Investigation of Equine In Vivo and In Vitro Derived Metabolites of the Selective Androgen Receptor Modulator (SARM) ACP-105 for Improved Doping Control.
Abstract: Selective Androgen Receptor Modulators (SARMs) have anabolic properties but less adverse effects than anabolic androgenic steroids. They are prohibited in both equine and human sports and there have been several cases of SARMs findings reported over the last few years. The aim of this study was to investigate the metabolite profile of the SARM ACP-105 (2-chloro-4-[(3-endo)-3-hydroxy-3-methyl-8-azabicyclo[3.2.1]oct-8-yl]-3-methylbenzonitrile) in order to find analytical targets for doping control. Oral administration of ACP-105 was performed in horses, where blood and urine samples were collected over a time period of 96 h. The in vivo samples were compared with five in vitro incubation models encompassing , microsomes and S9 fractions of both human and equine origin. The analyses were performed using ultra-high performance liquid chromatography coupled to high resolution Q Exactive Orbitrap mass spectrometry (UHPLC-HRMS). A total of 21 metabolites were tentatively identified from the in vivo experiments, of which several novel glucuronides were detected in plasma and urine. In hydrolyzed urine, hydroxylated metabolites dominated. The in vitro models yielded several biotransformation products, including a number of monohydroxylated metabolites matching the in vivo results. The suggested analytical target for equine doping control in plasma is a dihydroxylated metabolite with a net loss of two hydrogens. In urine, the suggested targets are two monohydroxylated metabolites after hydrolysis with β-glucuronidase, selected both due to prolongation of the detection time and the availability of reference material from the in vitro models.
Publication Date: 2021-02-01 PubMed ID: 33535528PubMed Central: PMC7912737DOI: 10.3390/metabo11020085Google Scholar: Lookup
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Summary
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This research article reports on a study investigating the metabolic breakdown of a Selective Androgen Receptor Modulator (SARM) known as ACP-105 in horses to help improve doping control in equine sports. The study identified potential target metabolites in horse urine and blood that could be used to detect the use of this substance.
Objective of the Research
- The objective of this study was to analyze the metabolic profile or breakdown of the Selective Androgen Receptor Modulator (SARM) called ACP-105. This was done with the goal of identifying analytical targets to improve doping controls in equine sports.
Method of the Research
- The study involved oral administration of ACP-105 to horses and then collecting blood and urine samples over a 96-hour period.
- The in vivo samples (those taken from the living organism, in this case, the horses) were compared with in vitro samples (those prepared in a controlled environment outside a living organism).
- The in vitro models were generated using microsomes and S9 fractions (components of cell biology) of both human and equine origin.
- The analyses of the samples were conducted using ultra-high performance liquid chromatography coupled to high resolution Q Exactive Orbitrap mass spectrometry (UHPLC-HRMS), a powerful analytical method for identifying chemical compounds.
Findings of the Research
- In the in vivo experiments, a total of 21 metabolites (products of metabolism) of ACP-105 were identified, including several novel glucuronides (compounds resulting from the body’s detoxification processes).
- In hydrolyzed urine (urine that has been broken down chemically), hydroxylated metabolites (compounds gained an OH group) predominantly resulted.
- The in vitro models yielded a number of biotransformation products, including multiple monohydroxylated metabolites, providing confirmation for the in vivo results.
- The proposed targets for detecting ACP-105 in equine blood are a type of dihydroxylated metabolite, which loses two hydrogen atoms in metabolic processes. For equine urine, the suggested targets are two monohydroxylated metabolites after they have been hydrolyzed with β-glucuronidase, which were selected due to their potential for extending the detection time and the availability of reference materials from the in vitro models.
Importance of the Research
- The findings from this research contribute valuable insights into the metabolites produced from the use of the SARM ACP-105 in horses, which can aid the development of more effective doping controls in equine sports.
- The proposed metabolic targets in horse blood and urine offer new ways to test for the presence of this substance, potentially leading to improved fairness and integrity in equine sports.
Cite This Article
APA
Broberg MN, Knych H, Bondesson U, Pettersson C, Stanley S, Thevis M, Hedeland M.
(2021).
Investigation of Equine In Vivo and In Vitro Derived Metabolites of the Selective Androgen Receptor Modulator (SARM) ACP-105 for Improved Doping Control.
Metabolites, 11(2), 85.
https://doi.org/10.3390/metabo11020085 Publication
Researcher Affiliations
- Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123 Uppsala, Sweden.
- Kenneth L. Maddy Equine Analytical Pharmacology Laboratory, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
- Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123 Uppsala, Sweden.
- Department of Chemistry, Environment and Feed Hygiene, National Veterinary Institute (SVA), SE-75189 Uppsala, Sweden.
- Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123 Uppsala, Sweden.
- Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
- Institute of Biochemistry, Center for Preventive Doping Research, German Sport University, 50933 Cologne, Germany.
- Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123 Uppsala, Sweden.
Conflict of Interest Statement
The authors declare no conflict of interest.
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Citations
This article has been cited 4 times.- Vignali JD, Pak KC, Beverley HR, DeLuca JP, Downs JW, Kress AT, Sadowski BW, Selig DJ. Systematic Review of Safety of Selective Androgen Receptor Modulators in Healthy Adults: Implications for Recreational Users. J Xenobiot 2023 May 10;13(2):218-236.
- Monti MC, Scheurer E, Mercer-Chalmers-Bender K. Phase I In Vitro Metabolic Profiling of the Synthetic Cannabinoid Receptor Agonists CUMYL-THPINACA and ADAMANTYL-THPINACA. Metabolites 2021 Jul 21;11(8).
- Fijałkowska O, Jurowski K. First multifaceted ADME profile of ACP-105 (CAS: 1048998-11-3): a novel non-steroidal selective androgen receptor modulator used as doping in sports-integrative in silico toxicological studies for clinical and forensic toxicology purposes. Arch Toxicol 2025 Dec;99(12):5047-5063.
- Fijałkowska O, Jurowski K. Toxicity of ACP-105: a substance used as doping in sports: application of in silico methods for prediction of selected toxicological endpoints. Arch Toxicol 2025 Apr;99(4):1485-1503.
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