Detection and characterization of urinary metabolites of boldione by LC-MS/MS. Part I: Phase I metabolites excreted free, as glucuronide and sulfate conjugates, and released after alkaline treatment of the urine

Metabolites identification of anabolic steroid bolasterone in vitro and in rats by high resolution liquid chromatography mass spectrometry

Bolasterone (7α,17α-dimethyltestosterone) and anabolic androgenic steroids are included in the World Anti-Doping Agency's Prohibited list of substances. This study aimed to evaluate the metabolism of bolasterone through in vitro experiments using rat liver microsomes and in vivo experiments using rat urine after oral administration. Urine samples were collected over a 168-h period. Bolasterone and its metabolites were detected by liquid chromatography coupled with a Q-Exactive Obitrap mass spectrometry (LC-HRMS). Ultimately 16 hydroxylated metabolites (M1-M16), one metabolite from the reduction of the 3-keto function and 4-ene (M17), and one glucuronic acid conjugated metabolite (M18) were detected. Metabolites M17 and M18 were confirmed by comparison with available reference or authentic standards. Metabolic modifications in the structure of the parent bolasterone result in different fragmentation patterns. Based on the sensitivity of the HRMS data, characteristic ions such as m/z 121.064 (C8 H9 O) generated from ring A of the mono-hydroxylated metabolites and 121.101 (C9 H13 ) generated from ring D of the di-hydroxylated metabolites were observed that helped differentiate between the obtained metabolites. The structures of fragment ions were tentatively proposed based on their fragmentation pathways, where the significant ions were correlated to the possible structural fragments. In conclusion, new metabolites of bolasterone were detected and characterized by the use of the full-scan and dd-MS/MS using LC-HRMS, and this data can be useful for providing metabolite information for the interpretation of mass spectra of anabolic bolasterone analogues for doping screening tests.

Equine in vivo metabolite profiling of the selective androgen receptor modulator LGD-3303 for doping control

LGD-3303 is a Selective Androgen Receptor Modulator (SARM) that is prohibited in both equine and human sports due to its anabolic properties. The aim of this study was to investigate the equine in vivo metabolite profile of LGD-3303 and identify drug metabolites that can be suitable as new and improved analytical targets for equine doping control. This was performed by an oral administration of 0.05 mg·kg^-1 LGD-3303 to horses, where blood and urine samples were collected up to 96 h after administration. The in vivo samples consisting of plasma, urine and hydrolyzed urine were analyzed utilizing ultra-high performance liquid chromatography hyphenated to a Q Exactive™ Orbitrap™ high resolution mass spectrometer with a heated electrospray ionization source. A total of eight metabolites of LGD-3303 were tentatively identified, including one carboxylated and several hydroxylated metabolites in combination with glucuronic acid conjugates. A monohydroxylated metabolite is suggested as an analytical target for doping control analysis of plasma and urine after hydrolysis with β-glucuronidase, due to the high intensity and prolonged detection time in comparison to parent LGD-3303.

Liquid chromatography-mass spectrometry behavior of Girard's reagent T derivatives of oxosteroid intact phase II metabolites for doping control purposes

Intact phase II steroid metabolites have poor product ion mass spectra under collision-induced dissociation (CID) conditions. Therefore, we present herein the liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/(MS)) behavior of intact phase II metabolites of oxosteroids after derivatization. Based on the fact that Girard's reagent T (GRT), as derivatization reagent, was both convenient and efficient in terms of the enhancement in the ionization efficiency and the production of diagnostic product ions related to the steroid moiety, the latter was preferably selected between methoxamine and hydroxylamine upon the model compounds of androsterone glucuronide and androsterone sulfate. Sixteen different glucuronides and 29 sulfate conjugated metabolites of anabolic androgenic steroids (AASs), available either as pure reference materials or synthesized/extracted from administration studies, were derivatized with GRT, and their product ion spectra are presented. Product ion spectra include in all cases high number of product ions that in some cases are characteristic for certain structures of the steroid backbone. More specifically, preliminary results have shown major differences in fragmentation pattern for 17α/17β-isomers of the sulfate conjugates, but limited differentiation for 17α/17β-isomers of glucuronide conjugates and for 3α/3β- and 5α/5β-stereoisomers of both sulfate and glucuronide conjugates. Further to the suggestion of the current work, application on mesterolone administration studies confirmed-according to the World Anti-Doping Agency (WADA) TD2015IDCR-the presence of seven intact phase II metabolites, one glucuronide and six sulfates with use of LC-ESI-MS/(MS).

A further insight into methyltestosterone metabolism: New evidences from in vitro and in vivo experiments

RATIONALE

Although the metabolism of methyltestosterone (MT) has been extensively studied since the 1950s using different techniques, the aim of this study was to investigate the hydroxylation in positions C2, C4 and C6 after in vitro experiments and in vivo excretion studies using gas chromatography time-of-flight (GC/TOF) and gas chromatography/tandem mass spectrometry (GC/MS/MS). The results could be influenced by the mass spectrometric analyser used.

METHODS

Incubations were carried out with human liver microsomes and six enzymes belonging to the cytochrome P450 family using MT as a substrate. The trimethylsilyl derivatives of the samples were analysed using GC/TOF and GC/MS/MS once the correct MS/MS transitions had been selected, mainly for 6-hydroxymethyltestosterone (6-OH-MT) to avoid artefact interferences. A urinary excretion study was then performed after the administration of a 10 mg single oral dose of MT to a volunteer.

RESULTS

The formation of hydroxylated metabolites of MT in the C6, C4 and C2 positions after both in vitro and in vivo experiments was observed. Sample evaluation using GC/TOF showed an interference for 6-OH-MT that could only be resolved in GC/MS/MS by monitoring specific transitions. The transitory detection of these hydroxylated metabolites in urine agrees with previous investigations that had described this metabolic route as being of little significance.

CONCLUSIONS

In doping analysis, the formation of 4-hydroxymethyltestosterone (oxymesterone) from MT cannot be underestimated. Although it is only detected as a minor and short-term excretion metabolite, it cannot be overlooked as it was found in both in vitro and in vivo experiments. The use of a combination of different mass spectrometric instruments allowed reliable conclusions to be reached, and it was shown that special attention must be given to artefact formation.

The evolution of methods for urinary steroid metabolomics in clinical investigations particularly in childhood

The metabolites of cortisol, and the intermediates in the pathways from cholesterol to cortisol and the adrenal sex steroids can be analysed in a single separation of steroids by gas chromatography (GC) coupled to MS to give a urinary steroid profile (USP). Steroids individually and in profile are now commonly measured in plasma by liquid chromatography (LC) coupled with MS/MS. The steroid conjugates in urine can be determined after hydrolysis and derivative formation and for the first time without hydrolysis using GC-MS, GC-MS/MS and liquid chromatography with mass spectrometry (LC-MS/MS). The evolution of the technology, practicalities and clinical applications are examined in this review. The patterns and quantities of steroids changes through childhood. Information can be obtained on production rates, from which children with steroid excess and deficiency states can be recognised when presenting with obesity, adrenarche, adrenal suppression, hypertension, adrenal tumours, intersex condition and early puberty, as examples. Genetic defects in steroid production and action can be detected by abnormalities from the GC-MS of steroids in urine. New mechanisms of steroid synthesis and metabolism have been recognised through steroid profiling. GC with tandem mass spectrometry (GC-MS/MS) has been used for the tentative identification of unknown steroids in urine from newborn infants with congenital adrenal hyperplasia. Suggestions are made as to areas for future research and for future applications of steroid profiling. As routine hospital laboratories become more familiar with the problems of chromatographic and MS analysis they can consider steroid profiling in their test repertoire although with LC-MS/MS of urinary steroids this is unlikely to become a routine test because of the availability, cost and purity of the internal standards and the complexity of data interpretation. Steroid profiling with quantitative analysis by mass spectrometry (MS) after chromatography now provides the most versatile of tests of adrenal function in childhood.

Development of a multi-functional concurrent assay using weak cation-exchange solid-phase extraction (WCX-SPE) and reconstitution with a diluted sample aliquot for anti-doping analysis

RATIONALE

In addition to the development of adequate screening methods for multiple compounds, the World Anti-Doping Agency (WADA) requires anti-doping laboratories to analyze prohibited substances and their metabolites from various classes. This task presents a difficult challenge for all agencies and interests involved in the field of doping control.

METHODS

A screening method is reported in which hybrid sample preparation was performed using a combination of weak cation-exchange solid-phase extraction (WCX-SPE) and the 'Dilute and Shoot' strategy in order to take advantage of both the methodologies. Target substances were extracted using a WCX cartridge and reconstituted with a diluted sample aliquot that included 20% of an untreated urine sample. The target substances were further analyzed by high-performance liquid chromatography/triple quadrupole mass spectrometry (LC/MS).

RESULTS

The SPE procedure was optimized using a cartridge-washing step, elution conditions, and elution volume. The cartridge-washing step, which was performed using 10% methanol, improved the overall recovery of target substances. Since the recovery was observed to vary according to the pH of the eluting solution, we applied an elution step using both an acid and a basic organic solvent to achieve complementary recovery. Reconstitution of the diluted aliquot sample was performed to recover the polar substances.

CONCLUSIONS

The method was validated and applied to real samples in accordance with the external quality assessment scheme of WADA and to the previously reported samples that had provided positive test results. This novel method using hybrid sample preparation and LC/MS could be useful to screen multiple classes of the 264 targeted substances in anti-doping analysis.

Metabolomic response to coffee consumption: application to a three-stage clinical trial

BACKGROUND

Coffee is widely consumed and contains many bioactive compounds, any of which may impact pathways related to disease development.

OBJECTIVE

To identify individual metabolite changes in response to coffee.

METHODS

We profiled the metabolome of fasting serum samples collected from a previously reported single-blinded, three-stage clinical trial. Forty-seven habitual coffee consumers refrained from drinking coffee for 1 month, consumed four cups of coffee/day in the second month and eight cups/day in the third month. Samples collected after each coffee stage were subject to nontargeted metabolomic profiling using UPLC-ESI-MS/MS. A total of 733 metabolites were included for univariate and multivariate analyses.

RESULTS

A total of 115 metabolites were significantly associated with coffee intake (P < 0.05 and Q < 0.05). Eighty-two were of known identity and mapped to one of 33 predefined biological pathways. We observed a significant enrichment of metabolite members of five pathways (P < 0.05): (i) xanthine metabolism: includes caffeine metabolites, (ii) benzoate metabolism: reflects polyphenol metabolite products of gut microbiota metabolism, (iii) steroid: novel but may reflect phytosterol content of coffee, (iv) fatty acid metabolism (acylcholine): novel link to coffee and (v) endocannabinoid: novel link to coffee.

CONCLUSIONS

The novel metabolites and candidate pathways we have identified may provide new insight into the mechanisms by which coffee may be exerting its health effects.

Evaluation of markers out of the steroid profile for the screening of testosterone misuse. Part II: Intramuscular administration

In the fight against doping, the introduction of alternative markers to the steroid profile can be considered as an effective approach to improve the screening capabilities for the detection of testosterone (T) misuse. The aim of this study was to evaluate the potential of several T metabolites (cysteinyl conjugated and glucuronoconjugated resistant to enzymatic hydrolysis) to detect both the transdermal and the intramuscular administration of T. In Part I of the study, we studied the potential of these metabolites for the detection of T transdermal administration. Results revealed that resistant glucuronides can be a suitable complement to the current steroid profile. In this, Part II, dedicated to the intramuscular administration, we studied the potential of cysteinyl conjugated, resistant glucuronoconjugated and 1-cyclopentenoylglycine (1-CPG) for the detection of a single intramuscular injection of T cypionate. Possible differences in the excretion profile of all markers were explored between individuals with low basal (n=6) and medium basal (n=6) values of the testosterone/epitestosterone ratio (T/E). The results showed that all tested markers presented low intra-individual stability in basal conditions. Despite this, all glucuronoconjugated markers and 1-CPG, but not the cysteinyl conjugated markers, provided detection windows that were similar or longer than those obtained by markers currently included in the steroid profile. Based on the results obtained from the 2 parts of this study and from previously reported data, the potential applicability and the limitations of including these markers in the steroid profile are discussed.

Evaluation of markers out of the steroid profile for the screening of testosterone misuse. Part I: Transdermal administration

Although the introduction by the World Anti-Doping Agency (WADA) of the steroid module of the athlete biological passport (ABP) marked an important step forward in the screening of testosterone (T) misuse, it still remains one of the most difficult challenges in doping control analysis. The urinary determination of alternative markers has been recently reported as a promising tool for improving the screening of T oral administration. However, their evaluation for other, commonly used, administration routes is still required. The main goal of this study is the evaluation of the potential of 2 groups of metabolites (cysteinyl conjugated and glucuronoconjugated) after transdermal and intramuscular administration of T. Their suitability was evaluated in individuals with both low basal (L-T/E) and medium basal (M-T/E) values of T/E. In this Part I, we evaluated the urinary excretion profile of these 2 groups of T metabolites after the administration of 3 doses of T gel to 12 volunteers (6 L-T/E and 6 M-T/E) for 3 consecutive days. For this purpose, 9 different concentration ratios (5 cysteinyl conjugated and 4 glucuronoconjugated markers) were studied. Both, the intra-individual variability and the detection windows (DW) obtained by each ratio were evaluated. Cysteinyl conjugates showed a general low intra-individual variability and DWs that were shorter than any other tested marker. Despite the relatively large intra-individual variability, the DWs reached by glucuronoconjugates (2-3 days) were similar to those obtained by markers currently included in the ABP. Overall; this evaluation advises for the introduction of additional glucuronoconjugated markers in the screening of transdermal T administration.

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.

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-17β-hydroxymethyl-17α-methyl-5β-androsta-1,4,13-triene-3-one-17-glucuronide. One metabolite was resistant to hydrolysis with β-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.

Markers of mesterolone abuse in sulfate fraction for doping control in human urine

This manuscript describes the direct detection of mesteroloe sulfo-conjugated metabolites by liquid chromatography/quadrupole/time of flight mass spectrometry (LC/Q/TOFMS) with special focus on evaluation of their retrospective detectability and their structure elucidation. A comparison of their long-term detectability, with the mesterolone main metabolite (1α-methyl-5α-androstan-3α-ol-17-one) excreted in glucuronide fraction and detected by gas chromatography/high resolution mass spectrometry (GC/HRMS), is also presented. Studies on mesterolone were performed with samples obtained from two excretion studies after single oral administration of Proviron© by healthy volunteers. Potential sulfate metabolites were detected in post administration samples after liquid-liquid extraction (LLE) with ethyl acetate and LC/TOFMS analysis, in negative mode. Twelve mesterolone sulfate metabolites from the first excretion study and nine from the second were subsequently confirmed by LC/Q/TOFMS. Finally, six mesterolone sulfate metabolites were considered important taking into account their abundance and long-term detectability, encoded as M1, M2, M4, M5, M6 and M7. The proposed mesterolone sulfate metabolites M1, M2, M4 and M5 (excreted as sulfates) have the same retrospectivity with the main mesterolone metabolite, excreted in glucuronide fraction. For metabolite characterization, LC fractionation was performed. The metabolites were identified and characterized by GC/MS, after solvolysis and derivatization. Combined mass spectra data from trimethyl-silyl (TMS), TMS-enolTMS and methoxime-TMS derivatives were taken into account for the characterization of these metabolites. It was concluded that M1 is 1α-methyl-5α-androstan-3β-ol-17 one, M2 is 1α-methyl-5α-androstan-3α-ol-17 one, M4 is 1α-methyl-5a-androstan-3β, 16z-diol-17-one, M5 is 1α-methyl-5α-androstan-17z,4ξ-diol-3one, M6 is 1α-methyl-5α-androstan-3z,6z-diol-17-one and M7 is 4z-hydroxy-1α-methyl-5α-androstan-3,17-dione.

Current status and recent advantages in derivatization procedures in human doping control

Derivatization is one of the most important steps during sample preparation in doping control analysis. Its main purpose is the enhancement of chromatographic separation and mass spectrometric detection of analytes in the full range of laboratory doping control activities. Its application is shown to broaden the detectable range of compounds, even in LC–MS analysis, where derivatization is not a prerequisite. The impact of derivatization initiates from the stage of the metabolic studies of doping agents up to the discovery of doping markers, by inclusion of the screening and confirmation procedures of prohibited substances in athlete's urine samples. Derivatization renders an unlimited number of opportunities to advanced analyte detection.

Comparison of sulfo-conjugated and gluco-conjugated urinary metabolites for detection of methenolone misuse in doping control by LC-HRMS, GC-MS and GC-HRMS

Methenolone (17β-hydroxy-1-methyl-5α-androst-1-en-3-one) misuse in doping control is commonly detected by monitoring the parent molecule and its metabolite (1-methylene-5α-androstan-3α-ol-17-one) excreted conjugated with glucuronic acid using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS) for the parent molecule, after hydrolysis with β-glucuronidase. The aim of the present study was the evaluation of the sulfate fraction of methenolone metabolism by LC-high resolution (HR)MS and the estimation of the long-term detectability of its sulfate metabolites analyzed by liquid chromatography tandem mass spectrometry (LC-HRMSMS) compared with the current practice for the detection of methenolone misuse used by the anti-doping laboratories. Methenolone was administered to two healthy male volunteers, and urine samples were collected up to 12 and 26 days, respectively. Ethyl acetate extraction at weak alkaline pH was performed and then the sulfate conjugates were analyzed by LC-HRMS using electrospray ionization in negative mode searching for [M-H](-) ions corresponding to potential sulfate structures (comprising structure alterations such as hydroxylations, oxidations, reductions and combinations of them). Eight sulfate metabolites were finally detected, but four of them were considered important as the most abundant and long term detectable. LC clean up followed by solvolysis and GC/MS analysis of trimethylsilylated (TMS) derivatives reveal that the sulfate analogs of methenolone as well as of 1-methylene-5α-androstan-3α-ol-17-one, 3z-hydroxy-1β-methyl-5α-androstan-17-one and 16β-hydroxy-1-methyl-5α-androst-1-ene-3,17-dione were the major metabolites in the sulfate fraction. The results of the present study also document for the first time the methenolone sulfate as well as the 3z-hydroxy-1β-methyl-5α-androstan-17-one sulfate as metabolites of methenolone in human urine. The time window for the detectability of methenolone sulfate metabolites by LC-HRMS is comparable with that of their hydrolyzed glucuronide analogs analyzed by GC-MS. The results of the study demonstrate the importance of sulfation as a phase II metabolic pathway for methenolone metabolism, proposing four metabolites as significant components of the sulfate fraction.

Current status and bioanalytical challenges in the detection of unknown anabolic androgenic steroids in doping control analysis

Androgenic anabolic steroids (AAS) are prohibited in sports due to their anabolic effects. Doping control laboratories usually face the screening of AAS misuse by target methods based on MS detection. Although these methods allow for the sensitive and specific detection of targeted compounds and metabolites, the rest remain undetectable. This fact opens a door for cheaters, since different AAS can be synthesized in order to evade doping control tests. This situation was evidenced in 2003 with the discovery of the designer steroid tetrahydrogestrinone. One decade after this discovery, the detection of unknown AAS still remains one of the main analytical challenges in the doping control field. In this manuscript, the current situation in the detection of unknown AAS is reviewed. Although important steps have been made in order to minimize this analytical problem and different analytical strategies have been proposed, there are still some drawbacks related to each approach.