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Structural elucidation of N ‐oxidized clemastine metabolites by liquid chromatography/tandem mass spectrometry and the use of Cunninghamella elegans to facilitate drug metabolite identification
Author(s) -
Åberg Annica Tevell,
Löfgren Helena,
Bondesson Ulf,
Hedeland Mikael
Publication year - 2010
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4535
Subject(s) - chemistry , metabolite , mass spectrometry , tandem mass spectrometry , chromatography , chemical ionization , organic chemistry , ionization , biochemistry , ion
Cunninghamella elegans is a filamentous fungus that has been shown to biotransform drugs into the same metabolites as mammals. In this paper we describe the use of C. elegans to aid the identification of clemastine metabolites since high concentrations of the metabolites were produced and MS n experiments were facilitated. The combination of liquid chromatography and tandem mass spectrometry with two different ionization techniques and hydrogen/deuterium exchange were used for structural elucidation of the clemastine metabolites. Norclemastine, four isomers of hydroxylated clemastine, and two N ‐oxide metabolites were described for the first time in C. elegans incubations. The N ‐oxidations were confirmed by hydrogen/deuterium exchange and deoxygenation (−16 Da) upon atmospheric pressure chemical ionization mass spectrometry. By MS n fragmentation it was concluded that two of the hydroxylated metabolites were oxidized on the methylpyrridyl moiety, one on the aromatic ring with the chloro substituent, and one on the aromatic ring without the chlorine. Copyright © 2010 John Wiley & Sons, Ltd.