title: [Analysis of ephedrine and its metabolites in rat urine by HPLC-ESI-ITMSn].
abstract: OBJECTIVE
  To estabilish a rapid and sensitive LC-ESI-ITMSn method for the identification of ephedrine and its main metabolites in rat urine.
  
  
  METHODS
  After optimizing the detection condition of LC-ESI-ITMSn chromatography and mass spectrometry by using a standard ephedrine, the ionization and cleavage rules of ephedrine in ESI-MS and ESI-MSn modes were summarized, and then serving as the basis for the metabolite analysis of ephedrine in rat urine. Rat urine samples of 0-48 h were collected after ig 10 mg x kg(-1) ephedrine, then the samples were purified through C18 solid-phase extraction cartridge. The purified samples were analyzed by LC-ESI-ITMSn.
  
  
  RESULTS
  The structures of ephedrine metabolites were elucidated according to the changes of the molecular weights of the metabolites (deltaM) and their cleavage pattern in ESI-ITMSn. As a result, three phase I metabolites and the parent drug ephedrine were identified existing in rat urine, but no phase II metabolites were found.
  
  
  CONCLUSIONS
  The LC-ESI-ITMSn method is rapid and highly sensitive and sepecific, it is suitable for the identification of ephedrine and its metabolites in rat urine.
authors.affiliation: Bio-Technology of Traditional Chinese Medicine Key Lab of Hubei Province, Hubei University, Wuhan 430062, China. cy101610@npc.gov.cn
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.forename: Shao-Lin
authors.initials: SL
authors.lastname: Shen
authors.forename: Huai-Xia
authors.initials: HX
authors.lastname: Chen
authors.forename: Feng-Mei
authors.initials: FM
authors.lastname: Han
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004809:Ephedrine / Q000737:chemistry / Q000378:metabolism / Q000652:urine*; D008297:Male; D008970:Molecular Weight; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D004809:Ephedrine