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

Characterization and quantitation of a sulfoconjugated metabolite for detection of methyltestosterone misuse and direct identification by LC-MS

Methyltestosterone (MT) is one of the most frequently misused anabolic androgenic steroids detected in doping control analysis. The metabolism of MT in humans leads to several phase І metabolites and their corresponding phase Ⅱ conjugates. Previous studies have postulated the 3α-sulfoconjugate of 17α-methyl-5β-androstane-3α,17β-diol (S2) as principal sulfate metabolite of MT, with a detection window exceeding 10 days. However, a final direct and unambiguous confirmation of the structure of this metabolite is missing until now. In this study, we established an approach to detect and identify S2, using intact analysis by liquid chromatography hyphenated with tandem mass spectrometry (LC-MS/MS) without complex sample pretreatment. An in vitro study yielded the LC-MS/MS reference retention times of all 3-sulfated 17-methylandrostane-3,17-diol diastereomers, allowing for accurate structure assignment of potentially detected metabolites. In an in vivo excretion study with a single healthy male volunteer, the presence of the metabolite S2 was confirmed after a single oral dose of 10 mg MT. The reference standard was chemically synthesized, characterized by accurate mass mass spectrometry (MS) and nuclear magnetic resonance (NMR), and quantified by quantitative NMR (qNMR). Thus, this study finally provides accurate structure information on the S2 metabolite and a direct analytical method for detection of MT misuse. The availability of the reference material is expected to facilitate further evaluation and subsequent analytical method validation in anti-doping research.

Energy-Resolved Fragmentation Aiding the Structure Elucidation of Steroid Biomarkers

The identification and confirmation of steroid sulfate metabolites in biological samples are essential to various fields, including anti-doping analysis and clinical sciences. Ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) is the leading method for the detection of intact steroid conjugates in biofluids, but because of the inherent complexity of biological samples and the low concentration of many targets of interest, metabolite identification based solely on mass spectrometry remains a major challenge. The confirmation of new metabolites typically depends on a comparison with synthetically derived reference materials that encompass a range of possible conjugation sites and stereochemistries. Herein, energy-resolved collision-induced dissociation (CID) is used as part of UHPLC-HRMS/MS analysis to distinguish between regio- and stereo-isomeric steroid sulfate compounds. This wholly MS-based approach was employed to guide the synthesis of reference materials to unambiguously confirm the identity of an equine steroid sulfate biomarker of testosterone propionate administration.

Androgens, sports, and detection strategies for anabolic drug use

For decades, anabolic androgenic agents have represented the substance class most frequently observed in doping control samples. They comprise synthetic and pseudoendogenous anabolic androgenic steroids and other, mostly non-steroidal compounds with (presumed) positive effects on muscle mass and function. While exogenous substances can easily be detected by gas/liquid chromatography and mass spectrometry, significantly more complex methodologies including the longitudinal monitoring of individual urinary steroid concentrations/ratios and isotope ratio mass spectrometry are required to provide evidence for the exogenous administration of endogenous compounds. This narrative review summarizes the efforts made within the last 5 years to further improve the detection of anabolic agents in doping control samples. Different approaches such as the identification of novel metabolites and biomarkers, the acquisition of complementary mass spectrometric data, and the development of new analytical strategies were employed to increase method sensitivity and retrospectivity while simultaneously reducing method complexity to facilitate a higher and faster sample throughput.

Human Sulfotransferase Assays With PAPS Production in situ

For in vitro investigations on human sulfotransferase (SULT) catalyzed phase II metabolism, the costly cofactor 3′-phosphoadenosine-5′-phosphosulfate (PAPS) is generally needed. In the present study, we developed and optimized a new approach that combines SULT-dependent biotransformation using recombinant and permeabilized fission yeast cells (enzyme bags) with PAPS production in situ applying quality by design principles. In the initial application of the procedure, yeast cells expressing human SULT1A3 were used for the production of 4′-hydroxypropranolol-4-O-sulfate from 4-hydroxypropranolol. The optimized protocol was then successfully transferred to other sulfonation reactions catalyzed by SULT2A1, SULT1E1, or SULT1B1. The concomitant degradation of some sulfoconjugates was investigated, and further optimization of the reaction conditions was performed in order to reduce product loss. Also, the production of stable isotope labelled sulfoconjugates was demonstrated utilizing isotopically labelled substrates or ³⁴S-sulfate. Overall, this new approach results in higher space-time yields while at the same time reducing experimental cost.

Profiling Urinary Sulfate Metabolites With Mass Spectrometry

The study of urinary phase II sulfate metabolites is central to understanding the role and fate of endogenous and exogenous compounds in biological systems. This study describes a new workflow for the untargeted metabolic profiling of sulfated metabolites in a urine matrix. Analysis was performed using ultra-high-performance liquid chromatography-high resolution tandem mass spectrometry (UHPLC-HRMS/MS) with data dependent acquisition (DDA) coupled to an automated script-based data processing pipeline and differential metabolite level analysis. Sulfates were identified through k-means clustering analysis of sulfate ester derived MS/MS fragmentation intensities. The utility of the method was highlighted in two applications. Firstly, the urinary metabolome of a thoroughbred horse was examined before and after administration of the anabolic androgenic steroid (AAS) testosterone propionate. The analysis detected elevated levels of ten sulfated steroid metabolites, three of which were identified and confirmed by comparison with synthesised reference materials. This included 5α-androstane-3β,17α-diol 3-sulfate, a previously unreported equine metabolite of testosterone propionate. Secondly, the hydrolytic activity of four sulfatase enzymes on pooled human urine was examined. This revealed that Pseudomonas aeruginosa arylsulfatases (PaS) enzymes possessed higher selectivity for the hydrolysis of sulfated metabolites than the commercially available Helix pomatia arylsulfatase (HpS). This novel method provides a rapid tool for the systematic, untargeted metabolic profiling of sulfated metabolites in a urinary matrix.

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 17β-hydroxymethyl-17α-methyl-18-nor-androst-1,4,13-trien-3-one and 17α-hydroxymethyl-17β-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.

Enabling the inclusion of non-hydrolysed sulfated long term anabolic steroid metabolites in a screening for doping substances by means of gas chromatography quadrupole time-of-flight mass spectrometry

The World Anti-Doping Agency (WADA) publishes yearly their prohibited list, and sets a minimum required performance limit for each substance. To comply with these stringent requirements, the anti-doping laboratories have at least two complementary methods for their initial testing procedure (ITP), one using gas chromatography - mass spectrometry (GC-MS) and the other using liquid chromatography-MS (LC-MS). Anabolic androgenic steroids (AAS) have in previous years consistently been listed as the most frequently detected class of compounds. Over the last decade, evidence has emerged where a longer detection time is attained by focusing on sulfated metabolites of AAS instead of the conventional gluco-conjugated metabolites. Despite a decade of research on sulphated AAS using LC-MS, no LC-MS ITP has been developed that combines this class of compounds with the other mandatory targets. Such combination is essential for economical purposes. Recently, it was demonstrated that the direct injection of non-hydrolysed sulfates is compatible with GC-MS. Using this approach and by taking full use of the open screening capabilities of the quadrupole time of flight MS (QTOF-MS), this work describes for the first time a validated ITP that allows the detection of non-hydrolysed sulfated metabolites of AAS while, simultaneously, remaining capable of detecting a vast range of other classes of compounds, as well as the quantification of endogenous steroids, as required for an ITP compliant with the applicable WADA regulations. The method contains 263 compounds from 9 categories, including stimulants, narcotics, anabolic androgenic steroids and beta-blockers. Additionally, the advantages of the new method were illustrated by analysing excretion samples of drostanolone, mesterolone and metenolone. No negative effects were observed for the conventional markers and the detection time for mesterolone and metenolone increased by up to 150% and 144%, respectively compared to conventional markers.

Detection of anabolic androgenic steroid use by elite athletes and by members of the general public

Because national and international sports competitions are sources of community pride and financial revenue, there have been great efforts to prevent and detect the use of performance-enhancing drugs such as anabolic androgenic steroids by elite athletes. The World Anti-Doping Agency and its national affiliate anti-doping agencies have created sophisticated monitoring systems and advanced testing techniques to detect the use of banned substances including anabolic androgenic steroids by participants in international and national athletic competitions. The creation of a longitudinal monitoring program known as the biological passport is a recent, important development in the efforts to prevent and detect the use of banned performance-enhancing drugs and methods. The biological passport program consists of the measurement of urinary and blood markers of anabolic androgenic steroid use (and other banned drugs or methods) at baseline and at random times. A panel of experts reviews the longitudinal data and interprets the likelihood of the use of banned drugs and methods. These advances in anti-doping appear to be highly effective, but some athletes persist in their efforts to cheat the detection process. In addition, some members of the general public use anabolic androgenic steroids for a variety of reasons including to improve physical appearance or to enhance performance in athletics. Clinicians must depend on clinical acumen and the measurement of serum testosterone and gonadotropins to guide them in making a tentative diagnosis of anabolic androgenic steroid use. Definitive diagnosis requires that the patient disclose the use of the drugs. Because anabolic androgenic steroids are effective for improving certain aspects of physical performance, some elite athletes (and members of the general public) will continue to use these drugs. Effective efforts to curtail the use of these drugs will require decreasing the ease of access to them, continued advancements in laboratory techniques, and perhaps a shift in societal approbation for athletic performance and muscular appearance.

Ionization and collision induced dissociation of steroid bisglucuronides

Studies on steroid metabolism are of utmost importance to improve the detection capabilities of anabolic androgenic steroids (AASs) misuse in sports drug testing. In humans, glucuronoconjugates are the most abundant phase II metabolites of AAS. Bisglucuronidation is a reaction where two separated functional groups on the same molecule are conjugated with glucuronic acid. These metabolites have not been studied in depth for steroids and could be interesting markers for doping control. The aim of the present work was to study the ionization and collision-induced dissociation of steroid bisglucuronides to be able to develop mass spectrometric analytical strategies for their detection in urine samples after AAS administration. Because steroid bisglucuronides are not commercially available, 19 of them were qualitatively synthesized to study their mass spectrometric behavior. Bisglucuronides ionized as [M+NH₄ ]⁺ in positive mode, and as [M-H]^- and [M-2H]^2- in negative mode. The most specific product ions of steroid bisglucuronides in positive mode resulted from the neutral losses of 387 and 405 Da (corresponding to [M+NH₄ -NH₃ -2gluc-H₂ O]⁺ and [M+NH₄ -NH₃ -2gluc-2H₂ O]⁺ , respectively, being "gluc" a dehydrated glucuronide moiety), and in negative mode, the fragmentation of [M-2H]^2- showed ion losses of m/z 175 and 75 (gluc^- and HOCH₂ CO₂^- , respectively). On the basis of the common behavior, a selected reaction monitoring method was developed to detect bisglucuronide metabolites in urine samples. As a proof of concept, urines obtained after administration of norandrostenediol were studied, and a bisglucuronide metabolite was detected in those urines. The results demonstrate the usefulness of the analytical strategy to detect bisglucuronide metabolites in urine samples, and the formation of these metabolites after administration of AAS.