Wim Luijten

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The metabolism of tianeptine, a novel antidepressant that presents original neurochemical properties, was studied after a single oral administration of radioisotopically (14C) labeled compound to six healthy male volunteers. After 7 days, approximately 66% of the dose was eliminated by renal excretion (55% during the first 24 hr). Tianeptine is extensively(More)
Synthesis of postulated hydroxylated metabolites of gliclazide is described together with their detailed structural analysis using 1H-NMR, two-dimensional 1H-NMR, and MS to characterize the products. Metabolism of gliclazide has been investigated in the urine of nine patients of different ethnic origins receiving gliclazide therapy for the treatment of(More)
To validate a recently developed liquid chromatography/ultraviolet (LC/UV) method in a pharmacokinetic study of Vectarion (almitrine) where the unchanged drug, its five metabolites and an internal standard are analysed, on-line fast atom bombardment liquid chromatography/mass spectrometry (FAB LC/MS) with a moving belt interface has been used. Since the(More)
Preliminary metabolic profiling of a drug under pre-clinical development revealed the presence of a minor unknown metabolite with a positive ion electrospray ionization (ESI) mass spectrum identical to that of the unchanged compound. Since the low concentration of the compound did not allow any additional experiments, preparative bioconversion using fungi(More)
Fotemustine is a chemotherapeutic drug for the treatment of melanoma. In this study, we investigated the metabolic and chemical stability of fotemustine with 31P-NMR and FAB-MS. In the absence of GSH, 95% of fotemustine decomposed rapidly into a reactive diethyl ethylphosphonate (DEP) isocyanate, both in rat liver S9 fraction and in HEPES buffer (pH = 7.4).(More)
The metabolism of S12813, (3-(2-[4-phenyl piperazin-1-yl] ethyl)-2-oxo-2,3-dihydro oxazolo [4,5-b] pyridine chlorohydrate), in rat liver slice incubates was examined by high performance liquid chromatography combined with mass spectrometry. Electrospray ionization was used together with tandem mass spectrometric techniques of analysis (MS/MS). Polar phase I(More)
The electron impact and chemical ionization (ammonia and methane) mass spectral behaviour of the cis- and trans-(2-hydroxycyclohexyl)-mercapturic acid methyl esters, metabolites of cyclohexeneoxide, was examined. Only with chemical ionization was it possible to differentiate between these two configurational isomers, by observing the stereoselective loss of(More)
The application of post-column splitting in liquid chromatography (LC) coupled to dynamic liquid secondary ion (or continuous-flow fast atom bombardment) mass spectrometry allows more flexibility with respect to the use of conventional LC methods. Gradient elution and the presence of involatile mobile phase modifiers do not therefore constitute(More)