Some metal radionuclides can be used in diagnostic methods for imaging, such as single-photon emission computed tomography ( 99m Tc, 111 In) and positron emission tomography (PET) ( 44 Sc, 64 Cu, 68 Ga), as well as for therapeutic applications ( 47 Sc, 90 Y, 177 Lu, 212 Pb, 212/213 Bi, 225 Ac). A chelator, e.g., a ligand that binds a radiometal ion into a strong stable coordination complex, is an important component of a radiopharmaceutical (RP) based on radio metals. In the past decade, as part of the search for new highly effective chelating molecules, the number of studies related to the production of picolinate ligands and the characterization of their complexes with diagnostic and therapeutic radionuclides has sharply increased. Moreover, conjugates with biomolecules based on these chelators have already been synthesized and studied. In this review, data on the binding of cations of radionuclides by picolinate-containing ligands of various types, as well as their conjugates, are systematized and analyzed.

Dispersions based on sodium hyaluronate and hydroxyapatite, which is synthesized both by the classical method in an aqueous medium to obtain submicron particles and in a bioactive hyaluronan medium with the formation of nanosized particles, are obtained. The synthesized hydroxyapatite nanoparticles have a complex structure based on a monodentate complex hyaluronan–Ca 2+ which remains in the dispersion both when adding a hyaluronan solution and when diluted with water. Physicochemical methods show that there is a significant difference between the energy characteristics of the surfaces of biocomposites obtained from dispersions. The rheology of dispersions of hydroxyapatite micro- and nanoparticles is investigated, the effect of dispersed phase concentration on it is revealed, and the viscoplastic behavior of dispersions of microparticles is demonstrated. This behavior disappears upon addition of the hyaluronan solution, which, however, leads to the loss of stability by the system. The introduction of hydroxyapatite nanoparticle additives into hyaluronan solutions has a weak effect on the rheology; no flocculation of nanoparticles occurs. The resulting composites consisting of hydroxyapatite and sodium hyaluronate can be considered a basis of a drug for the rehabilitation treatment of periodontitis.

Binding of bismuth cation with two newly synthesized picolinate containing acyclic ( L1 ) and macrocyclic ( L2 ) ligands was studied. Both ligands demonstrate complex formation with Bi 3+ under ambient conditions with high complexation constants. Serum stability of the complexes was investigated in serum protein excess of 10- and 100-times. Experiments with no-carrier-added radiobismuth ( 207 Bi and 213 Bi) were performed. A one-column 225 Ac/ 213 Bi generator system, based on Ac resin (Triskem Inc.), was tested. The overall yield of 213 Bi was exceeding 85% with 225 Ac breakthrough below 10 −4 %.

New biocomposites based on hydroxyapatite and hyaluronic acid are obtained, and their structural and morphological characteristics are studied. With the use of a set of physicochemical methods, the effect of hyaluronic acid as an active medium in the synthesis of hydroxyapatite used to produce synthetic biocomposites close in structure to native hydroxyapatite is investigated.