Contributions of UDP-Glucuronosyltransferases to Human Hepatic and Intestinal Metabolism of Ticagrelor and Inhibition of UGTs and Cytochrome P450 Enzymes by Ticagrelor and its Glucuronidated Metabolite.

Shuaibing Liu,Xiaojian Zhang,Yibo Zhao,Lei Hou,Xia Yao,Xin Tian,Cai Li

doi:10.3389/fphar.2021.761814

Shuaibing Liu, Xiaojian Zhang + Show 5 more

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https://doi.org/10.3389/fphar.2021.761814

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Abstract

Ticagrelor is the first reversibly binding, direct-acting, oral P2Y12 receptor inhibitor. The contribution of UDP-glucuronosyltransferases (UGTs) enzymes to the metabolism of ticagrelor to its glucuronide conjugation, ticagrelor-O-glucuronide, in human liver microsomes (HLM) and human intestinal microsomes (HIM), was well characterized in the current study. The inhibition potential of human major UGTs by ticagrelor and ticagrelor-O-glucuronide was explored. The inhibitory effects of ticagrelor-O-glucuronide on cytochrome P450s (CYPs) enzymes were investigated as well. Ticagrelor glucuronidation exhibits substrate inhibition kinetics in both HLM and HIM with apparent Km values of 5.65 and 2.52 μM, Vmax values of 8.03 and 0.90 pmol min−1·mg protein−1, Ksi values of 1,343.0 and 292.9 respectively. The in vitro intrinsic clearances (V max/K m) for ticagrelor glucuronidation by HLM and HIM were 1.42 and 0.36 μl min−1·mg protein−1, respectively. Study with recombinant human UGTs suggested that multiple UGT isoforms including UGT1A9, UGT1A7, UGT1A3, UGT1A4, UGT1A1, UGT2B7 and UGT1A8 are involved in the conversion of ticagrelor to ticagrelor-O-glucuronide with UGT1A9 showing highest catalytic activity. The results were further supported by the inhibition studies on ticagrelor glucuronidation with typical UGT inhibitors in pooled HLM and HIM. Little or no inhibition of UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A9 and UGT2B7 by ticagrelor and ticagrelor-O-glucuronide was noted. Ticagrelor-O-glucuronide also exhibited limited inhibitory effects toward CYP2C8, CYP2D6 and CYP3A4. In contrast, ticagrelor-O-glucuronide weakly inhibited CYP2B6, CYP2C9 and CYP2C19 activity with apparent IC50 values of 45.0, 20.0 and 18.8 μM, respectively. The potential of ticagrelor-O-glucuronide to cause drug-drug interactions warrant further study.

Highlights

P2Y12 receptor inhibitors remain the cornerstone of the antiplatelet therapy in patients with acute coronary syndromes
The ticagrelor glucuronidation was firstly investigated by selecting various concentrations of ticagrelor utilizing pooled human liver microsomes (HLM) and human intestinal microsomes (HIM)
The results indicated that the formation of ticagrelor glucuronidation was best described by substrate inhibition kinetics (Figure 2) with apparent Km values of 5.65

Summary

INTRODUCTION

P2Y12 receptor inhibitors remain the cornerstone of the antiplatelet therapy in patients with acute coronary syndromes. 19 functional human UGTs have been identified. They are classified into subfamilies, 1A, 2A, and 2B according to gene structure and sequence homology (Mackenzie et al, 2005). Liver and intestine are the major organs mediating the first-pass metabolism of drugs that are substrates of UGTs. Distinct, but overlapping substrate and inhibitor selectivities have been documented for the individual UGT enzymes (Tukey and Strassburg, 2000; Kiang et al, 2005). Reference standard of ticagrelor O-Glu (purity 96.5%) and trifluoperazine N-glucuronide (purity>96%) were purchased from TLC Pharmachem (Concord, ON, Canada). Testosterone (purity >98%) was purchased from European Pharmacopoeia. 6β-hydroxy testosterone

MATERIALS AND METHODS

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DATA AVAILABILITY STATEMENT