Direct determination of E2020 enantiomers in plasma by liquid chromatography-mass spectrometry and column-switching techniques

J Chromatogr A. 1995 Mar 3;694(1):209-18. doi: 10.1016/0021-9673(94)01005-y.


High-performance liquid chromatography with column switching and mass spectrometry (MS) was applied to the on-line determination and resolution of the enantiomers of E2020 (acetylcholinesterase inhibitor) in plasma. This system employs two avidin columns and fast atom bombardment (FAB)-MS. A plasma sample was injected directly into an avidin trapping column (10 mm x 4.0 mm I.D.). The plasma protein was washed out from the trapping column immediately while E2020 was retained. After the column-switching procedure, E2020 was separated enantioselectivity in an avidin analytical column. The separated E2020 enantiomers were specifically detected by FAB-MS without interference from metabolites of E2020 and plasma constituents. The limit of quantification for each enantiomer of E2020 in plasma was 1.0 ng/ml and the intra- and inter-assay relative standard deviations for the method were less than 5.2%. The assay was validated for enantioselective pharmacokinetic studies in the dog.

MeSH terms

  • Animals
  • Cholinesterase Inhibitors / blood*
  • Cholinesterase Inhibitors / chemistry
  • Chromatography, High Pressure Liquid / methods*
  • Dogs
  • Donepezil
  • Gas Chromatography-Mass Spectrometry / methods*
  • Indans / blood*
  • Indans / chemistry
  • Male
  • Piperidines / blood*
  • Piperidines / chemistry
  • Reproducibility of Results
  • Spectrometry, Mass, Fast Atom Bombardment
  • Spectrophotometry, Ultraviolet
  • Stereoisomerism


  • Cholinesterase Inhibitors
  • Indans
  • Piperidines
  • Donepezil