title: Isotope-dilution mass spectrometric quantification of the prodrug lisdexamfetamine in human urine in doping control analysis.
abstract: BACKGROUND
  Therapeutic approaches concerning attention-deficit hyperactivity disorder (ADHD) commonly include the administration of drugs amplifying cerebral dopamine and norepinephrine signals. Among these, compounds belonging to the Prohibited List as established by the World Anti-Doping Agency (WADA) are present such as amfetamine or methylphenidate, and abuse of these can result in sanctions for athletes. The recently approved therapeutic lisdexamfetamine represents a slow-release prodrug of amfetamine for ADHD treatment. In order to support doping control laboratories in differentiating the abuse of amfetamine from a therapeutic administration of lisdexamfetamine, the determination of the prodrug from urine is desirable. Since approximately 2% of lisdexamfetamine are eliminated intact into urine, a liquid chromatography/high-resolution/high accuracy mass spectrometric method was developed, allowing the target analyte and one of its metabolites (4-hydroxyamfetamine sulfate) to be accurately quantified.
  
  
  METHODS
  Urine samples were fortified with fourfold deuterated lisdexamfetamine and analyzed directly using ultrahigh-performance liquid chromatography (UHPLC) interfaced via electrospray ionization to a second-generation quadrupole-orbitrap mass spectrometer. The assay was characterized concerning specificity, limits of quantification (0.15-5 ng/mL), intraday and interday imprecision (4-22%), accuracy (90-120%), linearity, and ion suppression/enhancement effects. A patient's urine samples were analyzed to provide proof-of-principle data demonstrating that the intact prodrug lisdexamfetamine is detectable in urine up to 11 h post-administration at concentrations up to 80 ng/mL. Moreover, amfetamine and sulfoconjugated 4-hydroxyamfetamine were measured, yielding up to 1146 and 56 ng/mL, respectively.
  
  
  CONCLUSIONS
  Considering the observed comparably low urinary concentrations of lisdexamfetamine and 4-hydroxyamfetamine sulfate, the preferred minimally labor-intense sample preparation, and the necessity of fast and robust result generation, the employed instrumental setup proved fit-for-purpose in sports drug testing.
authors.affiliation: Institute of Biochemistry - Center for Preventive Doping Research, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Thevis
authors.forename: Gerd
authors.initials: G
authors.lastname: Sigmund
authors.forename: Andreas
authors.initials: A
authors.lastname: Thomas
authors.forename: Matthias
authors.initials: M
authors.lastname: Vogel
authors.forename: Katja
authors.initials: K
authors.lastname: Walpurgis
authors.forename: Dorota
authors.initials: D
authors.lastname: Kwiatkowska
authors.forename: Hans
authors.initials: H
authors.lastname: Geyer
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Schänzer
mesh_terms: D003913:Dextroamphetamine / Q000737:chemistry / Q000652:urine*; D004300:Doping in Sports; D005260:Female; D006801:Humans; D057230:Limit of Detection; D016014:Linear Models; D000069478:Lisdexamfetamine Dimesylate; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D011355:Prodrugs; D015203:Reproducibility of Results
chemical_list: D011355:Prodrugs; D000069478:Lisdexamfetamine Dimesylate; D003913:Dextroamphetamine