Introduction. The study discusses the hydrogen isotope ²H effect on the biological activity of pharmaceutical substances.

Text. Two aspects of the deuterium effect on the properties of active pharmaceutical ingredients and excipients are considered. The first one involves the use of deuterated substances, new compounds or substituted counterparts. Replacing protium with deuterium is used to reduce the rate of biotransformation. The kinetic isotope effect (KIE), expressed in a decrease in the rate of biotransformation as a result of deuteration, allows us to predict the rapid development of new directions in the development of pharmaceuticals. With the same therapeutic effect, an improvement in pharmacokinetic characteristics, a decrease in toxicity, a blocking of the epimerization of optically active substances, a change in the mechanisms of action are observed. The second aspect of the deuterium effect is associated with an increase in KIE of known pharmaceutical substances in aqueous solutions with a deuterium/protium ratio (D/H) lower than in natural water. For the first time, dose-response diagrams for deuterium demonstrate identity with essential microelements. There is a safety zone for the certain D/H relationship, beyond which the organism's vitality decreases. Improved kinetic characteristics are demonstrated for molecular level and for biological objects of various hierarchical levels. In particular, they include the possibility of increasing the dissolution rate of substances, the influence on the processes of mutarotation and the optical activity of chiral substances, the degree of accumulation of necessary elements in medicinal plants, and other processes.

Conclusion. The results make it possible to predict the mechanisms of deuterium influence on the biochemical transformations of pharmaceutical substances in the body.

Introduction. The prospects of using nanoparticles in the production of medicines are widely discussed in the literature. In 2018 alone, the quantity of registration certificates issued by national regulators for medicines that use nanoparticles in one form or another is around forty. Most of them are medicines based on liposomes, polymers, iron oxides, micelles. So far, no registration certificates have been issued for selenium nanoparticles. One of the reasons for this situation in this area, from our point of view, is that the mechanisms of interaction of nanoparticles with cells are not sufficiently studied. The lack of basic research in this area is one of the main obstacles to the development of new-generation drugs based on nanoparticles.

Text. This review is devoted to the analysis of scientific data on the interaction of selenium nanoparticles with different types of cells. The article discusses the biological properties of selenium and its role in cell metabolism. Data on the cytotoxic effect of selenium nanoparticles on various cell cultures are presented. Methods of preparation of nanoparticles and methods for studying the interaction of nanoparticles with cell cultures are described.

Conclusion. Analysis of the literature data allows us to draw conclusions about the relevance of research on the interaction of selenium nanoparticles with living cells. This is necessary to determine the mechanisms of selenium nanoparticles absorption, study their cytotoxic and / or cytostatic action, and distribution in cells. Investigation of the biological interaction of selenium nanoparticles with tumor and normal cells will determine the most informative methods for registering and quantifying their antitumor activity, which is relevant for the development of new drugs to treat cancer.

Introduction. The most common way to maintain the viscoelastic properties of synovial fluid is intra-articular administration of hyaluronic acid solutions. Such forms have several features due to the method of administration, the characteristics of the substance, as well as their composition, technology, and packaging. The aim of the work to analyze the features of hyaluronic acid solutions for intra-articular administration, as well as to consider resent trends to their pharmaceutical development.

Text. Currently, in Russia, most of these forms are registered as medical devices. Each drug has its characteristics, including the source of the substance, the main molecular weight and the molecular weight range of hyaluronic acid, the structure of the molecule (linear or cross-linked), the method of its chemical modification, concentration, solution volume, dosage, etc. As excipients most often use sodium chloride, water for injection, and phosphate-buffered saline to maintain pH values close to the synovial fluid. Some prostheses contain mannitol as an antioxidant. Combinations of hyaluronic acid with active chondroprotective substances (chondroitin sulfate, sodium succinate) are known. The main type of primary packaging is glass prefilled syringes. The choice of sterilization methods is determined by the chemical structure of hyaluronic acid, aseptic production is used for most prostheses.

Conclusion. Currently, research solutions to create thermostable and enzyme-resistant compositions with hyaluronic acid for intra-articular administration are being successfully applied. Modern developments are aimed at creating polymer complexes of hyaluronic acid with substances that improve the lubricity of solutions, the development of nanosystems (liposomes, nanoparticles, nano micelles, etc.) with chondroprotective, as well as the creation of inert biocompatible prostheses with viscoelastic properties. The creation of forms of hyaluronic acid and alternative drugs that can support the rheological properties of synovial fluid is currently a promising area of research.

Introduction. The review describes various systems used as inclusion matrices or modifiers of biologically active substances to enhance their absorption or deposition and subsequent release, both continuous or «on demand», i.e. in response to a stimulus.

Text. Technologies for the incorporation of active substances into cyclodextrin nanoaggregates are developed to the greatest extent. Such technologies were used to obtain modified forms of hydrocortisone, glibenclamide, and a number of peptide drugs. Acetylcysteine immobilized on ethyl cellulose or other polymer particles significantly increases the bioavailability of peptide drugs on their intranasal administration. The deposition of active substances in the body takes place by way of their delayed controlled dissolution, adsorption, encapsulation, or esterification. The release of deposited substances upon exposure to an endogenous (change in pH, temperature) or external (exposure to ultrasound, electric or magnetic field, chemical activators) stimulus can be single or multiple, depending on the ability of the accommodating matrix for self-aggregation.

Conclusion. Self-aggregated peptides are most promising for stimulus-induced release/delivery of biologically active substances. Modern technologies for the modification of active substances increase the efficiency of their administration and favor targeted location and implementation time of biological effects.

Introduction. An innovative antifungal viscous solution based on naftifine hydrochloride with a combination of polyethylene glycols (PEG) was developed in the laboratory of Sechenov University. The developed preparation intended for external use. The active ingredient – naftifine hydrochloride has a wide spectrum of action against fungi cause onychomycosis. The polyethylene glycols are included in the developed dosage form of provide the necessary viscosity of the solution (for accurate application and retention in the field of application). The paper presents the results of a study of the stability of a viscous solution of naftifine hydrochloride with a combination of PEG for external use. Over the entire shelf life, the drug must retain the full its chemical, physical, biopharmaceutical and pharmacological properties.

Aim. Determination of stability and expiration date of the shelf life of the developed solution of naftifine hydrochloride for external use, intended for the treatment of mycosis of the nail.

Materials and methods. Naftifine hydrochloride solution, «Millipor» filter, UV spectrophotometry, potentiometry pH, capillary viscometry.

Results and discussion. In the course of the study, the shelf life of the developed alcohol solution of naftifin hydrochloride with a combination of PEG was experimentally determined. The stability of the dosage form was determined by accelerated aging at a temperature of 40 ± 2 °C, in vivo at a temperature of no higher than 25 °C; and in a refrigerator at a temperature of 8 ± 2 °C. Assessment of the stability of the alcohol solution of naftifine hydrochloride was carried out according to the following indicators: the volume of the contents of the bottle, appearance, pH, quantitative content of the active substance, viscosity.

Conclusion. Based on the studies, it is recommended to store the naftifine hydrochloride solution at room temperature not higher than 25 °C, in a dark place. It is also allowed to store the solution of naftifine hydrochloride in a refrigerator at a temperature of 8 ± 2 °C.

Introduction. There are a number of drugs, the absorption zone of which is the upper region of the gastrointestinal tract (GIT) – the stomach and duodenum. To increase bioavailability, gastroretentive (intragastric) systems for the controlled drug delivery are being developed. To date, there are various approaches to ensure intragastric drug delivery. One of the most promising approaches is the use of excipients with bioadhesive properties, both individually and in combination with other types of gastroretentive systems.

Aim. Development and research of new carriers for gastroretentive bioadhesive drug delivery systems based on interpolyelectrolyte complexes (IPEC) with the participation of chemically complementary poly(meth)acrylates of the Eudragit®.

Materials and methods. The study of swelling ability was carried out in a medium of 0.1 M hydrochloric acid solution (pH 1.2) at a temperature of 37 ± 0.5 °C for 6 hours. The study of the release of metronidazole (MZ) from matrices based on the corresponding IPEC was performed on a DFZ II instrument (ERWEKA, Germany) according to the Flow Trough Cell method in 0.1 M HCl medium, pH 1.2, flow rate 4 ml/min in a closed cycle within 6 hours. The amount of released MZ was estimated by UV spectrophotometry on a Lambda 25 instrument (PerkinElmer, USA) at a wavelength of 274 nm. IPEC adhesion was studied using a TA.XTplus texture analyzer (Stable Micro Systems, UK).

Results and discussion. Matrices based on IPEC 1 were disintegrated after being in a medium with a pH of 1.2 for 4 hours, matrices based on IPEC 4 were dissolved in an acidic medium for 3 hours. At the same time, matrices based on IPEC 2 and IPEC 3 retain their shape throughout the experiment and are characterized by rather high values of the degree of swelling. IPEC samples are characterized by higher adhesion performance compared to individual copolymers. The release of metronidazole from matrices based on IPEC 1 occurs in accordance with Fick's law of diffusion; from the matrix based on IPEC 4, MZ is released according to the anomalous transport mechanism.

Conclusion. IPEC 3 is promising for use as carrier for gastroretentive bioadhesive systems of controlled delivery of metronidazole.

Introduction. In recent years, substances extracted from plant materials have been widely used in the pharmaceutical, cosmetic and food industries. Such substances are used as solutions, dry extracts for the manufacture of medicines, dietary supplements, cosmetic creams, food additives in various forms – tablets, capsules, solutions, granular powders. The extraction of valuable substances from plant materials is carried out using the extraction process, which is carried out by various methods and in apparatuses of various designs. Earlier, a comparative study of the extraction of dioscin from fenugreek by various methods was carried out: in devices with a stirrer, in an ultrasonic field, supercritical, fluid СО₂ extraction, and in a vibro-cavitation homogenizer. It is shown that the most effective method is the extraction carried out in a vibrocavitation homogenizer.

Aim.To analyze the kinetics of the extraction of dioscin from fenugreek seeds, to determine the optimal values of the required degree of grinding of the raw materials, working temperature, the concentration of ethyl alcohol in the solution and the rotational speed of the rotor of the vibrocavitation homogenizer. Determine the effective mass transfer coefficient responsible for the intensity of mass transfer inside the particles.

Materials and methods. An experimental study of the extraction of valuable components from plant materials was carried out in a laboratory unit with a vibrocavitation homogenizer of periodic action. As raw materials were used seeds of hay fenugreek, ecotype of Morocco, acquired in the company Fitokasa, Casablanca (Morocco), which we used for research. Commodity analysis showed that raw materials comply with the requirements of the State Pharmacopoeia XIVth edition. As extractants, aqueous solutions of ethanol with an alcohol concentration of 40, 50, 60, 70, 80, and 90 %. The analysis of the kinetics of the process was based on the following ideas. Extraction begins with the surface of the particles of plant material. As the extracted component moves into the volume of the solution, the extractant penetrates into the internal pores of the particles, and the surface on which the extractant and the extracted component interact is gradually shifted into the individual particles. In this case, the resistance to mass transfer in the region between the specified surface and the outer surface of the particle increases over time.

Results and discussion. An analysis of the results shows that the rotor speed significantly intensifies the process. In addition, the influence of the rotor speed is most pronounced at the initial stage of the process, when the surface layers of particles of plant material are extracted. It was also found that the resistance to mass transfer inside particles increases significantly as it approaches the final stage of the process, and with an increase in the rotor speed, it increases, especially at the initial stage of the process, which is associated with the intensity of cavitation and the weakening of its effect as the process deepens inward particles.

Conclusions. The obtained dependences are necessary to determine the duration of the extraction process in a batch mode, or the average residence time of seeds in the working volume when organizing the process in a continuous mode.

Introduction. One of the well-known requirements for buccal drug delivery systems is the demonstration of mucoadhesive properties of the carrier, ensuring retention on the mucosa for a long time with the gradual release of the included drug. It should be noted that one of the advantages of buccal systems compared with oral ones is the absence of the «first pass effect» through the liver.

Aim. To carry out a physicochemical and pharmaceutical research of the interpolyelectrolyte complex (IPEC), obtained on the basis of pharmaceutically acceptable polymers – Eudragit® EPO and Noveon® AA-1, in comparison with the physical mixture and individual polymers, as a mucoadhesive delivery system of metronidazole for the treatment of periodontal diseases.

Materials and methods. Obtained on the basis of a pair of pharmaceutical polymers (Eudragit® EPO and Noveon® AA-1), two IPEC samples were characterized by elemental analysis, FTIR spectroscopy, and modulated temperature differential scanning calorimetry (mDSC) in comparison with individual polymers and their physical mixtures. The study of swelling ability, bioadhesion and release was carried out in a medium simulating artificial salivary fluid (pH 7.0) at a temperature of 37 ± 0.1 °C. Mucoadhesion of polymer samples and IPEC was studied using a TA.XTplus texture analyzer (Stable Micro Systems, UK). The release of metronidazole (MD) from matrices based on the developed IPEC was studied on a CE 7Smart USP 4 apparatus (Sotax, Switzerland) using the Flow Trough Cell method at a speed a flow of 20 ml/min in an open cycle within 5 hours. The amount of released MD was estimated by UV spectrophotometry on a Lambda 25 instrument (PerkinElmer, USA) at a wavelength of 319 nm.

Results and discussion. As a result of studies on the physicochemical and pharmaceutical properties, there was selected the optimal composition of a polycomplex carrier (IPEC 2) based on Eudragit® EPO and Noveon® AA-1, which is characterized by the required bioadhesive properties and the ability of providing controlled release of drug from the tablet matrix (with weight ratio MD/IPEC-2 1:0.5) in conditions mimicking oral cavity environment, which provides the necessary mode of buccal delivery of metronidazole in accordance with Fick's law of diffusion.

Conclusion. IPEC 2 is a perspective for use as carrier for buccal controlled delivery of metronidazole.

Introduction. According to the literature, nettle leaves contain polysaccharides and mucus as an integral part of the hydrophilic fraction. This group of biologically active substances (BAS) is involved in the manifestation of the physiological activity of the infusion. The traditional gravimetric method for the determination of polysaccharides in medicinal plant raw materials (PRM), pharmaceutical substances of plant origin and medicinal herbal preparations cannot provide a true picture of their content due to the presence of impurities. Therefore, it is advisable to determine the reducing sugars that are most fully extracted into the aqueous phase during the preparation of the infusion using modern physicochemical methods of analysis.

Aim. The aim of the work was to determine the amount of polysaccharides and simple sugars in nettle leaves by various physico-chemical methods and their comparative characteristics.

Materials and methods. A comparative determination of the sum of polysaccharides and simple sugars in the leaves of nettle by pharmacopoeial methods (picrine, anthrone and orcine) was carried out. Free and bound simple sugars were identified and quantified by thin layer chromatography (TLC). The composition and content of free simple sugars was studied by capillary electrophoresis (CE) in raw materials.

Results and discussion. The content of free and bound sugars in raw materials has been established. The largest content of both the sum of polysaccharides and free simple sugars in the polysaccharide complex of nettle leaves, as well as the sum of free reducing simple sugars, according to experimental data, was obtained using the picrine method. The content of pentoses in the studied PRM was four times less, which is consistent with the literature data on the preferential construction of polysaccharides of plant objects from sugars of the hexose class. The resulting total content of the fraction of free sugars in the leaves, determined by the CE method, is an order of magnitude less compared with spectrophotometric methods. The obtained results of quantitative determination of the amount of free and bound simple sugars in the studied PRM are consistent with the determination data by the picrine pharmacopoeial method.

Conclusion. In general, complete information, depending on the goals of the analysis, on the composition and quantitative content of simple and related sugars in the polysaccharide complex of plant objects can only be obtained by combining spectral methods with CE or TLC.

Introduction. Naltrexone, an antagonist of µ-opioid receptors, is promising for the treatment of various autoimmune and oncological diseases when used in doses of 1.5–5 mg/day. To date, there are no medications that provide such dosages of naltrexone.

Aim. Development and validation of a method for the quantitative determination of naltrexone hydrochloride in a nasal spray by high performance liquid chromatography (HPLC).

Materials and methods. As an object of research, a naltrexone hydrochloride nasal spray was used. The quantitative determination of naltrexone in the test sample was developed using a Dionex UltiMate 3000 high-performance liquid chromatograph (Thermo Scientific, USA) equipped with a diode-matrix detector.

Results and discussion. The possibility of using isocratic and gradient chromatographic modes for the quantitative determination of naltrexone hydrochloride in the nasal spray was studied. Based on these results, a new method of determination using the gradient mode is proposed, which allows minimizing the influence of the polymer component in the test sample on the analysis results.

Conclusion. A new technique of high-performance liquid chromatography (HPLC) is proposed that allows identification and quantification of naltrexone hydrochloride in a nasal spray containing a high concentration of water-soluble heat-sensitive poloxamer as a thickener. The developed method was validated according to the parameters: correctness, precision, specificity, linearity.

Introduction. The creation of rational combined medicines with hepatoprotective activity is an urgent task of medicinal science. Ademetionin shows pharmacological effectiveness in cytolysis, cholestasis, synthetic insufficiency. Silybin, in turn, is effective in cytolysis, synthetic insufficiency, mesenchymal inflammation, fibrosis and pathological regeneration. Thus, the combination of these substances covers almost the entire set of clinical and morphological syndromes of liver damage and has a wide range of effects in various liver pathologies.

Aim. The purpose of this study was to develop a combined granular dosage form containing a thick extract of milk thistle, ademetionin and analytical support for this process.

Materials and methods. To obtain a thick extract from the fruits of Silybum marianum L. a traditional percolation method was used in a battery of 3 diffusers. Extractant removal was performed using a rotary evaporator IR-1M3 under vacuum. For the analysis of silybin in the obtained thick extract from the fruit of S. marianum L. the method of HPLC was used. Validation evaluation of the method was performed according to generally accepted parameters.

Results and discussion. A modular combined dosage form based on a thick extract of S. marianum L. and ademethionine was developed. Lactose was introduced as an auxiliary agent. The quality of pellets was evaluated according to generally accepted criteria. The validation parameters of the manufactured dosage form were determined using the HPLC method. Accuracy and precision were determined by the method of additives in a series of 9 experimental samples of granules. The results of determining the linearity, precision and correctness of the method for determining silybin and ademetionin in a combined model drug form showed correct results.

Conclusion.Thus, a combined granular dosage form containing a thick extract of milk thistle, ademetionin, has been developed. Analytical support of this process using the HPLC method was performed. Validation studies of the developed methodology were carried out. The field of application of the obtained results is practical pharmacy. Further research should concern the conduct of a set of pharmacological tests.

Introduction. Drug encapsulation efficiency (EE) is the important parameter of the nanoparticle-based drug formulations. Generally, the methods for evaluation of the EE are based on separation of the free and NP-bound fractions of the drug; however, applicability of these methods for a particulate formulation needs careful consideration.

Aim. The purpose of the study was to optimize the procedure for evaluation of the EE for a nanoparticle-based drug formulation taking doxorubicin loaded in the PLGA nanoparticles (PLGA-Dox NP) as a model formulation.

Materials and methods. The PLGA-Dox NP were prepared by a “double emulsion” method at pH of the external aqueous phase of 7.4 or 6.4. The NP size and size distribution (PDI) were determined by photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM). For the EE evaluation of doxorubicin, the NP were separated by centrifugation (CF), ultrafiltration (UF), or gel filtration. The efficiency of NP separation by the CF method was evaluated by the PLGA content in the supernatant by capillary electrophoresis (CZE).

Results and discussion. The average hydrodynamic diameter of the PLGA-Dox/7.4 and PLGA-Dox/6.4 NP (FCS) was 103 ± 10 nm and 141 ± 8 nm, respectively. According to the TEM data, the main fraction of the NP averaged 50 ± 16 nm. The EE of doxorubicin, determined after the NP separation by centrifugation at 48254.g, was 78.9 ± 1.8 % for the PLGA-Dox/6.4 and 91.5 ± 0.9 % for the PLGA-Dox/7.4 NP with the residual PLGA content in the supernatant of ~5 %. At lower acceleration the NP separation was incomplete leading to underestimation of the EE. Also, the ultrafiltration method using the filters with the NMWL of 50 and 100 kDa enabled the reliable NP separation with the minimal doxorubicin adsorption on the filter (<4 %). Separation of the NP by gel filtration led to the underestimation of the EE due to considerable desorption of doxorubicin from the NP surface.

Introduction. Effective drug therapy for cancer patients with chronic pain syndrome (CPS) of high intensity is one of the priorities of modern healthcare. Currently, non-narcotic and narcotic analgesics are used for pain relief according to a three-steps scheme. In the absence of contraindications, it is preferable to prescribe medications per os and prolonged forms, which will allow the patient to maintain selfcare and comfort.

Aim. To study the pharmacokinetic properties of a drug with a prolonged mechanism of action «Morphine hydrochloride», in a film-coated tablet formof a dosage 30 mg, in cancer patients with severe CPS.

Materials and methods. For the analysis of the pharmacokinetics of the studied drug after single and multiple doses of 20 patients who received 10-day analgesic therapy with the studied drug «Morphine hydrochloride», long-acting film-coated 30 mgtablets. manufacturer FSUE Moscow Endocrine Plant, Russia. Route of administration: per os. The study duration was 17 days: screening duration up to 7 days; duration of therapy up to 10 days.

Results and discussion. The concentration of morphine in plasma was determined by HPLC-tandem mass spectrometry, within 12 hours after taking the study drug (1 of long-acting, film-coated tablet 30 mg). The following pharmacokinetic parameters were obtained on Day 5: T_1/2 – 6.08 ± 4.37 hours and 14.46 ± 30.86 hours, T_max – 2.5 ± 1.86 hours, C_max – 43.91 ± 27.24 ng/ml. Values of pharmacokinetic parameters averaged over all days are presented. It was found that T_1/2 for the studied drug T_1/2 is 9.21 ± 14.94 hours, T_max 2.87 ± 2.36 hours. The average maximum concentration (C_max) on the day of the study drug was 36.52 ng/ml.

Conclusion. As a result of the study of pharmacokinetics, it was found that the drug «Morphine hydrochloride», long-acting tablets film-coated with a of 30 mg was found in serum after oral administration after 15 minutes and reaches a maximum concentration in the blood in 3 hours, the half-life is on average 9 hours, the maximum concentration is 36.52 ng/ml.

Introduction. Insulin is the most effective hypoglycemic agent currently used in the clinical practice. Compared with recombinant human insulin, insulin lispro have a blood glucose profile that is much closer to physiological. The clinical trials program of insulin bioassays includes pharmacology studies: pharmacokinetics (PK), pharmacodynamics (PD), and a clinical safety study.

Aim. To compare PK and PD of RinLiz® U100, solution for intravenous and subcutaneous administration (LLC «GEROFARM», Russia) and Humalog® U100, solution for intravenous and subcutaneous administration (Lilly France, France) in hyperinsulinemic euglycemic clamp.

Materials and methods. This was randomized double-blind, two-arm crossover study in 28 healthy volunteers (NCT03604575). The studied preparations were injected before the clamp with a dose of 0.3 U/kg once subcutaneously in the area of subcutaneous fat in the anterior abdominal wall. During the study, regular blood sampling was performed; the amount of insulin lispro was determined by ELISA in the samples. The results of the determination were used to calculate the PK parameters and construct the curves «concentration – time». Based on the measurement of glycemia, the glucose infusion rate was adjusted. These data were used to calculate the PD parameters. The comparability of the studied drugs was considered proven if 90 % confidence intervals (CI) for the ratio of geometric mean PK parameters C_ins. max and AUC_ins. 0-8 and 95 % CI for the ratio of geometric mean PD parameters GIR_max and AUC_GIR0-8,5 were in the range of 80–125 %. Statistical data processing and presentation of the results was carried out using software packages R 3.4.2.

Results and discussion. In the course of CI comparative PK and PD of RinLiz® and Humalog®, it was revealed that they have comparable PK and PD profiles. The CI for the logarithmically converted ratios of the values of the PK parameters was C_ins. max 85.99–96.85 % and AUC_ins. 0-8 90.58–97.28 %, the PD of the parameters were 95.64–118.94 for GIR_max and 96.5–121.36 for AUC_GIR0-8.5, all the CIs correspond to the set the boundaries of 80–125 % to establish comparability between RinLiz® and the original drug.

Conclusion. The results demonstrated the high degree of similarity of RinLiz® U100 and Humalog® U100 in terms of PK, PD profiles and safety.

Introduction. Viral infections are a serious problem that occurs during the use of immunosuppressants in preparation for organ transplantation and in the postoperative period. Cytomegalovirus (CMV) infection is one of the main causes of diseases in people with weakened immune systems. It has a direct impact on one’s body and makes it more likely to reject a transplanted organ. Antiviral drugs are used to treat and prevent this infectious disease. Valganciclovir is a prodrug whose active metabolite is ganciclovir. Valganciclovir is the drug of choice in the treatment of CMV infections. Currently, there are no researches on the matter of simultaneous determination of both valganciclovir and ganciclovir in human blood plasma by means of high-performance liquid chromatography (HPLC) with ultraviolet detection. This research delivers a thorough description of development and validation of a particular method for simultaneous determination of valganciclovir and ganciclovir in the plasma after sample preparation by the method of protein precipitation.

Aim. The aim of this study is to develop method for the quantitative determination of valganciclovir and its active metabolite ganciclovir in human plasma by HPLC-UV for pharmacokinetic studies.

Materials and methods. Quantitative determination of tadalafil in plasma by HPLC-UV. A sample was prepared using protein precipitation.

Results and discussion. This method was validated by next validation parameters: selectivity, matrix effect, calibration curve, accuracy, precision, lower limit of quantification, carry-over and stability.

Conclusion. The method of the quantitative determination of valganciclovir and its active metabolite ganciclovir in human plasma was developed and validated by HPLC-UV. The analytical range of the was 5,0–1000,0 ng/ml for valganciclovir and 100,0–10000,0 ng/ml for ganciclovir in plasma. Method could be applied to determination of valganciclovir and ganciclovir in plasma for PK and BE studies.

Introduction. Neutropenia, which is an abnormally low concentration of neutrophils in the blood, is one of the common side effects in patients receiving radio- or chemotherapy. Neutropenia usually leads to higher risks of severe bacterial and fungal infections. Such medicines as colonystimulating factor filgrastim (and its conjugates) are used to prevent and treat neutropenia in oncology patients. Immunogenicity is a potential concern for any biological product, thus, its assessment is one of the most critical necessities during the development and registration of such products.

Aim. The main aim of this study was to validate the ELISA method for anti-pegfilgrastim antibodies detection in human serum samples and to apply the validated method to pegfilgrastim drugs immunogenicity assessment.

Materials and methods. To assess pegfilgrastim immunogenicity, the commercial ELISA kit «PEGylated Filgrastim (Neulasta®) ADA ELISA» was used for screening, confirmatory and titer assay. Moreover, to confirm the chosen commercial kit suits the study aims it was revalidated. The absorbance values were obtained using plate immunoassay analyzer Stat Fax 3200, plate washing was performed using an automatic twochannel plate washer.

Results and discussion. The ELISA method for anti-pegfilgrastim antibodies determination in human serum samples was validated and applied to the analytical part of the comparative, multicenter, blind, randomized study of pegfilgrastim efficacy and safety in patients with breast cancer, receiving myelosuppressive chemotherapy. Human serum samples were first screened for anti-drug antibodies, then «screening positive» samples were analyzed in confirmatory assay with % inhibition calculation for each sample. The «confirmed positive» samples were further characterized in titer assay.

Conclusions. The ELISA method for anti-pegfilgrastim antibodies determination in human serum samples was successfully validated and applied for pegfilgrastim drugs immunogenicity assessment.

Introduction. One of the purposes of dissolution profile comparison is to establish the equivalence of dissolution profiles of the studied drug and the comparison drug.

Text. According to the current regulatory documents, the main tool for quantitative confirmation of equivalence of drug release profiles is the calculation of the similarity factor (f₂). However, it does not consider the form of dissolution profiles, incomplete release of the drug substance, time correlation, and is not susceptible to the «outliers», which leads to false positive results. Special attention should be paid to the dissolution of drugs with high variability, which is not eliminated by either increasing the sample or changing the sampling scheme. If f₂ is not used, it is necessary to use model-dependent and model-independent methods that are statistically correct, and their use is sufficiently justified (difference factor f₁, Weibull distribution function, comparison of release degrees at different time points (according to the student's t-criterion). However, these models have an empirical nature that calls into question the application of such methods. Multivariate analysis is widely discussed in the literature and can be used to compare the similarity of dissolution with the assumption that the data has a normal distribution. The most common methods for checking similarity of dissolution profiles for highly variable drugs are the Mahalanobis distance test and the bootstrap for f₂. There is a document of EMA about suitability of the Mahalanobis distance as a tool to assess the comparability of drug dissolution profiles and to a larger extent to emphasise the importance of confidence intervals to quantify the uncertainty around the point estimate of the chosen metric. The bootstrap methodology for f₂ does not provide a clear understanding of the application to dissolution profile comparison for incomplete-release drugs, particularly in biorelevant environments. The «T2EQ» function, based on the Mahalanobis distance for highly variable drugs (Hoffelder), gives undefined results in practice.

Conclusion. The topic of equivalence of dissolution profiles requires discussion, since it is shown that the convergence factor is outdated and cannot be adequately applied. The use of modern methods does not have a clear regulatory confirmation by the regulatory authority. In the published scientific literature, several statistical methods have been explored and compared for their design and performance. It is necessary to develop a clear plan (decision treeы) for conducting the procedure for equivalence of dissolution profiles, employing a range of statistical methods.

Introduction. One of the key issues in the field of assessing the conformity of drug manufacturers with the requirements of good manufacturing practice (GMP) is a systematic methodology for classifying revealed deficiencies (deviations, non-conformities) by their level of criticality. Today the information included into regulatory documents regarding the definitions of critical, major and minor (other) deficiencies is not always sufficient for the use in GMP inspection practice, as well as in quality management systems of the pharmaceutical manufacturers. In terms to study approaches to the classification of GMP deviations applied in the practice of the Qualified persons of drug manufacturers in the Russian Federation, a survey was conducted in the form of a questionnaire. This work became a logical continuation of a previous study among employees of the pharmaceutical inspectorate of the Russian Federation.

Aim. To identify the correlation between the classification of critical and major GMP deviations and potential class I and II quality defects of medicinal products.

Materials and methods. The study was based on a survey of Qualified persons of drug manufacturers (56 respondents) using a questionnaire specially designed. The main hypothesis of the study is that specialists (Qualified persons) who make decisions on the classification of GMP deviations are guided by potential quality defects that may be caused by the indicated deviations. In the framework of the study, authors used the model of gradation of quality defects of the medicinal products into 3 classes (class I, II and III) according to the rate of their significance as indicated in the PIC/S and EMA guidelines. At the same time, for GMP deviations a three-level gradation system is also used: Critical, Major and Minor (Other). In designing of questionnaires for the survey, the focus was made on examples of quality defects of classes I and II and, accordingly, Critical and Major GMP deviations.

Results and discussion. The results of the processing and analysis of questionnaires summarize the opinion of the majority of respondents about the direct relationship between product quality defects of the high risk (class I) and critical GMP deviations. Respondents also expressed the opinion that deviations that could trigger the occurrence of the class II quality defects in most cases will be classified as critical. The results obtained during the study also indicate the similarity of existing approaches of the classification of GMP deviations (deficiencies) between QPs of the drug manufacturers and pharmaceutical inspectors.

Conclusion. The results of the study show that for the purpose of classifying (determining the criticality) of GMP deviations (deficiencies) , it is possible to use the rating system for the quality defects of medicinal products by the rate of their significance for the patient which is presented in EU regulatory documents and PIC/S guidelines. The results of the study also will facilitate the drawing of conclusions that today, not only from the position of regulatory authorities, but also for the pharmaceutical industry, there is a need to develop methodological guidelines with a focus on a risk-based classification of GMP deviations (deficiencies). These guidelines should take into account the potential impact of the mentioned GMPdeviations on the occurrence of the quality defects of medicinal products and, as a result, threats to the life and health of patients.