DEUTERIUM AS A TOOL FOR CHANGING THE PROPERTIES OF PHARMACEUTICAL SUBSTANCES (REVIEW)

The review is devoted to the influence of the hydrogen isotope–deuterium on biological models of organisms and the biological activity of pharmaceutical substances. The positions of the influence of deuterium on the properties of active pharmaceutical ingredients and excipients are examined from different perspectives. The first position reflects an increase in the kinetic isotope effect (KIE) in processes involving known pharmaceutical substances in aqueous solutions with a deuterium/protium ratio (D/H) below natural. For the first time, the dose-response diagram shows the identity of deuterium with essential trace elements, when a deficiency and excess of an element reduces the organism's vitality. Improved kinetic characteristics are demonstrated for the molecular and organism levels of different hierarchical gradations. In particular, they consist in the possibility of increasing the dissolution rate of substances by influencing the carbohydrate mutarotation processes and the optical activity of chiral substances, increased accumulation of essential elements in medicinal plants and other processes associated with a possible change in metabolic pathways in the cell and the organism as a whole. The second considered position of the influence of deuterium is associated with the use of deuterated substances–new compounds or obtained by substitution of protium in known protium analogues. The KIE is presented, which is expressed in a decrease in the biotransformation rate as a result of deuteration, it allows predicting a rapid development of the new direction in the development of drugs. Having an identical therapeutic effect, deuterated analogs provide improved pharmacokinetic characteristics, such as reduced toxicity, blocked epimerization of optically active substances, and a change in the mechanisms of biotransformation. The obtained results make it possible to predict the mechanisms of the effect of deuterium on the biochemical transformations of pharmaceutical substances in the organism

Nanodispersions of Polyelectrolytes Based on Humic Substances: Isolation, Physico-Chemical Characterization and Evaluation of Biological Activity

Natural polyelectrolytes, including in the form of complexes with colloidal particles, are increasingly used in pharmacy due to the possibility of regulated attachment of medicinal substances and their targeted delivery to the target organ. However, the formation, stability, and molecular-mass characteristics of polyelectrolyte nanodispersions (ND) vary depending on the nature and composition of the medium of their origin. This is due to the lack of standardized approaches to quality control and regulatory documentation for most natural ND. In this paper, we first introduced the isolation, followed by investigations into their physico-chemical properties and bioactivity. Using the dried droplet method, we were able to detect the “coffee ring effect”. Fractographic studies of the surface structure of EHA and FA dried samples using SEM showed its heterogeneity and the presence of submicron particles encapsulated in the internal molecular cavities of polyelectrolyte. FTIR spectroscopy revealed the ND chemical structure of benzo-α-pyron and benzo-γ-pyron, consisting of nanoparticles and a branched frame part. The main elements detected by X-ray fluorescence in humic substance extract and fulvic acid include Si, P, S, K, Ca, Mn, Fe, Cu, Zn, whereas Fe is in high concentrations. The UV-spectra and fluorescent radiation demonstrated the possibility of studying the effect of the fulvate chromone structure on its optical properties. It is shown that dilution of the initial solutions of polyelectrolytes 1:10 contributes to the detection of smaller nanoparticles and an increase in the absolute value of the negative ζ-potential as a factor of ND stability. A study of the EHS effect on the SARS-CoV-2 virus infectious titer in the Vero E6 cell showed the effective against virus both in the virucidal scheme (the SI is 11.90–22.43) and treatment/prevention scheme (the SI is 34.85–57.33). We assume that polyelectrolyte ND prevent the binding of the coronavirus spike glycoprotein to the receptor. Taking into account the results obtained, we expect that the developed approach can become unified for the standardization of the ND natural polyelectrolytes complex, which has great prospects for use in pharmacy and medicine as a drug with antiviral activity