB was observed. 2) The conjugation efficiency of S¹²⁵IB and VIP was above 75% with TLC. HPLC showed the different retention time (t_R) as follows, ¹²⁵IBA-VIP: 13.3 min, S¹²⁵IB: 19.6 min, VIP: 8.32 min. The stability of ¹²⁵IBA-VIP was better than ¹²⁵I-VIP from direct radioiodination of VIP with iodogen oxidant, only 2.85% decrease was found after 7 d at 4 degree C. The biological activity of ¹²⁵IBA-VIP was kept as well as ¹²⁵I-VIP under the condition of 37 degree C 60 min. Conclusions: The indirect radiolabelling procedure with ATE was an excellent and efficient way of radiohalogenation of VIP and even for other proteins and peptides. The labelling efficiency was high and the purification was easy to operate. The most important is the excellent in vitro stability plus biological activity of ¹²⁵IBA-VIP, which makes the clinical application practicable

[en] Polyazamacrocyclic compounds, a group of effective bifunctional chelating agents, have been applied in radio-metals labeling peptides, protein and monoclonal antibodies. Those biomolecules with labeled ratio-metals are hopeful of becoming radiopharmaceuticals for radiodiagnosis and radiotherapy. Recent progress in the application of polyazamacrocyclic compounds in radio-metals labeling is summarized. This paper introduces polyazamacrocyclic compounds and, radionuclides used in the radio-metals labeling, and biological characters of the labeled conjugates. Both advantages and disadvantages of polyazamacrocyclic compounds in the labeling with different radionuclides are discussed. (authors)

[en] ¹⁸⁸Re labeled monoclonal antibodies are potential candidates for use in radioimmunotherapy. S-Bz-MAG₃ as a bifunctional chelating agent was used for labeling of IgG with carrier free ¹⁸⁸Re by pre-radiolabeling of the chelating approach. The conjugation conditions were optimized. The stability of ¹⁸⁸Re-MAG₃-IgG in vitro was high. The results may be useful to the studies of ¹⁸⁸Re labeled MAbs for radioimmunotherapy

[en] The biological behaviors of the labeling conjugates with MAG₃ were summarized. The ⁹⁹Tc^m labeling conjugates by using MAG₃ show high labeling efficiencies and high specific activities and hold desirable stability in vitro and in vivo. The binding of the labeling conjugates with plasma protein is low; the ^186/188Re labeling compounds, using MAG₃ as BFCA, also hold desirable stability in vitro and in vivo. So many potentially useful biomolecules labeled by ⁹⁹Tc^m, ^186/188Re for diagnosis and therapy may be produced via MAG₃. (authors)

[en] S-benzoyl mercaptoacetyltriglycine (S-Bz-MAG₃) was synthesized and labeled with carrier-free ¹⁸⁸Re. The overall yield of S-Bz-MAG₃ is higher than those published in the literature. Dependence of the labeling yield of ¹⁸⁸Re-MAG₃ upon concentration of reducing agent, pH, reaction time, and other parameters was examined and optimum conditions were obtained. The labeling yield of ¹⁸⁸Re-MAG₃ was more than 98%. The concentration procedure was succeeded with Sep-Pak C18 column to obtain highly concentrated ¹⁸⁸Re-MAG₃. The experimental conditions of labeling of IgG with carrier free ¹⁸⁸Re via S-Bz-MAG₃ as a bifunctional chelating agent (BFCA) by pre-radiolabeling of the chelate was studied. The conjugation conditions were optimized. The stability of ¹⁸⁸Re-MAG₃-IgG in vitro was high. The results of this study may be useful for ¹⁸⁸Re labeling of MAbs for radioimmunotherapy. (author)

[en] Synthesis of the carrier free ¹⁸⁸Re-norfloxacin was investigated using ¹⁸⁸Re eluted from a ¹⁸⁸W/¹⁸⁸Re generator. Stannous chloride was used as the reducing agent for the reduction of the carrier free ¹⁸⁸Re. Influences of concentration of reducing agent, pH, temperature and reaction time on the labelling yield of ¹⁸⁸Re-norfloxacin were examined and the optimum conditions were obtained. Under the optimum conditions, the labelling yield of ¹⁸⁸Re-norfloxacin was more than 92%. The stability of ¹⁸⁸Re-norfloxacin at pH4 was studied. Radiochemical purity of ¹⁸⁸Re-norfloxacin was nearly constant in 24 hours