@article{FeketeEgbertsPreissleretal.2021, author = {Fekete, Stefanie and Egberts, K. and Preissler, T. and Wewetzer, C. and Mehler-Wex, C. and Romanos, M. and Gerlach, M.}, title = {Estimation of a preliminary therapeutic reference range for children and adolescents with tic disorders treated with tiapride}, series = {European Journal of Clinical Pharmacology}, volume = {77}, journal = {European Journal of Clinical Pharmacology}, number = {2}, doi = {10.1007/s00228-020-03000-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-279893}, pages = {163-170}, year = {2021}, abstract = {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).}, language = {en} } @article{LindhoffLastBirschmannBidenharnetal.2022, author = {Lindhoff-Last, Edelgard and Birschmann, Ingvild and Bidenharn, Antonia J. and Kuhn, Joachim and Lindau, Simone and Konstantinides, Stavros and Grottke, Oliver and Nowak-G{\"o}ttl, Ulrike and Lucks, Jessica and Zydek, Barbara and Heymann, Christian von and S{\"u}mnig, Ariane and Beyer-Westendorf, Jan and Schellong, Sebastian and Meybohm, Patrick and Greinacher, Andreas and Herrmann, Eva}, title = {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)}, series = {Pharmaceuticals}, volume = {15}, journal = {Pharmaceuticals}, number = {11}, issn = {1424-8247}, doi = {10.3390/ph15111437}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-297226}, year = {2022}, abstract = {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.}, language = {en} } @article{GernerAghaiTrommeschlaegerKrausetal.2022, author = {Gerner, Bettina and Aghai-Trommeschlaeger, Fatemeh and Kraus, Sabrina and Grigoleit, G{\"o}tz Ulrich and Zimmermann, Sebastian and Kurlbaum, Max and Klinker, Hartwig and Isberner, Nora and Scherf-Clavel, Oliver}, title = {A physiologically-based pharmacokinetic model of ruxolitinib and posaconazole to predict CYP3A4-mediated drug-drug interaction frequently observed in graft versus host disease patients}, series = {Pharmaceutics}, volume = {14}, journal = {Pharmaceutics}, number = {12}, issn = {1999-4923}, doi = {10.3390/pharmaceutics14122556}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-297261}, year = {2022}, abstract = {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.}, language = {en} } @article{UmstaetterWernerZerlinetal.2022, author = {Umst{\"a}tter, Florian and Werner, Julia and Zerlin, Leah and M{\"u}hlberg, Eric and Kleist, Christian and Klika, Karel D. and Hertlein, Tobias and Beijer, Barbro and Domhan, Cornelius and Zimmermann, Stefan and Ohlsen, Knut and Haberkorn, Uwe and Mier, Walter and Uhl, Philipp}, title = {Impact of linker modification and PEGylation of vancomycin conjugates on structure-activity relationships and pharmacokinetics}, series = {Pharmaceuticals}, volume = {15}, journal = {Pharmaceuticals}, number = {2}, issn = {1424-8247}, doi = {10.3390/ph15020159}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-255197}, year = {2022}, abstract = {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.}, language = {en} } @article{SchlauersbachHanioRaschigetal.2022, author = {Schlauersbach, Jonas and Hanio, Simon and Raschig, Martina and Lenz, Bettina and Scherf-Cavel, Oliver and Meinel, Lorenz}, title = {Bile and excipient interactions directing drug pharmacokinetics in rats}, series = {European Journal of Pharmaceutics and Biopharmaceutics}, volume = {178}, journal = {European Journal of Pharmaceutics and Biopharmaceutics}, edition = {accepted version}, doi = {10.1016/j.ejpb.2022.07.016}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-296969}, pages = {65-68}, year = {2022}, abstract = {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.}, language = {en} } @article{GernerScherfClavel2021, author = {Gerner, Bettina and Scherf-Clavel, Oliver}, title = {Physiologically based pharmacokinetic modelling of Cabozantinib to simulate enterohepatic recirculation, drug-drug interaction with Rifampin and liver impairment}, series = {Pharmaceutics}, volume = {13}, journal = {Pharmaceutics}, number = {6}, issn = {1999-4923}, doi = {10.3390/pharmaceutics13060778}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-239661}, year = {2021}, abstract = {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.}, language = {en} }