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The resistance of bacteria to the disinfectants used is one of the pressing health problems requiring to be addressed in order to prevent formation and spread of resistant strains. Bacterial resistance leads to a sharply decreased effectiveness of anti-epidemic measures and contributes to maintaining a high morbidity level. In the context of the growing HAI incidence rate and related polyetiology, the large adaptive potential of opportunistic microorganisms, and the growing resistance to antimicrobial drugs, it is necessary to search for new or modify the corresponding substances of plant or synthetic origin exerting antimicrobial action used as antimicrobial agents. One of the representatives of this class of compounds are polyguanidines, characterized by high antimicrobial activity and low toxicity. Due to the high reactivity of the guanidine group, as well as ease of synthesis and relative availability of raw materials, N-phenyl- and N-octyl-substituted derivatives of polyhexamethylene guanidine hydrochloride were able to be obtained by melt polycondensation, their molecular weight characteristics were measured as well as the structure investigated by IR spectroscopy. An earlier study on the acute toxicity for polyhexamethylene guanidine hydrochloride derivatives after a single oral drug intake in laboratory animals (white mice) allowed to establish the following LD50 values: polyhexamethylene guanidine hydrochloride — 850.0±112.02 mg/ kg; N-phenyl-substituted polyhexamethylene guanidine hydrochloride — 1399.9±120.51 mg/kg; N-octyl-substituted polyhexamethylene guanidine hydrochloride — 1150.0±137.40 mg/kg. Such values, according to the tabulation of hazard classes, allow the synthesized derivatives to be classified into the fourth hazard class and open up an opportunity for using disinfectants as active components. The evaluation of the antibacterial sample properties was carried out by using serial dilutions in agar on hospital bacterial and fungal strains isolated from the biomaterial of patients at the Republican Clinical Hospital named after V.I. Semashko, according to the clinical guidelines “Laboratory diagnosis of community-acquired pneumonia” 2014, “Bacteriological analysis of urine” 2014, “Determination of the susceptibility of microorganisms to antimicrobial drugs” 2015. It was found that N-substituted derivatives exhibit a greater antimicrobial effect compared with unsubstituted polymer. The most sensitive to all the drugs presented was the yeast-like fungi Candida albicans (No. 2495) (complete suppression), as well as methicillin-resistant S. aureus (no. 2544), and the substituted samples almost completely suppress its growth. The most resistant strains are P. aeruginosa (No. 2281), A. baumannii (No. 2806) and K. pneumoniae (No. 3023), the percentage of reduction of these bacteria under the action of substituted samples does not exceed 41%, which is accounted for by their multi-resistance.

Background. Previously, we have shown that the polyhexamethylene guanidine hydrochloride hydrogel exhibits a pronounced wound healing. At the same time, no studies of the toxic effect of the hydrogel on animals have been conducted. Aim of the research. In the framework of this work, the acute toxicity of the hydrogel polyhexamethylene guanidine hydrochloride was studied in laboratory animals with intragastric administration. Materials and methods. The polyhexamethylene guanidine hydrochloride hydrogel was obtained by crosslinking the amino end groups with formaldehyde. An acute toxicity study was carried out (P 1.2.3156-13, GOST 32644-2014 and the Guidelines for conducting preclinical studies of drugs) in an experiment on outbred mice with a single addition of the test substance in different doses (1000, 3000, 5000, 8000 mg/kg) with fixing indicators (appearance, behavior, condition of the body hair coat, water and food consumption, excretion, body weight and its growth) during 14 days. After the animals were withdrawn from the experiment, autopsy, macroscopic evaluation and weighing of the internal organs were performed. The results showed that with the introduction of the test substance into the animal organism, death during the observation period (14 days) did not occur. It was not possible to determine the semi-lethal dose for the test compound. Conclusion. The conducted studies allow us to conclude that this substance is practically non-toxic and can be classified as hazard class V. Further research will be directed to the formation of hydrogel compositions with medicinal substances.

Polyguanidines are characterized by pronounced antimicrobial activity and are widely used as the main active substance of disinfectants. Polymers of this class possess the property of gel formation, which, together with biological activity, opens the prospect of obtaining an effective single-component agent or basis for an external preparation for the therapy of skin lesions. Earlier, we developed a method for the production of a hydrogel based on polyhexamethyleneguanidine hydrochloride, which involves the cross-linking of the terminal amino groups of the branched polymer with formaldehyde.The purpose of the study was to observe the effect of hydrogel polyhexamethyleneguanidine hydrochloride on the progression of wound healing.Materials and methods. An experiment on the evaluation of the wound healing action of hydrogel was carried out under conditions simulating a linear cutaneous wound, a muscular wound, and a thermal burn. The comparative drug was the pharmacopoeian drug Levomecol.Results. It has been established that hydrogel has a pronounced wound healing effect, as evidenced by the results of ruminant thoracic anatomy and pathomorphology of the sections, which shows accelerated ripening of granulation tissue and scar formation. By the method of vulnografiya it was shown that the daily decrease in wound area is most pronounced in the hydrogel group, which also indicates a pronounced reparative effect. It was determined that the hydrogel activates the growth of antioxidatic activity and leukocytes in the blood of animals in dynamics on the 10th, 17th and 24th day of the experiment, amounting to 56, 34 and 21%, and of leukocytes – 32, 30, 10% in relation to the intact animals.Conclusion. Thus, on the model of a linear cutaneous wound, a muscular wound, and a thermal burn, the healing effect of the hydrogel PGMGh/f is established, as evidenced by the results of the early exercise, vulnografiya and pathomorphological studies. It is noted that the hydrogel PGMG h/f has an effect on the content of antioxidants and leukocytes in the blood, contributing to the normalization of their quantity.

This article considers the wound-healing effect of a hydrogel based on polyhexamethyleneguanidine hydrochloride under conditions of thermal shock modeling. The presence of gelling properties in combination with the high biocidal activity of polyguanidins opens the prospect of obtaining an effective single-component external agent, which is very important for antimicrobial chemotherapy of wounds and burns, as in their treatment there is a high probability of infecting the wound with microorganisms causing various infectious diseases. Previously, we developed a method for the preparation of a hydrogel based on polyhexamethyleneguanidine hydrochloride, which involves the cross-linking of the amino-end groups of the branched polymer with formaldehyde, resulting in a cross-linked polymer, which is a lump-like mass. The mechanical treatment of the hydrogel makes it possible to give the material an ointment form that is convenient for application to the skin. An experiment on the evaluation of the wound healing action of hydrogel was carried out under the conditions of modeling a thermal burn. The comparative preparation was multicomponent gel "Levomekol", in which polyethylene oxide was used as the basis. It was established that the hydrogel activates the growth of antioxidants and leukocytes in the blood of animals in dynamics on the 10th, 17th and 24th day of the experiment, amounting to 56.4 %, 33.8 % and 20.9 %, and of leukocytes - 27.7 %, 19.6 %; 6,2 % in relation to the norm. The method of contrast radiography of penetrating wounds showed that the daily reduction in the wound area is most pronounced in the hydrogel group, which indicates a pronounced reparative effect.

This article present the evaluation of polyhexamethyleneguanidine hydrochloride hydrogel influence on the course of wound healing processes. Synthesis of hydrogel is based on the interaction of amino-end groups of the polymer with carbonyl compounds. The presence of significant biocidal properties of the gel-forming polymer is allowed to consider the hydrogel as a wound healing agent. Since most wound healing agents for external use are made in the form of gels, ointments, polymer-based, it was decided to use the wound healing agent "Levomekol", a gel which consists of poly (ethylene oxide) as a comparison drug. So, in terms of linear skin-muscle wound we established the pronounced wound-healing effect of a polyhexamethyleneguanidine hydrochloride hydrogel. The results of pathomorphological studies revealed that in animals of the experimental "hydrogel" group on the eighth day of the experiment, the wound was undergoing a process of rejection of the scab, the presence of mature granulation tissue and no exudate was also observed. In the comparison group, the healing process was more slow, on the eighth day of the experiment in the animal group we observed the presence of fluid under the eschar, and lower amount of mature granulation tissue. Tensiometry of the scar has shown that the strength of scar rupture in the "hydrogel" group requires 65 % more force compared to the control group, while in the group of comparison this parameter made only 48 %.

Polymers with amidine groups –NH–C(=NH)– in main chain were synthesized by two different approaches. The first strategy consists in polyaddition of dinitriles and diamines in acidic ionic liquids (ILs) which act as catalyst and solvent, while the second approach is based on polycondensation of 4,4'-oxybis(benzoic acid) diamide and diamines in Eaton’s reagent (ER). The resulting polyamidines (PADs) with Mw up to 25 000 g/mol possess thermal stability on air up to 288°C, and good solubility in polar organic solvents. Moreover dehydrocyclization of obtained PADs into polybenzimidazoles (PBIs) under the action of various oxidants was also studied in this work. The crosslinked films based on PBI and poly(amino imide) resin (PAIR) possess high mechanical characteristics. It has been proved that the crosslinked films based on PBI matrix are perspective materials for design the phosphoric acid electrolyte membranes for the medium temperature fuel cells.

It is established that N‐phenylsubstituted aromatic polyamides can be obtained via Chapman rearrangement of polybenzanyliminoesters synthesized by an interaction of bisphenols with imidoylchlorides. The rearrangements in melt or in film occur as a result of heating at 260–340 °C, and in a diphenyl ether solution rearrangement occurs at 240 °C. The resulting polymers are soluble in organic solvents and demonstrate high thermooxidative stability. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4656–4660, 2007 [ABSTRACT FROM AUTHOR]

Eight fractions of polystyrene with linear structure and different molecular weights were prepared by fractional precipitation with methanol from a solution of polystyrene in chloroform. The polystyrene fractions were dissolved in toluene to prepare solutions with different concentrations for dynamic property studies. The dynamic shear modulus and the tangent of the mechanical loss angle for these solutions were measured by the acoustic-resonance method. [ABSTRACT FROM AUTHOR]

Thermodynamic characteristics of adsorption of organic compounds on semiinterpenetrating networks based on polybenzimidazoles and polyaminoimide resin with different compositions were studied at small coverages using inverse gas chromatography. The following characteristics were determined: adsorption equilibrium constants (specific retention volumes) of substances of different classes (n-alkanes, aromatic hydrocarbons, ethers, ketones, alcohols, and nitrogen- and halogen-containing compounds), appropriate changes in differential molar internal energy and Helmholtz potential, and changes in standard molar entropy of the sorbates. The contributions of the molecular fragments to the heat of adsorption were calculated. The adsorption properties of the semiinterpenetrating networks based on polybenzimidazoles and polyaminoimide resin differ from those of the starting polymeric materials and their physical mixtures with the similar composition. Unlike graphitized thermal carbon black (nonspecific adsorbent), the network and starting materials manifest the specific properties (electron-donating and electron-accepting). The difference in the thermodynamic characteristics of adsorption on the semiinterpenetrating polymeric networks with different compositions is determined by the size and geometry of interphase regions. [ABSTRACT FROM AUTHOR]

Abstract The possibility of preparing modification solutions from sodium naphthalenide wastes and their effect on Teflon adhesion were studied. [ABSTRACT FROM AUTHOR]