TY - JOUR A1 - Umstätter, Florian A1 - Werner, Julia A1 - Zerlin, Leah A1 - Mühlberg, Eric A1 - Kleist, Christian A1 - Klika, Karel D. A1 - Hertlein, Tobias A1 - Beijer, Barbro A1 - Domhan, Cornelius A1 - Zimmermann, Stefan A1 - Ohlsen, Knut A1 - Haberkorn, Uwe A1 - Mier, Walter A1 - Uhl, Philipp T1 - Impact of linker modification and PEGylation of vancomycin conjugates on structure-activity relationships and pharmacokinetics JF - Pharmaceuticals N2 - As multidrug-resistant bacteria represent a concerning burden, experts insist on the need for a dramatic rethinking on antibiotic use and development in order to avoid a post-antibiotic era. New and rapidly developable strategies for antimicrobial substances, in particular substances highly potent against multidrug-resistant bacteria, are urgently required. Some of the treatment options currently available for multidrug-resistant bacteria are considerably limited by side effects and unfavorable pharmacokinetics. The glycopeptide vancomycin is considered an antibiotic of last resort. Its use is challenged by bacterial strains exhibiting various types of resistance. Therefore, in this study, highly active polycationic peptide-vancomycin conjugates with varying linker characteristics or the addition of PEG moieties were synthesized to optimize pharmacokinetics while retaining or even increasing antimicrobial activity in comparison to vancomycin. The antimicrobial activity of the novel conjugates was determined by microdilution assays on susceptible and vancomycin-resistant bacterial strains. VAN1 and VAN2, the most promising linker-modified derivatives, were further characterized in vivo with molecular imaging and biodistribution studies in rodents, showing that the linker moiety influences both antimicrobial activity and pharmacokinetics. Encouragingly, VAN2 was able to undercut the resistance breakpoint in microdilution assays on vanB and vanC vancomycin-resistant enterococci. Out of all PEGylated derivatives, VAN:PEG1 and VAN:PEG3 were able to overcome vanC resistance. Biodistribution studies of the novel derivatives revealed significant changes in pharmacokinetics when compared with vancomycin. In conclusion, linker modification of vancomycin-polycationic peptide conjugates represents a promising strategy for the modulation of pharmacokinetic behavior while providing potent antimicrobial activity. KW - glycopeptide antibiotics KW - antimicrobial resistance KW - vancomycin KW - polycationic peptides KW - linker influence KW - pharmacokinetics KW - PEGylation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-255197 SN - 1424-8247 VL - 15 IS - 2 ER - TY - JOUR A1 - Schlauersbach, Jonas A1 - Hanio, Simon A1 - Raschig, Martina A1 - Lenz, Bettina A1 - Scherf-Cavel, Oliver A1 - Meinel, Lorenz T1 - Bile and excipient interactions directing drug pharmacokinetics in rats JF - European Journal of Pharmaceutics and Biopharmaceutics N2 - Bile solubilization plays a major role in the absorption of poorly water-soluble drugs. Excipients used in oral drug formulations impact bile-colloidal properties and their molecular interactions. Polymer-induced changes of bile colloids, e.g., by Eudragit E, reduced the flux of the bile interacting drug Perphenazine whereas bile non-interacting Metoprolol was not impacted. This study corroborates these in vitro findings in rats. Eudragit E significantly reduced systemic availability of Perphenazine but not Metoprolol compared to the oral administrations without polymer. This study confirms the necessity to carefully select polymers for bile interacting drugs whereas non-bile interacting drugs are more robust in terms of excipient choice for formulation. The perspective of bile interaction may introduce interesting biopharmaceutical leverage for better performing oral formulations of tomorrow. KW - in vitro-in vivo correlation KW - pharmacokinetics KW - bile KW - excipient KW - rat study Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-296969 VL - 178 ET - accepted version ER - TY - JOUR A1 - Lindhoff-Last, Edelgard A1 - Birschmann, Ingvild A1 - Bidenharn, Antonia J. A1 - Kuhn, Joachim A1 - Lindau, Simone A1 - Konstantinides, Stavros A1 - Grottke, Oliver A1 - Nowak-Göttl, Ulrike A1 - Lucks, Jessica A1 - Zydek, Barbara A1 - Heymann, Christian von A1 - Sümnig, Ariane A1 - Beyer-Westendorf, Jan A1 - Schellong, Sebastian A1 - Meybohm, Patrick A1 - Greinacher, Andreas A1 - Herrmann, Eva T1 - Pharmacokinetics of phenprocoumon in emergency situations – results of the prospective observational RADOA-registry (reversal agent use in patients treated with direct oral anticoagulants or vitamin K antagonists registry) JF - Pharmaceuticals N2 - Background: Phenprocoumon has been used as an oral anticoagulant in patients with thromboembolic disease for more than 40 years. So far its pharmacokinetics have not been analyzed in emergency situations. Methods: Phenprocoumon-treated patients with major bleeding or urgent surgery were included in a prospective, observational registry. Phenprocoumon drug concentrations were analyzed in samples, collected as part of routine care using ultraperformance liquid chromatography tandem mass spectrometry. Moreover, anticoagulant intensity and drug half-life (t1/2) were calculated. Results: 115 patients were included. Phenprocoumon levels declined over time with a half-life of 5.27 and 5.29 days in patients with major bleedings (n = 82) and with urgent surgery (n = 33). Baseline phenprocoumon levels were 2.2 times higher in the bleeding group compared to the surgery group (1.92 vs. 0.87 ng/mL, p < 0.0001). International normalized ratio (INR) values decreased rapidly during the first 24 h. In 27.6% of patients a rebound of INR (recurrent increase > 1.5) was observed which was associated with significantly increased bleeding rates (22% vs. 4.2% in patients with or without INR rebound, p = 0.012). Conclusions: In emergency situations, the long half-life of phenprocoumon may cause INR rebound and associated recurrent bleedings. Optimal management may need to include repeated vitamin K supplementation over days. KW - phenprocoumon KW - pharmacokinetics KW - emergency KW - major bleeding KW - urgent surgery KW - INR rebound Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297226 SN - 1424-8247 VL - 15 IS - 11 ER - TY - JOUR A1 - Gerner, Bettina A1 - Scherf-Clavel, Oliver T1 - Physiologically based pharmacokinetic modelling of Cabozantinib to simulate enterohepatic recirculation, drug−drug interaction with Rifampin and liver impairment JF - Pharmaceutics N2 - Cabozantinib (CAB) is a receptor tyrosine kinase inhibitor approved for the treatment of several cancer types. Enterohepatic recirculation (EHC) of the substance is assumed but has not been further investigated yet. CAB is mainly metabolized via CYP3A4 and is susceptible for drug–drug interactions (DDI). The goal of this work was to develop a physiologically based pharmacokinetic (PBPK) model to investigate EHC, to simulate DDI with Rifampin and to simulate subjects with hepatic impairment. The model was established using PK-Sim® and six human clinical studies. The inclusion of an EHC process into the model led to the most accurate description of the pharmacokinetic behavior of CAB. The model was able to predict plasma concentrations with low bias and good precision. Ninety-seven percent of all simulated plasma concentrations fell within 2-fold of the corresponding concentration observed. Maximum plasma concentration (C\(_{max}\)) and area under the curve (AUC) were predicted correctly (predicted/observed ratio of 0.9–1.2 for AUC and 0.8–1.1 for C\(_{max}\)). DDI with Rifampin led to a reduction in predicted AUC by 77%. Several physiological parameters were adapted to simulate hepatic impairment correctly. This is the first CAB model used to simulate DDI with Rifampin and hepatic impairment including EHC, which can serve as a starting point for further simulations with regard to special populations. KW - physiologically based pharmacokinetic (PBPK) modeling KW - Cabozantinib KW - enterohepatic recirculation KW - drug–drug interactions (DDIs) KW - liver impairment KW - cytochrome P450 3A4 (CYP3A4) KW - pharmacokinetics Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239661 SN - 1999-4923 VL - 13 IS - 6 ER - TY - JOUR A1 - Gerner, Bettina A1 - Aghai-Trommeschlaeger, Fatemeh A1 - Kraus, Sabrina A1 - Grigoleit, Götz Ulrich A1 - Zimmermann, Sebastian A1 - Kurlbaum, Max A1 - Klinker, Hartwig A1 - Isberner, Nora A1 - Scherf-Clavel, Oliver T1 - A physiologically-based pharmacokinetic model of ruxolitinib and posaconazole to predict CYP3A4-mediated drug–drug interaction frequently observed in graft versus host disease patients JF - Pharmaceutics N2 - Ruxolitinib (RUX) is approved for the treatment of steroid-refractory acute and chronic graft versus host disease (GvHD). It is predominantly metabolized via cytochrome P450 (CYP) 3A4. As patients with GvHD have an increased risk of invasive fungal infections, RUX is frequently combined with posaconazole (POS), a strong CYP3A4 inhibitor. Knowledge of RUX exposure under concomitant POS treatment is scarce and recommendations on dose modifications are inconsistent. A physiologically based pharmacokinetic (PBPK) model was developed to investigate the drug–drug interaction (DDI) between POS and RUX. The predicted RUX exposure was compared to observed concentrations in patients with GvHD in the clinical routine. PBPK models for RUX and POS were independently set up using PK-Sim\(^®\) Version 11. Plasma concentration-time profiles were described successfully and all predicted area under the curve (AUC) values were within 2-fold of the observed values. The increase in RUX exposure was predicted with a DDI ratio of 1.21 (C\(_{max}\)) and 1.59 (AUC). Standard dosing in patients with GvHD led to higher RUX exposure than expected, suggesting further dose reduction if combined with POS. The developed model can serve as a starting point for further simulations of the implemented DDI and can be extended to further perpetrators of CYP-mediated PK-DDIs or disease-specific physiological changes. KW - physiologically based pharmacokinetic (PBPK) modeling KW - ruxolitinib KW - posaconazole KW - drug–drug interactions (DDIs) KW - graft versus host disease KW - cytochrome P450 3A4 (CYP3A4) KW - pharmacokinetics Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297261 SN - 1999-4923 VL - 14 IS - 12 ER - TY - JOUR A1 - Fekete, Stefanie A1 - Egberts, K. A1 - Preissler, T. A1 - Wewetzer, C. A1 - Mehler-Wex, C. A1 - Romanos, M. A1 - Gerlach, M. T1 - Estimation of a preliminary therapeutic reference range for children and adolescents with tic disorders treated with tiapride JF - European Journal of Clinical Pharmacology N2 - Purpose Tiapride is commonly used in Europe for the treatment of tics. The aim of this study was to examine the relationship between dose and serum concentrations of tiapride and potential influential pharmacokinetic factors in children and adolescents. In addition, a preliminary therapeutic reference range for children and adolescents with tics treated with tiapride was calculated. Methods Children and adolescents treated with tiapride at three university hospitals and two departments of child and adolescents psychiatry in Germany and Austria were included in the study. Patient characteristics, doses, serum concentrations, and therapeutic outcome were assessed during clinical routine care using standardised measures. Results In the 49 paediatric patients (83.7% male, mean age = 12.5 years), a positive correlation was found between tiapride dose (median 6.9 mg/kg, range 0.97–19.35) and serum concentration with marked inter-individual variability. The variation in dose explained 57% of the inter-patient variability in tiapride serum concentrations; age, gender, and concomitant medication did not contribute to the variability. The symptoms improved in 83.3% of the patients. 27.1% of the patients had mild or moderate ADRs. No patient suffered from severe ADRs. Conclusions This study shows that tiapride treatment was effective and safe in most patients with tics. Compared with the therapeutic concentration range established for adults with Chorea Huntington, our data hinted at a lower lower limit (560 ng/ml) and similar upper limit (2000 ng/ml). KW - Tourette syndrome KW - therapeutic drug monitoring KW - serum concentration KW - paediatrics KW - pharmacokinetics Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-279893 VL - 77 IS - 2 ER -