Metabolic study of hypoxia-inducible factor stabilizers BAY 87-2243, MK-8617, and PT-2385 in equine liver microsomes for doping control

A number of erythropoiesis stimulants are entering the final stage of clinical trials due to recent scientific progress in hypoxia-regulated erythropoiesis. Considering how erythropoiesis-stimulating compounds enhance the capacity of the organism to transport oxygen, they pose a great risk of being misused as performance enhancers. In this paper, we report the metabolic fate of three popular hypoxia-inducible factor-prolyl hydroxylase Inhibitors (HIF-PHI) compounds, namely, BAY 87-2243, MK-8617, and PT-2385 in equine liver microsomes using Q-Exactive high-resolution mass spectrometry. This study found 22 metabolites for BAY 87-2243 (19 phase I and three phase II), three metabolites for MK-8617 (all phase I), and five metabolites for PT-2385 (two phase I and three phase II). The major findings of the present study are as follows: (1) all three potential HIF-PHI drug candidates, namely, BAY 87-2243, MK-8617, and PT-2385 are susceptible to oxidation, producing their corresponding hydroxylated metabolites; (2) the ring dissociated metabolites were detected for BAY 87-2243 and PT-2385; (3) in the case of BAY 87-2243 and PT-2385, glucuronic acid conjugated metabolites were detected; and (4) none of the drugs produced sulfonic acid conjugated metabolites.

 

Comments:

In this paper, the authors conducted a study to investigate the metabolic fate of three hypoxia-inducible factor-prolyl hydroxylase inhibitor (HIF-PHI) compounds, namely BAY 87-2243, MK-8617, and PT-2385, in equine liver microsomes. The objective of the study was to gain insights into the metabolism of these compounds using Q-Exactive high-resolution mass spectrometry. Understanding the metabolic pathways of these compounds is crucial for evaluating their potential use and detecting any misuse as performance-enhancing substances.

The researchers found that BAY 87-2243 produced a total of 22 metabolites, out of which 19 were phase I metabolites and three were phase II metabolites. Phase I metabolism involves oxidation reactions, and phase II metabolism involves conjugation reactions. MK-8617 produced three metabolites, all of which were phase I metabolites. PT-2385 produced five metabolites, two of which were phase I metabolites and three were phase II metabolites.

One of the major findings of the study was that all three HIF-PHI compounds were susceptible to oxidation, resulting in the production of their corresponding hydroxylated metabolites. This suggests that the compounds undergo metabolic transformations in the liver, which could impact their pharmacological properties and efficacy.

Additionally, the researchers observed ring dissociated metabolites for BAY 87-2243 and PT-2385. Ring dissociation is a metabolic process where a compound's ring structure is cleaved, leading to the formation of different metabolites. This finding further highlights the complexity of the metabolic pathways of these compounds.

Furthermore, glucuronic acid conjugated metabolites were detected for both BAY 87-2243 and PT-2385. Glucuronidation is a common conjugation reaction where glucuronic acid is attached to a compound, facilitating its elimination from the body. The presence of glucuronic acid conjugated metabolites suggests that these compounds undergo this metabolic pathway.

Notably, none of the drugs produced sulfonic acid conjugated metabolites. Sulfonation is another conjugation reaction where a compound is attached to a sulfate group. The absence of sulfonic acid conjugated metabolites suggests that sulfonation is not a major metabolic pathway for these HIF-PHI compounds in equine liver microsomes.

In summary, this study provides valuable insights into the metabolic fate of three HIF-PHI compounds, namely BAY 87-2243, MK-8617, and PT-2385, in equine liver microsomes. The findings reveal the occurrence of various metabolites resulting from oxidation, ring dissociation, and glucuronidation. Understanding the metabolic pathways of these compounds is essential for evaluating their potential use in medical treatments and detecting their misuse as performance-enhancing substances.