Investigation of in vitro generated metabolites of LGD-4033, a selective androgen receptor modulator, in homogenized camel liver for anti-doping applications

RATIONALE

The use of selective androgen receptor modulators (SARM) in sports is prohibited by the World Anti-Doping Agency (WADA) due to their potential as performance-enhancing drugs, offering an unfair advantage. LGD-4033 is a SARM known for its similarities to anabolic steroids and can be easily purchased online, leading to increased availability and misuse. Adverse analytical findings have revealed the presence of SARMs in dietary supplements. Although LGD-4033 misuse has been reported in human sports over the years, concerns also arise regarding its illicit use in animal sports, including camel racing. Although various studies have investigated the metabolism of LGD-4033 in humans, horse, and other species, there is limited research specifically dedicated to racing camels.

METHODS

This study focuses on the in vitro metabolism of LGD-4033 in homogenized camel liver using liquid chromatography-high-resolution mass spectrometry (LC-HRMS) to identify and characterize the metabolites.

RESULTS

The findings indicated the presence of 12 phase I metabolites and 1 phase II metabolite. Hydroxylation was responsible for the formation of the main phase I metabolites that were identified. A glucuronic acid conjugate of the parent drug was observed in this study, but no sulfonic acid conjugate was found. The possible chemical structures of these metabolites, along with their fragmentation patterns, were identified using MS.

CONCLUSIONS

These findings provide valuable insights into the metabolism of LGD-4033 in camels and aid in the development of effective doping control methods for the detection of SARMs in camel racing.

Comprehensive LC-HRMS metabolomics analyses for the estimation of environmental inputs of altrenogest in pig breeding

Altrenogest (ALT), a synthetic progestogen, is used in pig farming for estrus synchronization in gilts. Residues of ALT and its metabolites may reach the aquatic environment via the spread of liquid manure and may present a risk for fish and other higher aquatic organisms due to its endocrine disrupting potential. A pilot study was conducted in which spot urine samples from ALT-treated and non-medicated gilts were collected. We applied LC-HRMS analysis to perform targeted analysis of ALT and known metabolites as well as non-targeted metabolomics analyses to find previously unknown metabolites. The targeted investigation showed that glucuronide conjugates of ALT and its photo-isomerization product are main urinary metabolites of ALT in gilts. Furthermore, an unknown isomerization product of ALT was observed at trace level, whereas ALT and ALT sulfate were not found. The chemometric analysis of non-targeted data revealed a clear difference between ALT-treated gilts and control animals. Furthermore, a hydroxylated ALT glucuronide was identified as highly significant in the ALT-treated group. Additional biomarker annotation and pathway mapping revealed changes in the metabolism of ALT-treated animals which can be explained by ALT's hormonal action. This study illustrates the exceptional potential of LC-HRMS and metabolomics for the detection of potentially new environmental contaminants with high biological activity. Further advantages of the method described are the sampling during routine breeding conditions, a relatively small number of animals required and no particular stress for the animals.

Development of a Standardized Microflow LC Gradient to Enable Sensitive and Long-Term Detection of Synthetic Anabolic-Androgenic Steroids for High-Throughput Doping Controls

Synthetic androgenic anabolic steroids (AAS) are banned compounds and considered as major threats by both racing and sports international authorities. Hence, doping control laboratories are continually looking into analytical improvements to increase their detection capabilities, notably by means of emerging technologies. To enhance analytical performances for the detection of synthetic AAS such as stanozolol, specific chromatographic procedures have been developed using recent quaternary liquid chromatography technology originally designed for high-throughput standardized proteomics connected to mass spectrometry. Applying the newly designed elution procedures described in this paper to the analyses of stanozolol and its metabolites in complex matrixes revealed improved sensitivity compared to previously described high-throughput methods. Indeed, we report the consistent and reliable detection of 16β-hydroxy-stanozolol down to 10 pg/mL in equine urine and being detectable up-to 3 months after a microdosing administration. Furthermore, a five months long elimination of stanozolol and its metabolites could be monitored on horse mane sections after a single dose administration. Our work highlights novel solutions to detect AAS with improved sensitivity. The application of such developments constitutes new landmarks for doping control laboratories and could be extended to other targeted compounds in residue analysis, toxicology, and metabolomics. Based on this work, the developed chromatographic method is now freely available within the Evosep Plus program.

Possible overestimation of bisphenol analogues in municipal wastewater analyzed with GC-MS

This work for the first time showed that sulfated BPA could be directly analyzed as BPA with GC-MS after the derivatization with N,O-bis-(trimethylsilyl) trifluoroacetamide (BSTFA)+1% trimethylchlorosilane (TMCS), i.e. the deconjugation step was not necessary. This was because sulfated BPA indeed could be simultaneously deconjugated and derivatized to BPA derivative during derivatization, suggesting that any co-elution of BPA and sulfated BPA during sample extraction led to BPA overestimation in the GC-MS method with BSTFA +1% TMCS as the derivative reagent. Using BPA 4,4'-disulfates (BPA diS) as the pure standard, the co-elution phenomena of sulfated BPA was confirmed with two widely used elution solvents (i.e. methanol and ethyl acetate) or their mixed solutions with different ratios, which further suggested if only sulfated BPA existed in any wastewater sample, BPA was likely over-determined. To further confirm this finding, both influent and effluent samples collected from a local municipal wastewater treatment plant were analyzed, which clearly showed the overestimation of BPA in the two wastewaters due to co-existence of sulfated BPA in the wastewater samples. In addition to BPA, the results also showed the overestimation of other nine bisphenol analogues. As sulfated micropollutants including estrogens, androgens, phytoestrogens, etc., have been widely found in municipal wastewater, the overestimating phenomenon observed in this study may also be extended to determination of other micropollutants, which should be addressed in future.

Serial-omics characterization of equine urine

Horse urine is easily collected and contains molecules readily measurable using mass spectrometry that can be used as biomarkers representative of health, disease or drug tampering. This study aimed at analyzing microliter levels of horse urine to purify, identify and quantify proteins, polar metabolites and non-polar lipids. Urine from a healthy 12 year old quarter horse mare on a diet of grass hay and vitamin/mineral supplements with limited pasture access was collected for serial-omics characterization. The urine was treated with methyl tert-butyl ether (MTBE) and methanol to partition into three distinct layers for protein, non-polar lipid and polar metabolite content from a single liquid-liquid extraction and was repeated two times. Each layer was analyzed by high performance liquid chromatography—high resolution tandem mass spectrometry (LC-MS/MS) to obtain protein sequence and relative protein levels as well as identify and quantify small polar metabolites and lipids. The results show 46 urine proteins, many related to normal kidney function, structural and circulatory proteins as well as 474 small polar metabolites but only 10 lipid molecules. Metabolites were mostly related to urea cycle and ammonia recycling as well as amino acid related pathways, plant diet specific molecules, etc. The few lipids represented triglycerides and phospholipids. These data show a complete mass spectrometry based—omics characterization of equine urine from a single 333 μL mid-stream urine aliquot. These omics data help serve as a baseline for healthy mare urine composition and the analyses can be used to monitor disease progression, health status, monitor drug use, etc.

Replacing PAPS: In vitro phase II sulfation of steroids with the liver S9 fraction employing ATP and sodium sulfate

In vitro technologies provide the capacity to study drug metabolism where in vivo studies are precluded due to ethical or financial constraints. The metabolites generated by in vitro studies can assist anti-doping laboratories to develop protocols for the detection of novel substances that would otherwise evade routine screening efforts. In addition, professional bodies such as the Association of Official Racing Chemists (AORC) currently permit the use of in-vitro-derived reference materials for confirmation purposes providing additional impetus for the development of cost effective in vitro metabolism platforms. In this work, alternative conditions for in vitro phase II sulfation using human, equine or canine liver S9 fraction were developed, with adenosine triphosphate (ATP) and sodium sulfate in place of the expensive and unstable co-factor 3'-phosphoadenosine-5'-phosphosulfate (PAPS), and employed for the generation of six representative steroidal sulfates. Using these conditions, the equine in vitro phase II metabolism of the synthetic or so-called designer steroid furazadrol ([1',2']isoxazolo[4',5':2,3]-5α-androstan-17β-ol) was investigated, with ATP and Na₂ SO₄ providing comparable metabolism to reactions using PAPS. The major in vitro metabolites of furazadrol matched those observed in a previously reported equine in vivo study. Finally, the equine in vitro phase II metabolism of the synthetic steroid superdrol (methasterone, 17β-hydroxy-2α,17α-dimethyl-5α-androstan-3-one) was performed as a prediction of the in vivo metabolic profile.

Impact of the emergence of designer drugs upon sports doping testing

Historically, dope-testing methods have been developed to target specific and known threats to the integrity of sport. Traditionally, the source of new analytical targets for which testing was required were derived almost exclusively from the pharmaceutical industry. More recently, the emergence of designer drugs, such as tetrahydrogestrinone that are specifically intended to evade detection, or novel chemicals intended to circumvent laws controlling the sale and distribution of recreational drugs, such as anabolic steroids, stimulants and cannabinoids, have become a significant issue. In this review, we shall consider the emergence of designer drugs and the response of dope-testing laboratories to these new threats, in particular developments in analytical methods, instrumentation and research intended to detect their abuse, and we consider the likely future impact of these approaches.

In vitro metabolism of tiletamine, zolazepam and nonbenzodiazepine sedatives: Identification of target metabolites for equine doping control

Within horseracing, the detection of prohibited substance doping often requires urine analysis; hence, it is necessary to understand the metabolism of the drugs in question. Here, the previously unknown equine metabolism of eight sedatives is reported in order to provide information on target metabolites for use in doping control. Phase I metabolite information was provided by incubation with equine liver S9 fraction. In vitro techniques were chosen in order to reduce the ethical and financial issues surrounding the study of so many compounds, none of which are licensed for use in horses in the UK. Several metabolites of each drug were identified using liquid chromatography-high resolution mass spectrometric (LC-HRMS) analysis on an LTQ-Orbitrap. Further structural information was obtained by tandem mass spectrometry (MS/MS) analysis; allowing postulation of the structure of some of the most abundant in vitro metabolites. The most abundant metabolites of alpidem, etifoxine, indiplon, tiletamine, zaleplon, zolazepam, zolpidem, and zopiclone related to hydroxylation/N-oxidation, deethylation, demethylation, deethylation, hydroxylation/N-oxidation, demethylation, hydroxylation/N-oxidation and hydroxylation/N-oxidation, respectively. In many cases, further work would be required to fully elucidate the precise positioning of the functional groups involved. The results of this study provide metabolite information that can be used to enhance equine anti-doping screening methods. However, the in vitro metabolites identified are at present only a prediction of those that may occur in vivo. In the future, any positive findings of these drugs and/or their metabolites in horse urine samples could help validate these findings and/or refine the choice of target metabolites.