Development and validation of a mass spectrometric detection method of peginesatide in dried blood spots for sports drug testing

As recently reported, dried blood spot (DBS) analysis is an advantageous technique for doping control purposes due to the minimal invasive sample collection, the simple and economic manner, as well as the low susceptibility to manipulation. Its general applicability to the sports drug testing arena has been shown for analytes of various substance classes, all of which comprise exclusively low molecular mass compounds. The aim of the present study was to investigate whether the technique of DBS analysis is applicable also to (pegylated) peptides with relevance for doping controls. As target analyte, peginesatide (Omontys, Hematide), a recently approved pegylated erythropoietin-mimetic peptide of approximately 45 kDa, tested for the treatment of anaemia in patients with renal failure, was chosen, which has been prohibited in elite sports due to its assumed endurance enhancing effects. Therefore, a detection method for peginesatide employing DBS was developed based on extraction, proteolytic digestion and cation-exchange purification followed by liquid chromatography-tandem mass spectrometry analysis. Eventually, the assay was validated for qualitative purposes and proved to be specific, sensitive (limit of detection, 10 ng/mL) and precise (relative standard deviations below 18 %), demonstrating the general suitability of DBS analysis in sports drug testing also for (pegylated) peptides.