Synthesis of new acyclic chelators H4aPyta and H6aPyha and their complexes with Cu2+, Ga3+, Y3+, and Bi3

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.

A Radionuclide Generator of High-Purity Bi-213 for Instant Labeling

A new two-column ²²⁵Ac/²¹³Bi generator was developed specifically for using ²²⁵Ac containing an impurity of long lived ²²⁷Ac. The parent ²²⁵Ac was retained on the first Actinide Resin column, while ²¹³Bi was accumulated on the second column filled with AG MP-50 resin via continuous elution and decay of intermediate ²²¹Fr. The ²¹³Bi accumulation was realized in circulation mode which allowed a compact generator design. It was demonstrated that ²¹³Bi could be quickly and effectively extracted from AG MP-50 in form of complexes with various chelating agents including DTPA and DOTA. The performance of the generator presented and a conventional single-column generator on the base of AG MP-50 was tested and both generators were loaded with ²²⁵Ac containing ²²⁷Ac impurity. The ²¹³Bi generation efficiencies were comparable and greater than 70%, whereas the developed generator provided a deeper degree of purification of ²¹³Bi from Ac isotopes and decay products of ²²⁷Ac.

PyRad: A software shell for simulating radiolysis with Qball package

The assessment of the radiolytic stability of media is an important task in the fields of nuclear power engineering and radiochemistry. Such studies must be carried out in special laboratory conditions with the use of sources of ionizing radiation, which may increase personal doses of the staff. In addition, difficulties arise in studying the products of irradiated media. While it is impossible to abandon experiments to obtain reliable results in this area, computational methods of quantum chemistry can reduce the number of experiments and help understand the mechanisms of the reactions that occur during radiolysis. Here we would like to present a software shell of the Qb@ll program performing time-dependent density functional theory simulations of the radiolysis process.

A search of a quantitative quantum-chemical approach for radiolytic stability prediction

Radiolytic stability is one of the main requirements of the substances that are used in the chemistry of nuclear cycle or in the radiopharmaceutical chemistry. Herein, we proposed an approach for the prediction of radiolytic stability by the estimation of the molecular reactivity. The DFT calculations of the atom-wise reactivity descriptor were made for a number of organic molecules. The theoretical simulations were validated by the experimental data. We irradiated the molecules by gamma-radiation and studied the products of radiolysis and changes in the molecular concentration by HPLC-MS analysis. The importance of the inclusion of the conformational influence and the steric accessibility in the calculation is shown in this study. We presente a new chemical reactivity descriptor (CRD) and recommend using CRD as the new quantitative estimation of the reactivity. A good correlation between the CRD and the constants of the radiolysis was obtained.