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In this article, we present the synthesis and characterization of new acyclic pyridine-containing polyaminocarboxylate ligands H4aPyta and H6aPyha, which differ in structural rigidity and the number of chelating groups. Their abilities to form complexes with Cu2+, Ga3+, Y3+, and Bi3+ cations, as well as the stability of the complexes, were evaluated by potentiometric titration method, radiolabeling with the corresponding radionuclides, in vitro studies, mass spectrometry, and HPLC. The structures of the resulting complexes were determined using NMR spectroscopy and DFT calculations. The results obtained made it possible to evaluate the influence of the structural features of the complexes on their stability. The developed chelators H4aPyta and H6aPyha were proved to be promising for further research in the field of radiopharmaceuticals. [ABSTRACT FROM AUTHOR]

A synthetic procedure for the synthesis of azacrown ethers with a combination of pendant arms has been developed and the synthesized ligand, characterized by various techniques, was studied. The prepared benzoazacrown ether with hybrid pendant arms and its complexes with copper and lead cations were studied in terms of biomedical applications. Similarly to a fully acetate analog, the new one binds both cations with close stability constants, despite the decrease in both constants. The calculated geometry of the complexes correlate with the data from X-ray absorption and NMR spectroscopy. Coordination of both cations differs due to the difference between the ionic radii. However, these chelation modes provide effective shielding of cations in both cases, that was shown by the stability of their complexes in the biologically relevant media towards transchelation and transmetallation. [ABSTRACT FROM AUTHOR]

In this work we presented a synthesis and investigation of relative acyclic and macrocyclic polyamines with picolinate pendant arms as potential chelators for copper radiopharmaceuticals. It has been shown that linear chelators lacking bisamide moiety are much more basic and form complexes with higher stability constants compared to macrocyclic ones. Both types of ligands possess many donor sites due to picolinate groups enabling formation of polynuclear complexes in the solution and solid state. According to crystal structures metal cations coordinates with studied ligands through the binding with aminogroups and picolinates donor atoms, while terminal aminogroups of acyclic ligands do not take part in the complex formation. Tripicolinate azacrown ligand coordinates cations outside the macrocyclic cavity in non‐equivalent positions. However this out‐cage location as well as a moderate logK value do not induce fast release of cation from this complex in the challenging medium of serum proteins. [ABSTRACT FROM AUTHOR]

Formation of Sc radioisotopes under the irradiation of titanium of natural isotopic composition by bremsstrahlung photons with energies up to 55 MeV was studied. The yield of 47Sc is 5·105 Bq/μA h (g/cm2). Inevitable impurities are 46Sc and 48Sc (1.5% and 9.1% of 47Sc radioactivity at EOB, respectively). 47Sc was separated by extraction chromatography on a DGA resin in HNO3 and HCl media. The separation procedure takes about 2 h, the radiochemical efficiency was > 97%. The result was compared with other photonuclear experiments on titanium nuclei. It is shown that the photonuclear method can be used for the production of therapeutic amounts of 47Sc. [ABSTRACT FROM AUTHOR]

Copper-based radiopharmaceuticals are of high interest these days owing to the decay properties of copper radioisotopes. In contrast, labeled zinc compounds have been less studied for applications in nuclear medicine. In this study, the stability of labeled zinc and copper complexes with two azacrown ether ligands was investigated and compared. Then, the in vitro and in vivo stability of the studied zinc complexes was demonstrated, with the complexes showing promise for biomedical applications. In contrast, analogous copper complexes quickly dissociated in the presence of serum proteins. Furthermore, a simple method for the production of radiochemically pure 65Zn was proposed, and the opportunity for its use as a surrogate radionuclide for research into potential zinc-containing radiopharmaceuticals was demonstrated. [ABSTRACT FROM AUTHOR]

Production of medical radionuclide 67Cu by the irradiation of Zn of natural isotopic composition by bremsstrahlung photons of maximum energy of 55 MeV was studied. Production yields of 67Cu and other activation products were determined. The yield of 67Cu is (2.34 ± 0.07) × 105 Bq/(μA h g/cm2) at EOB. The experimental data were compared with the results of other experiments and theoretical calculations based on the statistical model in the TALYS software and on the combined model of photonuclear reactions. Technique of chemical separation of 67Cu from irradiated zinc target based on extraction chromatography using CU Resin was applied. Radiochemical yield was > 95%, separation time was 1 h. The possibility of production of medical quantities was discussed. [ABSTRACT FROM AUTHOR]

In this work, the separation of 89Zr, a radionuclide promising for positron-emission tomography, from an irradiated yttrium target using different extraction-chromatographic resins (TEVA, UTEVA, TRU, and LN resins ©Triskem) was studied. Distribution coefficients of Zr(IV) onto TEVA, LN (in HCl solutions), and onto TRU (in HCl and HNO3) were determined. The optimum conditions for the separation of Zr(IV) and Y(III) using these resins were proposed. In each case, the maximum separation factor was higher than 105. The developed separation procedures allow to obtain 89Zr of high radiochemical purity for dilute mineral acids. [ABSTRACT FROM AUTHOR]

A method for obtaining 156, 155, 154m2, 154, 153Tb radiotracers by the irradiation of a europium oxide target of natural isotopic composition by 27 MeV α-particles is proposed. Terbium can be efficiently separated from bulk of europium by the reduction of the latter by zinc in an acidic solution and precipitation as EuSO4. The optimum Zn/Eu3+ and (NH4)2SO4/Eu3+ molar ratios are 20 and 3, respectively. Terbium is additionally purified from europium and gadolinium by extraction chromatography using LN Resin. It is demonstrated that optimum separation is attained in 0.6 M HNO3. The Tb/Eu separation coefficient was ~5 · 105. The yield of terbium was about 90 %. Time of all steps was 1.5-2 h. The proposed procedure makes it possible to obtain no carrier added terbium radiotracers. [ABSTRACT FROM AUTHOR]

In this article, we present the synthesis and characterization of new acyclic pyridine-containing polyaminocarboxylate ligands H4aPyta and H6aPyha, which differ in structural rigidity and the number of chelating groups. Their abilities to form complexes with Cu2+, Ga3+, Y3+, and Bi3+ cations, as well as the stability of the complexes, were evaluated by potentiometric titration method, radiolabeling with the corresponding radionuclides, in vitro studies, mass spectrometry, and HPLC. The structures of the resulting complexes were determined using NMR spectroscopy and DFT calculations. The results obtained made it possible to evaluate the influence of the structural features of the complexes on their stability. The developed chelators H4aPyta and H6aPyha were proved to be promising for further research in the field of radiopharmaceuticals. [ABSTRACT FROM AUTHOR]

In this article, we present the synthesis and characterization of new acyclic pyridine-containing polyaminocarboxylate ligands H4aPyta and H6aPyha, which differ in structural rigidity and the number of chelating groups. Their abilities to form complexes with Cu 2+ , Ga 3+ , Y 3+ , and Bi 3+ cations, as well as the stability of the complexes, were evaluated by potentiometric titration method, radiolabeling with the corresponding radionuclides, in vitro studies, mass spectrometry, and HPLC. The structures of the resulting complexes were determined using NMR spectroscopy and DFT calculations. The results obtained made it possible to evaluate the influence of the structural features of the complexes on their stability. The developed chelators H4aPyta and H6aPyha were proved to be promising for further research in the field of radiopharmaceuticals.

Copper-based radiopharmaceuticals are of high interest these days owing to the decay properties of copper radioisotopes. In contrast, labeled zinc compounds have been less studied for applications in nuclear medicine. In this study, the stability of labeled zinc and copper complexes with two azacrown ether ligands was investigated and compared. Then, the in vitro and in vivo stability of the studied zinc complexes was demonstrated, with the complexes showing promise for biomedical applications. In contrast, analogous copper complexes quickly dissociated in the presence of serum proteins. Furthermore, a simple method for the production of radiochemically pure 65Zn was proposed, and the opportunity for its use as a surrogate radionuclide for research into potential zinc-containing radiopharmaceuticals was demonstrated.