UDC 616-057:613.63/.65:547

Introduction. The situation of recent years during the SARS-CoV-2 pandemic has aggravated the problem of an insufficient number of approved hygienic standards of active substances included in disinfectants. This, in turn, has become a deterrent to the introduction of such agents into practice. For the proper organization of chemical safety of the workforce new methods of substantiating hygienic standards need to be developed. One of the ways to overcome the outlined higher problem, which will significantly speed up the resolution of the situation, is the introduction of read-across as an express method of substantiating the maximum permissible concentrations for a group (cluster) of compounds.

The purpose of the research is to substantiate the possibilities of developing group regulations for this cluster of compounds in the air of the working area based on data about the physicochemical and toxicological characteristics of dialkyldimethylammonium chloride С₈-С₁₀ homologues.

Results. Similar chemical structure of dialkyldimethylammonium chloride C₈-C₁₀ homologues determines their similarity in terms of physicochemical and toxicological properties. All substances are solids in their aggregate state, dissolve well in water, have the ability to penetrate biological membranes and disrupt their integrity. According to parameters of acute oral toxicity, dialkyldimethylammonium chloride C₈-C₁₀ homologues belong to moderately hazardous substances – hazard class 3, do not cause systemic toxicity; the main negative manifestation of their influence is an irritating effect which further provokes signs of general toxicity. The substances do not have carcinogenic, mutagenic effects, they do not affect reproductive function. The most studied representative of the cluster is didecyldimethylammonium chloride (DC₁₀DAC), which is accepted as a standard (analogue) for all dialkyldimethylammonium chloride C₈-C₁₀ homologues. In Ukraine a temporary hygienic standard for didecyldimethylammonium chloride in the air of the working area (approximately safe exposure level, ASEL) has been approved at the level of 0.2 mg/m³, where the limiting criteria for harmfulness are pronounced irritating effect on the skin and mucous membranes of the eyes and an acute inhalation effect. The calculation standard for quaternary ammonium compounds proposed by Dotson G.S. et al. is 0.1 mg/m³. Both standards belong to the II class of safety.

Conclusions. The read-across method allows for accepting didecyldimethylammonium chloride (DC₁₀DAC) as a standard (analogue) for all dialkyldimethylammonium chloride C₈-C₁₀ homologues. The hygienic regulation of the permissible content of didecyldimethylammonium chloride obtained on the basis of additional experimental studies as a result of the application of the cluster approach will be legitimate for dioctyldimethylammonium chloride (DC₈DAC); octyldecyldimethylammonium chloride (DC_8-10DAC), didecyldimethylammonium chloride (DC₁₀DAC) and their mixtures with different percentage ratios.

Keywords: dialkyldimethylammonium chloride C₈-C₁₀ homologues, dialkyl(C₈-C₁₀)dimethylammonium chloride, dioctyldimethylammonium chloride, didecyldimethylammonium chloride, read-across, hygienic standard, cluster approach, group hygienic regulation.

Рatients with diabetes have more complications and higher mortality from COVID-19. This is due to the fact that diabetes impairs the immune response. Hyperglycemia causes a violation of the immune response, which in turn cannot control the spread of pathogenic microorganisms and therefore patients
with diabetes are more susceptible to infections. The purpose of the work ₋₋ analysis of bibliometric databases of literature on new developments in diabetes and COVID-19 and focused on clinical recommendations for patients with diabetes infected with COVID-19. The search methods included a literature review of scientific articles that studied diabetes and COVID-19. According to the results of the analysis of the articles obtained as a result of the search in the PubMed, SCOPUS, Web of Science, MedScape databases, a combination of the terms “diabetes and SARS-CoV-2”, “diabetes and COVID-19”, “pathogenesis of diabetes in case of COVID-19”, "pancreas", "clinical features", "diagnosis", "treatment", "clinical recommendations", we found 32 messages from 2020 to 2022. The main parameters  of the study were outpatients and inpatients with diabetes and COVID-19 of middle and elderly age starting from 46 years and up to 82 years of age in France, China, the USA, Great Britain, in which a nationwide, retrospective, populationbased study was conducted. The following concomitant diseases are included in the main studies: arterial hypertension, cardiovascular diseases, heart failure, chronic kidney disease, chronic obstructive pulmonary disease, myocardial infarction, cerebrovascular diseases. Issues of pathogenetic mechanisms in DM and COVID-19, as well as management of patients with DM and COVID-19 are highlighted.
Key words. Diabetes mellitus, СOVID-19, SARS-CoV-2, angiotensin-converting enzyme-2, cytokines.

Aim: To study the process of hemoglobin oxidation and the enzymatic reactions associated with it.
Materials and Methods: Heparinized human blood (15 IU/ml) was obtained from the clinical department. The concentration of oxy- and methemoglobin,
auto-oxidation of hemoglobin was determined spectrophotometrically spectrophotometrically. Autooxidation of hemoglobin was recorded spectrophotometrically, and protein concentration was determined by the Lowry method. Monooxygenase activity of hemoglobin was also measured by the method described
by Lowry spectrophotometrically. The concentration of O₂ and H₂O₂ in the reaction media was determined on a biomicroanalyzer OR 210/3 (Redelkis).
Results: The obtained experimental data allow us to propose a mechanism of “spontaneous autooxidation” of oxyhemoglobin, which can be described by
the following equations:
Hb²⁺O₂ = Hb³⁺ + O₂ (1)
Hb²⁺O₂ + 2e^- + 2H⁺ = Hb³⁺ + H₂O₂ (2)
Hb²⁺O₂ + 2e ^- + 2H⁺ = Hb²⁺ + H₂O₂  (3)
Hb²⁺ + O_{2 ⁼}  Hb²⁺O2 (4)
Spectral characteristics of the process of “spontaneous auto-oxidation” indicate the formation of a metform of hemoglobin, the depletion of oxygen by the system was established, at pH 5.6, an increase in the monooxygenase activity of hemoglobin is observed 3-4 times compared to the physiological level.
Сonclusions: In addition to the main, previously known functions of hemoglobin (gas transport, peroxidase, monooxygenase), it catalyzes a two-electron
oxidase reaction in which O₂
 is reduced to H₂O₂. This is confirmed by experimental data on the formation of one of the products of “spontaneous autoxidation”
of oxyhemoglobin _ deoxyform at pH 5.6 _ 8.9.
 KEY WORDS: oxyhemoglobin, methemoglobin, autooxidation, monooxygenase activity, oxidase reaction, ligands