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A novel approach to perform metabolite screening during the quantitative LC–MS/MS analyses of in vitro metabolic stability samples using a hybrid triple‐quadrupole linear ion trap mass spectrometer
Author(s) -
Shou Wilson Z.,
Magis Lisa,
Li Austin C.,
Naidong Weng,
Bryant Matthew S.
Publication year - 2005
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.917
Subject(s) - chemistry , quadrupole ion trap , triple quadrupole mass spectrometer , metabolite , chromatography , mass spectrometry , ion trap , analytical chemistry (journal) , selected reaction monitoring , tandem mass spectrometry , biochemistry
In vitro metabolic stability experiments using microsomes or other liver preparations are important components in the discovery and lead‐optimization stages of compound selection in the pharmaceutical industry. Currently, liquid chromatography–tandem mass spectrometric (LC–MS/MS) support of in vitro metabolic stability studies primarily involves the monitoring of disappearance of parent compounds, using selected reaction monitoring (SRM) on triple‐quadrupole instruments. If moderate to high turnover is observed, separate metabolite identification experiments are then conducted to characterize the biotransformation products. In this paper, we present a novel method to simultaneously perform metabolite screening in addition to the quantitative stability measurements, both within the same chromatographic run. This is accomplished by combining SRM and SRM‐triggered, information‐dependent acquisition (IDA) of MS/MS spectra on a hybrid triple‐quadrupole linear ion trap (QqQ LIT ) mass spectrometer. Microsomal stability experiments using model compounds, bufuralol, propranolol, imipramine, midazolam, verapamil and diclofenac, were used to demonstrate the applicability of our approach. This SRM + SRM‐IDA approach generated metabolic stability results similar to those obtained by conventional SRM‐only approach. In addition, MS/MS spectra from potential metabolites were obtained with the enhanced product ion (EPI) scan function of LIT during the same injection. These spectra were correlated to the spectra of parent compounds to confirm the postulated structures. The time–concentration profiles of identified metabolites were also estimated from the acquired data. This approach has been successfully used to support discovery programs. Copyright © 2005 John Wiley & Sons, Ltd.