Poster Presentation 24th International Conference of Racing Analysts and Veterinarians 2026

Incorporation of iron-chelating substances into routine doping control (130335)

Lance Brooker 1 , Lauren Kennan 1 , Joshua Klingberg 1 , Abhishek Kumar 1 , John Keledjian 1 , Martin Wainscott 2 , Gregory L Challis 3
  1. Australian Racing Forensic Laboratory, Racing NSW, Sydney, New South Wales, Australia
  2. Harness Racing New South Wales, (HRNSW), Sydney, New South Wales, Australia
  3. Department of Biochemistry and Molecular Biology and ARC Centre of Excellence for Innovations in Peptide and Protein Science, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia

Iron chelators deferiprone (Ferriprox®), deferasirox (Exjade®) and deferoxamine (Desferal®) were developed to treat iron overload originating from disease and poisoning.1 Critical for the management of human diseases such as b-thalassaemia, these substances have been shown to be effective when used alone and in combination,2 including in veterinary care.3,4

With concerns in racing surrounding the application of blood doping substances (rhEPO, Roxadustat etc) and methods (blood transfusions) we sought to investigate the inclusion of deferiprone, deferasirox and deferoxamine into routine screening procedures at the ARFL. Complicating the situation is the fact that deferoxamine, also known as desferrioxamine B, is a naturally occurring siderophore excreted, alongside several congeners, by Streptomyces bacteria.5-9 Therefore, when reporting the detection of deferoxamine in a doping control sample, the possibility of ex-vivo production by soil-derived Streptomyces species must be considered.

Although deferiprone, deferasirox and deferoxamine all chelate iron effectively, they have very different chemical structures. Their metabolism and excretion have been investigated in humans10-12 and some laboratory animal species,13 but not in horses to our knowledge. Considering the cost and difficulties of obtaining administration samples or conducting in vitro metabolism studies, we will start here by investigating detection of the parent substance only, which is likely acceptable considering the dosages required for therapeutic use. Given their structural differences, this required a specific sample preparation and instrumental analysis approach for each substance.

In this poster, we will describe the routine sample preparation procedures found applicable for each substance and the optimised instrumental analysis parameters required. LC chromatograms and mass spectra will be presented for analyte characterisation. Preliminary validation data will be outlined, facilitating a short discussion for each substance of the difficulties of incorporating iron-chelating therapeutic substances into already established routine doping control procedures.

  1. Entezari, S. et al, Iron Chelators in Treatment of Iron Overload, J. Toxicol., 2022, 4911205, https://doi.org/10.1155/2022/4911205
  2. Premawardhena, A. et al. Deferoxamine, deferasirox, and deferiprone triple iron chelator combination therapy for transfusion-dependent β-thalassaemia with very high iron overload: a randomised clinical trial. Lancet Reg. Health Southeast Asia, 2024, 30, 100495, https://doi.org/10.1016/j.lansea.2024.100495
  3. Gummery, L. et al., Two cases of hepatopathy and hyperferraemia managed with deferoxamine and phlebotomy. Equine Vet. Educ., 2019, 31, 575-581, https://doi.org/10.1111/eve.12913
  4. Elfenbein, J.R. et al, The Effects of Deferoxamine Mesylate on Iron Elimination after Blood Transfusion in Neonatal Foals, J. Vet. Intern. Med., 2010; 24, 1475-1482, https://doi.org/10.1111/j.1939-1676.2010.0621.x
  5. F. Barona-Gomez, U. Wong, A. Giannakopulos, P.J. Derrick, and G.L. Challis. Identification of a cluster of genes that directs desferrioxamine biosynthesis in Streptomyces coelicolor M145. J. Am. Chem. Soc. 2004, 126, 16282-16283, https://doi.org/10.1021/ja045774k
  6. F. Barona-Gomez, S. Lautru, F-X. Francou, J.-L. Pernodet, P. Leblond, and G.L. Challis. Multiple biosynthetic and uptake systems mediate siderophore-dependent iron acquisition in Streptomyces coelicolor and Streptomyces ambofaciens. Microbiology, 2006, 152, 3355-3366, https://doi.org/10.1099/mic.0.29161-0
  7. N. Kadi, D. Oves-Costales, F. Barona-Gomez and G.L. Challis. A new family of ATP-dependent oligomerization-macrocyclization biocatalysts. Nat. Chem. Biol. 2007, 3, 652-656, https://doi.org/10.1038/nchembio.2007.23
  8. J.L. Ronan, N. Kadi, S.A. McMahon, J.H. Naismith, L.M. Alkhalaf and G.L. Challis. Desferrioxamine biosynthesis: diverse hydroxamate assembly by substrate tolerant acyl transferase DesC. Phil. Trans. Royal Soc. B, 2018, 373, 20170068, https://doi.org/10.1098/rstb.2017.0068
  9. H.E. Augustijn, Z.L. Reitz, L. Zhang, J.A. Boot, S.S. Elsayed, G.L. Challis, M.H. Medema and G.P. van Wezel. Genome mining based on transcriptional regulatory networks uncovers a novel locus involved in desferrioxamine biosynthesis. PLOSBiology, 2025, 23, e3003183, https://doi.org/10.1371/journal.pbio.3003183
  10. Haverfield, E.V. et al, Pharmacogenomics of Deferiprone Metabolism, Blood, 2005, 106, 11, p2703, https://doi.org/10.1182/blood.V106.11.2703.2703
  11. Waldmeier, F. et al. Pharmacokinetics, Metabolism, and Disposition of Deferasirox in β-Thalassemic Patients with Transfusion-Dependent Iron Overload Who Are at Pharmacokinetic Steady State, Drug Metab. Dispos., 2010, 38, 5, 808-816, https://doi.org/10.1124/dmd.109.030833
  12. Summers, M. R. Studies in Desferrioxamine and Ferrioxamine Metabolism in Normal and Iron-Loaded Subjects, Br. J. Haematol., 1979, 42, 4, 547-555, https://doi.org/10.1111/j.1365-2141.1979.tb01167.x
  13. Bruin, G.J.M. et al. Pharmacokinetics, Distribution, Metabolism, and Excretion of Deferasirox and Its Iron Complex in Rats, Drug Metab. and Dispos., 2008, 36, 12, 2523-2538, https://doi.org/10.1124/dmd.108.022962