Stable isotope ratio profiling of testosterone preparations.
Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is the preferred method of confirming the administration of exogenous testosterone by athletes. This relies on synthetic testosterone preparations being depleted in (13) C compared to natural testosterone. There is concern, however, about the existence of synthetic testosterone products that are unexpectedly (13) C-enriched and which may allow athletes to circumvent the current GC-C-IRMS test. Further to the reported studies of legitimate pharmaceutical-grade testosterone products, a detailed analysis of seized materials from border-level seizures was required to obtain intelligence concerning trends in 'black market' testosterone manufacture and distribution. The sample set collected for this study between 2006 and 2009 inclusive provided a δ(13) C range (n = 266) of -22.9‰ to -32.6‰ with mean and median values of -28.4‰ and -28.6‰, respectively. Within this distribution there were 24 samples (9%) confirmed to have δ(13) C values in the range reported for endogenous urinary steroid metabolites (≥ -25.8‰). The benefit of δ(13) C profiling for testosterone preparations was demonstrated by the ability to identify specific seized products that can be target tested for future intelligence purposes. In addition, the potential of stable hydrogen isotope ratio ((2) H/(1) H; δ(2) H) discrimination to complement δ(13) C analysis was investigated. Methodologies for the determination of δ(2) H values by gas chromatography-thermal conversion-isotope ratio mass spectrometry (GC-TC-IRMS) were developed to provide a δ(2) H range (n = 173) of -177‰ to -268‰ with mean and median values of -231‰ and -234‰, respectively.
Cawley
Adam
A
Australian Forensic Drug Laboratory, National Measurement Institute, 1 Suakin St., Pymble, Sydney 2073, Australia. adam.cawley@measurement.gov.au
Collins
Michael
M
Kazlauskas
Rymantas
R
Handelsman
David J
DJ
Heywood
Robert
R
Longworth
Mitchell
M
Arenas-Queralt
Andrea
A
D002247:Carbon Isotopes / Q000032:analysis; D003903:Deuterium / Q000032:analysis; D004867:Equipment Design; D008401:Gas Chromatography-Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D013739:Testosterone / Q000032:analysis*; D019155:Veterinary Drugs / Q000737:chemistry
D002247:Carbon Isotopes; D004364:Pharmaceutical Preparations; D019155:Veterinary Drugs; D013739:Testosterone; D003903:Deuterium