In vitro and in vivo metabolite identification by UHPLC-QTOF MS
Thirteen IVM metabolites (M1-M13) were identified from 60 minute
-incubated microsomes as shown in the metabolite chromatogram inFigure 2A. All metabolites were more polar than the IVM parent
compound. M1, M3, M5, and M6 were found in the medium of 24hour-exposed
primary human hepatocytes (Figure 2B) . M1, M3, and M6 were also
found in 24hour-post-treatment volunteer blood (Figure 2C).Reference MS/MS spectra of IVM-B1a and
IVM-B1b used in the library search were generated from
analysis of 100 ng/mL of IVM standard solution.
IVM- B1b (m/z 878.5) eluted 0.9 min earlier than
IVM-B1a (m/z 892.5) as shown in the extract ion
chromatogram (Figure 3A). Major product ions of
IVM-B1b were m/z 293.2, 537.3, and 555.3 (Figure
3B) and those of IVM-B1a were m/z 307.2, 551.3, and
569.3 (Figure 3C) . The fragment pattern of the
ammonium adduct ion of IVM-B1a and
IVM-B1b is presented in Figure 3D. MS/MS
spectra of M1 to M13 (Figure 4) were used to define the
molecular structure of the metabolites.