Identification of Carboxylesterase-Dependent Dabigatran Etexilate Hydrolysis

Abstract

Dabigatran etexilate (DABE) is an oral prodrug that is rapidly converted to the active thrombin inhibitor, dabigatran (DAB), by serine esterases. The aims of the present study were to investigate the in vitro kinetics and pathway of DABE hydrolysis by human carboxylesterase enzymes, and the effect of alcohol on these transformations. The kinetics of DABE hydrolysis in two human recombinant carboxylesterase enzymes (CES1 and CES2) and in human intestinal microsomes and human liver S9 fractions were determined. The effects of alcohol (a known CES1 inhibitor) on the formation of DABE metabolites in carboxylesterase enzymes and human liver S9 fractions were also examined. The inhibitory effect of bis(4-nitrophenyl) phosphate on the carboxylesterase-mediated metabolism of DABE and the effect of alcohol on the hydrolysis of a classic carboxylesterase substrate (cocaine) were studied to validate the in vitro model. The ethyl ester of DABE was hydrolyzed exclusively by CES1 to M1 (K m 24.9 6 2.9 mM, V max 676 6 26 pmol/min per milligram protein) and the carbamate ester of DABE was exclusively hydrolyzed by CES2 to M2 (K m 5.5 6 0.8 mM; V max 71.1 6 2.4 pmol/min per milligram protein). Sequential hydrolysis of DABE in human intestinal microsomes followed by hydrolysis in human liver S9 fractions resulted in complete conversion to DAB. These results suggest that after oral administration of DABE to humans, DABE is hydrolyzed by intestinal CES2 to the intermediate M2 metabolite followed by hydrolysis of M2 to DAB in the liver by CES1. Carboxylesterase-mediated hydrolysis of DABE was not inhibited by alcohol.

Sacubitril Is Selectively Activated by Carboxylesterase 1 (CES1) in the Liver and the Activation Is Affected by CES1 Genetic Variation

“…The CL int value for CES1-mediated sacubitril hydrolysis was determined to be 726.9 ml/mg CES1/min, which is higher than that of the established CES1 substrates d-methylphenidate (35.6 ml/mg CES1/min) and dabigatran etexilate (27.2 ml/mg CES1/min), suggesting sacubitril is a highly efficient CES1 substrate (Sun et al, 2004;Laizure et al, 2014).…”

Association between statin use and ischemic stroke or major hemorrhage in patients taking dabigatran for atrial fibrillation

“…1 Once absorbed, dabigatran etexilate is metabolized to the pharmacologically active direct thrombin inhibitor dabigatran by carboxylesterase enzymes. 2,3 The bioavailability of dabigatran is low (6.5%), in part because intestinal absorption of the prodrug is opposed by P-glycoprotein, a multidrug efflux transporter. 4 Importantly, P-glycoprotein and carboxylesterase are subject to inhibition by other drugs in the same manner as hepatic cytochrome P450 enzymes.…”

Cytochrome P450 and Non-Cytochrome P450 Oxidative Metabolism: Contributions to the Pharmacokinetics, Safety, and Efficacy of Xenobiotics

“…Much of the recent work on CESs has focused on the expression and regulation of the enzymes (CES1 and CES2). In terms of drug metabolism, efforts to characterize the CES-dependent pathways of compounds such as dabigatran etexilate, sacubitril, cabazitaxel, and angiotensin-converting enzyme inhibitors (e.g., ramipril and trandolapril) have been reported in recent years (Laizure et al, 2014;Thomsen et al, 2014;Tang et al, 2015;Shi et al, 2016) Furthermore, in vitro methods aimed at identifying selective CES inhibitors to use for human esterase phenotyping efforts and those to compare CES activity in immortalized cell lines from liver, intestine, and kidney sources have been undertaken (Lamego et al, 2015;Umehara et al, 2016).…”