M. Yu. Smirnova

Synthesis and biological activity of water-soluble polymer complexes of arbidol

We have synthesized water-soluble complexes between the antiviral drug arbidol and polymer compounds with molecular masses of 19–31 kDa representing copolymers of acrylamide (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AAMPS). The complexes are less toxic than arbidol and retain the high level of antiviral activity of this drug. The content of arbidol in the obtained complexes is within 26.4–32.1 mass%. The antiviral activity of the synthesized polymeric complexes against all studied viruses, including human epidemic influenza virus A (H3N2), bird highly pathogenic influenza virus A (H5N1), herpes type 1 virus (HSV-1), and adenovirus type III (AV-III) is comparable to the antiviral effect of nonmodified arbidol. The in vitro toxicity of the obtained complexes is about one order of magnitude lower than that of nonmodified arbidol; the pharmacological index, four times that of the initial low-molecular-weight drug. The synthesized water-soluble polymer complexes of arbidol can be useful in pharmacology since they can serve as the basis for new effective and safe parent antiviral substances and related formulations.

Complexation of anionic copolymers of acrylamide and N-(2-hydroxypropyl)methacrylamide with aminoglycoside antibiotics

The complexation of aminoglycoside antibiotics neomycin, gentamicin, kanamycin, and amikacin in the form of free bases with carboxyl- and sulfo-containing copolymers of acrylamide and N-(2-hydroxypropyl)methacrylamide (HPMA) in water and water-salt solutions is studied by means of viscometry, equilibrium dialysis, potentiometric titration, and molecular hydrodynamics. Factors influencing the stability of formed copolymer-antibiotic complexes and determinations of their toxicity are established.

Effect of metal content on the behavior of Pt/SAPO-31 catalysts in the hydroconversion of sunflower oil

It is shown that catalysts based on Pt/SAPO-31 can be used for the single-stage conversion (in contrast to the two-stage commercial process) of vegetable oil into waxy diesel fuel components. The effect of the content of metal (0.5–2 wt % Pt) in the catalyst on its physicochemical and catalytic properties is studied. It is found that regardless of the platinum content, the activity of the catalysts diminishes during the reaction, as is indicated by a drop in their isomerization ability and the presence of oxygen-containing compounds in the reaction products. The physicochemical properties of Pt/SAPO-31 catalysts are studied via the IR spectroscopy of adsorbed pyridine, hydrogen chemisorption, and transmission electron microscopy. It is shown that the catalytic degradation is caused by the poisoning of the acid sites and a reduction in the active surface area of the metallic component. Possible ways of improving the on-stream stability of Pt/SAPO-31 samples in the hydroconversion of vegetable oil are described.

Synthesis of low-molecular-weight N-(2-hydroxypropyl)methacrylamide sulfonated copolymers as carriers of biologically active substances

New water-soluble copolymers of N-(2-hydroxypropyl)methacrylamide with 2-acrylamido-2-methylpropanesulfonic acid as carriers of cationic biologically active substances were synthesized. The physicochemical properties of the copolymers were studied.

Complexes of aminoglycoside antibiotics with copolymers of acrylamide with acrylic and methacrylic acids

Polymer complexes of aminoglycoside antibiotics as bases with low molecular weight water-soluble copolymers of acrylamide (ACR) with acrylic (AA) and methacrylic (MA) acids containing 15 – 20 mol% carboxyl groups were synthesized. Complexes of antibiotics with ACR-MA copolymers were found to be more stable in aqueous and aqueous salt solutions and to have less toxicity in vitro than complexes based on ACR-AA copolymers. All polymer complexes retained high levels of antibacterial activity.

The Synthesis of Ce 1 – x Zr x O 2 Oxides in Supercritical Alcohols and Catalysts for Carbon Dioxide Reforming of Methane on Their Basis

The effect of the features of starting zirconium compounds on the solvothermal synthesis of mixed Ce–Zr oxides in a flow reactor using ethanol and isopropanol as a supercritical medium was studied. The phase composition and structural properties of the synthesized samples were investigated using X-ray diffraction analysis (XRD) and Raman spectroscopy. The morphology and textural properties were studied by transmission electron microscopy (TEM) and thermal desorption of nitrogen. It was found that the use of zirconium oxychloride or acetate as the starting substances results in the formation of a mixture of phases enriched with cerium or zirconium, whereas the use of zirconium butoxide with acetylacetone as a complexing agent allows obtaining a homogeneous solid solution. The catalytic properties of the synthesized oxides with supported Ni were tested in methane dry reforming (MDR). The catalyst containing a single-phase oxide synthesized in the presence of acetylacetone exhibited much higher activity, selectivity and coking stability.

Physicochemical and catalytic properties of SAPO-31 materials prepared from the silica sources characterized by a different degree of polymerization

Two series of microporous silicoaluminophosphates SAPO-31 with different Si content (Si/Al = 0—0.5) were synthesized using silica sources characterized by various degree of polymerization (fumed silica and tetraethoxysilane). Physicochemical properties of the resulted materials were studied by X-ray diffraction, XPS, scanning (SEM) and transmission (TEM) electron microscopy. The nature of the silicon species was identified by 29Si NMR method and the acidity was measured by IR-spectroscopy of adsorbed pyridine. The activity and selectivity of Pd modified SAPO-31 samples from both series were evaluated in the isomerization of n-decane. It was found that the use of the monomer as a silicon source ensured more efficient silicon incorporation, which resulted in the higher activity of Pd/SAPO-31 catalysts. Moreover, the selectivity of these samples for isomerization was found to be independent of the silicon content and its distribution.

Synthesis of water-soluble polymeric esters of the antibiotic cefuroxime

Water-soluble polymeric esters of the antibiotic cefuroxime were synthesized for the first time by the carbodiimide method using low-molecular-weight poly-(N-2-hydroxypropyl)methacrylamide as a carrier. The synthesized compounds contain 16.6 and 19.5 wt% antibiotic, exhibit antibacterial activity with respect to S. aureus, and are subject to hydrolysis in physiological solution at 37°C (45.4 and 53.2% for 24 and 30 h, respectively).

Antimicrobial activity of carbon fiber fabric modified with a polymer-gentamicin complex

Modified and unmodified carbon fiber supports were treated with solutions of a polymer-gentamicin complex, possessing high antimicrobial activity and low toxicity. It was found that the antimicrobial activity of modified carbon fiber fabrics depended on the nature of the support and on the immobilization conditions. The highest antimicrobial activity was observed with phosphorus-containing carbon fiber ion exchanger in salt form.

Synthesis and properties of low-molecular-weight copolymers of acrylamide with 2-acrylamido-2-methylpropanesulfonic acid, as potential drug carriers

Nontoxic water-soluble low-molecular-weight (MW 14 000–36 000 Da) copolymers of acrylamide with 2-acrylamido-2-methylpropanesulfonic acid, containing from 17.3 to 37.6 mol % sulfonate-containing monomeric units, were synthesized by heterophase radical polymerization in isopropanol or ethanol at 50°C with azobis(isobutyronitrile) as an initiator.