Detection of testosterone esters in human plasma

The detection of testosterone misuse in sports is currently based on the urinary testosterone to epitestosterone ratio, although in some rare instances physiological or pathological conditions could compromise the application of this general criterion. The detection in the body of traces of the unchanged testosterone esters really ingested would offer unequivocal confirmation of testosterone administration. In this work, the detectability of testosterone esters in humans was studied. Liquid–liquid extraction of human blood plasma and appropriate derivatization of nine testosterone esters are described. Different acyl (trifluoroacetyl, pentafluoropropionyl and heptafluorobutyryl) and trimethylsilyl derivatives were studied. The trimethylsilyl derivatives appear to be the best for screenign purposes based on the characteristics of their mass spectra, with abundant molecular ions in the high-mass range. They also offered good conditions for tandem mass spectrometric analysis, needed to achieve the required sensitivity after oral administration of the drugs. The method was successful in the detection and determination of intramuscularly administered testosterone propionate and testosterone enanthate and orally ingested testosterone undecanoate.