Publications by authors named "Maria-Kristina Parr"

Article Synopsis
  • - Methyltestosterone (MT) is a commonly misused anabolic steroid, and its primary sulfate metabolite, S2, has a long detection window but lacked confirmed structural evidence until now.
  • - This study developed a method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify S2 without needing complex sample prep, and it included both in vitro and in vivo analyses to solidify findings.
  • - By synthesizing and characterizing a reference standard of S2, the researchers provided definitive identification information, which is expected to improve anti-doping testing and evaluation methods.
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The phytosteroid ecdysterone is classified as an anabolic agent and has been included on the monitoring list of the World Anti-Doping Agency since 2020. Therefore, the consumption of food rich in ecdysterone, such as quinoa and spinach, is the focus of a lively debate. Thus, the urinary excretion of ecdysterone and its metabolites in humans was investigated following quinoa consumption alone and in combination with spinach.

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Supercritical fluid chromatography-mass spectrometry (SFC-MS) has proved to be a beneficial tool for sample analysis for a wide variety of compounds and, as such, has recently gained the attention of the anti-doping community. We have tested the applicability of SFC-MS for routine doping control analysing approximately 3 × 1000 identical anti-doping samples utilising SFC-MS instruments from three different vendors: Agilent Technologies, Waters Corporation and Shimadzu Corporation. A 'dilute and inject' approach either without or after hydrolysis of glucuronide metabolites was applied.

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The misuse of growth-promoting drugs such as beta-2 agonists and steroids is a known problem in farming and sports competitions. Prior to the analysis of biological samples via liquid chromatography (LC)-mass spectrometry (MS) or gas chromatography (GC)-MS, sufficient sample preparation is required to reliably identify or determine the residues of drugs. In practice, broad screening methods are often used to save time and analyze as many compounds as possible.

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The proposed ICH Q14 guideline "Analytical procedure development" describes science and risk-based approaches for development and maintenance of analytical procedures suitable for the assessment of the quality of drug substances and drug products. As a case study, the systematic development and validation of a supercritical fluid chromatography (SFC)-based purity method for carbamazepine is presented. Systematic analytical quality by design (AQbD) principles were applied using the software package Fusion QbD to the method development approach.

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In comparison to well-known drug-metabolizing organs such as the liver, the metabolic capacity of human skin is still not well elucidated despite the widespread use of topical drug application. To gain a comprehensive insight into anabolic steroid metabolism in the skin, six structurally related anabolic androgenic steroids, testosterone, metandienone, methyltestosterone, clostebol, dehydrochloromethyltestosterone, and methylclostebol, were applied to human keratinocytes and fibroblasts derived from the juvenile foreskin. Phase I metabolites obtained from incubation media were analyzed by gas chromatography-mass spectrometry.

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Propranolol, a non-selective beta-blocker medication, has been utilized in the treatment of cardiovascular diseases for several decades. Its hydroxynaphthyl metabolites have been recognized to possess varying degrees of beta-blocker activity due to the unaltered side-chain. This study achieved the successful separation and identification of diastereomeric glucuronic metabolites derived from 4-, 5-, and 7-hydroxypropranolol (4-OHP, 5-OHP, and 7-OHP) in human urine.

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Because of their performance-enhancing effect, anabolic androgenic steroids (AAS) are often misused in sports. Nearly half of the adverse analytical findings (AAF) in 2022 doping controls are correlated to AAS misuse. Metabolites play a crucial role in the bioanalysis of endogenous and exogenous steroids.

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Background: Reliable methods enabling detection of metal ions, and especially heavy metals, in different matrices are necessary in various fields such as ecology, pharmaceuticals and toxicology. As some of the currently used methods suffer from spectral and chemical interferences, this study investigates the applicability of SFC-MS/MS for the determination of metal ions.

Results: Effective novel approaches for metal ion analysis using CO-based mobile phase were developed using three ligands forming metal complexes.

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Cyrene (dihydrolevoglucosenone) was evaluated for the first time as a potential sustainable mobile phase solvent in reversed-phase chromatography. As a benign biodegradable solvent, Cyrene is an attractive replacement to classical non-green organic chromatographic solvents such as acetonitrile and a modifier, co-eluent to known green solvents such as ethanol. Compared to ethanol, Cyrene is less toxic, non-flammable, biobased, biodegradable, and a cheaper solvent.

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The aim of this study was to develop and optimize a chiral HPLC-MS/MS method for quantitative analysis of ()-/()-salbutamol and ()-/()-salbutamol-4'--sulfate in human urine to allow for bioanalytical quantitation of the targeted analytes and investigations of stereoselectivity in the sulfonation pathway of human phase Ⅱ metabolism. For analytical method development, a systematic screening of columns and mobile phases to develop a separation via enantiomerically selective high performance liquid chromatography was performed. Electrospray ionization settings were optimized via multiple-step screening and a full factorial design-of-experiment.

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Article Synopsis
  • * This study focused on the interaction between human CYP2D6 and four UGTs (UGT1A7, UGT1A8, UGT1A9, UGT2A1) using propranolol, revealing that three UGTs significantly enhanced CYP2D6 activity for metabolizing propranolol.
  • * However, all UGT activities were suppressed when CYP2D6 was co-expressed, indicating complex functional interactions that may impact drug effectiveness and side effects. *
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Monoclonal antibodies (mAbs) used as therapeutics need comprehensive characterization for appropriate quality assurance. For analysis, cost-effective methods are of high importance, especially when it comes to biosimilar development which is based on extended physicochemical characterization. The use of forced degradation to study the occurrence of modifications for analysis is well established in drug development and may be used for the evaluation of critical quality attributes (CQAs).

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Scope: The phytosteroid ecdysterone is present in spinach. In this study, the urinary elimination of ecdysterone and its metabolites in humans is investigated following spinach consumption of two different culinary preparations.

Methods And Results: Eight participants (four males, four females) ingested 950 (27.

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Rationale: The proposed metabolomic workflow, based on coupling high-resolution mass spectrometry with computational tools, can be an alternative strategy for metabolite detection and identification. This approach allows the extension of the investigation field to chemically different compounds, maximizing the information obtainable from the data and minimizing the time and resources required.

Methods: Urine samples were collected from five healthy volunteers before and after oral administration of 3β-hydroxyandrost-5-ene-7,17-dione as a model compound and defining three excretion time intervals.

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Article Synopsis
  • * A total of over 1000 samples were analyzed using a "dilute and inject" method after hydrolyzing glucuronide metabolites, demonstrating SFC's applicability in real-world scenarios.
  • * Comparative analysis with liquid chromatography-mass spectrometry indicated that SFC-tandem mass spectrometry offers advantages such as better analyte retention and meets the sensitivity and precision standards required by the World Anti-Doping Agency for doping tests.
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Neuroinflammation is one of the common features in most neurological diseases including multiple sclerosis (MScl) and neurodegenerative diseases such as Alzheimer's disease (AD). It is associated with local brain inflammation, microglial activation, and infiltration of peripheral immune cells into cerebrospinal fluid (CSF) and the central nervous system (CNS). It has been shown that the diversity of phenotypic changes in monocytes in CSF relates to neuroinflammation.

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Alprazolam is a triazolobenzodiazepine which is most commonly used in the short-term management of anxiety disorders, often in combination with antipsychotics. The four human members of the CYP3A subfamily are mainly responsible for its metabolism, which yields the main metabolites 4-hydroxyalprazolam and α-hydroxyalprazolam. We performed a comparison of alprazolam metabolism by all four CYP3A enzymes upon recombinant expression in the fission yeast .

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Myeloid cells are suggested as an important player in Alzheimer´s disease (AD). However, its continuum of phenotypic and functional changes across different body compartments and their use as a biomarker in AD remains elusive. Here, we perform multiple state-of-the-art analyses to phenotypically and metabolically characterize immune cells between peripheral blood (n = 117), cerebrospinal fluid (CSF, n = 117), choroid plexus (CP, n = 13) and brain parenchyma (n = 13).

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Differences in metabolic profiles can link to functional changes of immune cells in disease conditions. Here, we detail a protocol for the detection and quantitation of 19 metabolites in one analytical run. We provide the parameters for chromatographic separation and mass spectrometric analysis of isotopically labeled and unlabeled metabolites.

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Propranolol is a competitive non-selective beta-receptor antagonist that is available on the market as a racemic mixture. In the present study, glucuronidation of propranolol and its equipotent phase I metabolite 4-hydroxypropranolol by all 19 members of the human UGT1 and UGT2 families was monitored. UGT1A7, UGT1A9, UGT1A10 and UGT2A1 were found to glucuronidate propranolol, with UGT1A7, UGT1A9 and UGT2A1 mainly acting on ()-propranolol, while UGT1A10 displays the opposite stereoselectivity.

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1. Olanzapine is an atypical antipsychotic primarily used to treat schizophrenia and bipolar disorder. An intronic single nucleotide polymorphism (SNP) that highly significantly predicts increased olanzapine clearance (rs472660) was previously identified in the CYP3A43 gene, which encodes a cytochrome P450 enzyme.

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In anti-doping science, the knowledge of drug metabolism is a prerequisite to identify analytical targets for the detection of misused prohibited substances. As the most obvious way to study xenobiotic metabolism, the administration to human volunteers, faces ethical concerns, there is a need for model systems. In the present study, we investigated whether Oryzias latipes (medaka) embryos might be an alternative, non-animal test model to study human-like metabolism.

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For investigations on human sulfotransferase (SULT) catalyzed phase II metabolism, the costly cofactor 3'-phosphoadenosine-5'-phosphosulfate (PAPS) is generally needed. In the present study, we developed and optimized a new approach that combines SULT-dependent biotransformation using recombinant and permeabilized fission yeast cells (enzyme bags) with PAPS production applying quality by design principles. In the initial application of the procedure, yeast cells expressing human SULT1A3 were used for the production of 4'-hydroxypropranolol-4--sulfate from 4-hydroxypropranolol.

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