The article discusses application of two powerful NMR techniques ME-HSQC and HMBC to determine the structure of gemfibrozil molecules as an example on the benchtop NMR spectrometer X-Pulse. The obtained results give grounds to assert that the use of the benchtop X-Pulse NMR spectrometer allows obtaining reliable results in a short time.

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The present work is devoted to the problems of identifying critical components and excipients of biopharmaceuticals, such as O-linked glycans released from glycoproteins by reductive в-elimination; sialic acids; and vaccine adjuvants. The main problem of HPLC analysis of such compounds is the absence of a detection system that is independent of the presence or absence of chromophore and fluorophore groups in the molecule and gives an almost universal response regardless of the chemical structure of the analyte. The article describes the characteristics of a charged aerosol detector (CAD), the use of which makes it possible to solve most of the problems associated with the detection of chromophore-free substances. The article demonstrates several examples where CAD can be used to detect and quantify substances separated by reverse phase chromatography and hydrophilic interaction chromatography.

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"TD "CHIMMED" LLC offers services of designing laboratories of various profiles and their complex equipment with laboratory and analytical equipment, consumables, and furniture. Development of pre-project and project documentation in accordance with the Decree of the Government of the Russian Federation No. 87 dated 02/16/2008 is possible on request.

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The results of the eighth set of industry events in the field of biotechnology, biopharmaceuticals and virology OpenBio, which took place in the Koltsovo science city of the Novosibirsk region on October 5-8, were summed up. About 6 thousand people took part in the scientific conference and business forum.

Introduction. Etravirine, being one of the most popular antiretroviral drugs, doesn't have its physicochemical properties sufficiently described in scientific publications. Detailed information on the substance properties is necessary both for organizing the synthesis and for justifying the dosage form and technology for its production, as well as for identifying bottlenecks and critical parameters that affect the quality of the finished product.

Aim. Study the etravirine physicochemical properties to model the design of studies to create an innovative dosage form

Materials and methods. Etravirine (MSN Life Sciences Pvt. Ltd., Hetero Labs Ltd.). The melting point was determined by the capillary method. Etravirine samples were studied via differential scanning calorimetry (DSC), X-ray powder diffractometry, IR and NMR spectroscopy. Particle size was determined using laser diffraction analysis. The shape and size of the crystals were determined with the help of transmission electron microscopy (TEM). The concentration of etravirine in aqueous media was determined using the HPLC method with a fluorescence detector. The concentration of etravirine in organic solvents was determined spectrophotometrically.

Results and discussion. The X-ray powder diffractometry and IR spectroscopy helped to determine the fact that the studied substances represent the same polymorphic modification. The melting point of etravirine ranges from 259 to 263 °C. Melting is accompanied by decomposition. The substance is practically insoluble in aqueous media at pH values in the range from 1.2 to 6.8, soluble in some organic solvents, readily soluble in dimethyl sulfoxide, tetrahydrofuran, dimethylformamide, dimethylacetamide. The distribution coefficient in the "1-octanol/phosphate buffer solution pH 6.8" solvent system was 5.22. The experiment showed that the etravirine substance is lipophilic. Etravirine is found to be a highly crystalline substance and represents needle-shape prismatic crystals.

Conclusion. Etravirine is a lipophilic substance, practically insoluble in aqueous solutions, soluble in a number of organic solvents. The studied substances turned out to be the same polymorphic modification. Since the melting of the substance is accompanied by decomposition, high temperatures processes should be avoided.

Conflict of interest. The authors declare that they have no obvious and potential conflicts of interest related to the publication of this article.

Introduction. Chicory (Cichorium intybus L.) is widely applied for liver disease treatment by traditional medicine of different countries; as well, it is the object for pharmacological research of hepatoprotective activity. In this regard, the method for obtaining dry extract of wild chicory herb (WCHE) is developed in the All-Russian Research Institute of Medicinal and Aromatic Plants.

Aim. Aim of the research is determination of the qualitative composition of phenolic compounds, identification of the substances prevailing in WCHE and conducting pharmacological screening of the extract.

Materials and methods. WCHE chemical composition has been explored with HPLC-MS/MS method; the main components were determined quantitatively with HPLC-UF method using single compounds that were isolated by us earlier and identified by NMR spectroscopy. WCHE pharmacological screening of hepatoprotective activity research was involving 50 male rats. Acute toxic hepatitis in animals was induced by a single subcutaneous injection of 50 % oily solution of tetrachloromethane (TCM) at a dosage of 0.4 ml per 100 g body weight. One hour before administration TCM, animals received WCHE at the doses of 100 or 500 mg/kg. 48 hours after TCM administration, the activity of serum enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), as well as the content of total bilirubin were determined for preliminary establishment of pharmacological activity. Pathomorphological studies of rat liver were carried out using histological methods. The liver histological structure was inspected using liver sections stained with hematoxylin and eosin.

Results and discussion. The component composition of WCHE is represented by oxycoumarins, hydroxycinnamic acids and flavonoids. The dominant phenolic compounds are esculetin, chicoriin, chicoric, chlorogenic and caftaric acids. It was found under acute experimental toxic hepatitis, that preliminary WCHE administration reduces the toxic TCM effect on liver cells. In animals treated with WCHE at doses both 100 mg/kg and 500 mg/kg body weight, it was observed decreases in ALT activity by 35 % and 45 %, AST by 15 % and 28 %, alkaline phosphatase by 15 % and 21 %; the content of total bilirubin by 20 % and 29 %, respectively, in comparison with similar indicators in the group of animals that were not treated with the extract. The histological study showed that WCHE administration to animals at the doses of 100 and 500 mg/kg reduces dystrophic changes in hepatocytes, this effect is more pronounced at the extract dosage of 500 mg/kg.

Conclusion. Main WCHE components are oxycoumarins (esculetin, chicoriin), hydroxycinnamic acids (chicoric, chlorogenic and caftaric). According to the results of screening studies, it was established that WCHE in doses of 100 mg/kg and 500 mg/kg is a promising object for further pharmacological research.

Introduction. Silver nanoparticles are promising agents for suppressing resistant strains of microorganisms and accelerating the purulent wounds healing. Oxidative stress disrupts normal wound healing processes, which leads to the formation of chronic non-healing wounds. Therefore, the determination of the ability of new wound healing agents to decrease the production of reactive oxygen species is a relevant task.

Aim. The aim of the current study was to investigate the effect of silver-containing bionanocompositions based on humic substances on the basal and tert-butyl hydroperoxide-stimulated production of reactive oxygen species at the normal fibroblasts 3T3-L1 cell culture in vitro.

Materials and methods. The study was carried out on 7 samples of initial humic substances and biomaterials with silver nanoparticles synthesized in the Laboratory of Natural Humic Systems, Faculty of Chemistry, Moscow State University named after M. V. Lomonosov. The intracellular production of reactive oxygen species was assessed using a 2,7-dichlorodihydrofluorescein diacetate fluorescent probe. Cells were cultured with samples for 24 h; tret-butyl hydroperoxide was used to stimulate the production of reactive oxygen species. Detection was performed fluorometrically using a microplate reader.

Results and discussion. The most pronounced antioxidant activity was demonstrated by three samples of biomaterials with silver nanoparticles ultradispersed in humic substances matrices (CHS-AgNPs, CHP-AgNPs and CHE-AgNPs), which allows us to consider them as the most promising pharmaceutical agents for the treatment of purulent-inflammatory processes. The most probable mechanism of the high antioxidant activity of the studied biomaterials in relation to intracellular reactive oxygen species is the intrinsic activity of humic substances to bind reactive oxygen species, while silver nanoparticles in biomaterials catalyze the reduction processes of their interaction with reactive oxygen species.

Conclusion. For the studied samples of biomaterials with silver nanoparticles ultradispersed in matrices of humic substances pronounced antioxidant activity was shown. Together with antibacterial properties, it makes it possible to consider them as potential agents for purulent wounds healing accelerating.

Introduction. Intranasal delivery of in situ gel-forming systems is a complex but promising direction. Due to the high cost of developing a new chemical object or genetically engineered modification of biological molecules, pharmaceutical companies are focusing on developing technologies for new delivery systems for existing active pharmaceutical ingredients to improve their effectiveness and bioavailability. In situ systems for intranasal delivery, due to increased viscosity and mucoadhesion to the nasal mucosa, allow overcoming mucociliary clearance and ensuring complete absorption and prolonged release of drugs.

Text. The article discusses the main advantages of intranasal in situ delivery systems shown in preclinical studies, as well as approaches to the technology of obtaining and standardization of these systems. The results of scientific research in this field over the past 15 years are summarized, the most promising polymers for creating thermoreversible and pH-sensitive compositions are identified, and modern methods for evaluating the sol-gel transition in situ are analyzed.

Conclusion. The use of in situ systems for intranasal administration allows providing a high targeting of the delivery of synthetic and biological molecules to the brain. Currently, numerous pharmacokinetic and pharmacodynamic preclinical studies confirm the effectiveness of such systems, as well as their safety. Thermoreversible commercially available and directionally synthesized polymers (poloxamer 407, PLGA, NIPAAm, etc.), as well as chitosan, remain the most popular for the design of in situ delivery systems. In vitro and ex vivo methods with mucosa and artificial nasal fluid are widely used to assess the parameters of in situ gelation, but to increase the reproducibility of the methods and improve the correlation in vitro/in vivo, it is recommended to conduct modeling of the nasal cavity. Developing the technology and methods of screening of intranasal reversible systems will help to get closer to clinical trials and the entry of these delivery systems into the global pharmaceutical market.

Introduction. The mineral resource base of Russia has effective sorption substances that meet pharmaceutical requirements. Promising mineral raw materials are Zeolites, which combine the properties of an adsorbent and a "molecular sieve" due to the porous structure. In addition to the enterosorption direction, natural Zeolites are a source of macro-and microelements, which determines their use as biologically active food additives.

Aim. Study of the physical and chemical characteristics of the Zeolites of the Kholinsky deposit.

Materials and methods. The zeolite mineral raw materials of the Kholinsky deposit were used as objects of research. Optical microscopy was performed using a Leica DM direct microscope (Microsystems, Germany). Energy dispersion analysis was performed using an electron scanning microscope JSM-5300 (Jeol Ltd, Japan). The sorption characteristics were studied using the ASAP 2400 device (Micromeritics, USA) according to the method. The construction of a virtual three-dimensional molecular model of the Zeolite was carried out using the program Java Applet Jmol.

Results and discussion. The physicochemical properties of Zeolites are investigated. It is established that morphologically the particles of the zeolite phase have a size of 5-30 microns, they are evenly distributed over the entire area of the site and represent the first structural level. Particles of the zeolite phase with a size of 5-6 microns form the second structural level due to Clinoptilolite crystals, microcracks and microgeodes. Based on the energy-dispersion spectral analysis, an increased content of the elements K, Na was revealed, which indicates the alkaline composition of the cation exchange complex. The studied Zeolite samples have micropores (volume 0.0031 cm³/g), mesopores (volume 0.0675 cm³/g), and a specific surface area of 29.1840 m²/g. A virtual three-dimensional molecular model of the Zeolite of the Kholinsky deposit has been developed. According to the molecular model, the sorption characteristics of the Kholinsky deposit Zeolite were: specific surface area - 1096.31 m²/g (1916.34 m²/cm³), the average diameter of the spherical molecule for adsorption in the pores is 5.97 Å.

Conclusion. The analysis of the sorption characteristics of the Zeolite revealed the following features: the pores occupy half the volume of the entire Zeolite, which are available for the sorption of water and low-molecular substances. Each pore in three mutually perpendicular directions communicates with the neighboring ones through "windows". A system of intracrystalline pores and cavities is formed, in which the occlusion and adsorption of molecules of the appropriate size easily occurs.

Introduction. E. coli strains are the main microorganisms used for the production of a number of important biopharmaceutical products. There are no natural sources of microwave radiation on Earth, as it is absorbed by the upper atmosphere. No one doubts the importance of studying the biological effect of microwave radiation. The number of publications devoted to this problem is growing every year, and new ideas for the use of microwaves in drug production technology are emerging.

Aim. Reveal the main effects of microwave irradiation and develop a technology for microwave intensification of E. coli culture growth.

Materials and methods. This study presents the results of atomic force microscopy, refractometry, NMR relaxometry, turbidimetry, and lumimetry, demonstrating the possibility of microwave intensification of the cultivation process.

Results and discussion. It was found that microwave irradiation leads to changes in the mobility of protons and the adsorption of water molecules on biopolymers and cells. These are the main links in the mechanism of "non-thermal" microwave action. A single microwave irradiation, depending on a number of parameters, can decrease or increase the growth of biomass. Studies of the bioluminescence of the E. coli strain with the lux-operon have shown that the optimal processing conditions do not negatively affect the luciferase production and metabolic activity of cells. Conclusion. The intensification procedure using microwave radiation can be considered a promising method and can provide new ideas for various applications in biotechnology.

Introduction. The use of the anticancer drug paclitaxel is limited due to its high toxicity and lipophilicity. A new polymer composition of paclitaxel has been proposed, which provides targeted transport of the drug into tumor cells and improves its safety.

Aim. Method development for preparation of a novel paclitaxel formulation consisting of a conjugate of PLGA nanoparticles with the third domain of alpha-fetoprotein.

Materials and methods. The object of this study is paclitaxel-loaded nanoparticles based on a copolymer of lactic and glycolic acids, the surface of which is modified with a vector molecule - the recombinant third domain of alpha-fetoprotein. Nanoparticles were obtained by single emulsification method and precipitation. Conjugation with a protein molecule was performed by the carbodiimide method. The analysis of the obtained nanoparticles was carried out using dynamic and electrophoretic light scattering, high performance liquid chromatography, dialysis membrane method.

Results and discussion. Synthesis of paclitaxel-loaded nanoparticles based on a copolymer of lactic and glycolic acids and its conjugation optimization under varying a wide range of conditions have been carried out. The resulting conjugate had an average diameter of 280 ± 12 nm. The conjugation efficiency was 95 %. The release of paclitaxel from the polymer matrix in the release medium was 65 % in 220 h.

Conclusions. A method of obtaining and substantiating the composition of the original nanosized form of paclitaxel is proposed. The possibility of prolonged release of paclitaxel from the polymer matrix has been shown.

Introduction. Phytoecdysteroids are a group of natural compounds related in structure and physiological effect to ecdysone - the hormone of insect molting. Phytoecdisteroids have been found to have an antiflammatory effect, which suggests that they have regenerative properties. The development of a soft dosage form containing phytoecdysteroids is of interest.

Aim. Improvement of ointment compositions with phytoecdysteroids by optimizing the composition of base adjuvants.

Materials and methods. As an active substance was used Serpisten, containing the sum of phytoecdysteroids, the main of which is 20-hydroxyecdysone and obtained from the leaves of Serratulaecoronatae. Raw materials "Serpukhi crowned leaves" were registered by the Federal Service Rospotrebnadzor (Moscow) for the production of dietary supplements (Gr. No. 77.99.23.3.U.1922.3.08), substance Serpisten (Gr. No. 77.99.23.3.U.1923.3.08. TU 9369-002-15092611-2008). In work were used the excipients allowed for medical use: the monoglycerides distilled, T-2 emulsifier, tween 80, sodium - carboxymethylcellulose, polyvinyl alcohol, hydroxide of aluminum, aero forces, vaseline, oil vaseline, sunflower oil. Optimization of ointment auxiliary substances composition was carried out according to the Greco-Latin 4 x 4 square plan with repeated observations. The concentration of hydrogen ions from aqueous ointments was evaluated as process parameters; acid number; release of serpistene from ointment into agar gel, thermal stability of structure. The structural and mechanical properties of the optimal composition ointment composition were determined on a RV type REOTEST 2.1 rotary viscometer (RHEOTEST Medingen GmbH, Germany). Ointment Bepanten (GP Grenzach Produktions GmbH, Germany) was used as a comparison preparation.

Results and discussion. During optimization of the composition of the diphilic ointment with serpistene, was found that the ratio of hydrophobic and hydrophilic phases should be 1 : 1, it is advisable to introduce into the ointment base an emulsifier T-2, aerosil and a mixture of vaseline and vaseline oil in the proportion of 1 : 1. As a result of the carried out studies on the optimization of ointment compositions, the following serpisten ointment composition is proposed: serpisten - 0.02; emulsifier T-2 - 3.0; aerosil - 3.0; vaseline - 23.0; vaseline oil - 23.0; ethyl alcohol 40 % - 1 ml; purified water to 100.0. Comparative analysis of effective viscosity showed that the proposed composition is as close as possible to the Bepanten ointment.

Conclusion. A set of technological studies was carried out to optimize the composition of the Serpisten, 0.02 % ointment on a diphilic basis. The developed composition and technology made it possible to obtain a composition with thermal stability, bring the hydrogen index of the ointment closer to the pH of human skin and achieve the parameters included in the rheological optimum for dermatological ointments (0.34-108 Pa • s).

Introduction. This review examines the current state of technology for ultrasonic isolation of biologically active components from medicinal vegetal raw materials. The main emphasis is placed on "green" technologies that intensify the processes of isolation of components such as flavonoids.

Text. Modern technologies imply the use of combined methods, including, in addition to ultrasound, significant grinding of raw materials before the extraction process, the use of supercritical solvents (liquefied gases) under excessive pressure. The effect of ultrasound power and temperature on the output of the extracted components was also considered.

Conclusion. 1. To increase the yield of biologically active compounds from plant raw materials among various physical methods of extraction intensification, the use of ultrasound dominates. 2. Ultrasonic extraction can be divided into several main types: extraction in an ultrasonic bath, the use of submersible ultrasonic emitters, as well as the combination of ultrasonic extraction with additional types of influence. 3. In the literature, examples of the use of ultrasonic extraction for the isolation of phenolic compounds are most fully presented, it being noted that the parameters need to be selected individually for each individual plant. 4. The power of ultrasound and the nature of the extractant can affect the course of oxidative processes in the extract, and such phenomena are characteristic not only for too high capacities, but also for low ones. 5. Ultrasound can significantly increase the yield of biologically active compounds even in aqueous extraction of fresh raw materials. 6. The spectrum of extractants selection for ultrasonic extraction of plant raw materials is quite large. Both organic solvents (ethanol, methanol, ethyl acetate, acetone) and water can be used, as well as mixtures of various extractants.

Introduction. Intranasal drug delivery from nose-to-brain is one of the promising approaches for the treatment of brain diseases including neurodegenerative diseases, stroke, brain tumors, etc.

Text. Delivery of drugs through the nose has a number of advantages, including the rapid onset of a pharmacological effect, the ability to bypass the blood-brain barrier, avoidance of some side effects and fast and non-invasive route of administration. However, the significant disadvantages of this route are rapid elimination of the drug from the surface of the mucosal membrane, poor penetration of the drug through the nasal mucosa, mucociliary clearance and effects of proteolytic enzymes. Currently, to overcome the above limitations, various approaches are used, including the development of delivery systems from nose-to-brain, which are mucoadhesive, mucus-penetrating and gel-forming systems that facilitate the retention or penetration of drugs through the mucosal membranes. At the same time, high-molecular weight compounds play a significant role in the design of these systems. In particular, mucoadhesive systems can be prepared from cationic and anionic polymers. Recent studies have also shown that interpolyelectrolyte complexes also exhibit mucoadhesive properties. An improvement in mucoadhesive properties of polymers can also be achieved by conjugating various functional groups such as thiols, maleimides, acrylates, methacrylates, catechols, etc. Mucus-penetrating systems can be prepared by PEGylation of nanoparticles, as well as functionalization with some poly(2-oxazolines), polyvinyl alcohol, etc. The mucus-penetrating ability of these polymers has been shown in other mucosal membranes in the body. Finally, increased penetration can be achieved by using mucolytic agents in combination with non-ionic surfactants. Another approach to increase the efficiency of drug delivery from nose-to-brain is the use of in situ gelling systems. Initially, this type of formulation exists as a solution; then a phase transition to gel is observed in response to chemical and physical effects. Depending on the external stimulation of the phase transition, thermo-, pH-, ion-reversible and other systems are known. These systems have shown effectiveness for delivery to the brain by intranasal administration.

Conclusion. Effective intranasal delivery of drugs and therapeutic agents to the brain can be achieved by using mucoadhesive, mucus-penetrating, gelling systems and/or their combinations.

Introduction. Gramicidin S has been conventionally manufactured as buccal tablets. However, in the past decade, the interest in the development of spray formulations has been growing. Those formulations contain excipients that enhance the solubility of the antibiotic in water solutions. However, the real structure of gramicidin S containing sprays remains unrevealed.

Aim. Investigation of colloidal structure and biopharmaceutical properties of new gramicidin S antibacterial composition.

Materials and methods. The composition sample was obtained using gramicidin S dihydrochloride, propylene glycol, polysorbate-80, ethanol and purified water. Raman spectroscopy has been performed to determine the composition of the phases. Dynamic light scattering analysis was performed to characterize the composition particles. Release of gramicidin S was performed by dialysis method and the concentration was determined by HPLC. The antimicrobial properties were investigated in accordance with the requirements of the XIV edition of the Russian pharmacopoeia.

Results and discussion. Dynamic light scattering analysis results show gramicidin S formulation particles having an average size in solution 5–50 nm and ζ-potential (–1.1: +7.9 mV). Based on the obtained data on the composition properties and formulation parameters it was classified as colloidal solution. The kinetic stability evaluation was performed. We compared the solubility in water and release parameters of the active pharmaceutical ingredient in the native state and in the micelles. The enhancement of the antimicrobial activity of the peptide in the colloidal solution was confirmed and ascribed to the synergic effect gramicidin S – surfactant.

Conclusion. We reported the colloidal type of the composition, that aggregate gramicidin S at a concentration of 8 mg/mL. We found that gramicidin S inclusion into the colloidal solution led to significant efficiency increase, which reveals the potential to reduce the drug dose and side effects level.

Introduction. The Crataegus L. (Hawthorn) is a common herb in numerous Pharmacopoeias. The State Pharmacopoeia of the Russian Federation provides hawthorn fruits and flowers for medical utilization. With that, the literature data confirms the medical utility of hawthorn leaves since the “leaves” and the “flowers with leaves” have pharmacopoeial status worldwide. Therefore, those are considered as prospective forms of Crataegus raw material for Russian pharmaceutical production. However, most species remain poorly pharmacognostically investigated regarding the quantitative microscopic characteristics (the sizes of stomatal apparatus (SA) and epidermal leaf blade (LB) trichomes), which could be substantial for establishing the authenticity of the raw material.

Aim. Examine epidermal anatomy of Crataegus spp. Leaf blades (LBs) and perform a comparative study of several quantitative diagnostic features of LBs of hawthorn plants from the sect. Sanguineae and the sect. Crataegus, growing in diverse regions of the Russian Federation.

Materials and methods. Samples of hawthorn leaves (C. sanguinea, C. maximowiczii, C. dahurica, C. rhipidophylla, C. monogyna and C. pallasii) were collected in natural habitats in Western Siberia (Kemerovo) and in arboretums of Botanical Gardens (Moscow, Stavropol). Measurements of anatomical structures were carried out using a light microscope accompanied by an ocular micrometre.

Results and discussion. The LB surface phenotypic diversity within hawthorn species and sections was studied. The LBs were described in terms of meterages (longitude and width) of SA, meterages and shape of sedentary multicellular leaf teeth glands. The peculiarities of pubescence and the sizes of simple unicellular non-glandular trichomes were also observed.

Conclusion. The results of quantitative anatomical examination provided the characteristic features determining these elements at the species and section levels. Thus, it may facilitate authentication and quality control of whole or ground Crataegus medicinal raw material.

Introduction. Small-leaved linden flowers are mainly used for aquatic extracts, and their pharmacological benefit is based on water-soluble polysaccharides.

Aim. The aim of this study was to investigate the rate of accumulating all reducing sugars in small-leaved linden flowers, collected in agro- and urbo-cenoses of the Voronezh region.

Materials and methods. 51 sites were selected for collecting flowers from the small-leaved linden, which is a widespread deciduous tree species in Russia. In order to determine the total level of reducing sugars in the samples, we measured glucose levels using the method described in Pharmacopeia article "Linden Flower". Correlation coefficients were analyzed to examine in detail the effect of the major pollutants (heavy metals and arsenic) on the accumulation of reducing sugars in small-leaved linden flowers.

Results and discussion. All analyzed samples of medicinal plant raw materials were benign in terms of their reducing sugar levels. Samples collected in control (protected) areas contained reducing sugar levels 13.31 to 16.89 %, which is 6–8 times more than the lower numerical value established by the Pharmacopoeia article. In the agrocenoses of the region, the concentration of reducing sugars varied from 6.12 to 16.68 %, which is 3–8 times more than the value given in the Pharmacopoeia article. In the urbocenoses of the region, a lower level of reducing sugars was found compared to samples from protected areas (2.35–13.49 %). Correlation coefficients showed a noticeable negative impact of cadmium, chromium, cobalt, copper, zinc, as well as a moderate negative effect of lead and mercury on the accumulation of reducing sugars in the small-leaved linden flowers.

Conclusion. The lowest concentrations of reducing sugars were detected in samples harvested along the streets of large cities in the region, and along highways, roads and railways. This suggests that anthropogenic factors might negatively impact the accumulation of reducing sugars in small-leaved linden flowers in these areas. At the same time, it is possible that saccharide complexes might have reacted with heavy metals instead of the complexing agent when levels of reducing sugars in the samples were quantitatively determined. This would have the effect of underrepresenting reducing sugar levels in the raw materials.

Introduction. The production, standardization and quality control process of various dietary supplements containing chelated zinc requires validated quantitative assessment methods. In this work, we propose an X-ray fluorescence spectroscopy (XRF) technique for determining the zinc content in the composition of coordination compounds using the example of a synthesized chelate complex with methionine.

Aim. To synthesize Zn(Met)₂ chelate complex, to develop and validate a method for its quantitative analysis using the XRF method.

Materials and methods. The synthesized zinc chelate complex was investigated by IR spectroscopy. The XRF method was used to develop a method for quantifying the zinc content in the synthesized complex. We used dry mixtures of zinc sulfate monohydrate and L-methionine (Met) in a molar ratio of Zn to Met – 1 : 1, 1 : 2, 1 : 4, 1 : 8 and 1 : 16 and also aqueous solutions of zinc sulfate and L-methionine in a molar ratio of Zn to Met 1 : 2 with Zn concentrations from 0.5 to 100 mmol/l as calibration standards. Complexometric titration was used as an arbitration method for the quantitative determination of zinc content in the samples under study.

Results and discussion. The IR spectrum of chelate complex confirmed the presence of a donor-acceptor bond between Zn²⁺ and the nitrogen atom of amino group in methionine. The titration results showed chelate compounds have a composition corresponding to the stoichiometric formula Zn(Met)₂. XRF analysis of dry standard mixed samples demonstrated the presence of matrix effect, that makes impossible an accurate assessment of zinc content in the chelate compound. According to the XRF spectra of aqueous solutions containing zinc sulfate and methionine in a ratio of 1 : 2 at a zinc concentration of 0.5; 1; 2; 3; 4; 5; 10; 25; 50 and 100 mmol/L, a calibration graph was constructed – the dependence of the fluorescence signal intensity for the Kα line of zinc on the concentration of zinc in the solution (r = 0.9996). The method was evaluated by the following validation parameters: specificity, linearity, correctness, precision, and analytical range. The specificity of the validated method was proven in the presence of copper, iron, and silver.

Conclusion. The developed method make it possible to determine with sufficient precision and correctness the content of Zn²⁺ in its aqueous solutions of inorganic and organic nature by the XRF method in the concentration range from 3 to 100 mmol/l without the influence of the matrix.

Introduction. Clinical strains of microorganisms, including opportunistic yeast-like fungi (YLF) of the genus Candida, are resistant to currently used antifungal drugs. In this regard, the search for alternative ways to potentiate the activity of antimicrobial agents in relation to the infectious agent is an important and relevant area of research. The study of combinations of existing antimycotic drugs and a medicinal extract of plant origin – farnesol – is one of the promising approaches in the fight against resistant strains of YLF genus Candida. In our previous studies, farnesol has been shown to exhibit relative activity against YLF Candida albicans biofilms. In this study, we used 6 clinical isolates and one museum strain YLF C. albicans to study the effect of farnesol on the antifungal activity of antimycotic drugs.

Aim. To prove that farnesol can increase the antifungal activity of certain antimycotics.

Materials and methods. To determine the sensitivity of 7 strains of YLF C. albicans to the antimycotic drugs "Nystatin" (NYS 50 µg), "Ketoconazole" (KET 10 µg), "Clotrimazole" (CTR 10 µg), "Amphotericin B" (AMB 10 µg), "Voriconazole" (VRC 10 µg) disk diffusion test was used. A solution of farnesol in concentrations of 100, 50 and 25 µM in a volume of 25 µl was applied to the disk with the antimycotic drug. Sterile physiological (PhS) solution was used as a control (pH 7.0; V = 25 µl).

Results and discussion. In 34.3 % of of experiments we can talk about the modulating effect of farnesol solutions on the antifungal activity of antimycotic drugs. In all these cases, the sensitivity of YLF C. albicans to the antimycotic drug increases.

Conclusion. The results of this study provide useful information for understanding the mechanism of QS-molecules action with antifungal activity, as well as they are the basis for the practical application of some QS-molecules in the treatment of infectious diseases caused by YLF of the genus Candida. The study demonstrates that farnesol can be recommended as an active substance that improves the sensitivity of YLF Candida to antimycotic drugs, especially in the case of multi-resistant strains Candida.

Introduction. Viral hepatitis (HV) by its socio-economic significance occupies one of the leading places in human infectious pathology, therefore, the development of fundamentally new methods of prevention, diagnosis and treatment, as well as the creation of new antiviral drugs remain relevant. An antiviral herbal drug "Flakozid" has been created in VILAR, which is presented in a dosage form – 0,1 g tablets for oral administration.

Аim. To analyze the experimental and clinical efficacy and safety of flakozid therapy in viral hepatitis.

Materials and methods. Experimental study of the effect of flakozid on viral hepatitis A (HAV). The AGMK cell culture (BS-C-1 line) and the hepatitis A virus strain HM 175 adapted to it were used in the work. The studies were conducted in two series of experiments using different concentrations of the drug, which was introduced into cultures simultaneously with the infection of HAV. Experimental study of the effect of flakozid on viral hepatitis C (HCV). In the present experiments, a virus-containing culture fluid collected from infected cultures of chicken embryo fibroblasts containing 7,0 lg TCD₅₀/ml of infectious HCV (genotype 1b) was used. The cytotoxic, viricidal and antiviral activity of flakozid was studied using transplanted cultures of pig embryo kidney cells (SPEV) obtained from the collection of cell lines of the D. I. Ivanovsky Research institute of virology of the Ministry of Health of the Russian Federation. In the experiments, a one-day monolayer of cells grown in 96-well plastic culture panels was used. ID₅₀ – the concentration of the drug "Flacozid", which inhibits the development of the virus in the monolayer by 50 %, and CD₅₀ – its minimum concentration, which causes cytotoxic destruction of 50 % of the cells of the monolayer, as well as the CTI – chemotherapeutic index, calculated as the ratio of CD₅₀ to ID₅₀, were determined. A well – known domestic antiviral agent, "Ribavirin", was used as a comparison drug. Clinical studies of flakozid in viral hepatitis A. The results of clinical studies of the antiviral drug "Flakozid" (0,1 g tablets) were analyzed in 258 patients with viral hepatitis A. "Flakozid" was prescribed to patients with a moderate course of the disease, 0,1 g 3 times a day for 20 days against the background of basic therapy: diet, alkaline drinking, Enterodes®. The therapeutic effect was assessed by clinical (weakness, decreased appetite, nausea, vomiting) and biochemical parameters (the level of direct bilirubin, transaminase activity), as well as by the severity of hepatolienal syndrome. Clinical studies of flakozid in viral hepatitis В. The results of clinical studies of the antiviral drug "Flakozid"(0,1 g tablets) were analyzed in 410 patients with acute viral hepatitis B, which was regarded as moderate. "Flakozid" was prescribed against the background of basic therapy: diet and detoxification therapy: 5 % glucose solution, 5 % ascorbic acid solution, "Hemodesi", at a daily dose of 0,3–0,8 g for up to 38 days. The comparison group received the same basic therapy without flakozid. The dynamics of clinical symptoms (general weakness, headache, sleep disorders, dizziness, nausea, vomiting, impaired appetite, itchy skin, pain in the right hypochondrium, jaundice, etc.), data from laboratory examination methods were evaluated, markers of hepatitis B – HBeAg and Australian antigen (HBsAg) were determined every 10 days and indicators of cellular immunity before the appointment and after 21 days of treatment; the absolute number of lymphocytes, the total number of T-lymphocytes, as well as theophylline-resistant and theophylline-sensitive cells.

Results and discussion. The results of experimental studies revealed the antiviral effect of flakozid against the hepatitis A virus, confirmed during clinical studies in adult patients. Treatment with flakozid in patients with viral hepatitis A against the background of basic therapy at a daily dose of 0,3 g for 20 days led to a significant reduction in the symptoms of intoxication, a reduction in the jaundice period, normalization of the size of the liver and spleen. Treatment with flakozid as part of complex therapy of patients with acute viral hepatitis B (AHVB) of moderate severity in daily doses of 0,3–0,8 g for 38 days showed its high effectiveness, contributing to a faster disappearance of clinical symptoms of the disease (improvement of the general condition of patients, reduction of the severity and disappearance of clinical symptoms of intoxication, reducing of the jaundice period), normalization of biochemical parameters (reducing the level of bilirubin and transaminase activity), as well as elimination of HBsAg from the blood, stimulation of cellular immunity. "Flakozid" was well tolerated, did not cause allergic reactions. Based on the results of clinical studies, "Flakozid" is approved for medical use as an antiviral agent (registration number 90/248/7). The high antiviral activity of flakozid against the hepatitis C virus in cell cultures was established. In terms of the severity of the therapeutic effect, "Flakozid" was not inferior to ribavirin, and in terms of CTI it was noticeably superior.

Conclusion. Treatment with flakozid in patients with viral hepatitis A and B showed its high efficiency, contributed to a faster disappearance of clinical symptoms of the disease, normalization of biochemical parameters, elimination of HCV from the blood, good tolerability. "Flakozid" is recommended in clinical practice in the complex treatment of hepatitis A and B. In vitro experiments have established a high antiviral activity of flakozid against the hepatitis C virus, which justifies the possibility of conducting clinical studies of the drug in patients with the viral hepatitis C.

Introduction. Combined drugs have the greatest efficacy and safety in arterial hypertension treatment. The combination of candesartan and hydrochlorothiazide (AT₁-receptor antagonist and a thiazide diuretic, respectively) provides high efficiency of antihypertensive combination therapy, therefore it is widely used in medical practice. Developing a method for simultaneous determination of candesartan and hydrochlorithiazide in human blood plasma is necessary for performing the analytical part of pharmacokinetic studies and bioequivalence studies of multicomponent drugs.

Aim. The aim of this study is to develop a method for quantitative determination of candesartan and hydrochlorothiazide in human plasma by high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) for further bioequivalence studies.

Materials and methods. Determination of candesartan and hydrochlorothiazide in human plasma by HPLC-MS/MS. The samples were processed by acetonitrile protein precipitation. Internal standard: mixed solution of valsartan and indapamide. Mobile phase: 0.1 % formic acid solution in water (eluent A), 0.1 % formic acid in acetonitrile (eluent B). Column: Phenomenex Luna Phenyl-Hexyl, 50x4.6 mm, 5 μm. Analytical range: 2.00–300.00 ng/mL for candesartan, 2.00–200.00 ng/mL for hydrochlorothiazide in human plasma. Ionization source: electrospray ionization. Detection conditions: 441.10 → 192.00 m/z, 441.10 → 263.15 m/z (candesartan), 295.85 → 269.00 m/z (hydrochlorothiazide), 436.00 → 207.05 m/z (valsartan), 363.85 → 132.10, 363.85 → 189.00 m/z (indapamide).

Results and discussion. This method was validated by selectivity, matrix effect, calibration curve, accuracy, precision, spike recovery, the lower limit of quantification, carry-over effect and stability. The developed method meets the requirements for conducting bioequivalence studies of medicinal products within the framework of the Eurasian Economic Union.

Conclusion. The analytical range was 2.00–300.00 ng/mL for candesartan, 2.00–200.00 ng/mL for hydrochlorothiazide in human plasma. The method was applied in BE study of the combination of candesartan and hydrochlorothiazide.

Introduction. The article is devoted to the aspects of improving methodological approaches to the creation of a pharmaceutical quality system (PQS) at enterprises for the production of medicines, taking into account the possibility of using tools and means of digitalization. The relevance of the study is associated with the enduring importance of comprehensive high quality assurance in the development, production and release of medicines into circulation. The implementation of PQS requires numerous transformations of management and production processes, which can be facilitated by tools and elements of digitalization.

Aim. To consider the potential and specific areas of application of digital technologies to improve the methodology and practice of developing and implementing PQS.

Materials and methods. The state in the subject area was assessed on the basis of the results of economic and statistical analysis and forecasting of the implementation of PQS at Russian pharmaceutical enterprises that have positive and comparatively long experience in this area: the companies LLC "OZON" and JSC "AKRIKHIN". The assessment was carried out by calculating the integral indicator of the effectiveness of the functioning of PQS, which is a set of weighted key performance indicators (KPI) for quality.

Results and discussion. The importance of the introduction of PQS for the development of pharmaceutical enterprises and the presence of numerous difficulties in the implementation of PQS, which necessitates the improvement of methodological approaches in the subject area, are stated. It has been proven that even at those enterprises where PQS has been introduced with varying degrees of success, the use of digitalization tools would contribute to a faster, more systematic and high-quality implementation of PQS. Among the key areas of application of digital tools, the authors propose monitoring of quality indicators (using neural network cards) and the use of blockchain platforms and smart contracts to register the release of drugs of appropriate quality.

Conclusion. Digital tools contribute to complex improvement in many areas of socio-economic activity. Their active use at pharmaceutical enterprises is intended to contribute to ensuring the proper implementation and uninterrupted functioning of pharmaceutical quality systems, through constant monitoring of the quality of manufactured products and registration of manufactured batches in high-precision information storage systems.

Introduction. The article discusses the problem of assessing the similarity of the dissolution profiles of two batches of the nebivolol. The use of a generally accepted similarity factor for assessing equivalence is unacceptable in some cases, for example, for drugs with a high variability in the values of the release of the active substance from the formulation. At the same time, at present, there are no generally accepted approaches to comparing the profiles of the dissolution kinetics of drugs, with the exception of the method for assessing the comparability of profiles based on the mathematical calculation of the similarity factor f₂, which has certain criteria that limit its application.

Aim. To demonstrate alternative methods for assessing the similarity between the dissolution profiles of two drugs using a practical example.

Materials and methods. The results of the comparative dissolution test of two series of nebivolol at a dosage of 5 mg. Five model-independent methods for assessing the equivalence of drug dissolution were used. Statistical data processing was performed using Microsoft Excel software.

Results and discussion. The paper presents a practical example of using five alternative model-independent methods for assessing the equivalence of the dissolution profile. An example is used to illustrate the proposed equivalence limits and statistical methodology. Also, various approaches to determining the boundaries of equivalence have been proposed to assess the similarity of the dissolution profiles of an active substance.

Conclusion. According to the results of the comparative dissolution test of two batches of nebivolol, it was shown that the use of the similarity factor as a criterion for assessing dissolution profiles led to a false positive result. In such cases, the possibility of using alternative methods for assessing the equivalence of dissolution profiles described in the article, or other methods presented in the scientific literature, should be considered, with a justification of their acceptability in each specific case.

Razrabotka i registratsiya lekarstvennykh sredstv = Drug development & registration. 2021;10(2):87-99. (In Russ.) https:// doi.org/10.33380/2305-2066-2021-10-2-87-99. Published: 25.05.2021.