Helene Faber

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A novel method for the identification of glutathione/electrophile adducts that are inhibiting glutathione-S-transferase (GST) activity was developed and applied for the analysis of the mycotoxin patulin. The method is based on high-performance liquid chromatography (HPLC) coupled to a continuous-flow enzyme reactor serving as biochemical detector (BCD) in(More)
Diclofenac is a frequently prescribed drug for rheumatic diseases and muscle pain. In rare cases, it may be associated with a severe hepatotoxicity. In literature, it is discussed whether this toxicity is related to the oxidative phase I metabolism, resulting in electrophilic quinone imines, which can subsequently react with nucleophiles present in the(More)
The combination of electrochemistry (EC) and mass spectrometry (MS) has become a more and more frequently used approach in metabolism studies in the last decade. This review provides insight into the importance of metabolism studies during the drug development process and gives a short overview about the conventionally used methods since electrochemistry is(More)
Oxidative and potentially metabolic pathways of the five most frequently used contrast agents for magnetic resonance imaging (MRI) based on gadolinium (Gd) are examined. The oxidation of gadopentetate (Gd-DTPA) was studied with a focus on electrochemical oxidation coupled to analytical separation methods and mass spectrometric detection. Mass voltammograms(More)
A new liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method for the fast determination of phospholipase A(2) (PLA(2)) activity has been developed. For the first time, the method allows the parallel detection of glycerophosphatidylcholine (GroPCho) as PLA(2) substrate as well as of its products fatty acid (FA) and lyso-GroPCho.(More)
RATIONALE para-Phenylenediamine (PPD) is a potent and well-known allergen, which is commonly used in hair or fur dyes and can cause severe allergic contact dermatitis. In this work, the skin-sensitizing potential of PPD with respect to the conjugation of proteins was evaluated using an approach without animal testing. METHODS Electrochemistry (EC) coupled(More)
RATIONALE Although para-phenylenediamine (PPD) is known to cause severe allergic contact dermatitis in consequence of autoxidation and/or skin metabolism pathways, it is commonly utilized as an ingredient in permanent hair dyes. The aim of this work was to simultaneously accelerate the autoxidation process and to simulate the metabolic activation of PPD(More)
The first combination of electrochemistry (EC), NACE, and ESI-MS to mimic the metabolic fate of drugs is described. While the combination of EC, HPLC, and ESI-MS has been used for this purpose before, NACE is able to deliver valuable additional information about possible metabolites of harmane when compared to HPLC. In this paper, NACE is used as a(More)
In this work, the potential of electrochemical oxidation as a tool for the rapid prediction of transformation products in water appearing after ozonation is investigated. These two approaches were compared by choosing the two environmentally relevant model compounds diclofenac and metoprolol and comparison of their transformation products after(More)