Strategy for structural elucidation of drugs and drug metabolites using (MS)n fragmentation in an electrospray ion trap.
Triple-stage quadrupole (TSQ) electrospray ionization (ESI) tandem mass spectrometry (MS/MS) and ion trap ESI-MS/MS can be used to cleave protonated molecules to produce carbocations and neutral molecules in the positive ion mode. Dissociation products which correspond to protonated forms of neutral fragment molecules can also be trapped and detected. These protonated molecules in turn can cleave via carbocation cleavage, ipso cleavage, onium cleavage or McLafferty or related rearrangements. One can elucidate the structures of metabolites from the differences in m/z ratios of the fragments arising from the original drug compound and its metabolite. This strategy for structural elucidation is further facilitated by estimates of the reactivity of drugs with oxygen diradicals involved in cytochrome P-450 cycles.
Tozuka
Zenzaburo
Z
Biopharmaceutical and Pharmacokinetics Research Laboratories, Fujisawa Pharmaceutical Co. Ltd., 2-1-6 Kashima, Yodogawa-ku, Osaka 532-8514, Japan. zenzaburo_tozuka@po.fujisawa.co.jp
Kaneko
Hayato
H
Shiraga
Toshifumi
T
Mitani
Yasuyuki
Y
Beppu
Manabu
M
Terashita
Shigeyuki
S
Kawamura
Akio
A
Kagayama
Akira
A
D000818:Animals; D006801:Humans; D015394:Molecular Structure; D004364:Pharmaceutical Preparations / Q000737:chemistry / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D004364:Pharmaceutical Preparations