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Introduction. The introduction of devices – analogues of GIS (hereinafter–- Gastro-intestinal simulator) is one of the current ways to develop in-vitro assessment of the quality of solid dosage forms. Testing on a physiologically relevant test device (hereinafter referred to as PRT) makes it possible to predict pharmacokinetic profiles due to more relevant conditions, including the use of biorelevant dissolution media, physiological volumes of the gastrointestinal tract, as well as transit between them.Aim. Conduct a study of cladribine tablets on a physiologically relevant tester in order to predict the behavior of the drug in the human gastrointestinal tract.Materials and methods. The objects of the study are "Mavenclad®, tablets, 10 mg" (series 2200754, expiration date until 04.2025, NERPHARMA, S.r.L., Italy) and "Cladribine, tablets, 10 mg" of domestic production with valid expiration date. During the study, the reagents necessary for the preparation of biorelevant dissolution media and quantitative determination by HPLC. Physiologically relevant test were carried out using an apparatus of our own production, consisting of a DT-6 dissolution tester (ERWEKA GmbH, Germany), a water bath equipped with a Thermomix WB-4 heating element (B. Braun, Germany), and peristaltic pumps (Kamoer, China). The quantitative content of released cladribine was assessed using a highly efficient liquid chromatograph "Khromatek-Kristall HPLC 2014" (ZAO SKB "Khromatek", Russia) using a validated method at a wavelength of 252 nm, analysis time – 7 min, column – Grace HPLC Column Platinum C18-EPS, 250 × 4.6 mm, 5 mm (Grace, USA), temperature – 35 °C, elution mode – isocratic (A : B 80 : 20), mobile phase A – 0.1 % H3PO4 solution, phase B – acetonitrile.Results and discussion. Profiles were obtained to assess the dynamics and degree of release of the studied drugs in various parts of the human gastrointestinal tract. Despite the expected degradation of cladribine in an acidic environment (pH1.2), under physiologically relevant conditions, the drug reached the third section (small intestine model) without degradation. Complete release of cladribine from the test and reference dosage forms was observed. Also, in the future, based on the data obtained, it is possible to predict pharmacokinetic profiles using physiologically based pharmacokinetic modeling approaches.Conclusion. A PSF study was conducted for the drugs "Mavenclad®, tablets, 10 mg" and "Cladribine, tablets, 10 mg". Quantitative determination was carried out by HPLC-UV method. The test results showed complete release of both drugs and reaching the intestinal tract, indicating the absence of degradation of cladribine in the region simulating the stomach.

Introduction. The most important stage of pharmaceutical development of a generic drug is a clinical trial involving humans – a bioequivalence study. Considering the importance of finding rivaroxaban drugs in the list of vital and essential drugs, as part of ensuring technological sovereignty, the use of scientific robust and effective methods for determining the quality of the dosage form is required.Aim. Conduct a study of rivaroxaban tablets on a physiologically relevant tester to predict pharmacokinetic profiles.Materials and methods. The objects of the study are "Xarelto®, film-coated tablets, 10 mg" (series BXJS871, with an expiration date of October 31, 2024, Bayer AG, Germany), "Xarelto®, film-coated tablets, 20 mg" (series BXKDF32, with an expiration date of May 17, 2026, Bayer AG, Germany) and "Rivaroxaban, film-coated tablets, 10 mg" and "Rivaroxaban, film-coated tablets, 20 mg", domestically produced, with valid expiration dates. During the study, reagents were used to prepare dissolution media and perform quantitative determination. The physiologically relevant test was performed on the SC PRT-6 device (LLC "Scientific Compliance", Russia). The quantitative content of released rivaroxaban within the comparative dissolution kinetics test in a medium of 0.1 in a medium of 0.1 % sodium lauryl sulfate solution in a phosphate buffer solution pH 6.5 was carried out on a SF-2000 spectrophotometer (LLC "OKB Spektr", Russia). The quantitative content of released rivaroxaban within the comparative dissolution kinetics test in biorelevant dissolution media and physiological relevance test was assessed on a high-performance liquid chromatograph "Chromatec-Crystal HPLC 2014" (CJSC "Chromatec", Russia). Pharmacokinetic profiles were modeled in the PK-Sim® (Systems Biology Software Suite 11.2, Bayer Technology Services GmbH, Germany) program based on the data obtained within the physiologically relevant test. The clinical study of rivaroxaban tablets was a prospective, open-label, randomized, crossover, two-stage comparative study in two groups of volunteers with a single dose of drugs on the fast condition. The study randomized 30 healthy male volunteers aged 18–45 years.Results and discussion. A complex of in vitro tests was conducted, profiles were obtained that allow us to evaluate the dynamics and degree of release of the studied drugs in various parts of the human gastrointestinal tract. A comparison of the sequential and hybrid schemes for conducting the physiological relevance test was carried out. Within the framework of the set of tests, qualitative and quantitative correlation with the clinical trials data was observed only for the hybrid physiological relevance test scheme. Based on the results of physiological relevance test using different schemes, pharmacokinetic profiles for a pair of drugs were predicted and the prediction error was assessed.Conclusion. A set of scientific in vitro tests was conducted for the drugs "Xarelto®, film-coated tablets, 10 mg and 20 mg", "Rivaroxaban, film-coated tablets, 10 mg and 20 mg". Based on the physiological relevance test results, pharmacokinetic profiles for a pair of drugs were predicted with low error and high reliability. As part of the comparison of data obtained during clinical trial and modeling, the smallest prediction error was noted when performing physiological relevance test using a hybrid scheme.

Introduction. Deferasirox is a complexing drug and belongs to class II according to the biopharmaceutical classification system (BCS), has acidic properties and belongs to subclass “a” (acid). This class is characterized by high permeability and low solubility, which limits the absorption of the active substance into the blood. As a result, the development of drugs with an active substance that can be assigning BCS to this class is a difficult task, and for generic drugs it is also associated with a high risk of obtaining unproven equivalence during clinical trials. To minimize the above risks, a physiologically relevant test was carried out with further data processing and construction of putative pharmacokinetic profiles.Aim. The aim of the study is to conduct a physiologically relevant test (PRT) to predict in vitro pharmacokinetic profiles and compare them with in vivo data as part of a bioequivalence study of deferasirox.Materials and methods. The objects of the study are "Deferasirox, film-coated tablets, 360 mg" of a domestic manufacturer and "Jadenu®, film-coated tablets, 360 mg" (WTN22 series, expiration date until 10.2023, Novartis Pharma Stein AG, Switzerland). A physiologically relevant test was performed on the device SC PRT-6, Compliance. Quantitative analysis was carried out by HPLC-UV method.Pharmacokinetic profiles were modeled using PK-Sim® (Systems Biology Software Suite 11.2, Bayer Technology Services GmbH, Germany) based on data obtained from physiologically relevant test.Results and discussion. A physiologically relevant drug test for deferasirox was performed and release profiles were obtained, which formed the basis of a physiologically based pharmacokinetic model together with data on the physicochemical properties of the studied compound and literature data on the pharmacokinetics of deferasirox. The pharmacokinetic profiles obtained as part of the simulation on a virtual population were compared with data obtained during clinical trials.Conclusion. A physiologically relevant test for the drug deferasirox was carried out, quantitative determination in the samples was carried out by HPLC-UV. The test resulted in data that allowed prediction of pharmacokinetic profiles that reflected the same differences observed in the profiles of the test and reference drug in the comparative pharmacokinetics and bioequivalence study of deferasirox drugs.

Introduction. Sorafenib is an antineoplastic drug belonging to class IIc according to the biopharmaceutical classification system (BCS) due to the presence of both acidic and basic properties. In addition to low solubility, sorafenib is characterized by high variability during clinical trials, in particular bioequivalence studies (BE). To selecting batches that can be recommended for BE studies, the dissolution kinetics test is currently widely used, however, the results of this test are not always sufficient and additional tests, for example, a physiologically relevant test, are advisable. To minimize the risks of obtaining nonequivalent results during the BE study, a physiologically relevant test (PRT) was carried out with further data processing and interpretation of the results of physiologically based pharmacokinetic modeling (PBPK).Aim. The aim of the study is to conduct a physiologically relevant test (PRT) for the purpose of selecting a candidate batch for subsequent BE study of sorafenib drugs using the physiologically based pharmacokinetic model (PBPK).Materials and methods. The objects of the study are Nexavar®, film-coated tablets, 200 mg (Bayer AG, Germany) (one batch) and Sorafenib, film-coated tablets, 200 mg (two batches) (Russia). The physiologically relevant test was performed on the SC PRT-6 device (LLC "Scientific Compliance", Russia). Quantitative analysis was performed by HPLC-UV on the Chromatec-Crystal HPLC 2014 device (CJSC "Chromatec", Russia). The plasma concentration profiles were simulated using PK-Sim® software (Systems Biology Software Suite 11.2, Bayer Technology Services GmbH, Germany).Results and discussion. As part of the study, a method for the quantitative determination of sorafenib was developed and validated, a method for sample preparation was developed, and a method for conducting the PRT for sorafenib, as a representative of the IIc subclass of BCS, was developed. Based on the study results, release profiles were obtained that were used to select a candidate series for the BE study. The series were selected based on the PBPK analysis on a virtual population consisting of 36 healthy volunteers with activated enteropathic circulation, characteristic of sorafenib.Conclusion. The PRT was carried out for the drug sorafenib. Quantitative determination was carried out by HPLC-UV according to the developed and validated method. The test resulted in obtaining data that were subjected to PBPK analysis. It was shown that the studied batches have high risks of non-equivalence during the bioequivalence study.

Aim. A comparative study of the pharmacokinetics and safety of the investigational drug Duonica®, enteric-soluble, film-coated tablets, 10 mg + 10 mg (Valenta Pharm JSC, Russia) and the reference drug Diclectin®, delayed-release tablets, 10 mg + 10 mg (Duchesnay Inc, Canada) was conducted as part of the bioequivalence study in healthy volunteers under fed conditions.Material and methods. An open-label randomized crossover two-period bioequivalence study was conducted with 28 Caucasian female volunteers. The study participants were randomly divided into two groups of 14 people depending on the order of drug administration during Periods 1 and 2. Participants randomized to the first group received 2 tablets of Diclectin® during Period 1 and 2 tablets of Duonica® during Period 2. Volunteers from the second group took the study drugs in the reverse order. During each study Period, the drugs were administered after a high-calorie breakfast. The analytes studied were doxylamine and pyridoxal-5-phosphate (an active metabolite of pyridoxine). Methods were developed and validated using high-performance liquid chromatography with a triple quadrupole tandem mass spectrometric detector (HPLC-MS/MS) to quantify the analytes. Pharmacokinetic parameters were calculated from the obtained concentration values and statistical analysis was performed. To confirm bioequivalence, 90 % confidence intervals (CI) for the pharmacokinetic parameters AUC and Cmax of the studied analytes were calculated. The safety of the investigational drugs was assessed based on the frequency, severity and type of adverse events.Results. The 90 % CI values for the ratio of Cmax and AUC(0-t) values for doxylamine were 94.08–113.71 % and 90.63–102.50 %, and for pyridoxal-5-phosphate were 97.34–123.47 % and 90.30–111.03 %, respectively. The obtained CI values were within the limits set by the regulatory requirements and the study protocol (80.00–125.00 %), which allowed us to confirm the bioequivalence of the studied drugs for both components. No adverse events were reported during the study.Conclusion. The study investigated the pharmacokinetics of drugs containing a fixed combination of doxylamine and pyridoxine under fed conditions. The results obtained confirmed the bioequivalence of the drug Duonica® to the reference drug Diclectin®. Both drugs were well tolerated and no differences in the safety profile of the investigational drugs were observed.

Introduction. The use of tofacitinib as a pharmacological treatment for rheumatoid arthritis remains relevant in the light of the predicted increase in prevalence of the disease. At the same time, due to the withdrawal of several foreign pharmaceutical companies from the Russian pharmaceutical market, there has been a heightened demand for domestically produced medications, including generic formulations of tofacitinib. Registration of generic drugs necessitates the conduct of bioanalytical studies. Development and validation of a method for quantifying the analyte in biosamples remains to be a crucial part of the bioequivalence studies.Aim. The aim of this research is to develop and validate a method for the quantitative determination of tofacitinib in human plasma using high-performance liquid chromatography as the separation system coupled with a tandem mass spectrometer for detection purposes.Materials and methods. Biosample preparation was based on plasma proteins precipitation using acetonitrile. Baricitinib was selected as an internal standard. The analytical range of the method was 1.00 to 200.00 ng/mL and was further expanded to 0.30 to 200.00 ng/mL during the analytical phase of the study. The mobile phase consisted of water and acetonitrile, both acidified with formic acid (0.1 % v/v). The stationary phase was a Phenomenex Kinetex C18 column [100 × 3.0 mm, with a particle size of 5 µm (Phenomenex, USA)]. Sample separation and detection were carried out using high-performance liquid chromatography coupled with a tandem mass spectrometry (HPLC-MS/MS), operating in positive ion mode. The multiple reaction monitoring (MRM) transitions selected for the analyte and the internal standard were 313.30 to 173.00 m/z and 371.90 to 186.00 m/z, respectively.Results and discussion. The developed assay was validated in accordance with the current requirements of regulatory documentation from the EAEU (Eurasian Economic Union), FDA (US Food and Drug Administration), and EMA (European Medicines Agency) with the following parameters being evaluated: selectivity, specificity, carry-over, matrix effect, recovery, calibration curve, lower limit of quantitation, accuracy, precision, stability. The validated method was applied in the analytical part of a bioequivalence study of domestically produced generic tofacitinib.Conclusion. A method for the quantitative determination of tofacitinib in human blood plasma with an analytical range of 0.30–200.00 ng/mL was developed and validated. Application of the assay during the analytical phase of bioequivalence study of generic tofacitinib confirms the possibility of using the method in similar bioanalytical investigations.

Introduction. The number of peptide drugs being developed and registered has increased in recent years. Therefore, modern analytical approaches and methods are required to determine these substances in biological matrices during pharmacokinetic studies. Peptides are structurally intermediate between small molecules and biopolymers, making it difficult to develop methods for determining them using High Performance Liquid Chromatography with Tandem Mass Spectrometry (HPLC-MS/MS). Peptide derivatization can help achieve optimal chromatographic separation and increase method sensitivity.Aim. To develop and validate a method for the determination of the tetradecapeptide (TDP) threonyl-glutamyl-lysyl-lysyl-arginyl-arginyl-glutamayl-threonyl-valyl-glutamyl-arginyl-glutamyl-lysyl-glutamate in human plasma by HPLC-MS/MS.Materials and methods. The determination of TDP in human plasma was performed by HPLC-MS/MS. Sample preparation included a combination of blood plasma protein precipitation with propionic acid solution in methanol, liquid-liquid extraction with chloroform, and peptide derivatization with propionic anhydride. Internal standard (IS) was threonyl-glutamyl-lysyl-lysyl-arginyl-arginyl-glutamayl-threonyl-leucyl-glutamyl-arginyl-glutamyl-lysyl-glutamate. Chromatographic separation was performed in gradient mode, eluent A was 0.1 % formic acid solution in water, eluent B was 0.1 % formic acid in acetonitrile. Column: Waters XBridge C18, 4.6 × 50 mm, 5 µm. Ionization source was electrospray in positive mode. Multiple reaction monitoring (MRM) transitions for 4-substituted TDP propionate were: 681.30 → 73.95 m/z, 681.30 → 84.00 m/z, 681.30 → 101.90 m/z, 681.30 → 140.10 m/z, and for 4-substituted IS propionate: 686.00 → 74.10 m/z, 686.00 → 84.05 m/z, 686.00 → 102.00 m/z, 686.00 → 140.00 m/z.Results and discussion. Validation of the developed method was carried out in accordance with the requirements of Eurasian Economic Union and the following parameters were determined: selectivity, matrix effect, calibration curve, accuracy and precision, recovery, lower limit of quantification, sample carryover, stability.Conclusion. The method for the determination of TDP in human blood plasma by HPLC-MS/MS was developed and validated. The analytical range was 5.00–1000.00 ng/mL, allowing the method to be used to study TDP pharmacokinetics.

Introduction. The pandemic of the new coronavirus infection COVID-19 (Coronavirus Disease 2019) was caused by a single-stranded RNA virus SARS-CoV-2 (Severe acute respiratory syndrome-related coronavirus 2). Molnupiravir is an antiviral drug with activity against RNA viruses including SARS-CoV-2. Molnupiravir exerts the antiviral effect by introducing copy errors during viral RNA replication – by that the replication of SARS-CoV-2 inhibits. For oral administration of molnupiravir the drug Esperavir® has been registered in Russia.Aim. The aim is pharmacokinetics study of Esperavir®, capsules 200 mg (the manufacturer is JSC "Biokhimic", LLC "PROMOMED RUS", Russia, as registration certificate holder) by a single dose (800 mg) and multiple doses oral administration (800 mg twice a day with a gap of 12 hours between doses) in healthy volunteers in a phase I pharmacokinetics study, comparison the obtained data of pharmacokinetic parameters with the literature data.Materials and methods. The clinical and analytical phases of the pharmacokinetic study as well as pharmacokinetic analyses have been performed as a part of a clinical trial of the drug Esperavir®, capsules 200 mg (the manufacturer is JSC "Biokhimic", LLC "PROMOMED RUS", Russia, as registration certificate holder). Chromatographic separation and detection by Nexera XR high-performance liquid chromatograph with triple quadrupole tandem mass spectrometry LCMS-8040 (Shimadzu Corporation, Japan). The pharmacokinetic parameters were calculated with the Boomer pharmacokinetic analysis add-in for Microsoft Excel (Department of Pharmacokinetics and Drug Metabolism, Allergan, Irvine, CA 92606, USA). Descriptive pharmacokinetic statistics were calculated with Microsoft Excel (Microsoft Corporation, USA).Results and discussion. Pharmacokinetic parameters for cohort 1 (800 mg single dose of Esperavir®) and for cohort 2 (800 mg of Esperavir® twice a day with a gap of 12 hours between doses) were calculated. Averaged pharmacokinetic profiles of mean NHC concentrations over time in linear and log-linear scales were plotted. The geometric mean of Cmax and T1/2, the median, minimum and maximum of Tmax showed the comparability of the obtained data after a single dose administration of 800 mg of Esperavir® and the available literature data.Conclusion. According to the concentrations from the analytical phase of the pharmacokinetic study the pharmacokinetic parameters were calculated, averaged pharmacokinetic profiles in linear and log-linear scales were plotted after a single dose and multiple doses of the drug Esperavir®, capsules (the manufacturer is JSC "Biokhimic", LLC "PROMOMED RUS", Russia, as registration certificate holder). The comparability of the obtained data and the available literature data was shown. The results justified the study of the subsequent phases of clinical trials of Esperavir®.

Introduction. Favipiravir is an antiviral compound that inhibits the RNA-dependent polymerase and possesses antiviral properties against RNA viruses, including SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2). The new drug Areplivir® Zinc as a combination of favipiravir (200 mg) and zinc gluconate (70 mg) in the form of film-coated tablets has been developed by LLC "PROMOMED RUS", Russia. This combination of favipiravir and zinc gluconate could provide more effective treatment of COVID-19.Aim. The aim of the pharmacokinetics study is comparison between Areplivir® Zinc (INN: favipiravir + zinc gluconate), film-coated tablets (the manufacturer is JSC "Biokhimic", LLC "PROMOMED RUS" as registration certificate holder) and Areplivir® (INN: favipiravir), film-coated tablets (the manufacturer is JSC "Biokhimic", LLC "PROMOMED RUS" as registration certificate holder) to evaluate the effect of zinc on the favipiravir pharmacokinetics.Materials and methods. The clinical and analytical phases as well as pharmacokinetic analyses have been performed as a part of a phase I clinical trial. Chromatographic separation and detection of favipiravir were performed by high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) method using Nexera XR high-performance liquid chromatograph with triple quadrupole tandem mass spectrometer LCMS-8040 (Shimadzu Corporation, Japan). The validated analytical range of the method was 50.00–15 000.00 ng/mL in human plasma. The plasma zinc concentrations were measured by a biochemical method with the use of the kit «Zinc-Novo (50)» (JSC "Vector-Best", Russia). The descriptive statistics were calculated using Microsoft Excel (Microsoft Corporation, USA). The pharmacokinetic parameters, analysis of variance (ANOVA), 90 % confidence intervals (90 % CIs) and the intra-subject variability (CVintra) were calculated by R Project 3.5.1 software (package «bear», version 2.8.3-2), originally created by Hsin-ya Lee and Yung-jin Lee, Taiwan.Results and discussion. The 90 % confidence intervals of the ratios for Сmax and AUC(0–t) were 86.48–100.38 % and 103.77–119.47 %, respectively. The 90 % confidence intervals were all within the acceptance range of 80.00–125.00 % which means there is no effect of zinc on the favipiravir pharmacokinetics. The intra-subject variability (CVintra) of favipiravir for the pharmacokinetic parameters Cmax and AUC(0–t) were 15.06 % and 14.23 %.Conclusion. The results justified the subsequent phases of clinical trials of Areplivir® Zinc (INN: favipiravir + zinc gluconate), film-coated tablets (LLC "PROMOMED RUS", Russia). This combination of favipiravir and zinc could expand the existing armamentarium of antiviral drugs for the treatment of COVID-19.

Introduction. COVID-19 (Coronavirus disease 2019) almost 4 years after he start of the pandemic is still a significant public health problem. SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) that causes COVID-19 continues to mutate and spread throughout the world. Molnupiravir and favipiravir have been shown to be efficacious against variety of RNA viruses including the SARS-CoV-2. The Ministry of Health of the Russian Federation approved the use of these drugs as a treatment of COVID-19. The developed drug contains the combination of two antiviral agents with different mechanisms of suppressing viral RNA replication, which suggests efficacy against the vast majority of ARVI pathogens found in the human population including SARS-CoV-2 and influenza.Aim. The aim of the pharmacokinetics study is comparison between JTBC00301 (INN: molnupiravir + favipiravir), film-coated tablets (LLC "PROMOMED RUS", Russia), Esperavir® (INN: molnupiravir), capsules (LLC "PROMOMED RUS", Russia) and Areplivir® (INN: favipiravir), film-coated tablets (LLC "PROMOMED RUS", Russia) to evaluate the impact of monocomponents on each other's pharmacokinetics.Materials and methods. The clinical and analytical phases as well as pharmacokinetic analyses have been performed as a part of a phase I, randomized, open-label, 3-period crossover study of drug JTBC00301 (INN: molnupiravir + favipiravir), film-coated tablets, 400 + 400 mg (LLC "PROMOMED RUS", Russia). The plasma concentration of β-D-N4-hydroxycytidine (NHC), the active metabolite of molnupiravir and favipiravir were determined in 42 healthy volunteers after taking the test drug JTBC00301 (1 tablet of 400 + 400 mg), the reference drug Esperavir® (2 capsules of 200 mg) and the reference drug Areplivir® (2 tablets of 200 mg). The descriptive statistics were calculated using Microsoft Excel (Microsoft Corporation, USA). The pharmacokinetic parameters, analysis of variance (ANOVA), the intra-subject coefficient of variation (CVintra) and 90 % confidence intervals (90 % CI) were calculated by R Project 3.5.1 software (package «bear», version 2.8.3-2), originally created by Hsin-ya Lee and Yung-jin Lee, Taiwan.Results and discussion. Pharmacokinetic parameters of NHC and favipiravir were determined, averaged pharmacokinetic profiles in linear and log-linear scales were plotted, analysis of variance was carried out. The 90% CIs for geometric mean ratios of Сmax and AUC(0–t) for NHC and favipiravir were all within the acceptance range of 80–125 % which means there is no effect of monocomponents on each other’s pharmacokinetics.Conclusion. The development of the fixed-dose drug combination of molnupiravir and favipiravir has great potential as it may allow to increase the safety profile and improve the tolerability of therapy as well as increase the effectiveness of antiviral therapy. The results justified the study of the subsequent phases of clinical trials of JTBC00301 (INN: molnupiravir + favipiravir), film-coated tablets, 400 + 400 mg (LLC "PROMOMED RUS", Russia).

Introduction. Etmaben is a promising drug for the treatment of cardiovascular diseases, widely studied in preclinical studies. In order to conduct phase I clinical trials, it is necessary to develop a bioanalytical method for the quantitative determination of etmaben in human blood plasma.Aim. The aim of the study is to develop and validate a method for the quantitative determination of etmaben in human blood plasma using high-performance liquid chromatography with tandem mass spectrometric detection (HPLC-MS/MS) for the pharmacokinetic study.Materials and methods. The determination of etmaben in human blood plasma was carried out on a Nexera XR chromatograph with a mass-selective detector LCMS-8040 (Shimadzu Corporation, Japan). Sample preparation: precipitation with acetonitrile. Internal standard: promethazine. Column: Luna C18, 100 Å, 50 × 2.00 mm, 5 µm. Elution in gradient mode at a flow rate of 1.00 mL/min. Mobile phase: 0.1 % formic acid solution in water (eluent A), 0.1 % formic acid solution in acetonitrile (eluent B). Retention time for etmaben and promethazine is approximately 1.18 min and 1.15 min, respectively. Total chromatogram registration time: 4.00 min. Ionization method and mode: electrospray; negative mode for etmaben, positive mode for promethazine. Detection was carried out in the mode of multiple reaction monitoring (MRM): 249.90 → 92.15 m/z; 249.90 → 160.20 m/z (etmaben); 284.95 → 197.95 m/z (promethazine).Results and discussion. We have developed, for the first time, a method for determining etmaben and performed its full and partial validation according to current regulatory requirements.Conclusion. The method for determining etmaben in human blood plasma with a confirmed analytical range of 0.250–30.000 µg/mL has been developed and validated. The confirmed analytical range of the method based on the results of the partial validation was 0.040–35.000 µg/mL. The method was successfully applied in phase I clinical trials and can be used for other pharmacokinetic studies of etmaben.

Introduction. Apixaban is an anticoagulant used in a number of thromboembolic diseases with an improved benefit-to-risk ratio, according to multiple clinical studies. Due to the prescription of apixaban as antithrombotic therapy in patients with COVID-19, an increase in its use has been observed. Thus, due to the widespread use of apixaban and the need to conduct pharmacokinetic and bioequivalence studies of the drug, it is important to develop and validate a simple and sensitive method for the quantitative determination of apixaban in human blood plasma.Aim. The aim of the study is to develop and validate a method for the determination of apixaban in human blood plasma using high-performance liquid chromatography with tandem mass selective detection (HPLC-MS/MS) for the subsequent bioanalytical study.Materials and methods. The determination of apixaban in human plasma was carried out by HPLC-MS/MS with rivaroxaban as an internal standard. The method of protein precipitation with acetonitrile was used as sample preparation. Mobile phase: 0.1 % solution of formic acid in water (eluent A); 0.1 % solution of formic acid in acetonitrile (eluent B). The total run time was 3.00 min. Column: Shim-pack Velox Biphenyl; 2.7 µm; 50 × 2.1 mm. Ionization source: electrospray with positive ionization mode. MRM transitions: 460.15 → 443.10 m/z (apixaban); 436.05 → 144.95 m/z (rivaroxaban).Results and discussion. The developed method was validated in accordance with the EAEU requirements for the following parameters: selectivity, calibration curve, accuracy and precision, lower limit of quantitation, suitability of standard samples, matrix effect, recovery, stability, carry-over, dilution effects. The parameters met the acceptance criteria.Conclusion. The confirmed analytical range of the developed and validated method was 1.00–300.00 ng/mL in blood plasma. The method for determining apixaban in blood plasma is simple and sensitive. This method was tested during the analytical part of the bioanalytical study and can be used to conduct other pharmacokinetic studies of apixaban drugs.

SCIENTIFIC RELEVANCE. Biowaiver is a procedure for establishing the bioequivalence of generic and reference products without in vivo studies. Regulatory requirements for this procedure, as described in a variety of documents, differ in certain features and aspects. These differences need to be analysed.AIM. The aim was to compare international and Russian regulatory approaches to the Biopharmaceutics Classification System-based biowaivers, provide recommendations on comparative dissolution testing, and outline opportunities for streamlining the regulatory framework of the Eurasian Economic Union (EAEU).DISCUSSION. In this article, the authors analyse biowaiver requirements and describe procedures for assessing the permeability and pH-dependent solubility of medicines, comparing dissolution profiles in various media that simulate the gastrointestinal environment, and interpreting test results. This paper shows the role of excipients in the solubility and permeability of an active substance.CONCLUSIONS. The authors recommend a methodological approach to the biowaiver procedure for replacing in vivo bioequivalence studies with in vitro tests under the current EAEU regulatory framework and list the characteristics of medicines that limit the applicability of the procedure. In conclusion, this article provides a rationale for harmonising the existing guidelines and requirements.

Introduction. Favipiravir is one of the most well-known broad-spectrum drugs against many RNA viruses, including the severe acute respiratory syndrome virus 2 [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)]. Due to its structure, favipiravir is embedded in the RNA of the virus and blocks its further replication in the cell of the human body. Favipiravir is also included in the list of vital and essential medicines, which confirms the importance for Russian healthcare of this drug in the fight against common RNA viruses. We have already published bioanalytical methods for determining favipiravir in human blood plasma by high-performance liquid chromatography with an ultraviolet detector (HPLC–UV) in order to study the pharmacokinetics of favipiravir with parenteral administration (the analytical range of the technique was 0.25–200.00 µg/ ml for the dosage of favipiravir 400 mg in 1 vial of lyophilizate for the preparation of concentrate for the preparation of solution for infusions) and by HPLC with tandem mass-selective detection (HPLC-MS/MS) in order to study the pharmacokinetics of β-D-N4-hydroxycytidine and favipiravir in their joint determination in blood plasma with oral administration (the analytical range of the technique was 250.00–20000.00 ng/ml for the dosage of favipiravir 400 mg in 1 tablet). The expectation of low favipiravir’s concentrations (the dosage of favipiravir in the drugs in question is 200 mg in 1 tablet in this study) and, in this regard, the expansion of the range by reducing the value of the lower limit of quantitative determination (LLOQ) used in this study necessitates the development of another method. Therefore, this study is given the development and validation of a method for determining favipiravir in human blood plasma by HPLC-MS/MS with an analytical range of 50.00–15000.00 ng/ml.Aim. The aim of this study is to develop a method for quantitative determination of favipiravir in human blood plasma by HPLC-MS/MS for further for further researches of pharmacokinetics and bioequivalence of drugs.Materials and methods. In the process of sample preparation, a method of proteins precipitation with methanol was used. A solution labeled with stable isotopes of favipiravir-13C3 was used as an internal standard, the mobile phase was a 0.1 % solution of formic acid in water (eluent A) and methanol (eluent B). Chromatographic column – Phenomenex Kinetex C18, 100×3.0 mm. The determination of favipiravir in human blood plasma was carried out by HPLC using a tandem mass spectrometric detector with a triple quadrupole. The analytical range for favipiravir is 50.00– 15000.00 ng/ml in human blood plasma.Results and discussion. This method was validated by selectivity, calibration curve, accuracy, precision, matrix effect, spike recovery, carry-over effect, the lower limit of quantification and stability.Conclusion. A method of quantitative favipiravir’s determination in human blood plasma by HPLC-MS/MS with a confirmed analytical range of 50.00–15000.00 ng/ml in human blood plasma has been developed and validated. This method allows using it for the analytical part of pharmacokinetics and bioequivalence studies of drugs containing favipiravir in order to expand their range in the domestic pharmaceutical market.

Introduction. SARS-CoV-2 (severe acute respiratory syndrome-related coronavirus 2) is expected to remain a persistent global threat. Therefore, development of coronavirus disease 2019 (COVID-19) drugs is the most urgent global issue. Nirmatrelvir and ritonavir combination is an oral antiviral drug combination with activity against SARS-CoV-2. Nirmatrelvir and ritonavir combination is highly efficacious in reducing the risk of COVID-19. The study describes development and validation of high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) method for the simultaneous determination of nirmatrelvir and ritonavir in human blood plasma. The method could be applied in pharmacokinetic study of nirmatrelvir and ritonavir.Aim. The aim of this study is to develop and validate a HPLC-MS/MS bioanalytical method for the determination of nirmatrelvir and ritonavir in human plasma.Materials and methods. The determination of nirmatrelvir and ritonavir in human plasma by HPLC-MS/MS. The samples were processed by acetonitrile protein precipitation. Internal standard: promethazine. Mobile phase: 0.1% formic acid solution in water (Eluent A), 0.1% formic acid in acetonitrile (Eluent B). Column: Phenomenex Luna C18 50 × 2.0 mm, 5 μm. Analytical range: 50.00–10000.00 ng/mL for nirmatrelvir, 5.00–1000.00 ng/mL for ritonavir in human plasma. Ionization source and ionization: electrospray ionization, positive. Detection conditions: 499.90 → 110.10 m/z, 499.90 → 319.20 m/z (nirmatrelvir), 720.90 → 426.00 m/z, 720.90 → 296.20 m/z, 720.90 → 268.10 m/z, 720.90 → 197.10 m/z, 720.90 → 139.90 m/z (ritonavir), 285.15 → 198.05 m/z (promethazine).Results and discussion. This method was validated for selectivity, matrix effect, calibration curve, accuracy, precision, spike recovery, the lower limit of quantification, carry-over effect and stability.Conclusion. The HPLC-MS/MS method for quantitative determination of nirmatrelvir and ritonavir in human plasma was developed and validated. The analytical range was 50.00–10000.00 ng/mL for nirmatrelvir, 5.00–1000.00 ng/mL for ritonavir in human plasma. This method was applied to investigate the pharmacokinetics of nirmatrelvir and ritonavir.

Introduction. The novel coronavirus infection COVID-19 (Coronavirus Disease 2019) is caused by an enveloped, positive-sense, single-stranded ribonucleic acid (RNA) virus SARS-CoV-2 (severe acute respiratory syndrome-related coronavirus 2). Favipiravir is the antiviral drug recommended for etiotropic treatment of COVID-19. Parenteral therapy has advantages over the other routes of the drug administration: there are no interaction with food and digestive enzymes, may be used for patients with diseases of the digestive system and unconscious patients. For parenteral drug administration of favipiravir the drug "Areplivir" has been registered in Russia.Aim. The aim is pharmacokinetics study of drug "Areplivir", a lyophilisate for the preparation of a concentrate for the infusion solution (the manufacturer is JSC "Biokhimic", LLC "Promomed RUS" as registration certificate holder) by intravenous infusion in healthy volunteers in a phase I pharmacokinetics study.Materials and methods. The clinical and analytical phases of the pharmacokinetic study as well as pharmacokinetic analyses have been performed as part of a clinical trial of the drug "Areplivir" in different doses, a lyophilisate for the preparation of a concentrate for the infusion solution (LLC "Promomed RUS", Russia). Chromatographic separation and detection were carried out on a LC-2040C high-performance liquid chromatograph (Shimadzu Corporation, Japan) with a built-in UV detector, a low-pressure four-component gradient pump, a degasser, an autosampler, a column thermostat and a controller. The pharmacokinetic parameters were calculated with the Boomer pharmacokinetic analysis add-in for Microsoft Excel (Department of Pharmacokinetics and Drug Metabolism, Allergan, Irvine, CA 92606, USA). Descriptive pharmacokinetic statistics were calculated with Microsoft Excel (Microsoft Corporation, USA). Correlation and Regression Analysis were conducted with IBM SPSS Statistics (version 23.0), IBM, USA.Results and discussion. For single dose administration of 400, 800, 1600 and 1800 mg in 4 cohorts of 5 volunteers pharmacokinetic parameters were calculated. For Cmax and an administered dose the strong correlation coefficient on the Chaddock scale (r = 0,98; p = 0,02; r – Pearson correlation coefficient; p – the reached significance value) and the determination coefficient (R2 = 0,96; F = 45,97; p = 0,02; R2 – determination coefficient; F – the actual value of the Fisher's criterion) were statistically significant. For AUC0-t and an administered dose the strong correlation coefficient on the Chaddock scale (r = 0,97; p = 0,03) and the determination coefficient (R2 = 0,94; F = 33,54; p = 0,03) were statistically significant. The obtained results show the linearity of Cmax and an administered dose and the linearity of AUC0-t and an administered dose (400–1800 mg).Conclusion. According to the concentrations of favipiravir from the analytical phase of the pharmacokinetic study the pharmacokinetic parameters were calculated, averaged pharmacokinetic profiles in linear and log-linear scales were plotted after single dose administrations of the drug "Areplivir" in different doses, a lyophilisate for the preparation of a concentrate for the infusion solution (LLC "Promomed RUS", Russia). The linearity of Cmax and a single administered dose and the linearity of AUC0-t and a single administered dose of the drug "Areplivir" have been demonstrated for doses of 400 to 1800 mg. The results justified the study of multiple dose administration of "AREPLIVIR" and the subsequent phases of clinical trials.

Introduction. Taurine is a non-proteinogenic amino acid. The molecule is involved in lipid metabolism, adsorbs fat-soluble vitamins, and its conjugates with bile acids contribute to the emulsification of fats in the intestine. Drugs, which include a taurine molecule, have anti-cataract, cardiotonic, metabolic effects, and also stimulate regeneration. Among the dosage forms, where taurine acts as an active substance, there is a solid dosage form – film-coated tablets. One of the methods for assessing the quality of solid dosage forms is a comparative dissolution kinetics test. High-performance chromatography with ultraviolet detection is a widely used method for quantification within the dissolution test, however, for taurine, which does not contain chromophore groups in its structure, this method is not directly applicable. To solve this problem, one can apply the method of pre-column derivatization, because of which an fragment is introduced into the structure, providing a bathochromic shift in the UV spectrum of the starting compound.Aim. Development, validation and approbation analytical method for the quantitative determination of taurine by high-performance chromatography with ultraviolet detection as part of a test comparative kinetics dissolution of taurine tablets with a dosage of 250 and 500 mg.Materials and methods. The following preparations were used for the analysis: taurine tablets, film-coated 250 mg and 500 mg, domestic production with a valid expiration date. The comparative dissolution kinetics test was carried out on a DT 126 Light instrument for the "Dissolution" test (ERWEKA GmbH, Germany). Chromatographic separation and detection were performed on a Nexera-i LC-2040 high-performance liquid chromatograph (Shimadzu Corporation, Japan) equipped with a column and sample thermostat, a degasser, an autosampler, and an ultraviolet detector. Detection was carried out at a wavelength of 254 nm after derivatization of the taurine molecule with 4-toluenesulfonyl chloride. Were used a Shim-pack Velox C18 5 μm 4.6 × 150 mm column (Shimadzu Corporation, Japan) and a Shim-pack Velox C18 EXP Guard Column Cartridge 5 μm 4.6 × 5 mm (Shimadzu Corporation, Japan). Primary data were processed using LabSolutions Single LC software (Shimadzu Corporation, Japan).Results and discussion. The optimal conditions for taurine derivatization have been selected, and a method for the quantitative determination of taurine by HPLC-UV in test comparative kinetics dissolution in three dissolution media: 0.1 M hydrochloric acid solution with pH 1.2, acetate buffer solution with pH 4.5, phosphate buffer solution with pH 6.8, as well as in the quality control medium – purified water has been developed and validated. During the validation of the developed methodology, it was found that the validation characteristics are within the acceptance criteria in 4 dissolution media. The analytical range of the method was 0.05–1.2 mg/mL and allows the developed method to be used for the quantitative determination of tablets with a dosage of 250 mg and 500 mg as part of the test comparative kinetics dissolution. The method was tested in 4 dissolution media, in all media, there was a complete release in both dosages (more than 85 % by 30 minutes).Conclusion. The method was tested in three dissolution media: 0.1 M hydrochloric acid solution with pH 1.2, acetate buffer solution with pH 4.5, phosphate buffer solution with pH 6.8, as well as in the quality control medium – purified water. In all media, there was a complete release in both dosages (more than 85 % by 30 minutes).

Drug development & registration. 2023;12(2):62–72. (In Russ.) https://doi.org/10.33380/2305-2066-2023-12-2-62-72. Published: 25.05.2023.

Introduction. Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus (severe acute respiratory syndrome-related coronavirus 2). COVID-19 is now expected to stay with us for many years as a recurring disease. Molnupiravir and favipiravir are oral antiviral drugs with anti-RNA polymerase activity. The Russian Health Ministry has approved molnupiravir and favipiravir for the treatment of COVID-19. The study describes development and validation of high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) method for the simultaneous determination of β-D-N4-Hydroxycytidine and favipiravir in human blood plasma. The method could be applied in pharmacokinetic study of molnupiravir and favipiravir.Aim. The aim of this study is to develop and validate a HPLC-MS/MS bioanalytical method for the determination of β-D-N4-Hydroxycytidine and favipiravir in human plasma.Materials and methods. The determination of β-D-N4-Hydroxycytidine and favipiravir in human plasma by HPLC-MS/MS. The samples were processed by 0.1 % formic acid in acetonitrile. Internal standard: promethazine. Mobile phase: 0.01 mol/L Ammonium formate buffer solution (Eluent A), 0.1 % formic acid and 0.08 % aqueous ammonia in water/acetonitrile 10 : 90 (Eluent B). Column: Shim-pack GWS C18, 150 × 4.6 mm, 5 μm. Analytical range: 50.00–10000.00 ng/mL for β-D-N4-Hydroxycytidine, 250.00–20000.00 ng/mL for favipiravir in human plasma. Ionization source: electrospray ionization. Detection conditions: 260.00 m/z → 82.10 m/z, 260.00 m/z → 111.00 m/z, 260.00 m/z → 127.95 m/z (β-D-N4-Hydroxycytidine); 156.15 m/z → 65.95 m/z, 156.15 m/z → 85.00 m/z, 156.15 m/z → 113.10 m/z (favipiravir); 285.05 m/z → 198.05 m/z (promethazine).Results and discussion. This method was validated by selectivity, suitability of reference standard, matrix effect, calibration curve, accuracy, precision, spike recovery, the lower limit of quantification, carry-over effect and stability.Conclusion. The HPLC-MS/MS method for quantitative determination of β-D-N4-Hydroxycytidine and favipiravir in human plasma was developed and validated. The analytical range was 50.00–10000.00 ng/mL for β-D-N4-Hydroxycytidine, 250.00–20000.00 ng/mL for favipiravir in human plasma. This method was applied to investigate the pharmacokinetics of molnupiravir and favipiravir.

Introduction. Coronavirus disease (COVID-19) is an acute infectious disease caused by SARS-CoV-2 (severe acute respiratory syndrome-related coronavirus 2). Favipiravir is a synthetic prodrug with antiviral activity used for the treatment of COVID-19. There are oral and parenteral dosage forms of favipiravir. Compared with oral administration, parenteral administration has some advantages. Developing a method for the determination of favipiravir in human blood plasma is necessary for performing the analytical part of clinical studies of favipiravir for parenteral administration as an infusion, studying pharmacokinetics, and choosing the optimal dosage of the drug.Aim. The aim of this study is to develop and validate a method for quantitative determination of favipiravir in human plasma by high-performance liquid chromatography with ultraviolet detection (HPLC-UV) for pharmacokinetic studies.Materials and methods. Determination of favipiravir in human plasma by HPLC-UV. The UV detection was set at 323 ± 2 nm. The samples were processed by methanol protein precipitation. Internal standard: raltegravir. Mobile phase: 0.1 % formic acid in water with 0.08 % aqueous ammonia (eluent A), 0.1 % formic acid in acetonitrile with 0.08 % aqueous ammonia (eluent B). Column: Phenomenex Kinetex®, C18, 150 × 4.6 mm, 5 μm. Analytical range: 0.25–200.00 μg/mL.Results and discussion. This method was validated by selectivity, calibration curve, accuracy, precision, spike recovery, the lower limit of quantification, carry-over effect and stability.Conclusion. We developed and validated the method of quantitative determination of favipiravir in human plasma by HPLC-UV. The analytical range was 0.25–200.00 μg/mL in human plasma. The method could be applied in pharmacokinetics studies of favipiravir.

Introduction. Coronavirus infection is an acute viral disease with a predominant lesion of the upper respiratory tract caused by an RNA-containing virus of the Coronaviridae family. However, it is known that neutralizing antibodies play an important role in antiviral therapy because they effectively inhibit the reproduction of viruses and reduce the severity of the disease. Polyclonal antibodies contained in convalescent plasma are usually used as emergency therapy for emerging infectious diseases. In this aspect, the use of a human immunoglobulin G preparation containing specific antibodies to SARS-CoV-2 ("COVID-globulin") appears to be safer and more effective.Aim. The aim is pharmacokinetics study of drug "COVID-globulin" (specific human immunoglobulin against COVID-19, solution for infusions, not less than 160 anti-COVID units/mL (ACU/mL), JSC "NPO Microgen", owner of the registration certificate of JSC "Natsibio", Russia), in addition to standard therapy for the treatment of patients with middle-grade COVID-19.Materials and methods. The clinical and analytical stages of the study of the pharmacokinetics of drug "COVID-globulin", as well as the analysis of the safety and parameters of pharmacokinetics were carried as part of a clinical study of the safety, tolerability and pharmacokinetics of the drug immunoglobulin ("COVID-globulin"), not less than 160 anti-COVID units/mL (ACU/mL), JSC "NPO Microgen", owner of the registration certificate of JSC "Natsibio", Russia. Quantitative determination of antibody concentrations against SARS-CoV-2 was carried out by enzyme-linked immunosorbent assay using spectrophotometric detection in the visible range of the spectrum on an automatic plate enzyme-linked immunosorbent assay analyzer Lazurite (Dynex Technologies Inc., USA). The calculation of pharmacokinetic parameters was carried out using the Microsoft Excel package with an extension for pharmacokinetic analysis Boomer (Department of Pharmacokinetics and Drug Metabolism, Allergan, Irvine, CA 92606, USA).Results and discussion. No serious adverse events were reported in the study, and the only adverse event that resulted in a volunteer withdrawing from the study was not related to the use of the drug. The pharmacokinetic parameters of the drug "COVID-globulin" were calculated for two batches of drugs. The pharmacokinetics of the "COVID-globulin" (the content of antibodies to SARS-CoV-2 – 330 ACU/ml) was assessed on a sample of 8 volunteers. The maximum concentration of specific IgG antibodies to the SARS-CoV-2 virus was 25.46 ± 8.71 ACU/ml (Mean ± SD, where Mean is the arithmetic mean, SD is the standard deviation). The median value of the time to maximum concentration of specific IgG antibodies to the SARS-CoV-2 virus was 0.25 hours. Specific IgG antibodies to the SARS-CoV-2 virus were eliminated from blood plasma with a half-life value 266.89 ± 59.92 hours. The pharmacokinetics of the "COVID-globulin" (the content of antibodies to SARS-CoV-2 – 250 ACU/ml) was assessed on a sample of 15 volunteers. The maximum concentration of specific IgG antibodies to the SARS-CoV-2 virus was 20.93 ± 3.82 ACU/ml. The median value of the time to maximum concentration of specific IgG antibodies to the SARS-CoV-2 virus was 0.25 hours. Specific IgG antibodies to the SARS-CoV-2 virus were eliminated from blood plasma with a half-life value 295.56 ± 50.68 hours.Conclusion. According to the results of the study, the safety profile of the drug "COVID-globulin" is assessed as favorable. Based on the concentrations of specific IgG antibodies to the SARS-CoV-2 virus obtained during the analytical stage of the study, the main pharmacokinetic parameters were calculated, and the average pharmacokinetic profiles of the test drug "COVID-globulin" were plotted after a single injection. The results obtained were the basis for the subsequent phases of clinical trials of the drug "COVID-globulin".

Introduction. Deferasirox is one of the most well-known complexing drugs chelators and is successfully used in chelating therapy for the treatment of excess iron in the human body. Deferasirox is also included in the list of vital and essential medicines, which indicates the importance of this drug for Russian healthcare. In this document, there are drugs only from a foreign manufacturer, therefore, within the framework of the trend towards import substitution, the development of deferasirox preparations of domestic production is a necessary and promising direction. In this connection, there is a need to develop a method that allows quantifying deferasirox in human blood plasma with minimal time and resource costs as part of a pharmacokinetic study.Aim. The aim of this study is to develop a method for quantitative determination of deferasirox in human blood plasma by high performance liquid chromatography coupled with ultraviolet detection (HPLC-UV) for further bioequivalence studies.Materials and methods. Determination of the deferasirox in human blood plasma was carried out by HPLC-UV. The method of proteins precipitation by acetonitrile was used as a sample preparation. Erlotinib solution was used as an internal standard. Mobile phase: 0.3 % solution of orthophosphoric acid in water, brought to pH 3.0 (eluent A) and 0.1 % solution of formic acid in acetonitrile (eluent B). Column was Symmetry®, 75 × 4,6 mm (Waters, США). Analytical range of the technique for deferasirox was 0.25–70.00 µg/ml in human blood plasma. Detection was carried out using a UV detector at an absorption wavelength of 299 ± 2 nm.Results and discussion. This method was validated by selectivity, calibration curve, accuracy, precision, spike recovery, the lower limit of quantification, carry-over effect and stability.Conclusion. A method of quantitative determination of deferasirox in human blood plasma was developed and validated by HPLC-UV. The analytical range was 0.25–70.00 µg/ml in human blood plasma. This method was used as part of a study of the pharmacokinetics and bioequivalence of deferasirox drugs.

Introduction. Allaforte® (JSC "Pharmcenter VILAR", Russia) is an antiarrhythmic long-acting drug. The dosage form of the drug Allaforte® provides a decrease in the frequency of taking the drug and also reduces the risk of side effects. It is relevant when taking antiarrhythmic drugs of the IC class. However, the pharmacokinetics of this drug has not been studied on humans. Therefore, it is important to fully study the pharmacokinetics to ensure the maximum efficacy and safety of arrhythmia therapy.Aim. The aim is pharmacokinetics study of long-acting antiarrhythmic drug Allaforte® (JSC "Pharmcenter VILAR", Russia), 25 mg.Materials and methods. Concentration of lappaconitine and its active metabolite N-desacetyllappaconitine in human plasma determinates by high performance liquid chromatography with tandem mass-spectrometry. Pharmacokinetic parameters calculated by R Project 3.5.1 software (package «bear», version 2.8.3-2), originally created by Hsin-ya Lee and Yung-jin Lee, Taiwan.Results and discussion. Pharmacokinetic parameters of lappaconitine and N-desacetyllappaconitine were calculated. Averaged pharmacokinetic profiles (in linear and semi-log scale) of lappaconitine and N-desacetyllappaconitine after single administration under fasting were built. The means of the maximum concentrations (Cmax) determined in the blood plasma of volunteers after single administration Allaforte® are 5.09 ± 4.07 ng/ml for lappaconitine and 11.66 ± 6.21 ng/ml for N-deacetyllappaconitine (Mean ± SD). The peak time of the maximum concentrations (Tmax) is 4.43 ± 3.54 hours for lappaconitine and 4.04 ± 2.18 hours for N-deacetyllappaconitine. The means of the areas under the curve plasma concentration – time from 0 to 48 hours (AUC0-t) and under the curve plasma concentration–time from zero to infinity (AUC0-∞) of Allaforte® is 42.96 ± 34.48 ng ∙ h/ml and 71.24 ± 43.20 ng ∙ h/ml for lappaconitine; 167.42 ± 114.41 ng ∙ h/ml and 189.42 ± 115.20 ng ∙ h/ml for N-deacetyllappaconitine. Allaforte® was eliminated from blood plasma with means of terminal half-life (T1/2) 8.45 ± 5.10 hours for lappaconitine and 9.04 ± 2.57 hours for N-deacetyllappaconitine.Conclusion. Pharmacokinetics study of long-acting antiarrhythmic drug Allaforte® (JSC "Pharmcenter VILAR", Russia) after single administration was researched. Results of the study allows to conduct an effective therapy of arrhythmia by study drug and minimize side effects.

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.

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.

Introduction. Due to increase in the frequency of detecting cases of tuberculosis caused by strains of mycobacteria with resistance not only to traditional, but also recently introduced into clinical circulation anti-tuberculosis drugs, it is urgent to search for and develop new drugs that can be effective against multidrug-resistant (MDR-TB) and extensively drug resistant (XDR-TB) strains. One of the most promising classes of such compounds are fluorine derivatives of benzothiazinones, and particularly compound PBTZ169 (INN macozinone). This antibiotic has a high specificity against mycobacteria tuberculosis (M. tuberculosis), inhibiting one of the key enzymes of cell wall synthesis. However, macozinone as an active pharmaceutical ingredient has significant features of physical and chemical properties that hinder the development of oral dosage forms based on it. It is classified as class IV by BCS and is characterized by a very low solubility and lipophilicity, a pronounced dependence of dissolution rate on the pH of the medium, and very low bioavailability when taken orally.Aim. To substantiate the target profile, critical quality attributes and to develop a prototype of an oral dosage form with modified release of macozinone, allowing to maximize its pharmacological activity.Materials and methods. Using pharmaceutical substance macozinone hydrochloride and various excipients, experimental tablets with a dosage of 500 mg macozinone were developed. The influence of the composition of the media and the added excipients on the solubility of macozinone in various biorelevant media, the degree of swelling in the liquid and the degree of mucoadhesion of the experimental tablets to the mucus of the pig stomach were evaluated. The HPLC method was used to evaluate the kinetics of the release of the active substance.Results and discussion. In this work, the expediency of creating macozinone-containing gastro-retentive dosage forms with a slow release of the active substance, the delay mechanism of which is provided by swelling and increased adhesion to the gastric mucosa, has been substantiated. Various tablet samples were experimentally tested in which the modification of the release of the active substance and the degree of swelling and mucoadhesion were varied by introducing various excipients into the formulations, including known swelling and bioadhesive matrix agents.Conclusion. According to the results of the experiments, samples of high-dose (500 mg) swellable and mucoadhesive tablets created by the technology of two-stage granulation with the inclusion of macozinone - hydroxypropyl-beta-cyclodextrin mixtures in the primary granules and introduction of combinations of soluble and insoluble hydrophilic matrix agents into the intergranular space were recognized as the most promising for subsequent pharmacokinetic studies.

Introduction. Lappaconitine is an alkaloid, contained into Aconitum leucostomum Vorosh. roots and herbs. The alkaloid is indicated to arrhythmia. The lappaconitine drugs are metabolized into eight pharmacologically active substances, but N-desacetyllappaconitine is the most effective. Drugs based on a lappaconitine has narrow therapeutic range and many kinds of side effects. Pharmacokinetics of lappaconitine should be more studied for safety medical use of lappaconitine drugs.Aim. The aim of this study is to develop method for the quantitative determination of lappaconitine and its active metabolite N-desacetyllappaconitine in human plasma and blood by high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS).Materials and methods. Determination of lappaconitine and N-desacetyllappaconitine in plasma and blood was carried out by HPLC-MS/MS. The samples were processed by acetonitrile protein precipitation.Results and discussion. This method was validated by next parameters: selectivity, matrix effect, calibration curve, accuracy, precision, spike recovery, lower limit of quantification, carry-over effect and stability.Conclusion. The method of the quantitative determination of lappaconitine and N-desacetyllappaconitine in human plasma and blood was developed and validated by HPLC-MS/MS. The analytical range of the was 0.50-50.00 ng/ml for lappaconitine and 0.50-100.00 ng/ml for N-desacetyllappaconitine in biological matrix. Method could be applied to determination of lappaconitine and N-desacetyllappaconitine for PK studies.

Introduction. Tranexamic acid is one of the most common drugs used to stop bleeding after trauma, in surgery and gynecology. The most common analytical method for the determination of this compound is reversed-phase high-performance liquid chromatography (HPLC). However, this compound belongs to the group of so-called poorly retained compounds due to its chemical structure. It is necessary to develop an analytical method that will allow the determination of tranexamic acid in human blood plasma with the least time, resource costs and without the use of specialized columns.Aim. The aim of this study is to develop a method for tranexamic acid in human plasma by high performance liquid chromatography with tandem mass-spectrometry (HPLC-MS/MS) for pharmacokinetic studies.Materials and methods. Determination of tranexamic acid in plasma by HPLC-MS/MS. The samples were processed by acetonitrile protein precipitation.Results and discussion. This method was validated by next parameters: selectivity, matrix effect, calibration curve, accuracy, precision, recovery, lower limit of quantification, carry-over effect and stability.Conclusion. The method of the determination of tranexamic acid in human plasma was developed and validated by HPLC-MS/MS. The linearity in plasma sample was achieved in the concentration range of 100.00–15000.00 ng/ml. Method could be applied to tranexamic acid determination in plasma for pharmacokinetics and bioequivalence studies.

ErratumIntroduction. An inadequate diet and living in the northern regions can lead to a lack of vitamin D3 and the development of diseases, including a decrease in immunity. To compensate for the lack of vitamin D, vitamin drugs are used that contain vitamin D in one of its active forms (usually in the form of cholecalciferol, vitamin D3).Aim. To develop and validate HPLC-UV method for the determination of vitamin D3 in vitamin drugs and to evaluate the content of cholecalciferol in selected drugs anddietary supplements presented in the Russian Federation.Materials and methods. Determination of vitamin D3 was carried out by HPLC with UV detection at a wavelength 266 nm. Sample preparation of vitamin drugs was carried out by extraction with methanol (for liquid dosage forms based on aqueous or triglyceride solutions) and extraction with an aqueous-methanol solution (for solid dosage forms based on water-soluble substances with vitamin D3) in a ratio of 2 to 8 (water-methanol).Results and discussions. The analysis methodology for the parameter "Vitamin D3 (cholecalciferol) content" in vitamin dosage forms by HPLC was validated according to the following validation parameters: specificity; accuracy; precision; linearity; range.Conclusion. The analysis methodology for the parameter "Vitamin D3 (cholecalciferol) content" in vitamin dosage forms by HPLC was developed. The method was validated according to the following validation parameters: specificity; accuracy; precision; linearity; range. The range of the method was 9,5–38 μg/ml. The method was used to determine vitamin D3 in vitamin drugs based on water-soluble forms of vitamin D3, in the form of aqueous solutions and form of fatty acids triglyceridessolutions.

Introduction. Cancer is one of the most serious and common diseases with a high level of mortality. Due to this reason the searching of new directions and methods of cancer treatment is becoming more and more important with each passing year. Significant advances in cancer immunotherapy have been reached over the past few decades. Moreover, an inhibition of the interaction between the programmed cell death receptor (PD-1) and its ligand (PD-L1), is sure to be perspective direction of the immuno-oncological therapy development.Text. PD-1/PD-L1 interaction plays a pivotal role in negative regulation of immune system, that protects host’s cells and tissues from the excessive immune response. However, it is also used by tumor cells to avoid the host's immune system. The discovery of this mechanism led to the development of inhibiting PD-1 or PD-L1 agents that enhance anti-tumor immunity. Meanwhile, anti-PD-L1 agents provide less toxicity in comparison with anti-PD-1 agents. FDA currently approved Atesolizumab, Durvalumab, and Avelumab PD-L1 inhibitors for cancer treatment. These agents demonstrated effective response during the clinical trials, however, they are used for a limited number of oncological diseases. In addition, BMS-936559 is a promising agent that had passed the first stage of the clinical trials. Nevertheless, immunotherapy involving PD-L1 inhibitors is closely related to a vast number of severe side effects including immune-mediated effects caused by the inhibition of PD-L1 ligands located on healthy cells. In these terms, the development of new agents deprived of these disadvantages is the reason for further studies.Conclusion. Immunotherapy in cancer uncovers new perspectives in treatment of refractory to standard therapies forms of cancer. And the development of new and improvement of existing PD-L1 blocking agents are of great importance in fighting against tumoral diseases.

Introduction. Currently, physicochemical methods of quantification are actively used to determine the content of drugs in biological fluids. High-performance liquid chromatography with various detection methods is particularly widespread. One of the most difficult practical tasks is the chromatographic separation of so-called poorly retained compounds – drug substances poorly retained on the chromatographic column. Valganciclovir and Ganciclovir are among such substances.Aim. The aim of this study is to develop a method for valganciclovir and ganciclovir in human plasma by high performance liquid chromatography with tandem mass-spectrometry (HPLC-MS/MS) for pharmacokinetic studies.Materials and methods. Determination of valganciclovir and ganciclovir in plasma by HPLC-MS/MS. The samples were processed by acetonitrile protein precipitation.Results and discussion. This method was validated by next parameters: selectivity, matrix effect, calibration curve, accuracy, precision, recovery, lower limit of quantification, carry-over and stability.Conclusion. The method of the determination of valganciclovir and ganciclovir in human plasma was developed and validated by HPLC-MS/MS. The linearity in plasma sample was achieved in the concentration range of 5.00–1000.00 ng/ml for valganciclovir and 50.00–10000.00 ng/ml for ganciclovir. Method could be applied to valganciclovir and ganciclovir determination in plasma for PK and BE studies.

Introduction. B-cell malignancies of the plasma cell leads to the second most spread hematological malignancy disease, called multiple myeloma. Pomalidomide is used in case of previous multiple myeloma ineffective treatment. Pomalidomide is a thalidomide synthetic derived, approved as immunomodulatory drug by the Food and Drug Administration (FDA). Nowadays, detection of pomalidomide in blood plasma by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) is not spread. Moreover, the detection and the experimental setting accumulated data are varying greatly. This investigation provides development and validation of pomalidomide aiming to determine human blood plasma by HPLC-MS/MS method. The samples were processed by methanol protein precipitation.Aim. The aim of this study is to develop a method for the pomalidomide in human plasma by HPLC-MS/MS for pharmacokinetic studies.Materials and methods. Determination of pomalidomide in plasma by HPLC-MS/MS. The samples were processed by methanol protein precipitation.Results and discussion. This method was validated by next parameters: selectivity, matrix effect, calibration curve, accuracy, precision, spike recovery, lower limit of quantification, detection limit, carry-over and stability.Conclusion. The method of the determination of pomalidomide in human plasma was developed and validated by HPLC-MS/MS. The linearity in plasma sample was achieved in the concentration range of 1,00 – 500,00 ng/ml. Method could be applied to pomalidomide determination in plasma for PK and BE studies.

Introduction. The quality control of a medicinal product needs to be systematically improved in connection with a continuous increase in the requirements for the quality of medicines. When assessing the quality of substances and drugs, the most important indicators are authenticity, the content of the main substance and impurities. This makes it relevant to introduce modern physical and chemical methods of analysis into industrial practice in determining parameters such as authenticity, the content of the main substance and impurities. The choice and applicability of a particular method is possible only when conducting comparative studies on the application of a particular method to solve this problem. The method should preferably be recommended by the Pharmacopoeia, give unambiguous results, and the analysis should not be expensive and affordable. The methods chosen for comparative analysis are well known, but it should be noted that in recent years, instrument-making companies have significantly improved their instrument base and expanded their capabilities. Therefore, one of the objectives of this article is to demonstrate the capabilities of the selected methods for solving the problems of drug quality control using dalargin as an example.Aim. To develop methods for determining the authenticity of the active substance in a substance - Dalargin powder using NMR spectroscopy, IR spectrometry, and Mass spectroscopy. Conduct a comparative analysis of the applicability of the selected methods to solve the problem.Materials and methods. To determine the authenticity of the substance - the powder «Dalargin» used the methods of mass spectrometry, 13C NMR and 1H NMR spectrometry and IR spectrometry.Results and discussions. Methods have been developed for determining the authenticity of the test substance by NMR, IR, and mass spectrometry. A comparative study of the possibilities of the selected methods in solving the problem. Conclusions were drawn about the applicability of the NMR method not only in determining the authenticity of dalargin, but also in solving the problem of determining the content of the main substance and impurities.Conclusion. Authenticity methods have been developed in the substance - Dalargin powder by Mass, IR, and NMR spectrometry. It has been established that 1H NMR spectrometry is a more informative method for authenticating.

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. 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. HIV infection is one of the most relevant diseases from a medical, epidemiological and social point of view. Timely diagnosis, detection and control of the disease, adequate prescription of antiretroviral therapy can sufficiently reduce the viral load on the patient's body, reduce the risk of transmission of infection. Currently, combinations of various antiretroviral drugs are increasingly being prescribed as therapy. One of the most important is combination of atazanavir and ritonavir. The most important stage for the study of pharmacokinetics, studies of comparative pharmacokinetics and bioequivalence is the development of an analytical method that allows you to determine the investigated substances in human plasma. There are currently no published methods for the determination of atazanavir and ritonavir in human plasma using high performance liquid chromatography with mass selective detection using a single quadrupole mass detector. In this article presents the development and validation of a method for the determination of atazanavir and ritonavir in blood plasma after sample preparation by the method of protein precipitation.Aim. The aim of the study is to develop a method for the quantitative determination of atazanavir and ritonavir in human plasma by HPLC with mass spectrometric detection for performing the analytical part of pharmacokinetic studies.Materials and methods. Determination of atazanavir and ritonavir in human plasma by HPLC with mass spectrometric detection. A sample was prepared using protein deposition.Results and discussion. The method was validated of selectivity, matrix effect, calibration curve, accuracy, precision, limit of quantification, carry-over effect and sample stability.Conclusion. The method of the determination of atazanavir and ritonavir in human plasma was developed and validated by HPLC-MS. The analytical range of the was 50.0–10000.0 ng/mL in plasma for atazanavir and 10.0–2500.0 ng/mL in plasma for ritonavir. Method could be applied to determination of atazanavir and ritonavir in plasma for PK and BE studies.

Introduction. Human Immunodeficiency Virus (HIV) is one of the main socially significant infection all over the world. HIV-positive patients take medical care, including antiretroviral drugs (ARVs) pharmacotherapy. Like all drugs, ARVs have lots of side effects that should be taken when prescribing drugs as part of highly active antiretroviral therapy. There are many cases when side effects of ARVs caused patients to enter the toxicology department. Therefore, the development of new methods for the analysis of ARV in biological fluids for the timely diagnosis of treatment of poisoning of this group of drugs is relevant today.Aim. The aim of this study is development of screening analysis of atazanavir, abacavir, nevirapine, ritonavir, lopinavir, zidovudine, darunavir and efavirenz in the urine to identify these drugs as possible toxicants for poisoning by high-performance liquid chromatography with tandem massselective detection (HPLC-MS/MS).Materials and methods. Identification of ARV was performed by HPLC-MS/MS. Methanol precipitation method was used as a sample preparation.Results and discussion. The optimal conditions for sample preparation, chromatographic separation, and mass-spectrometric detection were selected to determine the studied ARVs. This method was tested on urine samples from patients in the Department of Acute Poisoning and Somatopsychiatric Disorders (OOSPD) with acute ARV poisoning.Conclusion. This screening method for analyse atazanavir, abacavir, nevirapine, ritonavir, lopinavir, zidovudine, darunavir and efavirenz in human urine has been developed by HPLC-MS/MS. The developed method can be used to identify these drugs as possible toxicants in case of poisoning. The prospect for the development of the topic is the inclusion of new molecules in the method and quantitative determination of the studied ARVs.

Introduction. Multicomponent oral drugs containing salbutamol, bromhexine, ambroxol and guaifenesin have a mucolytic, expectorant and bronchodilator effect. The development method for determination substances in biological fluids is a main procedure for performing the analytical part of pharmacokinetic studies and bioequivalence studies of multicomponent drugs. There is no published data of the determination of bromhexine, ambroxol and guaifenesin, but there a lot of published methods for divided determination analytes in a biological fluid. This study presents the development and validation of a method of the determination of salbutamol, bromhexine, ambroxol and guaifenesin in human blood plasma by high performance liquid chromatography with tandem mass spectrometric detection. A sample preparation was perfomed by solid-phase extraction. Deuterated derivatives were used as internal standards.Aim. The aim of the study is to develop a method for the quantitative determination of salbutamol, bromhexine, ambroxol and guaifenesin in human plasma by HPLC with tandem mass spectrometric detection for performing the analytical part of pharmacokinetic studies.Materials and methods. Determination of salbutamol, bromhexine, ambroxol and guaifenesin in human plasma by HPLC with tandem mass spectrometric detection. A sample was prepared using solid-phase extraction.Results and discussion. The method was validated by next validation parameters: selectivity, matrix effect, calibration curve, accuracy, precision, limit of quantification, carry-over and stability.Conclusion. The method of the determination of salbutamol, bromhexine, ambroxol and guaifenesin in human plasma was developed and validated by HPLC-MS/MS. The analytical range of the was 0.1–20 ng/mL in plasma for salbutamol, 0.25–25 ng/mL in plasma for bromhexine, 0.075–3 ng/mL in plasma for ambroxol, and 10–2000 ng/mL in plasma for guaifenesin. Method could be applied to determination of salbutamol, bromhexine, ambroxol and guaifenesin in plasma for PK and BE studies.

Introduction. Bevacizumab is a monoclonal IgG1 antibody that binds to and inhibits the biologic activity of human vascular endothelial growth factor (VEGF). Bevacizumab is used as a targeted monoor combination therapy for different solid tumors. Phase I clinical trial was performed to assess pharmacokinetics (PK) and immunogenicity of bevacizumab drugs. For this study 80 healthy male volunteers were recruited and randomized to either Avastin or RPH-001 group.Aim. To assess and compare pharmacokinetics and immunogenicity (safety) following single intravenous administration of Avastin® (manufactured by F. Hoffmann-La Roche Ltd., Switzerland) and bevacizumab biosimilar RPH-001 (manufactured by R-Pharm Group, Russia).Materials and methods. Bevacizumab quantitation and quasi-quantitative anti-bevacizumab antibodies detection in human blood serum were carried out using photometric ELISA. Two different methods were successfully validated.Results and discussion. Bevacizumab quantitation method was validated for selectivity and specificity, calibration curve, sensitivity, accuracy and precision, minimal required dilution, dilution linearity and stability. The anti-bevacizumab antibodies detection method was validated for cut-point (with normalization factor calculation), selectivity, sensitivity, precision, drug tolerance, dilution linearity, matrix effect (in case of serum hemolysis), and stability. The validated methods were successfully applied to pharmacokinetic and immunogenicity assessment of bevacizumab drugs.Conclusion. The results of the PK-study showed that test and reference bevacizumab drugs were equivalent. Immunogenicity study did not show any evidence of anti-bevacizumab antibodies in blood serum samples.

Introduction. Tadalafil is a drug used to treat erectile dysfunction. For the quantitative determination of tadalafil in human plasma are used methods of high performance liquid chromatography with ultraviolet and tandem mass spectrometric detection, during the analytical part of pharmacokinetic studies. In the majority of the considered methods the method of liquid-liquid extraction and the method of solid-phase extraction are used, these methods are difficult and expensive. Therefore, the method of protein precipitation was considered as sample preparation. This method is simple and there is important to analysis a lot of clinical samples in bioequivalence studies.Aim. The aim of this study is to develop method for the quantitative determination of tadalafil in human plasma by HPLC-MS for the analytical part of pharmacokinetic studies.Materials and methods. Quantitative determination of tadalafil in plasma by HPLC-MS. A sample was prepared using acetonitrile 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 tadalafil in human plasma was developed and validated by HPLC-MS. The analytical range of the was 5,00–1000,00 ng/ml tadalafil in plasma. Method could be applied to determination of tadalafil in plasma for PK and BE studies.

Introduction. In 2018 «Center of Pharmaceutical Analytics» LLC successfully passed the certification of quality management system for compliance with the requirements of ISO 9001: 2015 and GOST R ISO 9001-2015 «Quality Management System. Requirements».Text. Certification was conducted by the Certification Association «Russian Register» – a Russian company, which is an accredited body for certification of management systems of organizations. This article describes the program of certification audit of the «Russian Register», which includes: certification, consisting of two stages, inspection checks during the first and second year and re-certification audit during the third year before the expiration of the certificate. The structure of works on confirmation of the certificate of conformity of «Russian Register» includes field audits designed to assess the degree of compliance of the organization with the established requirements of the standard for compliance with which certification was carried out [1]. The objectives of the certification audit were: verification of compliance of the management system with the requirements of ISO 9001: 2015 (GOST R ISO 9001-2015), verification of established processes and documentation of the management system of the organization; assessment of the ability of the management system to ensure compliance with applicable legislative, regulatory and contractual requirements; assessment of the effectiveness of the management system to ensure that the goals can be achieved; identification of areas for possible improvement of the management system. The audit was conducted over two days on processes and units related to the activities of the organization. The audit confirmed the scope of certification in respect of: research work, bioanalytical studies, pharmacokinetic studies, STCR (comparative text of dissolution kinetics). The scope of the audit included verification of adequacy, compliance of activities and elements of the management system, including: production, management and support processes; policies; goals; organizational structure of management; documentation of management system, analysis of measures taken by the organization to eliminate the problem areas identified at the 1st stage of certification [2]. Conclusion. In September 2018, the analytical center was issued certificates of compliance with the requirements of GOST R ISO 9001:2015 in the certification Association «Russian Register» with the accreditation of the Federal service for accreditation of the Russian Federation (Rosaccreditation); international standard ISO 9001: 2015 in the Certification system of the Russian Register, a member of the international forum on accreditation IAF; certificate of conformity.

A method for quantification of capecitabine and 5-fluorouracil in human plasma was developed. The sample preparation was carried out by protein precipitation with methanol. The quantitative determination was performed by HPLC with a triple quadrupole mass-detector. The method was validated in terms of selectivity, calibration curve, accuracy, precision, lower limit of quantification, and stability. The analytical range was 10.0-20000.0 ng/mL for capecitabine and 10.0-400.0 ng/ml for 5-fluorouracil. The developed method may be used for bioequivalence studies of capecitabine drug products.

Certificate of compliance to GOST 33044-2014 "Principles of Good Laboratory Practice" issued by an internationally recognized, competent and independent certification body serves, is one of the criteria for the selection of the contractor and the guarantee of the quality of services provided to many customers, as one of the mandatory conditions and exit organization development at the global, national or sectoral markets. This paper describes the first experience of GLP-certification for Russian bioanalytical laboratory.

The article describes the dissolution test results for the Betaserc (betahistine) IR tablets using the equipment with manual sampling and automatic sampling. The results were compared using F-test and Student's t-test and considered to be comparable for manual and automatic dissolution equipment.

The article describes the main historical stages in the development of the science of drug dissolution and the dissolution profile test from the theoretical foundations of dissolution, developed in the first half of the 20th century, and the development of a relationship between dissolution and bioavailability in the 1950s, going to the introduction of biowaiver based on the BCS.

Validation of UV-spectrometry assay method for dissolution profile test for levofloxacine tablets was carried out. The evaluated validation characteristics were: specificity, linearity, accuracy, precision, analytical range. It was shown than main validation characteristics meet the Russian State Pharmacopoeia requirements.

Center of Pharmaceutical Analytics purchased and installed LabWare LIMS laboratory information system, LabWare ELN electronic laboratory journals from LabWare company. At the moment, the system is integrating into the work of the laboratory, templates for research work are created and employees are trained. The article opens a series of articles of the integration of the LIMS system into the work of the analytical center. LabWare has received universal recognition, is a leader in the global market of global Laboratory information systems (LIMS) and has a wide range of loyal users.

Modern approaches of dissolution profile test were reviewed in terms of documents, research design, principles of choice of test conditions, selection and validation of assay methods, results evaluation and technique of the carrying out of experiment directly. The article reflects both Russian and foreign perspectives on dissolution profile test.

Validation of UV-spectrometry assay method for dissolution profile test for levofloxacine tablets was carried out. The evaluated validation characteristics were: specificity, linearity, accuracy, precision, and analytical range. It was shown than main validation characteristics meet the Russian State Pharmacopoeia XIII requirements.