Репозиторий Университета

© 2020 John Wiley  &  Sons, Ltd. GMDP (glucosoaminyl-muramyl-dipeptide), a synthetic analog of the peptidoglycan fragment of the bacterial cell wall, is an active component of the immunomodulatory drug Licopid. But the pharmacokinetic parameters of GMDP in humans after oral administration have not been investigated yet. The present study aimed at developing and validating a sensitive LC–MS/MS method for the analysis of GMDP in human plasma. The sample was prepared by solid-phase extraction using Strata-X 33 μm polymeric reversed-phase 60 mg/3 mL cartridges Phenomenex (Torrance, CA, USA). The analytes were separated using an Acquity UPLC BEN C18 column, 1.7 μm 2.1 × 50 mm Waters (Milford, USA). GMDP and internal standard growth hormone releasing peptide-2 (pralmorelin) were ionized in positive electrospray ionization mode and detected in multiple reaction monitoring mode. The developed method was validated within a linear range of 50–3000 pg/mL for GMDP. Accuracy for all analytes, given as the deviation between the nominal and measured concentration and assay variability, ranged from 1.61 to 3.02% and from 0.89 to 1.79%, respectively, for both within- and between-run variabilities. The developed and validated HPLC–MS/MS method was successfully used to obtain the plasma pharmacokinetic profiles of GMDP distribution in human plasma.

© 2019 Elsevier B.V. A new sample extraction protocol was developed for pharmacokinetic studies of dabigatran with high-performance liquid chromatography separation - electrospray ionization time-of-flight mass spectrometry analysis. After protein precipitation with acetonitrile, free dabigatran and its metabolites are separated into water phase by water-dichloromethane liquid-liquid extraction to purify the sample from proteins and endogenous lipophilic compounds. Chromatographic separation was achieved on an Agilent Zorbax SB-CN column (150 × 4.6 mm, 5 µm)) using 0.1% aqueous solution of formic acid and acetonitrile (80:20) as the mobile phase. Agilent Zorbax SB-CN column was selected to improve sample resolution and to avoided early elution of dabigatran previously seen when using a C18 column. The extended calibration curve was constructed from 5 to 1000 ng/L while precision and accuracy were assessed at four levels across the linear dynamic ranges. Within-run precision was <5.6% and the between-run precision was <3.9%. The method accuracy ranged from 89.8% to 104.4%. The developed method was successfully applied to 30 patient samples to evaluate antithrombotic efficacy and anticoagulant activity of dabigatran following knee endoprosthesis surgery.

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Issues pertaining to determination of the pharmacokinetic parameters of calcium preparations are examined using their comparative bioavailability as an example. Pharmacokinetic parameters of calcium such as area under the concentration—time curve (AUC) and maximum concentration (Cmax) are calculated considering the background calcium contents in volunteers. Calcium excretion with urine is assessed as clearance of creatinine, a calcium elimination factor. The dynamics of the content of parathormone (PTH), the main hormone regulating calcium homeostasis, are studied. The results can be used to plan clinical trials for assessing the pharmacokinetics of drug analogs of endogenous compounds.

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. A validated method for quantitative determination of flupirtine in human blood plasma using liquid chromatography combined with tandem mass spectrometry (HPLC-MS/MS) was proposed. Biological samples were prepared by precipitating proteins using MeOH. The chromatographic separation used a Zorbax Eclipse Plus C18 column with gradient elution. A Shimadzu 8040 triple quadrupole mass spectrometer in multiple-reaction-monitoring mode (+MRM) with chemical ionization at atmospheric pressure (APCI) was used to determine the molecular ion of flupirtine with m/z 305.2. Acalibration curve for flupirtine was linear (R = 0.994) in the concentration range 25 – 2,500 ng/mL with a lower detection limit of 25 ng/mL. Validation of the method indicated that it was highly sensitive, specific, accurate, and precise and that the analyte was stable. The method was successfully applied to comparative pharmacokinetic studies of drugs containing flupirtine.

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The pharmacokinetics, bioequivalence, and safety of Femorix®(Valenta Pharm Co., Russia) and Aubagio®(SanofiWinthrop Industrie, France) film-coated tablets (14 mg) were compared in a double-blind randomized investigation in parallel groups of healthy volunteers. The bioavailabilities of Femorix®film-coated tablets (14 mg, Valenta Pharm Co., Russia) were 96.18% [87.92 – 105.22%] for ln(Cmax) and 96.24% [88.67 – 104.44%] for ln(AUC0–72) of those for Aubagio®film-coated tablets (14 mg, Sanofi Winthrop Industrie, France), which fell in the commonly accepted range (80 – 125%) for proving the bioequivalence of the tested products.

© 2018 Pirogov Russian National Research Medical University. All rights reserved. Mathematical modeling of pharmacokinetic (PK) and pharmacodynamic (PD) parameters essential for establishing correct dosing regimens is an alternative to pharmacokinetic studies (PKS) adopted in the clinical setting. The aim of this work was to compare the values of PK parameters for vancomycin obtained in an actual PKS and through MM in postoperative patients with kidney injury. Our prospective study included 61 patients (47 males and 14 females aged 60.59 ± 12.23 years). During PKS, drug concentrations at steady state Сtrough and Cpeak were measured by high-performance liquid chromatography followed by the calculation of the area under the plasma concentration-time curve AUC24. For mathematical modeling, a single-compartment model was employed; PK parameters were estimated using R 3.4.0. The values of Ctrough measured 48 h after the onset of antibiotic therapy during PKS were significantly lower than those predicted by MM (р = 0.004). In a group of patients with acute kidney injury (AKI), AUC24 measured at the end of treatment was significantly higher than its value predicted by MM (р = 0.011). The probability of achieving the target AUC24 to MIC ratio of over 400 µg•h /ml is higher in the group of patients with Ctrough = 10–15 µg /ml. Our findings confirm that the use of MM in postoperative patients with renal dysfunction is limited and therapeutic drug monitoring should be used instead.

© 2018 Publishing House of the Union of Pediatricians. All rights reserved. The rational use of antibacterial drugs in children implies an adequate choice of the necessary medication, its dosing regimen, and the duration of treatment in order to achieve maximum efficacy and minimize toxic effects. The knowledge of pharmacokinetic and pharmacodynamic profiles of the antibacterial drug plays a crucial role for optimizing the dosing regimen. The strategy of individual choice of the dosing regimen, taking into account the principles of pharmacokinetics and pharmacodynamics, can be especially effective in patients with the expectedly changed parameters of pharmacokinetics and in infections caused by bacteria strains with low sensitivity to antibiotics. The review presents a contemporary view of pharmacokinetic and pharmacodynamic profiles of antibacterial drugs most commonly used in pediatrics and their relationship to the clinical efficacy of the administered therapy.

© 2018 Kryukov et al. Introduction: Difficulties in non-vitamin K anticoagulant (NOAC) administration in acute stroke can be associated with changes in pharmacokinetic parameters of NOAC such as biotransformation, distribution, and excretion. Therefore, obtaining data on pharmacokinetics of NOAC and factors that affect it may help develop algorithms for personalized use of this drug class in patients with acute cardioembolic stroke. Patients and methods: Pharmacokinetics of apixaban in patients with acute stroke was studied earlier by Kryukov et al. The present study enrolled 17 patients with cardioembolic stroke, who received 5 mg of apixaban. In order to evaluate the pharmacokinetic parameters of apixaban, venous blood samples were collected before taking 5 mg of apixaban (point 0) and 1, 2, 3, 4, 10, and 12 hours after drug intake. Blood samples were centrifuged at 3000 rpm for 15 minutes. Separate plasma was aliquoted in Eppendorf tubes and frozen at —70°C until analysis. High-performance liquid chromatography mass spectrometry analysis was used to determine apixaban plasma concentration. Genotyping was performed by real-time polymerase chain reaction. CYP3A isoenzyme group activity was evaluated by determining urinary concentration of endogenous substrate of the enzyme and its metabolite (6-β-hydroxycortisol to cortisol ratio). Statistical analysis was performed using SPSS Statistics version 20.0. The protocol of this study was reviewed and approved by the ethics committee; patients or their representatives signed an informed consent. Results: ABCB1 (rs1045642 and rs4148738) gene polymorphisms do not affect the pharmacokinetics of apixaban as well as CYP3A5 (rs776746) gene polymorphisms. Apixaban pharmacokinetics in groups with different genotypes did not differ statistically significantly. Correlation analysis showed no statistically significant relationship between pharmacokinetic parameters of apixaban and the metabolic activity of CYP3A. Conclusion: Questions such as depending on genotyping results for apixaban dosing and implementation of express genotyping in clinical practice remain open for NOACs. Large population studies are required to clarify the clinical significance of genotyping for this drug class.