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Home / Equine Research Bank / Drug Test Anal / In Vivo Metabolic Studies of 2-Hydroxyethyl Salicylate in Ho...
Drug testing and analysis2025; doi: 10.1002/dta.3885

In Vivo Metabolic Studies of 2-Hydroxyethyl Salicylate in Horses.

Abstract: 2-Hydroxyethyl salicylate (2HES), a nonsteroidal anti-inflammatory drug (NSAID), is a medication to treat musculoskeletal injuries and inflammation swelling of humans and horses. Its misuse could affect the performance of horses and mask injuries, which could pose significant health risks. In horseracing, it is reported as an adverse finding once detected in competition. The metabolism of 2HES in either human or horse has not been reported, and therefore, little is known about its metabolic fate. This paper describes the in vivo metabolism of 2HES in horse with an objective to identify the most appropriate target(s) for detecting 2HES administration. To study the elimination and biotransformation of 2HES, topical administrations were performed by giving three castrated horses (geldings) each a total of 100-g Tensolvet gel (equivalent to 5 g of 2HES). The postulated in vivo metabolites included glucuronide-conjugated 2HES (2HES-Glu) and sulphate-conjugated 2HES (2HES-SO) from Phase II conjugation possibly at hydroxyethyl moiety and salicylic acid (SA) from hydrolysis of 2HES. To control the misuse of 2HES in horses effectively, 2HES was found to be the most suitable target. Total 2HES could be detected for up to 10 days in urine, whereas free 2HES could be detected for 16 h in plasma. As the maximum concentration of SA in postadministration urine and plasma sample did not exceed its corresponding international thresholds, monitoring the amount of SA could not be used as an indicator for possible 2HES exposure.
© 2025 John Wiley & Sons Ltd.
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Publication Date: 2025-03-12 PubMed ID: 40075191DOI: 10.1002/dta.3885Google 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.

This research article details an investigative study into the metabolism and elimination of 2-Hydroxyethyl Salicylate (2HES), a nonsteroidal anti-inflammatory drug, in horses to identify suitable targets for detecting its administration.

Objectives of the Study

  • The study aims to analyse the metabolism of 2-Hydroxyethyl Salicylate (2HES) in horses to allow for efficient detection of its administration.
  • As 2HES can potentially improve a horse’s performance or mask injuries, understanding its metabolic process can help ensure the integrity of horse racing and safeguard the wellbeing of horses.

Methodology

  • To investigate the in vivo metabolism of 2HES, a topical application of a gel equivalent to 5g of 2HES was administered to three geldings (castrated horses).
  • The researchers theorised potential in vivo metabolites including glucuronide-conjugated 2HES, sulphate-conjugated 2HES, and salicylic acid resulting from the hydrolysis of 2HES.
  • They expected these metabolites to be prominent in the Phase II conjugation and hydroxyethyl moiety.

Findings

  • The researchers discovered that to control the misuse of 2HES in horses effectively, monitoring the presence of 2HES is the most suitable method.
  • They noted that total 2HES could be detected for up to 10 days in urine, whereas free 2HES could be detected for 16 hours in plasma.
  • Finally, they found that the level of salicylic acid in post-administration urine and plasma samples did not exceed the corresponding international thresholds. Hence, the quantity of salicylic acid cannot be used as an indication for possible 2HES exposure.

In conclusion, this study provides valuable insights into the metabolism of 2HES in horses. This information can guide more effective methods to detect its administration, maintain the integrity of horse races, and protect the health of horses.

Cite This Article

APA
Ho HSM, Farrington AF, Ho ENM, Wong WT. (2025). In Vivo Metabolic Studies of 2-Hydroxyethyl Salicylate in Horses. Drug Test Anal. https://doi.org/10.1002/dta.3885

Publication

Drug testing and analysis
ISSN: 1942-7611
NlmUniqueID: 101483449
Country: England
Language: English

Researcher Affiliations

Ho, Helen S M
  • Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Kowloon, Hong Kong Special Administrative Region, China.
Farrington, Adrian F
  • Department of Veterinary Clinical Services, Hong Kong Jockey Club, Sha Tin, Hong Kong Special Administrative Region, China.
Ho, Emmie N M
  • Racing Laboratory, Hong Kong Jockey Club, Sha tin Racecourse, Sha Tin, Hong Kong Special Administrative Region, China.
Wong, Wing-Tak
  • Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Kowloon, Hong Kong Special Administrative Region, China.

References

This article includes 28 references
  1. Jedziniak P, Szprengier‐Juszkiewicz T, Pietruk K, Śledzińska E, Żmudzki J. Determination of Non‐Steroidal Anti‐Inflammatory Drugs and Their Metabolites in Milk by Liquid Chromatography–Tandem Mass Spectrometry. Analytical and Bioanalytical Chemistry 403, no. 10 (2012): 2955–2963.
    doi: 10.1007/s00216-012-5860-7google scholar: lookup
  2. Göktaş EF, Kabil E, Arıöz F. Quantification and Validation of Nine Nonsteroidal Anti‐Inflammatory Drugs in Equine Urine Using Gas Chromatography–Mass Spectrometry for Doping Control. Drug Testing and Analysis 12, no. 8 (2020): 1065–1077.
    doi: 10.1002/dta.2864google scholar: lookup
  3. González G, Ventura R, Smith AK, de la Torre R, Segura J. Detection of Non‐Steroidal Anti‐Inflammatory Drugs in Equine Plasma and Urine by Gas Chromatography‐Mass Spectrometry. Journal of Chromatography A 719, no. 1 (1996): 251–264.
    doi: 10.1016/0021-9673(95)00370-3google scholar: lookup
  4. Knych HK. Nonsteroidal Anti‐Inflammatory Drug Use in Horses. Veterinary Clinics of North America: Equine Practice 33, no. 1 (2017): 1–15.
    doi: 10.1016/j.cveq.2016.11.001google scholar: lookup
  5. Fédération Équestre Internationale. Equine Prohibited Substances List—Controlled Medication. (2023).
  6. International Federation of Horseracing Authorities. Article 6A of the International Agreement on Breeding, Racing and Wagering [Online]. (2023).
  7. International Federation of Horseracing Authorities. Article 6D of the International Agreement on Breeding, Racing and Wagering [Online]. (2023).
  8. Tang PW, Crone DL. A New Method for Hydrolyzing Sulfate and Glucuronyl Conjugates of Steroids. Analytical Biochemistry 182, no. 2 (1989): 289–294.
    doi: 10.1016/0003-2697(89)90596-4google scholar: lookup
  9. Vonaparti A, Lyris E, Panderi I, Koupparis M, Georgakopoulos C. Direct Injection Horse Urine Analysis for the Quantification and Identification of Threshold Substances for Doping Control. III. Determination of Salicylic Acid by Liquid Chromatography/Quadrupole Time‐of‐Flight Mass Spectrometry. Analytical and Bioanalytical Chemistry 395, no. 5 (2009): 1403–1410.
    doi: 10.1007/s00216-009-3047-7google scholar: lookup
  10. Bury D, Griem P, Wildemann T, Brüning T, Koch HM. Urinary Metabolites of the UV Filter 2‐Ethylhexyl Salicylate as Biomarkers of Exposure in Humans. Toxicology Letters 309 (2019): 35–41.
    doi: 10.1016/j.toxlet.2019.04.001google scholar: lookup
  11. Anderson A, McConville A, Fanthorpe L, Davis J. Salicylate Poisoning Potential of Topical Pain Relief Agents: From Age Old Remedies to Engineered Smart Patches. Medicine 4, no. 3 (2017): 48.
    doi: 10.3390/medicines4030048google scholar: lookup
  12. Flomenbaum NE, Goldfrank LP, Hoffman RS, Howland MA, Lewlin NA, Nelson LS. Salicylates. Goldfrank's Toxicologic Emergencies 8th ed. (New York: McGraw‐Hill, 2006).
  13. Chyka PA, Erdman AR, Christianson G. Salicylate Poisoning: An Evidence‐Based Consensus Guideline for Out‐Of‐Hospital Management. Clinical Toxicology 45, no. 2 (2007): 95–131.
    doi: 10.1080/15563650600907140google scholar: lookup
  14. Vree TB, van Ewijk‐Beneken Kolmer EWJ, van Verwey‐Wissen CPWG, Hekster YA. Direct Gradient Reversed‐Phase High‐Performance Liquid Chromatographic Determination of Salicylic Acid, With the Corresponding glycine and Glucuronide Conjugates in Human Plasma and Urine. Journal of Chromatography B: Biomedical Sciences and Applications 652, no. 2 (1994): 161–170.
    doi: 10.1016/0378-4347(93)e0381-ygoogle scholar: lookup
  15. Dubovska D, Piotrovskij VK, Gajdos M, Krivosikova V. Pharmacokinetics of Acetylsalicylic Acid and Its Metabolites at Low Doses: A Compartmental Modeling. Methods and Findings in Experimental and Clinical Pharmacology 17, no. 1 (1995): 67–77.
  16. Uzzaman M, Chowdhury MK, Belal Hossen M. Thermochemical, Molecular Docking and ADMET Studies of Aspirin Metabolites. Frontiers in Drug, Chemistry and Clinical Research 2, no. 3 (2019): 1–5.
    doi: 10.15761/fdccr.1000130google scholar: lookup
  17. Broome TA, Brown MP, Gronwall RR, Casey MF, Meritt KA. Pharmacokinetics and Plasma Concentrations of Acetylsalicylic Acid After Intravenous, Rectal, and Intragastric Administration to Horses. Canadian Journal of Veterinary Research 67, no. 4 (2003): 297–302.
  18. Friebe M, Schumacher S, Stahl J, Kietzmann M. Synovial Distribution of “Systemically” Administered Acetylsalicylic Acid in the Isolated Perfused Equine Distal Limb. BMC Veterinary Research 9 (2013): 56.
    doi: 10.1186/1746-6148-9-56google scholar: lookup
  19. Morra P, Bartle WR, Walker SE, Lee SN, Bowles SK, Reeves RA. Serum Concentrations of Salicylic Acid Following Topically Applied Salicylate Derivatives. Annals of Pharmacotherapy 30, no. 9 (1996): 935–940.
    doi: 10.1177/106002809603000903google scholar: lookup
  20. Beaumier P, Fenwick J, Young L. Salicylic Acid in the Horse: Studies Conducted for Agriculture Canada by the Canadian Race Testing Laboratories. (Canadian Section, Association of Official Racing Chemists, Can Test Limited, Mann Testing Laboratories Ltd. and Lynn & Johnston Laboratories Inc., 1983), 12–20.
  21. Moss MS, Blay P, Houghton E. Normal and Post‐Administration Concentrations of Salicylic Acid in Thoroughbred Horses. (Hong Kong: Macmillan Publishers (HK) Limited, Hong Kong and The Royal Hong Kong Jockey Club, 1985), 97–102.
  22. Lakhani KH, Lambert M, Sluyter F, Devolz R, Maylin G, Higgins AJ. Estimation of the Critical Threshold Value for Presence of Salicylic Acid in the Urine of Thoroughbred Horses. (R & W Communications: Newmarket, 2004), 67–77.
  23. Schenk I, Machnik M, Roettgen H, Flenker U, Guddat S, Schänzer W. Evaluation of Salicylic Acid Concentrations in Horse Blood and Urine With Regard to the Actual Threshold. Proceedings of 19th International Conference of Racing Analysts and Veterinarians, Philadelphia (International Conference of Racing Analysts and Veterinarians, 2012).
  24. Tang PW, Williams JM. A Method for the Selective Release and, Hence, Assay of the Carbohydrate Moieties of Collagen. Analytical Biochemistry 142, no. 1 (1984): 37–42.
    doi: 10.1016/0003-2697(84)90513-xgoogle scholar: lookup
  25. Tang PW, Scudder P, Mehmet H, Hounsell EF, Feizi T. Sulphate Groups Are Involved in the Antigenicity of Keratan Sulphate and Mask i Antigen Expression on Their Poly‐N‐Acetyllactosamine Backbones. European Journal of Biochemistry 160, no. 3 (1986): 537–545.
    doi: 10.1111/j.1432-1033.1986.tb10072.xgoogle scholar: lookup
  26. Ho ENM, Leung DKK, Wan TSM, Yu NH. Metabolic Studies of Methenolone Acetate in Horses. Analytica Chimica Acta 540, no. 1 (2005): 111–119.
    doi: 10.1016/j.aca.2004.10.019google scholar: lookup
  27. Kwok WH, Leung GNW, Wan TSM, Curl P, Schiff PJ. Metabolic Study of Androsta‐1,4,6‐Triene‐3,17‐Dione in Horses Using Liquid Chromatography/High Resolution Mass Spectrometry. Journal of Steroid Biochemistry and Molecular Biology 152 (2015): 142–154.
    doi: 10.1016/j.jsbmb.2015.05.011google scholar: lookup
  28. Choi TLS, Wong JKY, Kwok WH, Curl P, Mechie S, Wan TSM. Metabolic Study of Methylstenbolone in Horses Using Liquid Chromatography‐High Resolution Mass Spectrometry and Gas Chromatography‐Mass Spectrometry. Journal of Chromatography A 1546 (2018): 106–118.
    doi: 10.1016/j.chroma.2018.02.041google scholar: lookup

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