In vivo and in vitro metabolism of the designer anabolic steroid furazadrol in thoroughbred racehorses.
Abstract: Furazadrol ([1',2']isoxazolo[4',5':2,3]-5α-androstan-17β-ol) is a designer anabolic androgenic steroid that is readily available via the internet. It contains an isoxazole fused to the steroid A-ring which offers metabolic stability and noteworthy anabolic activity raising concerns over the potential for abuse of this compound in equine sports. The metabolism of furazadrol was studied by in vivo and in vitro methods for the first time. Urinary furazadrol 17-sulfate and furazadrol 17-glucuronide metabolites were detected in vivo after a controlled administration and compared with synthetically-derived reference materials in order to confirm their identities. They were quantified to establish the excretion profile and a suitable limit of detection. Minor metabolites were also detected, including epifurazadrol, hydroxylated furazadrol, and hydroxylated and oxidised furazadrol, present as the sulfate and glucuronide conjugates. Phase II metabolites were subjected to enzymatic hydrolysis by Escherichia coli β-glucuronidase and Pseudomonas aeruginosa arylsulfatase to further confirm the identity of the corresponding phase I metabolites. The metabolism profile was compared to the products obtained from an in vitro phase I metabolism study, with all but two of the minor in vivo phase I metabolites observed in the in vitro system. These investigations identify the key urinary metabolites of furazadrol following oral administration, which can be incorporated into anti-doping screening and confirmation procedures.
Copyright © 2016 Elsevier B.V. All rights reserved.
Publication Date: 2016-02-26 PubMed ID: 26962720DOI: 10.1016/j.jpba.2016.02.031Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research studied the metabolism of a designer anabolic steroid called furazadrol in racehorses. It identifies key urinary metabolites which can be useful in anti-doping screenings.
Understanding Furazadrol
- Furazadrol is a designer anabolic androgenic steroid that is easily accessible over the internet.
- This compound has a unique structure, made up of an isoxazole ring fused to the A-ring of a steroid, enabling metabolic stability and significant anabolic activity.
- There have been concerns raised regarding the potential misuse of this steroid in equine sports.
In vivo and In vitro Metabolism
- For the first time, the metabolism of furazadrol was examined both in vivo (inside an organism) and in vitro (outside of a living organism).
- In the in vivo approach, furazadrol 17-sulfate and furazadrol 17-glucuronide metabolites were identified in horse urine after controlled administration.
- To confirm their identities, these metabolites were compared with synthetically derived reference materials.
- Excretion profiles were established, and a suitable detection limit was set by quantifying these metabolites.
- Minor metabolites like epifurazadrol, hydroxylated furazadrol, and hydroxylated and oxidised furazadrol were also found.
Confirming Metabolite Identities
- The Phase II metabolites were subjected to enzymatic hydrolysis, a process that breaks down compounds using enzymes, to confirm the identities of the corresponding Phase I metabolites.
- The enzymes used for this process were β-glucuronidase from Escherichia coli and arylsulfatase from Pseudomonas aeruginosa.
- The in vivo metabolism profile was then compared to the results obtained from the in vitro phase I metabolism study.
- All but two of the minor in vivo phase I metabolites were observed in the in vitro system.
Anti-Doping Implications
- The findings from this research are significant because they identify the key urinary metabolites of furazadrol after oral administration.
- This opens up the potential for these metabolites to be included in anti-doping screening and confirmation procedures, helping to maintain the integrity of equine sports.
Cite This Article
APA
Waller CC, Cawley AT, Suann CJ, Ma P, McLeod MD.
(2016).
In vivo and in vitro metabolism of the designer anabolic steroid furazadrol in thoroughbred racehorses.
J Pharm Biomed Anal, 124, 198-206.
https://doi.org/10.1016/j.jpba.2016.02.031 Publication
Researcher Affiliations
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
- Racing NSW-Australian Racing Forensic Laboratory, Sydney, NSW, 2000, Australia.
- Racing NSW-Australian Racing Forensic Laboratory, Sydney, NSW, 2000, Australia.
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia. Electronic address: malcolm.mcleod@anu.edu.au.
MeSH Terms
- Anabolic Agents / pharmacokinetics
- Androstanes / pharmacokinetics
- Animals
- Designer Drugs
- Horses
- In Vitro Techniques
- Male
- Reference Standards
Citations
This article has been cited 1 times.- Fitzgerald CCJ, Hedman R, Uduwela DR, Paszerbovics B, Carroll AJ, Neeman T, Cawley A, Brooker L, McLeod MD. Profiling Urinary Sulfate Metabolites With Mass Spectrometry.. Front Mol Biosci 2022;9:829511.
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