Development and validation of a liquid chromatography-tandem mass spectrometry assay for hair analysis of atomoxetine and its metabolites: Application in clinical practice

Forensic Sci Int. 2012 May 10;218(1-3):62-7. doi: 10.1016/j.forsciint.2011.10.012. Epub 2011 Oct 22.


Atomoxetine (ATX) is a potent inhibitor of the noradrenaline reuptake transporter approved since 2002 for the treatment of attention-deficit/hyperactivity disorder (ADHD) in children, adolescents, and adults as alternative treatment to methylphenidate. A procedure based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of ATX and its main metabolites (4-hydroxyatomoxetine - 4 hydroxyATX - and N-desmethylatomoxetine - des-methylATX) in hair of one treated child and five treated adolescents. Since hair samples can be easily collected without the need for specials skills and exposing a patient to discomfort, hair testing of ATX and eventually of its metabolites should be useful, especially in case of pediatric patients, to check compliance in a wider time-window. After addition of duloxetine as internal standard, hair samples were overnight digested with 2ml 1M NaOH at 45°C. Then, analytes were extracted from alkaline solution with two different 2ml aliquots of tert-butyl methyl ether. Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a mobile phase of 40% of water-60% 5mM ammonium acetate, 50mM formic acid, 4mM trifluoroacetic acid in acetonitrile-water (85:15, v/v). The mass spectrometer was operated in positive ion mode using multiple reaction monitoring. The method was linear over the concentration range 0.2-50ng/mg hair for the all analytes under investigation, with an intra- and inter-assay imprecision and inaccuracy always less than 20% and an analytical recovery between 33.1% and 76.1%, depending on the considered analyte. Only ATX and 4-hydroxyATX were detected in hair samples with concentrations varying from 0.2 to 2.0ng/mg hair and from 0.3 to 1.0ng/mg, respectively. Notwithstanding the absence of any dose-hair concentration relationship, hair monitoring of ATX and concomitant medications commonly administrated in ADHD children and adolescents can be crucial in verifying long-term compliance to prescribed medication in individuals displaying a non negligible tendency to refuse drugs and to lie on the adherence to therapy as a specific symptom of the disease.

Publication types

  • Validation Study

MeSH terms

  • Adolescent
  • Adrenergic Uptake Inhibitors / analysis*
  • Atomoxetine Hydrochloride
  • Attention Deficit Disorder with Hyperactivity / drug therapy
  • Child
  • Chromatography, Liquid*
  • Female
  • Hair / chemistry*
  • Humans
  • Male
  • Medication Adherence
  • Phenols / analysis
  • Phenyl Ethers / analysis
  • Propylamines / analysis*
  • Tandem Mass Spectrometry*


  • Adrenergic Uptake Inhibitors
  • Phenols
  • Phenyl Ethers
  • Propylamines
  • N-desmethylatomoxetine
  • Atomoxetine Hydrochloride
  • 4-hydroxyatomoxetine