Detectability of oxandrolone, metandienone, clostebol and dehydrochloromethyltestosterone in urine after transdermal application.

Situations of both, intentional and inadvertent or accidental doping, necessitate consideration in today's doping controls, especially in the light of the substantial consequences that athletes are facing in case of so-called adverse analytical findings. The aim of this study was to investigate, whether a transdermal uptake of doping substances would be possible. In addition to the period of detectability of the particular substances or respective characteristic metabolites, the possibility of deducing the route of administration by metabolite patterns was also assessed. Twelve male subjects were included in the study. Four common anabolic androgenic steroids (AAS) were dissolved in dimethylsulfoxide to facilitate transdermal administration on different skin regions. One half of the test persons received only oxandrolone (17α-methyl-2-oxa-4,5α-dihydrotestosterone), and the other half were applied a mixture of oxandrolone, metandienone (17ß-hydroxy-17α-methylandrosta-1,4-dien-3-one), clostebol (4-chlorotestosterone-17ß-acetate) and dehydrochloromethyltestosterone (DHCMT). Urine samples were collected 1 h, 6 h and one sample per day for the next 14 consecutive days. Measurements were conducted on a tandem-gas chromatography-mass spectrometry (GC-MS/MS) or tandem-liquid chromatography-MS/MS (LC-MS/MS) system. Substance findings were obtained at least 1 day after application on nearly all skin locations. The results indicated inter-individual variability in detection windows, also varying between the different analytes and possible impact of skin location and skin thickness, respectively. Nevertheless, a rapid and rather long detectability of all substances (or respective metabolites) was given, in some cases within hours after administration and for up to 10-14 days. Hence, the transdermal application or exposure to the investigated AAS is a plausible scenario that warrants consideration in anti-doping.

HepG2 as promising cell-based model for biosynthesis of long-term metabolites: Exemplified for metandienone.

In order to detect the abuse of substances in sports, the knowledge of their metabolism is of undisputable importance. As in vivo administration of compounds faces ethical problems and might even not be applicable for nonapproved compounds, cell-based models might be a versatile tool for biotransformation studies. We coincubated HepG2 cells with metandienone and D3 -epitestosterone for 14 days. Phase I and II metabolites were analyzed by high-performance liquid chromatography (HPLC)-tandem mass spectrometry and confirmed by gas chromatography-mass spectrometry (GC-MS). The metandienone metabolites formed by HepG2 cells were comparable with those renally excreted by humans. HepG2 cells also generated the two long-term metabolites 17ß-hydroxymethyl-17α-methyl-18-nor-androst-1,4,13-trien-3-one and 17α-hydroxymethyl-17ß-methyl-18-nor-androst-1,4,13-trien-3-one used in doping analyses, though in an inverse ratio compared with that observed in human urine. In conclusion, we showed that HepG2 cells are suitable as model for the investigation of biotransformation of androgens, especially for the anabolic androgenic steroid metandienone. They further proved to cover phase I and II metabolic pathways, which combined with a prolonged incubation time with metandienone resulted in the generation of its respective long-term metabolites known from in vivo metabolism. Moreover, we showed the usability of D3 -epitestosterone as internal standard for the incubation. The method used herein appears to be suitable and advantageous compared with other models for the investigation of doping-relevant compounds, probably enabling the discovery of candidate metabolites for doping analyses.

New Insights into the Metabolism of Methyltestosterone and Metandienone: Detection of Novel A-Ring Reduced Metabolites.

Metandienone and methyltestosterone are orally active anabolic-androgenic steroids with a 17α-methyl structure that are prohibited in sports but are frequently detected in anti-doping analysis. Following the previously reported detection of long-term metabolites with a 17ξ-hydroxymethyl-17ξ-methyl-18-nor-5ξ-androst-13-en-3ξ-ol structure in the chlorinated metandienone analog dehydrochloromethyltestosterone ("oral turinabol"), in this study we investigated the formation of similar metabolites of metandienone and 17α-methyltestosterone with a rearranged D-ring and a fully reduced A-ring. Using a semi-targeted approach including the synthesis of reference compounds, two diastereomeric substances, viz. 17α-hydroxymethyl-17ß-methyl-18-nor-5ß-androst-13-en-3α-ol and its 5α-analog, were identified following an administration of methyltestosterone. In post-administration urines of metandienone, only the 5ß-metabolite was detected. Additionally, 3α,5ß-tetrahydro-epi-methyltestosterone was identified in the urines of both administrations besides the classical metabolites included in the screening procedures. Besides their applicability for anti-doping analysis, the results provide new insights into the metabolism of 17α-methyl steroids with respect to the order of reductions in the A-ring, the participation of different enzymes, and alterations to the D-ring.

Isotopically labeled boldenone as a better marker of derivatization efficiency for improved quality control in anti-doping analysis.

At present, anti-doping laboratories use androsterone, a major urinary steroid metabolite, to evaluate completeness of the derivatization step. This is typically done by calculating the ratio of mono-trimethylsilyl (TMS) androsterone to the total mono- and di-TMS androsterone. Certain samples may show an elevated percentage of mono-TMS androsterone indicating a failed derivatization step. In such cases, the laboratory would have to repeat the analysis or perform other remedial actions to ensure that completeness of derivatization is achieved. We have noticed that a poorly derivatized positive control sample spiked with various target analytes has a disproportionally low abundance of the di-TMS derivatives of boldenone and 18-nor-17ß-hydroxymethyl-17α-methylandrosta-1,4,13-trien-3-one (methandienone long-term metabolite). A follow-up investigation confirmed that 1,4-diene-3-one steroids are more likely to fail during the trimethylsilylation step. To better control derivatization efficiency, 13 C3 -boldenone (13C-BLD) was incorporated into our routine procedure as an additional internal standard. Analysis of a large number of urine samples has shown that derivatization of 13C-BLD could be grossly incomplete even in cases when mono-TMS androsterone is well below 1%. In other words, one or both of boldenone and the long-term metabolite of methandienone could remain undetected unless the laboratory has the means to recognize samples where derivatization of 1,4-diene-3-one steroids failed.

Drug-drug interaction and doping: Effect of non-prohibited drugs on the urinary excretion profile of methandienone.

The potential consequences of drug-drug interactions on the excretion profile of the anabolic androgenic steroid methandienone (17ß-hydroxy-17α-methylandrosta-1,4-dien-3-one) are discussed. More specifically, we have evaluated by in vitro and in vivo experiments the effects of 7 non-prohibited drugs (fluconazole, ketoconazole, itraconazole, miconazole, fluoxetine, paroxetine, and nefazodone) on the main metabolic pathways of methandienone. These are selected among those most commonly used by the athletes. The in vitro assays were based on the use of human liver microsomes, specific recombinant enzyme isoforms of cytochrome P450 and uridine 5'-diphospho-glucuronosyl-transferase. The in vivo study was performed by analyzing urines collected after the oral administration of methandienone with and without the co-administration of ketoconazole. Methandienone and its metabolites were determined by liquid chromatography-mass spectrometry-based techniques after sample pretreatment including an enzymatic hydrolysis step (performed only for the investigation on phase II metabolism) and liquid/liquid extraction with t-butyl methyl-ether. The results from the in vitro experiments showed that the formation of the hydroxylated and dehydrogenated metabolites was significantly reduced in the presence of itraconazole, ketoconazole, miconazole and nefazodone, whereas the production of the 18-nor-hydroxylated metabolites and glucuronidation reactions was reduced significantly only in the presence of ketoconazole and miconazole. The analysis of the post-administration samples confirmed the in vitro observations, validating the hypothesis that drug-drug interaction may cause significant alterations in the metabolic profile of banned drugs, making their detection during doping control tests more challenging.

Sulfate metabolites as alternative markers for the detection of 4-chlorometandienone misuse in doping control.

Sulfate metabolites have been described as long-term metabolites for some anabolic androgenic steroids (AAS). 4-chlorometandienone (4Cl-MTD) is one of the most frequently detected AAS in sports drug testing and it is commonly detected by monitoring metabolites excreted free or conjugated with glucuronic acid. Sulfation reactions of 4Cl-MTD have not been studied. The aim of this work was to evaluate the sulfate fraction of 4Cl-MTD metabolism by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to establish potential long-term metabolites valuable for doping control purposes. 4Cl-MTD was administered to two healthy male volunteers and urine samples were collected up to 8 days after administration. A theoretical selected reaction monitoring (SRM) method working in negative mode was developed. Ion transitions were based on ionization and fragmentation behaviour of sulfate metabolites as well as specific neutral losses (NL of 15 Da and NL of 36 Da) of compounds with related chemical structure. Six sulfate metabolites were detected after the analysis of excretion study samples. Three of the identified metabolites were characterized by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Results showed that five out of the six identified sulfate metabolites were detected in urine up to the last collected samples from both excretion studies. Copyright © 2016 John Wiley & Sons, Ltd.

LC-MS/MS detection of unaltered glucuronoconjugated metabolites of metandienone.

The aim of this study was to evaluate the direct detection of glucuronoconjugated metabolites of metandienone (MTD) and their detection times. Metabolites resistant to enzymatic hydrolysis were also evaluated. Based on the common mass spectrometric behaviour of steroid glucuronides, three liquid chromatography-tandem mass spectrometry (LC-MS/MS) strategies were applied for the detection of unpredicted and predicted metabolites: precursor ion scan (PI), neutral loss scan (NL), and theoretical selected reaction monitoring (SRM) methods. Samples from four excretion studies of MTD were analyzed for both the detection of metabolites and the establishment of their detection times. Using PI and NL methods, seven metabolites were observed in post-administration samples. SRM methods allowed for the detection of 13 glucuronide metabolites. The detection times, measured by analysis with an SRM method, were between 1 and 22 days. The metabolite detected for the longest time was 18-nor-17ß-hydroxymethyl-17α-methyl-5ß-androsta-1,4,13-triene-3-one-17-glucuronide. One metabolite was resistant to hydrolysis with ß-glucuronidase; however it was only detected in urine up to four days after administration. The three glucuronide metabolites with the highest retrospectivity were identified by chemical synthesis or mass spectrometric data, and although they were previously reported, this is the first time that analytical data of the intact phase II metabolites are presented for some of them. The LC-MS/MS strategies applied have demonstrated to be useful for detecting glucuronoconjugated metabolites of MTD, including glucuronides resistant to enzymatic hydrolysis which cannot be detected by conventional approaches. Copyright © 2016 John Wiley & Sons, Ltd.

Efficient approach for the detection and identification of new androgenic metabolites by applying SRM GC-CI-MS/MS: a methandienone case study.

Identification of anabolic androgenic steroids (AAS) is a vital issue in doping control and toxicology, and searching for metabolites with longer detection times remains an important task. Recently, a gas chromatography chemical ionization triple quadrupole mass spectrometry (GC-CI-MS/MS) method was introduced, and CI, in comparison with electron ionization (EI), proved to be capable of increasing the sensitivity significantly. In addition, correlations between AAS structure and fragmentation behavior could be revealed. This enables the search for previously unknown but expected metabolites by selection of their predicted transitions. The combination of both factors allows the setup of an efficient approach to search for new metabolites. The approach uses selected reaction monitoring which is inherently more sensitive than full scan or precursor ion scan. Additionally, structural information obtained from the structure specific CI fragmentation pattern facilitates metabolite identification. The procedure was demonstrated by a methandienone case study. Its metabolites have been studied extensively in the past, and this allowed an adequate evaluation of the efficiency of the approach. Thirty three metabolites were detected, including all relevant previously discovered metabolites. In our study, the previously reported long-term metabolite (18-nor-17ß-hydroxymethyl,17α-methyl-androst-1,4,13-trien-3-one) could be detected up to 26 days by using GC-CI-MS/MS. The study proves the validity of the approach to search for metabolites of new synthetic AAS and new long-term metabolites of less studied AAS and illustrates the increase in sensitivity by using CI. Copyright © 2016 John Wiley & Sons, Ltd.

Sudden or unnatural deaths involving anabolic-androgenic steroids.

Anabolic-androgenic steroids (AASs) are frequently misused. To determine causes of death, characteristics, toxicology, and pathology of AAS positive cases, all cases (n = 24) presenting to the New South Wales Department of Forensic Medicine (1995-2012) were retrieved. All were male, and the mean age was 31.7 years. Deaths were mainly due to accidental drug toxicity (62.5%), then suicide (16.7%) and homicide (12.5%). Abnormal testosterone/epitestosterone ratios were reported in 62.5%, followed by metabolites of nandrolone (58.3%), stanozolol (33.3%), and methandienone (20.8%). In 23 of 24 cases, substances other than steroids were detected, most commonly psychostimulants (66.7%). In nearly half, testicular atrophy was noted, as was testicular fibrosis and arrested spermatogenesis. Left ventricular hypertrophy was noted in 30.4%, and moderate to severe narrowing of the coronary arteries in 26.1%. To summarize, the typical case was a male polydrug user aged in their thirties, with death due to drug toxicity. Extensive cardiovascular disease was particularly notable.

A novel protocol for molecularly imprinted polymer filaments online coupled to GC-MS for the determination of androgenic steroids in urine.

An online system that can perform dynamic microextraction, on-coating derivatization and desorption, and subsequent GC-MS analysis with a large-volume injection was developed. A derivatization cell as the conjunction of the online system was developed for the online extraction and derivatization. To evaluate the feasibility of the online system, methyltestosterone molecularly imprinted polymer filaments (MIPFs) were prepared for the selective online extraction of five androgenic steroids, namely, methyltestosterone, testosterone, epitestosterone, nandrolone, and metandienone. Under the optimized conditions, the detection limits of testosterone and epitestosterone were 0.09 and 0.12 µg/L, respectively, which were under the minimum required performance limits between 2 and 10 µg/L from the World Anti-Doping Agency. The detection limits of the other three androgenic steroids were varied from 0.04 to 0.18 µg/L. Finally, the MIPFs-GC-MS method was applied for the determination of androgenic steroids in urine, and satisfactory recovery (78.0-96.9%) and reproducibility (3.2-8.9%) were obtained. The proposed online coupling system offers an attractive alternative for hyphenation to GC instruments and could also be extended to other adsorptive materials.

A new sulphate metabolite as a long-term marker of metandienone misuse.

Metandienone is one of the most frequently detected anabolic androgenic steroids in sports drug testing. Metandienone misuse is commonly detected by monitoring different metabolites excreted free or conjugated with glucuronic acid using gas chromatography mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) after hydrolysis with ß-glucuronidase and liquid-liquid extraction. It is known that several metabolites are the result of the formation of sulphate conjugates in C17, which are converted to their 17-epimers in urine. Therefore, sulphation is an important phase II metabolic pathway of metandienone that has not been comprehensively studied. The aim of this work was to evaluate the sulphate fraction of metandienone metabolism by LC-MS/MS. Seven sulphate metabolites were detected after the analysis of excretion study samples by applying different neutral loss scan, precursor ion scan and SRM methods. One of the metabolites (M1) was identified and characterised by GC-MS/MS and LC-MS/MS as 18-nor-17ß-hydroxymethyl-17α-methylandrost-1,4,13-triene-3-one sulphate. M1 could be detected up to 26 days after the administration of a single dose of metandienone (5 mg), thus improving the period in which the misuse can be reported with respect to the last long-term metandienone metabolite described (18-nor-17ß-hydroxymethyl-17α-methylandrost-1,4,13-triene-3-one excreted in the glucuronide fraction).

Unexpected contribution of cytochrome P450 enzymes CYP11B2 and CYP21, as well as CYP3A4 in xenobiotic androgen elimination - insights from metandienone metabolism.

The metabolism of a variety of anabolic steroids frequently misused for doping purposes has been investigated in the last years. This research mainly focused on main and long-term metabolites suitable for detection, but detailed clearance mechanisms have rarely been elucidated. Recent studies on metandienone focused on the identification of 17ß-hydroxymethyl-17α-methyl-18-norandrosta-1,4,13-trien-3-one (20ßOH-NorMD) as long-term metabolite, however, the metabolic pathway of its generation remained unclear. Metandienone and its Wagner-Meerwein rearrangement product 17,17-dimethyl-18-norandrosta-1,4,13-trien-3-one (NorMD) were hydroxylated by different human cytochrome P450 enzymes (CYPs). Some of their hydroxylation products were chemically synthesized and characterized by mass spectrometry to allow for their trace detection in urine samples. Following oral administration of metandienone or NorMD in one human volunteer each the post administration urines were checked for the presence of those hydroxylated metabolites using GC-MS/MS analysis. The human mitochondrial steroid hydroxylating enzymes CYP11B1 and CYP11B2 were capable to metabolize metandienone leading to the formation of 11ß-hydroxymetandienone and 18-hydroxymetandienone. Following Wagner-Meerwein rearrangement, the resulting products could be assigned to 20ßOH-NorMD and 11ßOH-NorMD. The contribution of CYP11B1 and CYP11B2 in human metabolism of metandienone was confirmed by analysis of post-administration samples of metandienone and NorMD. Combined with the results from a previous study, enzymatic pathways were identified that involve CYP21 and CYP3A4 in the hydroxylation of NorMD, while CYP21, CYP3A4 and CYP11B2 take part in 20ßOH-NorMD generation from MD. The current study represents a valuable contribution to the elucidation of clearance mechanisms of anabolic steroids and also indicates that mainly non-liver CYPs seem to be involved in these processes.

[Determination of doping in human urine by gas chromatography-high resolution mass spectrometry].

A method was evaluated for determination of twenty-one doping (including nandrolone, boldenone and methandienone) in human urine by gas chromatography-high resolution mass spectrometry. Samples were prepared by liquid-liquid extraction, concentrated, TMS derivatization and limit of detection at ng x mL(-1) by MID/GC/HRMS. According to the code of the World Anti-Doping Agency (WADA), precision and recoveries of the procedure were evaluated by replicate analysis (n = 6), the recoveries in the range of 66%-103%, with the RSD below 10.0%. The precision within the day of the method with three different concentrations was also determined RSD were less than 9.5%, 10.0% and 9.7%.

Feasibility of capillary liquid chromatography/microchip atmospheric pressure photoionization mass spectrometry in analyzing anabolic steroids in urine samples.

We examined the feasibility of capillary liquid chromatography/microchip atmospheric pressure photoionization tandem mass spectrometry (capLC/microAPPI-MS/MS) for the analysis of anabolic steroids in human urine. The urine samples were pretreated by enzymatic hydrolysis (with beta-glucuronidase from Helix pomatia), and the compounds were liquid-liquid extracted with diethyl ether. After separation the compounds were vaporized by microchip APPI, photoionized by a 10 eV krypton discharge lamp, and detected by selected reaction monitoring. The capLC/microAPPI-MS/MS method showed good sensitivity with detection limits at the level of 1.0 ng mL(-1), good linearity with correlation coefficients between 0.9954 and 0.9990, and good repeatability with relative standard deviations below 10%. These results demonstrate that microchip APPI combined with capLC/MS/MS provides a new potential method for analyzing non-polar and neutral compounds in biological samples.

CYP21-catalyzed production of the long-term urinary metandienone metabolite 17beta-hydroxymethyl-17 alpha-methyl-18-norandrosta-1,4,13-trien-3-one: a contribution to the fight against doping.

Anabolic-androgenic steroids are some of the most frequently misused drugs in human sports. Recently, a previously unknown urinary metabolite of metandienone, 17beta-hydroxymethyl-17 alpha-methyl-18-norandrosta-1,4,13-trien-3-one (20OH-NorMD), was discovered via LC-MS/MS and GC-MS. This metabolite was reported to be detected in urine samples up to 19 days after administration of metandienone. However, so far it was not possible to obtain purified reference material of this metabolite and to confirm its structure via NMR. Eleven recombinant strains of the fission yeast Schizosaccharomyces pombe that express different human hepatic or steroidogenic cytochrome P450 enzymes were screened for production of this metabolite in a whole-cell biotransformation reaction. 17,17-Dimethyl-18-norandrosta-1,4,13-trien-3-one, chemically derived from metandienone, was used as substrate for the bioconversion, because it could be converted to the final product in a single hydroxylation step. The obtained results demonstrate that CYP21 and to a lesser extent also CYP3A4 expressing strains can catalyze this steroid hydroxylation. Subsequent 5 l-scale fermentation resulted in the production and purification of 10 mg of metabolite and its unequivocal structure determination via NMR. The synthesis of this urinary metandienone metabolite via S. pombe-based whole-cell biotransformation now allows its use as a reference substance in doping control assays.

uPA+/+-SCID mouse with humanized liver as a model for in vivo metabolism of exogenous steroids: methandienone as a case study.

BACKGROUND: Adequate detection of designer steroids in the urine of athletes is still a challenge in doping control analysis and requires knowledge of steroid metabolism. In this study we investigated whether uPA(+/+)-SCID mice carrying functional primary human hepatocytes in their liver would provide a suitable alternative small animal model for the investigation of human steroid metabolism in vivo. METHODS: A quantitative method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated for the urinary detection of 7 known methandienone metabolites. Application of this method to urine samples from humanized mice after methandienone administration allowed for comparison with data from in vivo human samples and with reported methandienone data from in vitro hepatocyte cultures. RESULTS: The LC-MS/MS method validation in mouse and human urine indicated good linearity, precision, and recovery. Using this method we quantified 6 of 7 known human methandienone metabolites in the urine of chimeric mice, whereas in control nonchimeric mice we detected only 2 metabolites. These results correlated very well with methandienone metabolism in humans. In addition, we detected 4 isomers of methandienone metabolites in both human and chimeric mouse urine. One of these isomers has never been reported before. CONCLUSIONS: The results of this proof-of-concept study indicate that the human liver-uPA(+/+)-SCID mouse appears to be a suitable small animal model for the investigation of human-type metabolism of anabolic steroids and possibly also for other types of drugs and medications.

Combination of liquid-chromatography tandem mass spectrometry in different scan modes with human and chimeric mouse urine for the study of steroid metabolism.

Anabolic steroids are among the most frequently detected compounds in doping analysis. They are extensively metabolized and therefore an in-depth knowledge about steroid metabolism is needed. In this study, a liquid chromatography tandem mass spectometry (LC-MS/MS) method based on a precursor ion scan with a uPA-SCID mouse with humanized liver (a chimeric mouse) was explored for the detection of steroid metabolism. Methandienone was used as a model compound. The application of the precursor ion scan method in positive human samples and chimeric mice samples after methandienone administration allowed the detection of most steroid metabolites without any structural restriction. Three hitherto unreported metabolites were found using this approach. These metabolites were characterized using LC-MS/MS and feasible structures were proposed. The structure of one of them, 6-ene-epimethandienone, was confirmed by the synthesis of the reference compound. A selected reaction monitoring (SRM) method for the specific detection of all these metabolites has been developed. The application of this method to several human and chimeric mouse samples confirmed that more than 80% of the steroid metabolites were found in both samples. Only metabolites that are poorly detectable by LC-MS/MS were not detected in some urine samples. The metabolic nature of the unreported metabolites was also confirmed. A global strategy for the detection of steroid metabolites combining both human and chimeric mouse urine is proposed.

Detection of urinary metabolites common to structurally related 17alpha-alkyl anabolic steroids in horses and application to doping tests in racehorses: methandienone, methandriol, and oxymetholone.

Methandienone, methandriol, and oxymetholone, which are anabolic steroids possessing 17alpha-methyl and 17beta-hydroxy groups, were developed as oral formulations for therapeutic purposes. However, they have been used in racehorses to enhance racing performance. In humans, it has been reported that structurally related anabolic steroids having the 17alpha-methyl and 17beta-hydroxy groups, including 17alpha-methyltestosterone, mestanolone, methandienone, methandriol, and oxymetholone, have metabolites in common. In this study, we found that metabolites common to those of 17alpha-methyltestosterone and mestanolone were detected in horse urine after the administration of oxymetholone, methandienone, and methandriol. Based on analytical data, we confirmed these to be the common metabolites of five structurally related steroids, 17alpha-methyltestosterone, mestanolone, oxymetholone, methandienone, and methandriol. Furthermore, we detected hitherto unknown urinary metabolites of methandriol and oxymetholone in horses. The parent steroid itself was detected in horse urine after the administration of methandriol, other than metabolites common to 17alpha-methyltestosterone and mestanolone. On the other hand, the major metabolite of oxymetholone was mestanolone, aside from metabolites presumed to be the stereoisomers of 2-hydroxymethyl-17alpha-methyl-5alpha-androstan-3,17beta-diol and 2,17alpha-di(hydroxymethyl)-5alpha-androstan-3,17beta-diol. The simultaneous detection of common metabolites and other main metabolites would help us narrow down the candidate-administered steroid for the doping tests in racehorses.

Mass spectrometric identification and characterization of a new long-term metabolite of metandienone in human urine.

Anabolic-androgenic steroids are some of the most frequently detected drugs in amateur and professional sports. Doping control laboratories have developed numerous assays enabling the determination of administered drugs and/or their metabolic products that allow retrospectives with respect to pharmacokinetics and excretion profiles of steroids and their metabolites. A new metabolite generated from metandienone has been identified as 18-nor-17beta-hydroxymethyl,17alpha-methyl-androst-1,4,13-trien-3-one in excretion study urine samples providing a valuable tool for the long-term detection of metandienone abuse by athletes in sports drug testing. The metabolite was characterized using gas chromatography/(tandem) mass spectrometry, liquid chromatography/tandem mass spectrometry and liquid chromatography/high-resolution/high-accuracy (tandem) mass spectrometry by characteristic fragmentation patterns representing the intact 3-keto-1,4-diene structure in combination with typical product ions substantiating the proposed C/D-ring structure of the steroid metabolite. In addition, structure confirmation was obtained by the analysis of excretion study urine specimens obtained after administration of 17-CD(3)-labeled metandienone providing the deuterated analogue to the newly identified metabolite. 18-Nor-17beta-hydroxymethyl,17alpha-methyl-androst-1,4,13-trien-3-one was determined in metandienone administration study urine specimens up to 19 days after application of a single dose of 5 mg, hence providing an extended detection period compared with commonly employed strategies.