title: Detection of peginesatide in equine serum using liquid chromatography-tandem mass spectrometry for doping control purposes.
abstract: Erythropoietin (EPO) and its recombinant analogues are suspected to be illicitly administered to horses for performance enhancing purposes and, consequently, prohibited in equine sports. Recently, a new erythropoiesis-stimulating agent, peginesatide (Omontys, formerly referred to as Hematide), belonging to the upcoming class of EPO-mimetic peptides, received approval for the treatment of anaemia in humans with chronic kidney disease on dialysis. As the pegylated dimeric peptide of approximately 45 kDa without sequence  homology to EPO is not detectable by conventional EPO detection assays, specific methods are bound to be established for horse sports drug testing. Thus, by fortifying equine serum with peginesatide, an approach consisting of a proteolytic digestion with subtilisin after protein precipitation was developed, eventually targeting a proteotypic and xenobiotic pentapeptide which is easily accessible to liquid chromatography- tandem mass spectrometry analysis. The method was validated for qualitative purposes and demonstrated to be  specific, precise (relative standard deviations below 14%), sensitive (limit of detection 10 ng mL(-1)) and linear. Being simple, cost-effective and readily transferable to other doping control laboratories, a mass spectrometric assay for the detection of therapeutic concentrations of peginesatide in equine serum is, in terms of preventive doping research, applicable to routine analysis shortly after approval of the drug.
authors.affiliation: Institute of Biochemistry-Center for Preventive Doping Research, German Sport University   Cologne, Am Sportpark  Müngersdorf 6, 50933 Cologne, Germany.
authors.forename: Ines
authors.initials: I
authors.lastname: Möller
authors.forename: Andreas
authors.initials: A
authors.lastname: Thomas
authors.forename: Anke
authors.initials: A
authors.lastname: Wingender
authors.forename: Marc
authors.initials: M
authors.lastname: Machnik
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Schänzer
authors.forename: Mario
authors.initials: M
authors.lastname: Thevis
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods*; D004300:Doping in Sports / Q000379:methods* / Q000517:prevention & control*; D006736:Horses / Q000097:blood*; D010455:Peptides / Q000097:blood*; D015813:Substance Abuse Detection / Q000379:methods / Q000662:veterinary*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010455:Peptides; C556270:peginesatide