Selective androgen receptor modulators: comparative excretion study of bicalutamide in bovine urine and faeces

Enhanced UHPLC-MS/MS screening of selective androgen receptor modulators following urine hydrolysis

Selective androgen receptor modulators (SARMs) represent non-steroidal agents commonly abused in human and animal (i.e. equine, canine) sports, with potential for further misuse as growth promoting agents in livestock-based farming. As a direct response to the real and possible implications of illicit application in both sport as well as food production systems, this study incorporated enzymatic hydrolysis (β-glucuronidase/arylsulfatase) into a previously established protocol while maintaining the minimal volume (200 µL) of urine sample required to detect SARMs encompassing various pharmacophores in urine from a range of species (i.e. equine, bovine, human, canine and rodent). The newly presented semi-quantitative UHPLC-MS/MS-based assay is shown to be fit-for-purpose, being rapid and offering high-throughput, with validation findings fulfilling criteria stipulated within relevant doping and food control legislation.•

CCβ values determined at 1 ng mL⁻¹ for majority of analytes.

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Deconjugation step included in the method led to significantly increased relative abundance of ostarine in analysed incurred urine samples demonstrating the requirement for hydrolysis to detect a total form of emerging SARMs.

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Assay amenable for use within routine testing to ensure fair play in animal and human sports and that animal-derived food is free from contamination with SARM residues.

Investigation of stability of selective androgen receptor modulators in urine

Selective androgen receptor modulators (SARMs) are a class of new emerging "designer" steroid compounds gaining popularity over more well established anabolic-androgenic steroids (AAS) amongst both non-professional and elite athletes. Moreover, due to their anabolic activity, SARM compounds may also potentially be abused in livestock animals to increase meat production. Consequently, SARM residues should be monitored as a part of routine testing employed within both anti-doping and drug residue laboratories. Since only a limited amount of information on SARM compound stability is currently available within the peer-reviewed literature, this study reports a practical approach to assess optimal storage conditions for 15 SARM compounds in solvent solutions (standard stock and intermediate mixed standard solutions) stored at -20°C for up to 1 year, as well as in a range of urine test matrices (bovine, equine, canine and human) under frozen (-20°C, -80°C) storage for up to 20 weeks and post freeze-thaw cycles. Moreover, SARM storage stability within solvent extracts was assessed at -20°C (0-4 weeks) and 4°C (0-2 weeks). Findings demonstrate that SARM analytes are stable in reference solutions when stored at -20°C, apart from PF-06260414 (stock solution) which should be stored at lower temperatures (e.g. -80°C). A limited degree of compound instability was observed for a number of SARM analytes in urine both when stored at -20°C, and after repeated freeze-thaw cycles. Moreover, SARM compounds within reconstituted urine solvent extracts were found to be effectively stable when stored for up to 4 weeks at -20°C and for 2 weeks at 4°C. The long-term stability testing data reported here will inform the more timely and effective development and validation of analytical methods for SARM residue detection and analysis, ensuring confidence in findings from monitoring of livestock animals and anti-doping processes.

Monitoring of selective androgen receptor modulators in bovine muscle tissue by ultra-high performance liquid chromatography-tandem mass spectrometry

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First UHPLC-MS/MS assay for screening of 15 emerging SARMs in muscle tissue.

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Method fully validated according to relevant EU food control legislation.

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Analyte detection capability (CCβ) determined in the range of 0.5–5 ng g⁻¹.

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Assay amenable for use within routine residue control programmes.

Selective androgen receptor modulators (SARMs) are non-steroidal compounds widely reported as drugs of abuse in human and animal sports, with potential for misuse as growth promoters in animal-based food production. In this study, a first analytical methodology to simultaneous screen for a panel of emerging SARMs in bovine muscle was developed, validated (CCβ values from 0.5–5 ng g⁻¹), and applied to detect 15 structurally diverse compounds from nine SARM families. Muscle samples (200 mg) were homogenised in extraction solvent (MeCN:H₂O, 4:1, v/v) before clean-up (end-capped C₁₈ dSPE), defatting (n-hexane pre-saturated with MeCN partitioning) and concentration prior to UHPLC-MS/MS analysis. In the absence of incurred bovine muscle, method applicability was demonstrated by the analysis of rodent muscle tissue. The developed screening assay serves as a rapid, simple and cost-effective tool for surveillance monitoring of SARM abuse in livestock production systems as a pre-emptive measure ensuring food safety.