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Drug testing and analysis2021; 13(6); 1203-1215; doi: 10.1002/dta.3014

Identification of Hypoxia-inducible factor (HIF) stabilizer roxadustat and its possible metabolites in thoroughbred horses for doping control.

Abstract: Hypoxia-inducible factor (HIF) stabilizer belongs to a novel class of pharmacologically active substances, which are capable of inducing the endogenous erythropoietic system. The transcriptional activator HIF has been shown to significantly increase blood hemoglobin and is well set for the treatment of anemia resulting from chronic kidney disease. This research work reports a comprehensive study of the most popular HIF stabilizer roxadustat and its metabolites in thoroughbred horse urine after oral administration. The plausible structures of the detected metabolites were postulated using liquid chromatography-high-resolution mass spectrometry. Under the experimental condition 13 metabolites (7 phase I, 1 phase II, and 5 conjugates of phase I metabolism) were positively detected (M1-M13). The major phase I metabolites identified were formed by hydroxylation. Dealkylated and hydrolyzed phase I metabolites were also observed in this study. In phase II, a glucuronic acid conjugate of roxadustat was detected as the major metabolite. The sulfonic acid conjugates were observed to be formed from phase I metabolites. The characterized in vivo metabolites can potentially serve as target analytes for doping control analysis; hence, the result is an important tool for assessing its use and abuse in competitive sport.
© 2021 John Wiley & Sons, Ltd.
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Publication Date: 2021-02-23 PubMed ID: 33569900DOI: 10.1002/dta.3014Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The article discusses a study on the HIF stabilizer, roxadustat, which enhances the body’s red blood cell production and can be used to treat anemia derived from chronic kidney disease. It details how roxadustat and its metabolites are identified in horse urine, highlighting the possibility of using these findings to prevent doping in competitive sports.

Exploration of HIF Stabilizers

  • Researchers look into hypoxia-inducible factor (HIF) stabilizers, a new class of pharmacologically active substances. These stabilizers have the ability to stimulate the body’s natural erythropoietic system, a process that involves the production of red blood cells.
  • The study primarily focuses on roxadustat, the most widely recognized HIF stabilizer. Roxadustat has been found to significantly escalate the level of blood hemoglobin, making it an effective treatment for anemia resulting from chronic kidney disease.

Roxadustat Metabolites in Thoroughbred Horses

  • In this research, the team seeks to identify roxadustat and its metabolites in the urine of thoroughbred horses after it has been orally administered. This is done through the use of liquid chromatography-high-resolution mass spectrometry.
  • While the experiment identified 13 metabolites overall (7 from phase I metabolisms, 1 from phase II, and 5 conjugates that had undergone phase I metabolism), they could only be certain about the metabolites M1-M13.
  • The majority of the phase I metabolites were found to have undergone hydroxylation. Other metabolic mechanisms such as dealkylation and hydrolyzation were also observed amongst the phase I metabolites.
  • The main metabolite from phase II metabolism is a glucuronic acid conjugate of roxadustat. There were also sulfonic acid conjugates identified, believed to have originated from phase I metabolites.

Implications for Doping Control

  • The metabolites of roxadustat detected in the horses can serve as target analytes for doping control tests. As these drugs can enhance the production of red blood cells, there’s potential for misuse in the sporting world, particularly competitive horse racing, since higher red blood cell count can theoretically improve the performance of an athlete.
  • By establishing a way to test for the use of these substances, this research provides a vital tool for ensuring the integrity of competitive sports.

Cite This Article

APA
Mathew B, Philip M, Perwad Z, Karatt TK, Caveney MR, Subhahar MB, Karakka Kal AK. (2021). Identification of Hypoxia-inducible factor (HIF) stabilizer roxadustat and its possible metabolites in thoroughbred horses for doping control. Drug Test Anal, 13(6), 1203-1215. https://doi.org/10.1002/dta.3014

Publication

Drug testing and analysis
ISSN: 1942-7611
NlmUniqueID: 101483449
Country: England
Language: English
Volume: 13
Issue: 6
Pages: 1203-1215

Researcher Affiliations

Mathew, Binoy
  • Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
Philip, Moses
  • Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
Perwad, Zubair
  • Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
Karatt, Tajudheen K
  • Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
Caveney, Marina Rodriguez
  • Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
Subhahar, Michael Benedict
  • Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
Karakka Kal, Abdul Khader
  • Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.

MeSH Terms

  • Administration, Oral
  • Animals
  • Chromatography, Liquid / methods
  • Doping in Sports / prevention & control
  • Female
  • Glycine / analogs & derivatives
  • Glycine / analysis
  • Glycine / metabolism
  • Glycine / urine
  • Horses
  • Hypoxia-Inducible Factor-Proline Dioxygenases / antagonists & inhibitors
  • Isoquinolines / analysis
  • Isoquinolines / metabolism
  • Isoquinolines / urine
  • Male
  • Substance Abuse Detection / methods
  • Tandem Mass Spectrometry / methods

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Citations

This article has been cited 4 times.
  1. Ishii H, Shibuya M, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Sato F, Kuroda T, Yamada M, Leung GN. Pharmacokinetic Study of Vadadustat and High-Resolution Mass Spectrometric Characterization of its Novel Metabolites in Equines for the Purpose of Doping Control. Curr Drug Metab 2022;23(10):850-865.
    doi: 10.2174/1389200223666220825093945pubmed: 36017833google scholar: lookup
  2. Creangă EC, Ott C, Nicolae AC, Drăgoi CM, Stan R. Roxadustat as a Hypoxia-Mimetic Agent: Erythropoietic Mechanisms, Bioanalytical Detection, and Regulatory Considerations in Sports Medicine. Curr Issues Mol Biol 2025 Sep 9;47(9).
    doi: 10.3390/cimb47090734pubmed: 41020856google scholar: lookup
  3. Jain S, Patil R, Sharma S. Bioanalysis, Analysis, Chemistry, and Pharmacological Aspects of Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors. Curr Top Med Chem 2025;25(12):1451-1466.
    doi: 10.2174/0115680266324419241227102847pubmed: 39791153google scholar: lookup
  4. Mahajan R, Samanthula G, Srivastava S, Asthana A. A critical review of Roxadustat formulations, solid state studies, and analytical methodology. Heliyon 2023 Jun;9(6):e16595.
    doi: 10.1016/j.heliyon.2023.e16595pubmed: 37346363google scholar: lookup
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