Liana Zubaidullina

A strategy based on the hyperbranched polyol process (HB-polyol process) is presented for the synthesis of hemocompatible cobalt nanocomposites Co/G_nOH with controlled morphology and predictable functional properties. Third-generation (G₃OH) and fourth-generation (G₄OH) hyperbranched polyester polyols were used as smart polyol nanoreactors. We establish, for the first time, the fundamental physicochemical principles of the HB-polyol process based on a comprehensive analysis of FT-IR, UV-Vis, NMR, NTA, and TEM data. These principles encompass the stages of pre-organization, nucleation, polyol oxidation and the stabilization of cobalt-loaded metallopolymer nanocomposites within the binary [CoCl₂–G_nOH] system (n = 3, 4). Magnetic measurements revealed that the samples exhibit paramagnetic properties at 5 K. The size of the magnetic cores in the Co/G₃OH samples was estimated by fitting the field-dependent magnetization curves to the Langevin function and was found to range from 1.4 nm to 7.2 nm, indicating the superparamagnetic behavior of the nanocomposites. In vitro biological tests of the Co/G_nOH nanocomposites demonstrated high hemocompatibility, as well as pronounced modulatory and antimycotic activity across all samples. The obtained results hold promise for the development of simple design technologies for multifunctional “intelligent” materials based on metal and dendritic nanoparticles for biomedical applications.

Obtaining amorphous forms of drugs is one of the ways to increase bioavailability. This is especially important for active pharmaceutical ingredients belonging to class II and IV according to the biopharmaceutical classification. These compounds include the currently widely used fluoroquinolone antibiotics. They have low solubility in water and are therefore typically used as hydrochlorides. The presence of a strong acid and a charged active pharmaceutical ingredient in the drug increases solubility, but can also lead to additional side effects and decreased permeability. One way to improve the properties of active pharmaceutical ingredients is to convert them to amorphous form. In this study, an amorphous form of the fluoroquinolone antibiotic norfloxacin was obtained, its stability was determined, and its solubility was studied. It was shown that the resulting amorphous form has good temporal stability. The optimal models describing the cold crystallization process are the Nakamura and Sbirrazzuoli models. Despite the slower dissolution kinetics compared to the crystalline sample, the amorphous form shows higher equilibrium solubility values. These results can be used in pharmaceutical engineering to produce amorphous forms of active pharmaceutical ingredients and determine their stability.

Non-isothermal calorimetry is performed to study the kinetics of metal-free A₂/B₂-type azide–alkyne polyaddition between the dipropargyl ether of bisphenol A with different organic diazides. The diazide structure is varied to probe the effect of the nature of a hydrocarbon spacer between the azide groups on their reactivity. Isoconversional analysis demonstrates that the polymerization processes are characterized by the same activation energy of 84 kJ mol⁻¹ for all studied diazides. It is found that diazides with aromatic spacers demonstrate ~1.6 times higher reactivity than that of diazides with the alkyl spacer. The difference in the reactivity is explained by the difference in the electronic effects of the hydrocarbon spacers on the azide groups as well as by the difference in their steric availability. The veracity of the obtained kinetic parameters is validated by a polymerization test at the time–temperature conditions predicted from the obtained kinetic data followed by independent assessment of the monomer conversion using FTIR.