Bohdan Murashevych’s research while affiliated with Odessa State Medical University and other places

The disinfection of air in premises, especially in the presence of people, is an important element of the system for the prevention of infectious diseases. A promising solution for this is to fill the premises with an antimicrobial chemical agent that would quickly neutralize pathogens directly at the moment they enter the air. It is advisable to use hypochlorous acid HOCl as such an agent. But traditional methods of administering HOCl into the air by aerosolizing its solutions may be accompanied by a number of risks that can be prevented by using gaseous HOCl. Therefore, it is relevant to develop evaporation devices that would take into account the specifics of chlorine-active compounds and determine the influence of various factors on the release of gaseous HOCl from them into the air being treated. During the study, a design of a device was developed in which the transfer of HOCl into the air is carried out by contact of the latter with a foamed working solution of sodium hypochlorite NaOCl. The HOCl concentration in the treated air mainly depends on its concentration in the working solution, which, in turn, is determined by the pH of the solution and the total content of free chlorine in it. Additionally, the influence of the air and working solution temperatures, the volume of the working solution, the power of air flows and other technological factors on the air HOCl concentration was studied. When using an electrochemically generated approx. 1000 mg/l NaOCl solution with pH 8.50–8.60 at 20 °C, it is possible to maintain the total chlorine concentration in the air flow with a capacity of 50 m3/h at a level of about 0.30 mg/m3 for a long time. Simple design, multifunctionality and the fundamental possibility of combining the processes of electrochemical synthesis of HOCl and its immediate administering into the air open up broad prospects for using the developed installations for continuous disinfection of premises

Treatment of styrene-divinylbenzene sulfonated cation exchangers with a small amount of thionyl chloride prior to reaction with chlorosulfonic acid significantly facilitates the production of sulfochlorides from polymeric sulfonic acids and their salts. Polymeric sulfochlorides were synthesized by sequential treatment of gel and macroporous styrene-divinylbenzene cation exchangers in Na and H forms with thionyl chloride and chlorosulfonic acid. Transformation of these sulfochlorides into sulfamides via reaction with ammonia, followed by treatment with gaseous chlorine, yielded polymeric sodium N-chlorosulfonamides with an active chlorine content exceeding 15%. Consequently, the conversion rate of the starting material to polymeric sodium N-chlorosulfonamide was enhanced from 25–35% to 45–55%. The optimal ratio of reagents per 100 g of starting material was determined to be 10 g of thionyl chloride and 120–150 g of chlorosulfonic acid, with a reaction duration of 4–5 hours. It was confirmed that the type of initial cation exchanger (Na or H form) has no significant effect on the final outcome.

BACKGROUND The synthesis of sodium hypochlorite (NaClO) by classical electrolysis of NaCl solutions on a Ti/Pt anode is characterized by parallel formation of undesirable sodium chlorate (NaClO3) impurities. Oxidation of hypochlorite to chlorate with high current efficiency (CE) is realized on the oxidized, passivated Pt surface. On a Pt surface reduced by cathodic polarization, NaClO synthesis can be realized with the CE close to 90% almost without chlorate accumulation. Long‐term electrolysis leads to passivation of the Pt surface. RESULTS Electrolysis while periodically changing the polarity of the electrodes (current reverse mode) increases the time the Pt surface remains in the activated state. Carrying out electrolysis in this way makes it possible to increase CE(NaClO) 1.5–2.0‐fold while simultaneously reducing CE(NaClO3) (sodium chlorate) by ≤10‐fold. This study additionally determined the optimal parameters of reverse electrolysis, examined the effect of changing polarity on the state of the Ti/Pt electrode surface and studied the kinetic patterns of active platinum coating dissolution. CONCLUSION The optimal conditions for electrolysis in current reverse mode are current densities of 5–10 mA cm⁻² with the period of polarity change close to 30 s. The result of such a process is an isotonic solution containing 500 mg L⁻¹ NaClO with an admixture of <10 mg L⁻¹ NaClO3 and 0.1 mg L⁻¹ Pt in the form of soluble chloride complexes. The rate of Pt accumulation is determined by the frequency of polarity change. The resulting solutions have sufficiently high purity for use in medicine and aerosol air disinfection. © 2024 Society of Chemical Industry (SCI).

N-chlorotaurine (NCT) is a broad-spectrum antimicrobial agent with outstanding tolerability, effective for topical and inhalation use. This paper presents the results of studies of single and repeated intravenous infusions of NCT to laboratory animals. The studies were conducted on female Wistar Han rats. The effect of NCT infusions on the general condition, behavioral reactions, main biochemical and hematological parameters, hemocoagulation system, cardiovascular system, and on the condition of the internal organs was studied. It was found that NCT infusions do not reveal deviations in the studied parameters that could indicate a toxic effect. The estimated LD50 is more than 80 mg/kg. In a subchronic experiment, a statistically significant decrease in cholesterol (by up to 11%), glucose (by up to 15%) and excess bases (up to four times) in the blood, and an increase in heart rate (by up to 31%) and frequency of defecations (by up to 35%), as well as pronounced antiplatelet effect, were found. In animals with simulated endotoxicosis, a decrease in the cytolysis and oxidative stress markers was observed. Such effects are caused by both chlorine-active compounds and taurine.The results obtained indicate broad prospects for the use of NCT solutions as an infusion detoxifying agent.

Hypochlorous acid HOCl is an effective disinfectant with a broad spectrum and high rate of microbicidal action. Its use for air treatment can be an effective tool for the prevention and therapy of infectious diseases. In this work, the in vivo study was conducted on 110 Wistar Han rats (12 and 72 weeks old) on the effect of a single inhalation of air containing gaseous HOCl on the activity of antioxidant system enzymes. For this, a special installation was designed to uniformly maintain the concentration of HOCl in the air and regulate it over a wide range. Inhalation exposure was carried out for 4 h at total chlorine concentrations in the air of approximately 2.0 mg/m3 and 5.0 mg/m3, after which the animals were observed for 14 days. The effect of inhalation on the antioxidant system activity varied significantly in animals of different ages. Catalase activity in young rats increased approximately 2-fold on days 1-2 after inhalation, regardless of the HOCl concentration, while in old animals a sharp dose-dependent decrease was initially observed. The glutathione peroxidase activity in animals of both ages increased upon inhalation of air with 5.0 mg/m3 HOCl, and in old animals this was more pronounced; when the HOCl concentration decreased to 2.0 mg/m3, this indicator increased slightly in old rats and remained virtually unchanged in young ones. The glutathione reductase activity when exposed to 2.0 mg/m3 HOCl did not change for both age groups, and with increasing HOCl concentration it increased by 1.5-2.0 times in all animals.

Polymer materials with immobilized functional groups–donors of active chlorine are widely used to create products with a microbiocidal effect and increased resistance to microbial contamination. In this work, various methods for the synthesis of granular styrene–divinylbenzene polymers with N‐chlorosulfonamide groups were investigated. It has been shown that the synthesis of polymers with chlorine‐active SO2NNaCl groups from a non‐functionalized styrene–divinylbenzene polymer matrix through the stage of its sulfochlorination with chlorosulfonic acid in dichloromethane for 6–7 h is optimal. These products contain approximately 11% of active chlorine and maintain a stable particle size distribution. When cation exchangers such as Purolite C100 are used as the initial polymer carrier, the content of chlorine‐active groups in the target product is approximately 9%, and an increase in the content of the dust fraction is observed. The obtained samples, regardless of the synthesis method, are capable of releasing active chlorine into solutions containing amino compounds. The microbial impurities in water also cause the emission of active chlorine in an amount that does not depend on the loading of the polymer, but is determined by the concentration of microbes, due to which a pronounced antimicrobial effect is observed. In this case, the resulting products do not cause further decomposition of the functional groups of the polymer, which indicates the high service life of the latter. The availability of raw materials, relative ease of synthesis, stability, possibility of regeneration and microbiocidal properties of the studied polymers make them promising for use as components of water and air purification systems and other products for medical and industrial purposes. © 2024 Society of Chemical Industry.

Solutions of N-chlorotaurine (NCT) are effective microbiocidal agents with a broad spectrum of pharmacological activity and outstanding tolerability. The main problem limiting their medical use is their instability, which is generally inherent in solutions of all chlorine-active compounds. In this work, we developed a new synthetic approach to the synthesis of such solutions, which consists in the activation of granular and fibrous polymeric materials with immobilized N-chlorosulfonamide groups, which act here as a chlorinating agent. It was shown that when such polymers are added to taurine solutions, NCT solutions with a chemical composition suitable for immediate medical use can be obtained. The stability of such solutions under various conditions was analyzed in comparison with NCTs obtained by the classical method from sodium hypochlorite. It was confirmed that the process of decomposition of all studied solutions obeys the kinetic laws of the first-order reaction. It was proven that solutions obtained from granular polymers are more stable both in terms of active chlorine concentration and in terms of pH, and their additional buffering is not needed. The stability of solutions decreases when they are stored in the presence of polymers used, with an increase in the excess of taurine and with acidification. The high sensitivity of all obtained solutions to UV radiation was also noted. The antimicrobial properties of NCT solutions obtained from polymers are not inferior to those obtained from sodium hypochlorite at the same concentration of active chlorine. Considering the stability and compactness of the initial chlorine-active polymers, as well as the possibility of their multiple regeneration, the developed method can form the basis of the technology for obtaining multifunctional NCT solutions for medical purposes with the desired physical and chemical properties without using special equipment or specific reagents.

Introduction: Microorganisms colonizing the surface of dental implants can form biofilms that protect their microcolonies from mechanical impact, antimicrobial compounds, and immune factors. Prophylactic use of antibiotics during dental implantation can exert selective pressure on the development of antimicrobial resistance. In this context, N-chlorotaurine (NCT) is a promising compound to combat resistant agents. The aim is to investigate the efficacy of NCT against pathogens associated with dental implant complications. Materials and methods. A buffered 1% NCT solution adjusted to pH 7.1 was used for the study. Multidrug-resistant cultures (MDR) were identified. Determination of NCT activity was carried out by the agar and suspension method. The results. After standard antibiotic susceptibility testing, cultures classified as MDR were selected. 12 cultures were included in the MDR group, including seven S. aureus, three K. pneumoniae and three A. baumannii. MDR cultures of S. aureus had MRSA profile. Production of carbapenemases was confirmed in all MDR K. pneumoniae isolates, 2 of them showed production of metallo-β-lactamases. MDR isolates A. baumannii were also producers of metallo-β-lactamases. All 12 investigated MDR cultures were sensitive to NCT, the diameter of the zones of growth retardation was at least 15 mm. No significant difference was found between the effectiveness of 1% NCT solution against microorganisms with different mechanisms of drug resistance (t-test, p>0.05). When conducting studies in a liquid environment, a 1% NCT solution showed similar results, all MDR cultures were sensitive and showed a decrease in the microbial load (CFU/ml) by at least 2 log10 steps already 15 minutes after the start of the study. Notably, there was no significant difference in the efficacy of NCT against conditionally susceptible and MDR agents. Conclusions. Reducing the threat and burden of MDR pathogens is one of the goals announced by WHO and the Centres for Disease Control. Our study clearly confirms that various antibiotic resistance mechanisms do not affect the bactericidal activity of NCT, making it promising for the treatment of resistant infections.

Electrodes made of platinized titanium with a surface platinum content of 2–3 mg/cm2 can be used in non-diaphragm flow- and accumulative-type electrolyzers for the electrolysis of low-concentrated NaCl solutions in order to obtain pure NaClO solutions. If electrolysis of 0.15 M NaCl solution is carried out on platinized titanium electrodes in the usual mode at current densities of 20–40 mA/cm2, then the anode surface passes into an oxidized passive state. In this case, the current efficiency of hypochlorite does not exceed 40%, and the current efficiency of chlorate is more than 20%. During a short electrolysis on a preliminarily reduced surface of platinized titanium, the current efficiency of hypochlorite reaches 90% with almost no accumulation of chlorate. Carrying out the long-term electrolysis of low-concentrated NaCl solutions in the regime of periodic polarity reverse makes it possible to significantly (up to 10 times) reduce the content of chlorate in the resulting sodium hypochlorite solutions. The most promising is the synthesis of sodium hypochlorite solutions in flow-type electrochemical reactors consisting of several series-connected electrochemical modules with an undivided electrode space in the mode of periodic current reverse. The electrolyzer of two series-connected cells in the mode without current reverse allows obtaining a solution that contains 500 mg/L of sodium hypochlorite and 130 mg/L of sodium chlorate. Carrying out the electrolysis in the reverse current mode every 30 s reduces the content of sodium chlorate to 25 mg/L, which makes it possible to produce high-purity NaClO solutions.

BACKGROUND The synthesis of sodium hypochlorite solutions by electrolysis of low‐concentration and isotonic NaCl solutions using the most available dimensionally stable anodes from platinized titanium is promising from the point of view of the economics of the process. However, such synthesis is seriously complicated by the formation of toxic sodium chlorate impurity. RESULTS It is shown that in low‐concentration NaCl solutions under anodic polarization, the platinum surface rapidly passes into an oxidized passive state with a NaClO current efficiency (CE) of less than 30% and CE of NaClO3 of more than 20%. Carrying out short‐term electrolysis on the reduced surface of platinum makes it possible to increase the CE of NaClO to almost 90% in the absence of chlorate accumulation. Carrying out electrolysis in the mode of periodic change of electrode polarity (current reverse) allows solving the problem of anode passivation and significantly increasing the purity of the resulting sodium hypochlorite solutions. CONCLUSION Electrolysis of an isotonic 0.15 mol L⁻¹ NaCl solution in the current reverse mode allows increasing CE(NaClO) from 21% to 40% and significantly decreasing CE(NaClO3) from 21% to 4%. Based on the results obtained, a membraneless electrolyzer can be constructed to produce disinfectant solutions ‘on the spot’ using a commercially available pharmaceutical isotonic solution of NaCl. © 2023 Society of Chemical Industry (SCI).