title: Hollow-fiber liquid-phase microextraction and chiral LC-MS/MS analysis of venlafaxine and its metabolites in plasma.
abstract: BACKGROUND
  An enantioselective analytical method was developed and validated for determination of venlafaxine and its metabolites O-desmethylvenlafaxine and N-desmethylvenlafaxine in plasma samples. The method employed LC-MS/MS analysis and hollow-fiber liquid-phase microextraction (HF LPME) for sample preparation.
  
  
  RESULTS
  After HF LPME optimization the following condition was established: sample volume of 4 ml, sample agitation at 1750 rpm, 20 min of extraction, 0.1 mol/l acetic acid as acceptor phase, 1-octanol as organic phase and donor phase pH adjustment to 10. Under these conditions, the method was linear over the concentration range of 5-500 ng/ml with quantification limits of 5 ng/ml.
  
  
  CONCLUSIONS
  The use of HF LPME for sample preparation provided suitable recoveries, efficient clean-up and low consumption of organic solvent.
authors.affiliation: Department of Physics & Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, 14040-903, Ribeirão Preto, SP, Brazil.
authors.forename: Patrícia
authors.initials: P
authors.lastname: da Fonseca
authors.forename: Pierina Sueli
authors.initials: PS
authors.lastname: Bonato
mesh_terms: D020003:1-Octanol / Q000737:chemistry; D018687:Antidepressive Agents, Second-Generation / Q000097:blood* / Q000378:metabolism / Q000592:standards; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000592:standards; D003511:Cyclohexanols / Q000097:blood* / Q000302:isolation & purification / Q000378:metabolism / Q000592:standards; D000069468:Desvenlafaxine Succinate; D006801:Humans; D006863:Hydrogen-Ion Concentration; D059627:Liquid Phase Microextraction / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000592:standards; D000069470:Venlafaxine Hydrochloride
chemical_list: D018687:Antidepressive Agents, Second-Generation; D003511:Cyclohexanols; C434332:N-desmethylvenlafaxine; D000069470:Venlafaxine Hydrochloride; D020003:1-Octanol; D000069468:Desvenlafaxine Succinate