TY - JOUR A1 - Kaya-Zeeb, Sinan A1 - Engelmayer, Lorenz A1 - Straßburger, Mara A1 - Bayer, Jasmin A1 - Bähre, Heike A1 - Seifert, Roland A1 - Scherf-Clavel, Oliver A1 - Thamm, Markus T1 - Octopamine drives honeybee thermogenesis JF - eLife N2 - In times of environmental change species have two options to survive: they either relocate to a new habitat or they adapt to the altered environment. Adaptation requires physiological plasticity and provides a selection benefit. In this regard, the Western honeybee (Apis mellifera) protrudes with its thermoregulatory capabilities, which enables a nearly worldwide distribution. Especially in the cold, shivering thermogenesis enables foraging as well as proper brood development and thus survival. In this study, we present octopamine signaling as a neurochemical prerequisite for honeybee thermogenesis: we were able to induce hypothermia by depleting octopamine in the flight muscles. Additionally, we could restore the ability to increase body temperature by administering octopamine. Thus, we conclude that octopamine signaling in the flight muscles is necessary for thermogenesis. Moreover, we show that these effects are mediated by β octopamine receptors. The significance of our results is highlighted by the fact the respective receptor genes underlie enormous selective pressure due to adaptation to cold climates. Finally, octopamine signaling in the service of thermogenesis might be a key strategy to survive in a changing environment. KW - honeybee KW - octopamine KW - thermogenesis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301327 VL - 11 ER - TY - JOUR A1 - Aghai, Fatemeh A1 - Zimmermann, Sebastian A1 - Kurlbaum, Max A1 - Jung, Pius A1 - Pelzer, Theo A1 - Klinker, Hartwig A1 - Isberner, Nora A1 - Scherf-Clavel, Oliver T1 - Development and validation of a sensitive liquid chromatography tandem mass spectrometry assay for the simultaneous determination of ten kinase inhibitors in human serum and plasma JF - Analytical and Bioanalytical Chemistry N2 - A liquid chromatography tandem mass spectrometry method for the analysis of ten kinase inhibitors (afatinib, axitinib, bosutinib,cabozantinib, dabrafenib, lenvatinib, nilotinib, osimertinib, ruxolitinib, and trametinib) in human serum and plasma for theapplication in daily clinical routine has been developed and validated according to the US Food and Drug Administration andEuropean Medicines Agency validation guidelines for bioanalytical methods. After protein precipitation of plasma samples withacetonitrile, chromatographic separation was performed at ambient temperature using a Waters XBridge® Phenyl 3.5μm(2.1×50 mm) column. The mobile phases consisted of water-methanol (9:1, v/v) with 10 mM ammonium bicarbonate as phase A andmethanol-water (9:1, v/v) with 10 mM ammonium bicarbonate as phase B. Gradient elution was applied at a flow rate of 400μL/min. Analytes were detected and quantified using multiple reaction monitoring in electrospray ionization positive mode. Stableisotopically labeled compounds of each kinase inhibitor were used as internal standards. The acquisition time was 7.0 min perrun. All analytes and internal standards eluted within 3.0 min. The calibration curves were linear over the range of 2–500 ng/mLfor afatinib, axitinib, bosutinib, lenvatinib, ruxolitinib, and trametinib, and 6–1500 ng/mL for cabozantinib, dabrafenib, nilotinib,and osimertinib (coefficients of correlation≥0.99). Validation assays for accuracy and precision, matrix effect, recovery,carryover, and stability were appropriate according to regulatory agencies. The rapid and sensitive assay ensures high throughputand was successfully applied to monitor concentrations of kinase inhibitors in patients. KW - kinase inhibitors KW - therapeutic drug monitoring KW - liquid chromatography tandem mass spectrometry (LC-MS/MS KW - afatinib KW - osimertinib Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231925 SN - 1618-2642 VL - 413 ER - TY - JOUR A1 - Isberner, Nora A1 - Kraus, Sabrina A1 - Grigoleit, Götz Ulrich A1 - Aghai, Fatemeh A1 - Kurlbaum, Max A1 - Zimmermann, Sebastian A1 - Klinker, Hartwig A1 - Scherf-Clavel, Oliver T1 - Ruxolitinib exposure in patients with acute and chronic graft versus host disease in routine clinical practice-a prospective single-center trial JF - Cancer Chemotherapy and Pharmacology N2 - Purpose Knowledge on Ruxolitinib exposure in patients with graft versus host disease (GvHD) is scarce. The purpose of this prospective study was to analyze Ruxolitinib concentrations of GvHD patients and to investigate effects of CYP3A4 and CYP2C9 inhibitors and other covariates as well as concentration-dependent effects. Methods 262 blood samples of 29 patients with acute or chronic GvHD who were administered Ruxolitinib during clinical routine were analyzed. A population pharmacokinetic model obtained from myelofibrosis patients was adapted to our population and was used to identify relevant pharmacokinetic properties and covariates on drug exposure. Relationships between Ruxolitinib exposure and adverse events were assessed. Results Median of individual mean trough serum concentrations was 39.9 ng/mL at 10 mg twice daily (IQR 27.1 ng/mL, range 5.6-99.8 ng/mL). Applying a population pharmacokinetic model revealed that concentrations in our cohort were significantly higher compared to myelofibrosis patients receiving the same daily dose (p < 0.001). Increased Ruxolitinib exposure was caused by a significant reduction in Ruxolitinib clearance by approximately 50%. Additional comedication with at least one strong CYP3A4 or CYP2C9 inhibitor led to a further reduction by 15% (p < 0.05). No other covariate affected pharmacokinetics significantly. Mean trough concentrations of patients requiring dose reduction related to adverse events were significantly elevated (p < 0.05). Conclusion Ruxolitinib exposure is increased in GvHD patients in comparison to myelofibrosis patients due to reduced clearance and comedication with CYP3A4 or CYP2C9 inhibitors. Elevated Ruxolitinib trough concentrations might be a surrogate for toxicity. KW - toxicity KW - Ruxolitinib KW - graft versus host disease KW - therapeutic drug monitoring KW - CYP3A4 KW - CYP2C9 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266476 SN - 1432-0843 VL - 88 IS - 6 ER - TY - JOUR A1 - Mc Laughlin, Anna M. A1 - Schmulenson, Eduard A1 - Teplytska, Olga A1 - Zimmermann, Sebastian A1 - Opitz, Patrick A1 - Groenland, Stefanie L. A1 - Huitema, Alwin D. R. A1 - Steeghs, Neeltje A1 - Müller, Lothar A1 - Fuxius, Stefan A1 - Illerhaus, Gerald A1 - Joerger, Markus A1 - Mayer, Frank A1 - Fuhr, Uwe A1 - Holdenrieder, Stefan A1 - Hempel, Georg A1 - Scherf-Clavel, Oliver A1 - Jaehde, Ulrich A1 - Kloft, Charlotte T1 - Developing a nationwide infrastructure for therapeutic drug monitoring of targeted oral anticancer drugs: the ON-TARGET study protocol JF - Cancers N2 - Exposure-efficacy and/or exposure-toxicity relationships have been identified for up to 80% of oral anticancer drugs (OADs). Usually, OADs are administered at fixed doses despite their high interindividual pharmacokinetic variability resulting in large differences in drug exposure. Consequently, a substantial proportion of patients receive a suboptimal dose. Therapeutic Drug Monitoring (TDM), i.e., dosing based on measured drug concentrations, may be used to improve treatment outcomes. The prospective, multicenter, non-interventional ON-TARGET study (DRKS00025325) aims to investigate the potential of routine TDM to reduce adverse drug reactions in renal cell carcinoma patients receiving axitinib or cabozantinib. Furthermore, the feasibility of using volumetric absorptive microsampling (VAMS), a minimally invasive and easy to handle blood sampling technique, for sample collection is examined. During routine visits, blood samples are collected and sent to bioanalytical laboratories. Venous and VAMS blood samples are collected in the first study phase to facilitate home-based capillary blood sampling in the second study phase. Within one week, the drug plasma concentrations are measured, interpreted, and reported back to the physician. Patients report their drug intake and toxicity using PRO-CTCAE-based questionnaires in dedicated diaries. Ultimately, the ON-TARGET study aims to develop a nationwide infrastructure for TDM for oral anticancer drugs. KW - therapeutic drug monitoring KW - oral anticancer drugs KW - renal cell carcinoma KW - volumetric absorptive microsampling Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-252196 SN - 2072-6694 VL - 13 IS - 24 ER - TY - JOUR A1 - Haider, Malik Salman A1 - Ahmad, Taufiq A1 - Groll, Jürgen A1 - Scherf-Clavel, Oliver A1 - Kroiss, Matthias A1 - Luxenhofer, Robert T1 - The Challenging Pharmacokinetics of Mitotane: An Old Drug in Need of New Packaging JF - European Journal of Drug Metabolism and Pharmacokinetics N2 - Adrenocortical carcinoma (ACC) is a malignant tumor originating from the adrenal gland cortex with a heterogeneous but overall dismal prognosis in advanced stages. For more than 50 years, mitotane has remained a cornerstone for the treatment of ACC as adjuvant and palliative therapy. It has a very poor aqueous solubility of 0.1 mg/l and high partition coefficient in octanol/water (log P) value of 6. The commercially available dosage form is 500 mg tablets (Lysodren®). Even at doses up to 6 g/day (12 tablets in divided doses) for several months, > 50% patients do not achieve therapeutic plasma concentration > 14 mg/l due to poor water solubility, large volume of distribution and inter/intra-individual variability in bioavailability. This article aims to give a concise update of the clinical challenges associated with the administration of high-dose mitotane oral therapy which encompass the issues of poor bioavailability, difficult-to-predict pharmacokinetics and associated adverse events. Moreover, we present recent efforts to improve mitotane formulations. Their success has been limited, and we therefore propose an injectable mitotane formulation instead of oral administration, which could bypass many of the main issues associated with high-dose oral mitotane therapy. A parenteral administration of mitotane could not only help to alleviate the adverse effects but also circumvent the variable oral absorption, give better control over therapeutic plasma mitotane concentration and potentially shorten the time to achieve therapeutic drug plasma concentrations considerably. Mitotane as tablet form is currently the standard treatment for adrenocortical carcinoma. It has been used for 5 decades but suffers from highly variable responses in patients, subsequent adverse effects and overall lower response rate. This can be fundamentally linked to the exceedingly poor water solubility of mitotane itself. In terms of enhancing water solubility, a few research groups have attempted to develop better formulations of mitotane to overcome the issues associated with tablet dosage form. However, the success rate was limited, and these formulations did not make it into the clinics. In this article, we have comprehensively reviewed the properties of these formulations and discuss the reasons for their limited utility. Furthermore, we discuss a recently developed mitotane nanoformulation that led us to propose a novel approach to mitotane therapy, where intravenous delivery supplements the standard oral administration. With this article, we combine the current state of knowledge as a single piece of information about the various problems associated with the use of mitotane tablets, and herein we postulate the development of a new injectable mitotane formulation, which can potentially circumvent the major problems associated to mitotane's poor water solubility. KW - Mitotane KW - cancer KW - adrenal gland Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270476 SN - 2107-0180 VL - 46 IS - 5 ER - TY - JOUR A1 - Volpp, Linda A1 - Ferianec, Vladimír A1 - Ježovičová, Miriam A1 - Ďuračková, Zdeňka A1 - Scherf-Clavel, Oliver A1 - Högger, Petra T1 - Constituents and Metabolites of a French Oak Wood Extract (Robuvit®) in Serum and Blood Cell Samples of Women Undergoing Hysterectomy JF - Frontiers in Pharmacology N2 - Ellagitannins are signature constituents of oak wood and their consumption has been associated with various health benefits. In vivo, they undergo metabolic degradation including gut microbial metabolism yielding urolithins. Only limited data is available about compounds being present in blood after intake of an extract from French oak wood, Robuvit®. In the course of a randomized, double-blind, controlled clinical investigation, 66 patients undergoing hysterectomy received placebo or 300 mg Robuvit® per day before and over 8 weeks after surgery. Serum and blood cell samples were analyzed by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The number of urolithin producers and the urolithin levels increased after intake of Robuvit®. In serum samples, the median concentration of urolithin A was 14.0 ng/ml [interquartile range (IQR) 57.4] after 8 weeks. Urolithin B was determined at 22.3 ng/ml (IQR 12.6), urolithin C at 2.66 ng/ml (IQR 2.08). In blood cells, lower concentrations and only urolithins A and B were detected. A statistically significant association of lower post-surgical pain scores with metabotype A was detected (p < 0.05). To conclude, supplementation with French oak wood extract raised urolithin generation in patients and suggested health advantages for urolithin-producers. KW - polyphenols KW - urolithins KW - oak wood KW - post-surgery recovery KW - human KW - liquid chromatography electrospray ionization tandem mass spectrometry Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200105 SN - 1663-9812 VL - 11 IS - 74 ER - TY - JOUR A1 - Penagos-Calvete, Diana A1 - Duque, Valeria A1 - Marimon, Claudia A1 - Parra, Diana M. A1 - Restrepo-Arango, Sandra K. A1 - Scherf-Clavel, Oliver A1 - Holzgrabe, Ulrike A1 - Montoya, Guillermo A1 - Salamanca, Constain H. T1 - Glycerolipid composition and advanced physicochemical considerations of sacha inchi oil toward cosmetic products formulation JF - Cosmetics N2 - Sacha inchi oil is a premier raw material with highly nutritional and functional features for the foodstuff, pharmaceutical, beauty, and personal care industries. One of the most important facts about this oil is the huge chemical content of unsaturated and polyunsaturated fatty acids. However, the current available information on the characterization of the triglyceride composition and the advance physicochemical parameters relevant to emulsion development is limited. Therefore, this research focused on providing a detailed description of the lipid composition using high-resolution tandem mass spectrometry and thorough physicochemical characterization to find the value of the required hydrophilic–lipophilic balance (HLB). For this, a study in the interfacial tension was evaluated, followed by the assessment of different parameters such as creaming index, droplet size, viscosity, zeta potential, pH, and electrical conductivity for a series emulsified at thermal stress condition. The results show that fatty acids are arranged into glycerolipids and the required HLB to achieve the maximum physical stability is around 8. KW - sacha inchi oil KW - unsaturated fatty acids KW - triacylglycerides KW - high-resolution tandem mass spectrometry KW - emulsions oil-in-water KW - required hydrophilic–lipophilic balance Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193857 SN - 2079-9284 VL - 6 IS - 4 ER - TY - JOUR A1 - Kaya-Zeeb, Sinan A1 - Delac, Saskia A1 - Wolf, Lena A1 - Marante, Ana Luiza A1 - Scherf-Clavel, Oliver A1 - Thamm, Markus T1 - Robustness of the honeybee neuro-muscular octopaminergic system in the face of cold stress JF - Frontiers in Physiology N2 - In recent decades, our planet has undergone dramatic environmental changes resulting in the loss of numerous species. This contrasts with species that can adapt quickly to rapidly changing ambient conditions, which require physiological plasticity and must occur rapidly. The Western honeybee (Apis mellifera) apparently meets this challenge with remarkable success, as this species is adapted to numerous climates, resulting in an almost worldwide distribution. Here, coordinated individual thermoregulatory activities ensure survival at the colony level and thus the transmission of genetic material. Recently, we showed that shivering thermogenesis, which is critical for honeybee thermoregulation, depends on octopamine signaling. In this study, we tested the hypothesis that the thoracic neuro-muscular octopaminergic system strives for a steady-state equilibrium under cold stress to maintain endogenous thermogenesis. We can show that this applies for both, octopamine provision by flight muscle innervating neurons and octopamine receptor expression in the flight muscles. Additionally, we discovered alternative splicing for AmOARβ2. At least the expression of one isoform is needed to survive cold stress conditions. We assume that the thoracic neuro-muscular octopaminergic system is finely tuned in order to contribute decisively to survival in a changing environment. KW - honeybees KW - thermogenesis KW - cold stress KW - octopamine KW - octopamine receptors KW - gene expression Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288753 SN - 1664-042X VL - 13 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 - Urlaub, Jonas A1 - Kaiser, Reinhard P. A1 - Scherf‐Clavel, Oliver A1 - Bolm, Carsten A1 - Holzgrabe, Ulrike T1 - Investigation of isomerization of dexibuprofen in a ball mill using chiral capillary electrophoresis JF - Electrophoresis N2 - Besides the racemate, the S‐enantiomer of ibuprofen (Ibu) is used for the treatment of inflammation and pain. Since the configurational stability of S‐Ibu in solid state is of interest, it was studied by means of ball milling experiments. For the evaluation of the enantiomeric composition, a chiral CE method was developed and validated according to the ICH guideline Q2(R1). The addition of Mg\(^{2+}\), Ca\(^{2+}\), or Zn\(^{2+}\) ions to the background electrolyte (BGE) was found to improve Ibu enantioresolution. Chiral separation of Ibu enantiomers was achieved on a 60.2 cm (50.0 cm effective length) x 75 μm fused‐silica capillary using a background electrolyte (BGE) composed of 50 mM sodium acetate, 10 mM magnesium acetate tetrahydrate, and 35 mM heptakis‐(2,3,6‐tri‐O‐methyl)‐β‐cyclodextrin (TM‐β‐CD) as chiral selector. The quantification of R‐Ibu in the mixture was performed using the normalization procedure. Linearity was evaluated in the range of 0.68–5.49% R‐Ibu (R\(^{2}\) = 0.999), recovery was found to range between 97 and 103%, the RSD of intra‐ and interday precision below 2.5%, and the limit of quantification for R‐ in S‐Ibu was calculated to be 0.21% (extrapolated) and 0.15% (dilution of racemic ibuprofen), respectively. Isomerization of S‐Ibu was observed under basic conditions by applying long milling times and high milling frequencies. KW - capillary electrophoresis KW - chiral separation KW - Ibuprofen KW - isomerization KW - validation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225852 VL - 42 IS - 17-18 SP - 1790 EP - 1799 ER -