title: [Determination of tramadol and its active metabolite O-desmethyltramadol in plasma and amniotic fluid using LC/MS/MS].
abstract: OBJECTIVE
  To determinate tramadol and O-desmethyltramadol in human plasma and amniotic fluid by LC/MS/MS, and distribution of tramadol and O-desmethyltramadol in maternity and fetus were studied.
  
  
  METHODS
  Samples containing tramadol, O-desmethyltramadol and diphenhydramine (internal standard, IS ) were extracted using liquid-liquid extraction, followed by liquid chromatographic separation and on-line MS/MS using atmospheric pressure chemical ionization as an interface detection. The analytes were detected in the selected reaction monitoring mode.
  
  
  RESULTS
  The calibration curves for tramadol and O-desmethytramadol in plasma and amniotic fluid were linear in the range from 8.0 to 800.0 microg x L(-1) (plasma) and 1.0 to 400.0 microg x L(-1) (amniotic fluid). The method was applied to the measurement of tramadol and O-desmethytramadol concentrations in maternal vein, umbilical vein, umbilical artery and amniotic fluid. Following intramuscular pre-operative administration 1.5 mg x kg(-1) doses of tramadol to parturients, plasma concentrations of tramadol were significantly higher than those in amniotic fluid. The concentrations of O-desmethyltramadol in plasma were lower, and were not detected in amniotic fluid.
  
  
  CONCLUSIONS
  The method is shown to be accurate, robust and convenient, and suitable for clinical pharmacokinetics studies of tramadol and O-desmethyltramadol.
authors.affiliation: Laboratory of Clinical Pharmacology, China Medical University No. 2 Hospital, Shenyang 110004, China.
authors.forename: Li-mei
authors.initials: LM
authors.lastname: Zhao
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Chen
authors.forename: Jian-jun
authors.initials: JJ
authors.lastname: Cui
authors.forename: Maleku
authors.initials: M
authors.lastname: Sunita
authors.forename: Da-fang
authors.initials: DF
authors.lastname: Zhong
mesh_terms: D000653:Amniotic Fluid / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005333:Fetus; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D011247:Pregnancy; D021241:Spectrometry, Mass, Electrospray Ionization; D014147:Tramadol / Q000031:analogs & derivatives* / Q000097:blood* / Q000378:metabolism / Q000493:pharmacokinetics; D014469:Umbilical Arteries / Q000378:metabolism; D014471:Umbilical Veins / Q000378:metabolism*
chemical_list: C080580:O-demethyltramadol; D014147:Tramadol