Various techniques for the delivery of nucleic acids into cells are described herein. Particularly, the use of cationic liposomes was evaluated in detail. Cationic liposomes typically consist of amphiphilic cationic lipids. Neutral helper lipids may be added to cationic liposomes to enhance the transfection efficiency. The review discusses the structures and efficiency of such compounds and commercially available transfection agents.
Objectives. Gene therapy is based on the introduction of genetic material into cells, tissues, or organs for the treatment of hereditary or acquired diseases. A key factor in the success of gene therapy is the development of delivery systems that can efficiently transfer genetic material to the place of their therapeutic action without causing any associated side effects. Over the past 10 years, significant effort has been directed toward creating more efficient and biocompatible vectors capable of transferring nucleic acids (NAs) into cells without inducing an immune response. Cationic liposomes are among the most versatile tools for delivering NAs into cells; however, the use of liposomes for gene therapy is limited by their low specificity. This is due to the presence of various biological barriers to the complex of liposomes with NA, including instability in biological fluids, interaction with serum proteins, plasma and nuclear membranes, and endosomal degradation. This review summarizes the results of research in recent years on the development of cationic liposomes that are effective in vitro and in vivo. Particular attention is paid to the individual structural elements of cationic liposomes that determine the transfection efficiency and cytotoxicity. The purpose of this review was to provide a theoretical justification of the most promising choice of cationic liposomes for the delivery of NAs into eukaryotic cells and study the effect of the composition of cationic lipids (CLs) on the transfection efficiency in vitro.
Results. As a result of the analysis of the related literature, it can be argued that one of the most promising delivery systems of NAs is CL based on cholesterol and spermine with the addition of a helper lipid DOPE. In addition, it was found that varying the composition of cationic liposomes, the ratio of CL to NA, or the size and zeta potential of liposomes has a significant effect on the transfection efficiency.
Conclusions. Further studies in this direction should include optimization of the conditions for obtaining cationic liposomes, taking into account the physicochemical properties and established laws. It is necessary to identify mechanisms that increase the efficiency of NA delivery in vitro by searching for optimal structures of cationic liposomes, determining the ratio of lipoplex components, and studying the delivery efficiency and properties of multicomponent liposomes.
THEORETICAL BASIS OF CHEMICAL TECHNOLOGY
Thermodynamics properties of menthol were analyzed utilizing various experimental techniques and calculations. The relationships between the temperature and heat capacity, enthalpy, entropy, and Gibbs free energy were established for menthol. Quantum chemical modeling was used to determine the structure of the most stable menthol conformer.
Objectives. Menthol causes a cooling sensation and reduces the nerve activity when it is applied locally, ingested, or inhaled. This feature explains its extensive use as both an aromatizer and a flavoring agent in food manufacturing, tobacco industry, cosmetics production, as well as a mild anesthetic and antiseptic in dentistry. This work aimed to perform a comprehensive thermodynamic study of L-menthol in both crystalline and gaseous states.
Methods. To determine the combustion energy of L-menthol in the crystalline state, combustion bomb calorimetry was used. The temperature dependence of L-menthol’s heat capacity in the range of 5–370 K and the melting (fusion) parameters were determined using adiabatic calorimetry. Quantum chemical calculations were performed on a standalone virtual machine in the Google Cloud Platform using an eight-core Intel Xeon Scalable Processor (Skylake) with a 2.0 GHz (up to 2.7 GHz at peak load) clock frequency and 8 GB RAM.
Results. The energy and enthalpy of L-menthol combustion in the crystalline state were determined, and the standard enthalpy of L-menthol formation in the gaseous state was calculated using the standard enthalpy of sublimation. The standard thermodynamic functions (reduced enthalpy, entropy, and reduced Gibbs energy) of L-menthol in both crystalline and liquid states were obtained based on the smoothed values of heat capacity and melting parameters. The group of isodesmic reactions for the ab initio calculation of the enthalpy of formation for gaseous L-menthol was substantiated. Electronic energy and frequencies of normal modes of the molecules involved in these reactions were calculated using the Gaussian 4 composite quantum chemical method. Further, the sublimation enthalpy of L-menthol was calculated using the extended Politzer equation according to the electrostatic potential model.
Conclusions. The first comprehensive thermodynamic study of L-menthol in various states of aggregation was performed, and the values calculated using semiempirical methods were consistent with the experimental values within error limits, which confirms the reliability of the results.
Efficient energy redistribution is proposed for the Duosol and dewaxing processes. The separation of the regeneration unit furnace into two chambers is suggested to prevent the contamination of propane, which is used for column heating, with water. The new approach can prevent the formation of contaminated effluents at oil dewaxing plants.
Objectives. The synthesis of high-viscosity oils is a fundamental aspect of oil refinement and contributes toward improvements in their production technologies. However, current methods of oil extraction are characterized by the inefficient use of energy resources. Therefore, refinement costs continue to increase. Furthermore, high production emissions affect the environment. For example, the Duosol-type process uses a large quantity of gas used in solvent recovery units in existing furnaces, and excess heat is wasted. Additionally, oil dewaxing plants use water steam, whose condensate can be contaminated with petroleum products or ketone-aromatic solvents. The purpose of this study was to identify ways of improving the efficiency of high-viscosity oil production technologies for energy efficiency and environmental safety as well as prove the feasibility of computational methods of oil production plants’ improvement.
Methods. The heat quantity required for high-viscosity oil production is calculated using a thermal equation and data obtained from industrial equivalents, empirical dependencies, and reference data. The heat capacities and heat quantities of Duosol and dewaxing plants are calculated using conventional methods based on the heat recovery principle.
Results. At the solvent regeneration unit of a Duosol plant, excessive heating of the cube in one of the distillation columns was measured, leading to excessive heat consumption. This may result in contamination of the low boiling distillation component with water—one of the still bottom mixture components. Calculations show that the furnace should be divided into two chambers to lower the temperature of the column cube to help solve this problem. Water steam is currently used in the raw material preparation unit of the dewaxing plant. It has been found, however, that the quantity of heat carried away by the flue gases of the furnaces is sufficient to heat the raw material preparation unit of the oil dewaxing plant if water steam is completely excluded from this operation.
Conclusions. Technology improvement at Duosol and dewaxing plants, which are part of the process of obtaining high-viscosity oils at refineries, is possible through the effective redistribution of energy resources.
Phase envelopes and critical points were determined for several multicomponent systems using flash calculations. The calculations employed the Soave−Redlich−Kwong (SRK) equation of state with Van der Waals (VdW) mixing rules, Peng−Robinson (PR) equation of state with Wong−Sandler (WS) mixing rules, and the non-random two-liquid (NRTL) activity coefficient model.
Objectives. This study aims to draw PT-phase envelopes and calculate the critical points for multicomponent systems using flash calculations.
Methods. Flash calculations with an equation of state and a mixing rule were used to construct phase envelopes for multicomponent systems. In general, the methodology uses the Soave–RedlichKwong equation of state and Van der Waals mixing rules; and the Peng–Robinson equation of state with Wong–Sandler mixing rules and the non-random two-liquid activity coefficient model.
Results. The method was applied to the following mixtures: ethane (1)–butane (2) (four different compositions); ethane (1)–propane (2) (four different compositions); butane (1)–carbon dioxide (2) (three different compositions); C2C3C4C5C6 (one composition); isobutane–methanol–methyl tertbutyl ether–1-butene (one composition); and propylene–water–isopropyl alcohol–diisopropyl ether (one composition).
Conclusions. Our results agreed to a large extent with the experimental data available in the literature. For mixtures that contained CO2 , the best results were obtained using the PengRobinson equation of state and the Wong–Sandler mixing rules. Our methodology, based on flash calculations, equations of state, and mixing rules, may be viewed as a shortcut procedure for drawing phase envelopes and estimating critical points of multicomponent systems.
CHEMISTRY AND TECHNOLOGY OF ORGANIC SUBSTANCES
The synthesis of propylene carbonate from propylene glycol and carbamide (urea) is described herein. The synthetic yield depended on the initial ratio of the reactants, temperature, time, and concentration of the catalyst. Zinc acetate was used as the reaction catalyst.
Objectives. Cyclic carbonates are important products of organic synthesis, which are widely used as solvents, catalysts, and reagents for the production of various compounds (in particular, urethane-containing polymers) by the non-isocyanate method. The process of carbamide alcoholysis with polybasic alcohols is a promising method for the synthesis of cyclic carbonates. The purpose of this study is to determine the reaction conditions for the interaction of propylene glycol with carbamide in the presence of zinc acetate as a catalyst.
Methods. We conducted experiments to study the synthesis of propylene carbonate in a batch laboratory apparatus. Moreover, we analyzed the starting reagents and final products using gas–liquid chromatography.
Results. We studied the synthesis of propylene carbonate by carbamide alcoholysis with propylene glycol in the presence of a catalyst (zinc acetate) by varying the following parameters: initial molar ratio of propylene glycol/carbamide = (0.5–5):1, synthesis temperature 130–190°С, reagent residence time in the reactor 0.5–4 h, and the catalyst amount in the reaction mixture 0–1.5 wt %.
Conclusions. We determined the technological parameters of propylene carbonate synthesis in a batch reactor. Moreover, we showed that the process allowed the production of propylene carbonate with a sufficiently high yield of 80%—at the initial molar ratio of propylene glycol/ carbamide = 3:1, temperature 170°C, and residence time 2 h.
SYNTHESIS AND PROCESSING OF POLYMERS AND POLYMERIC COMPOSITES
The compositions of different dispersion-filled polymer composite materials were presented in mass or volume units. It was determined that mass units were not suitable for describing the structural types of composites and volume units should be used instead.
Objectives. The aim is to calculate the composition of dispersion-filled polymer composite materials with different fillers and structures and to highlight differences in the expression of said composition in mass and volume units.
Methods. The paper presents the calculation of compositions in mass and volume units for various types of structures comprising dispersion-filled polymer composite materials according to their classification: diluted, low-filled, medium-filled, and highly-filled systems.
Results. For calculations, we used fillers with densities ranging from 0.00129 (air) to 22.0 g/cm3 (osmium) and polymer matrices with densities between 0.8 g/cm3 and 1.5 g/cm3 , which represent almost all known fillers and polymer matrices used to create dispersion-filled polymer composite materials. The general dependences of the filler content on the ratio of the filler density to the density of the polymer matrix for dispersion-filled polymer composite materials with different types of dispersed structures are presented. It is shown that to describe structures comprising different types of dispersion-filled polymer composite materials (diluted, low-filled, medium-filled, and highly-filled) it is necessary to use only the volume ratios of components in the calculations. Compositions presented in mass units do not describe the construction of dispersion-filled polymer composite material structures because using the same composition in volume units, different ratios of components can be obtained for different fillers.
Conclusions. The dependences of the properties of dispersion-filled polymer composite materials should be represented in the coordinates of the property – content of the dispersed phase only in volume units (vol % or vol. fract.) because the structure determines the properties. Compositions presented in mass units are necessary for receiving batches upon receipt of dispersion-filled polymer composite materials. Formulas are given for calculating and converting dispersion-filled polymer composite material compositions from bulk to mass units, and vice versa.
ANALYTICAL METHODS IN CHEMISTRY AND CHEMICAL TECHNOLOGY
A novel nasal spray was developed for the prevention of influenza and other viral respiratory infections. The spray contains aminocaproic acid and a copolymer of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine. The viscosity of different nasal spray compositions was analyzed to determine the optimal formulation. The nasal spray can be stored for up to 2 years without any efficacy loss.
Objectives. Prevention of influenza and viral respiratory infections is one of the major public health problems today. The aim of the study was to develop the formulation and production conditions for a nasal spray that can be used in the prevention of influenza and other viral respiratory infections, based on aminocaproic acid and a copolymer of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine.
Methods. The influence of pH and temperature on the transparency of the copolymer solution was investigated using a turbidimeter to determine the optimal pH for the dosage form. The pH value was determined using a pH meter equipped with a combined glass electrode. The presence or absence of opalescence in the solution was determined visually, whereas the dynamic viscosity of the solution was determined at 25.0±0.5°С using a rotational viscometer. The optimal temperature and mixing speeds were selected as part of the technological development process. Quantitation of the active substances in the resulting drug was conducted using a previously reported high performance liquid chromatography method. A preliminary evaluation of the drug’s shelf life was performed via stability studies using the accelerated aging method.
Results. Drug stability was ensured when the pH range of the dosage form was between 5.5 and 6.2. The addition of a thickening agent is not advisable due to undesired interactions between the excipients and the active substances during storage. Ideally, the drug composition for nasal use was aminocaproic acid (1 wt %) and the copolymer (0.5 wt %) in aqueous solution. A phosphate buffer solution with pH 5.5 was selected as the solvent for the dosage form to ensure the stability of the drug solution and ease-of-use without any disruptions in the normal functioning of the cilia in the nasal cavity. The optimal technology for drug production was determined, and the control parameters for this process were highlighted. Drug stability studies conducted via the accelerated aging method revealed that the estimated shelf life of the dosage form was 2 years.
Conclusions. A new formulation and optimized production conditions were developed for a drug based on aminocaproic acid and a copolymer of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine, in the form of a nasal spray, for the prevention of influenza and other viral respiratory infections.
In the present study, carbonized rice husk is suggested as a sorbent for oil products. Production of carbonized rice husk is described, and its properties are investigated by mercury porosimetry. It was established that rice husk is effective at purifying water by removing oil and oil products.
Objectives. This study aims to establish the available porosity of a sorbent based on carbonized rice husk and investigate its sorption properties for oil and oil products.
Methods. A rice-husk-based sorbent carbonized at 400°С for 30 min was selected as the subject. The porosity of this sorbent is analyzed with the help of mercury porosimeters, the Pascal 140 EVO and Pascal 240 EVO. The sorption properties of the sorbent are also studied when cleaning water containing oil and oil products.
Results. The test sample is a bulk porous material with a pore volume of 0.015 cm/g; porosity higher than 15% was found, and the pore size distribution is shown. Studies were conducted on the sorption of oil and oil products as well as the possibility of using the aforementioned sorbent as a filtering material in the purification of water containing oil products. We investigated the sorption processes under dynamic and static conditions. The methodology for measuring the porous structure of solid materials on the mercury porosimeter, Pascal 140 EVO, was examined. The texture characteristics of the sorbent’s porous structure were determined, which is primarily the total volume of pores, the values of the specific surface area, and the volume of the microspores and mesopores.
Conclusions. The materials studied can be used as sorbents with a developed porous structure for purification of water with dissolved and emulsified petroleum products.
ISSN 2686-7575 (Online)
