title: Micropreparative isolation and NMR structure elucidation of metabolites of the drug candidate 1-isopropyl-4-(4-isopropylphenyl)-6-(prop-2-yn-1-yloxy) quinazolin-2(1H)-one from rat bile and urine.
abstract: LC-MS based drug metabolism studies are effective in the optimization stage of drug discovery for rapid partial structure identification of metabolites. However, these studies usually do not provide unambiguous structural characterization of all metabolites, due to the limitations of MS-based structure identification. LC-MS-SPE-NMR is a technique that allows complete structure identification, but is difficult to apply to complex in vivo samples (such as bile collected during in vivo drug metabolism studies) due to the presence, at high concentrations, of interfering endogenous components, and potentially also dosage excipient components (e.g. polyethylene glycols). Here, we describe the isolation and structure characterization of seven metabolites of the drug development candidate 1-isopropyl-4-(4-isopropylphenyl)-6-(prop-2-yn-1-yloxy) quinazolin-2(1H)-one from a routine metabolism study in a bile-duct cannulated rat by LC-MS-SPE. The metabolites were isolated from bile and urine by repeated automatic trapping of the chromatographic peak of each metabolite on separate Oasis HLB SPE columns. The micropreparative HPLC/MS was performed on an XBridge BEH130 C18 HPLC column using aqueous formic acid/acetonitrile/methanol as mobile phase for the gradient elution. Mass spectrometric detection was performed on a LTQ XL linear ion trap mass spectrometer using electrospray ionization. Desorption of each metabolite was performed after the separation sequence. NMR spectra ((1)H, (13)C, 2D ROESY, HSQC and HMBC were measured on a Bruker AVANCE III spectrometer (600 MHz proton frequency) equipped with a 1.7 mm (1)H{(13)C,(15)N} Bruker Biospin's TCI MicroCryoProbe™.
authors: Analytical Sciences & Imaging, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland. Electronic address: Joachim.Blanz@novartis.com.
authors: Joachim
authors: J
authors: Blanz
authors: Analytical Sciences & Imaging, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Thierry
authors: T
authors: Délémonté
authors: Analytical Sciences & Imaging, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: David
authors: D
authors: Pearson
authors: Global Discovery Chemistry, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Alexandre
authors: A
authors: Luneau
authors: Global Discovery Chemistry, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Michael
authors: M
authors: Ritzau
authors: Analytical Sciences & Imaging, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Werner
authors: W
authors: Gertsch
authors: Analytical Sciences & Imaging, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Philippe
authors: P
authors: Ramstein
authors: Analytical Sciences & Imaging, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Jérôme
authors: J
authors: Dayer
authors: Metabolism & Pharmacokinetics, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Sandrine
authors: S
authors: Desrayaud
authors: Metabolism & Pharmacokinetics, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Elisabeth
authors: E
authors: Braun
authors: Analytical Sciences & Imaging, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland.
authors: Reiner
authors: R
authors: Aichholz
mesh_terms: D000818:Animals; D001646:Bile / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D015394:Molecular Structure; D011799:Quinazolines / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000652:urine; D051381:Rats; D017207:Rats, Sprague-Dawley; D052616:Solid Phase Extraction
chemical_list: D011799:Quinazolines
keywords: Biotransformation; Drug metabolism; HPLC-MS-SPE-NMR; Metabolite identification; Micropreparative isolation