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.

Статья получена: 15.01.2020. Статья принята к печати: 21.02.2020 Резюме Введение. ВИЧ-инфекция является одним из наиболее актуальных заболеваний современности с медицинской, эпидемиологической и социальной точки зрения. Своевременная диагностика, выявление и контроль заболевания, адекватное назначение антиретровирусной терапии позволяют в достаточной степени снизить вирусную нагрузку на организм пациента, снизить риски передачи инфекции. В настоящее время в качестве терапии всё чаще назначаются комбинации различных антиретровирусных лекарственных средств. Одной из перспективных комбинаций является совместное применение атазанавира и ритонавира. Важнейшим этапом для изучения фармакокинетического взаимодействия, исследований сравнительной фармакокинетики и биоэквивалентности является разработка аналитической методики, позволяющей определять исследуемые вещества в плазме крови человека. В настоящее время нет опубликованных методик о совместном определении атазанавира и ритонавира в плазме крови человека с помощью метода высокоэффективной жидкостной хроматографии с массселективным детектированием с применением одноквадрупольного масс-детектора. В данной работе приведена разработка и валидация методики совместного определения атазанавира и ритонавира в плазме крови после пробоподготовки способом осаждения белков. Цель. Целью исследования является разработка методики количественного определения атазанавира и ритонавира в плазме крови человека методом высокоэффективной жидкостной хроматографии с одноквадрупольным масс-спектрометрическим детектированием (ВЭЖХ-МС) для проведения аналитической части фармакокинетических исследований. Материалы и методы. Количественное определение атазанавира и ритонавира в плазме крови человека методом ВЭЖХ-МС. В качестве пробоподготовки был использован способ осаждения белков. Результаты и обсуждение. Разработанная методика была валидирована по следующим валидационным параметрам: селективность, эффект матрицы, линейность, точность, прецизионность, предел количественного определения, перенос пробы, стабильность. Заключение. Разработана и валидирована методика количественного определения атазанавира и ритонавира в плазме крови человека методом ВЭЖХ-МС. Подтвержденный аналитический диапазон методики составил 50,0-10000,0 нг/мл для атазанавира и 10,0-2500,0 нг/мл для ритонавира. Полученный аналитический диапазон позволяет применять разработанную методику для проведения аналитической части исследований фармакокинетики препаратов, содержащих атазанавир и ритонавир.

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. 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. 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.