Doping control approach: Identification of equine in vitro metabolites of voxelotor (GBT440), a hemoglobin S polymerization inhibitor.
Abstract: Sickle cell disease, a debilitating genetic disorder affecting numerous newborns globally, has historically received limited attention in pharmaceutical research. However, recent years have witnessed a notable shift, with the Food and Drug Administration approving three innovative disease-modifying medications. Voxelotor, also known as GBT440, is a promising compound that effectively prevents sickling, providing a safe approach to alleviate chronic hemolytic anemia in sickle cell disease. It is a novel, orally bioavailable small molecule that inhibits hemoglobin S polymerization by enhancing oxygen affinity to hemoglobin. The investigation demonstrated that voxelotor led to an unintended elevation of hemoglobin levels in healthy individuals by increasing serum erythropoietin levels. Methods: Voxelotor and its metabolites in an in vitro setting utilizing equine liver microsomes were discussed. Plausible structures of the identified metabolites were inferred through the application of liquid chromatography in conjunction with high-resolution mass spectrometry. Results: Under the experimental conditions, a total of 31 metabolites were detected, including 16 phase I metabolites, two phase II metabolites, and 13 conjugates of phase I metabolites. The principal phase I metabolites were generated through processes such as hydroxylation, reduction, and dissociation. The presence of glucuronide and sulfate conjugates of the parent drug were also observed, along with hydroxylated, reduced, and dissociated analogs. Conclusions: The data acquired will accelerate the identification of voxelotor and related compounds, aiding in the detection of their illicit use in competitive sports. It is crucial to emphasize that the metabolites detailed in this manuscript were identified through in vitro experiments and their detection in an in vivo study may not be guaranteed.
© 2023 John Wiley & Sons Ltd.
Publication Date: 2023-12-21 PubMed ID: 38124165DOI: 10.1002/rcm.9671Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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Overview
- This research focuses on identifying the metabolites of voxelotor (GBT440), a drug used to treat sickle cell disease by preventing hemoglobin S polymerization, using equine liver microsomes in vitro.
- The goal is to support doping control efforts by understanding how the drug is metabolized, which could help detect its potential illicit use in sports.
Introduction to Voxelotor and Sickle Cell Disease
- Sickle cell disease is a genetic disorder characterized by abnormal hemoglobin that causes red blood cells to sickle and leads to chronic anemia and other complications.
- Voxelotor (GBT440) is a novel, orally available small molecule that inhibits the polymerization of hemoglobin S, the defective hemoglobin in sickle cell disease.
- The drug works by increasing hemoglobin’s affinity for oxygen, thereby reducing sickling of red blood cells.
- Recent FDA approvals of disease-modifying treatments like voxelotor mark significant progress in managing sickle cell disease.
- Interestingly, voxelotor has been shown to increase hemoglobin levels in healthy people by raising levels of erythropoietin, a hormone that promotes red blood cell production.
Purpose of the Study
- To characterize the metabolic profile of voxelotor in an in vitro equine model, as horses are often used in doping control studies.
- To identify metabolites that could serve as biomarkers for detecting voxelotor use, especially in competitive sports settings where doping is a concern.
- To provide insight into the drug’s metabolic pathways and support regulatory and forensic efforts related to doping control.
Methods
- Equine liver microsomes were used as the in vitro system to simulate drug metabolism.
- Liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) was employed to detect and analyze voxelotor metabolites.
- The study involved structure elucidation of metabolites based on their mass spectrometry profiles and chromatographic behavior.
Results
- A total of 31 metabolites were detected under the experimental conditions.
- These included:
- 16 phase I metabolites, formed by modifications like hydroxylation (adding hydroxyl groups), reduction (gain of electrons or hydrogen), and dissociation (breaking of chemical bonds).
- 2 phase II metabolites, which are conjugated forms typically increasing solubility and aiding excretion.
- 13 conjugates of phase I metabolites, including glucuronide and sulfate conjugates.
- Hydroxylated, reduced, and dissociated analogues as well as glucuronide and sulfate conjugates of the parent voxelotor were identified.
Conclusions and Implications
- The identification of voxelotor metabolites in an equine in vitro system provides valuable data for doping control laboratories to detect voxelotor misuse.
- Knowing these metabolites helps create analytical methods to accurately identify drug use in athletes and prevent unfair advantages.
- The results are limited to in vitro metabolism data; actual in vivo metabolism in humans or horses might vary, so further studies are necessary for confirmation.
- The study contributes to the broader effort of ensuring fair play in sports by enabling the detection of emerging therapeutic agents like voxelotor that might be abused for performance enhancement.
Cite This Article
APA
Subhahar MB, Karakka Kal AK, Philip M, Muhammed Ajeebsanu M, Karatt TK, Perwad Z.
(2023).
Doping control approach: Identification of equine in vitro metabolites of voxelotor (GBT440), a hemoglobin S polymerization inhibitor.
Rapid Commun Mass Spectrom, 38(2), e9671.
https://doi.org/10.1002/rcm.9671 Publication
Researcher Affiliations
- Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
- Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
- Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
- Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
- Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
- Equine Forensic Unit, Central Veterinary Research Laboratory, Dubai, United Arab Emirates.
MeSH Terms
- Infant, Newborn
- Humans
- Animals
- Horses
- Hemoglobin, Sickle / chemistry
- Hemoglobin, Sickle / metabolism
- Hemoglobin, Sickle / therapeutic use
- Doping in Sports / prevention & control
- Polymerization
- Anemia, Sickle Cell / drug therapy
- Anemia, Sickle Cell / metabolism
- Benzaldehydes / pharmacology
- Benzaldehydes / therapeutic use
- Hemoglobins
- Pyrazines
- Pyrazoles
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Citations
This article has been cited 1 times.- Liang X, Tian T, Zheng Z, Geng H, Shan Y, Deng X. Metabolic profile characterization of voxelotor in human urine based on in vivo and in vitro models for doping control.. Anal Bioanal Chem 2024 Nov;416(28):6575-6588.
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