PT  - JOURNAL ARTICLE
AU  - Yanli Deng
AU  - Armina Madatian
AU  - Mary Beth Wire
AU  - Carolyn Bowen
AU  - Jung Wook Park
AU  - Daphne Williams
AU  - Bin Peng
AU  - Ernest Schubert
AU  - Frances Gorycki
AU  - Mark Levy
AU  - Peter D. Gorycki
TI  - Metabolism and Disposition of Eltrombopag, an Oral, Nonpeptide Thrombopoietin Receptor Agonist, in Healthy Human Subjects
AID  - 10.1124/dmd.111.040170
DP  - 2011 Sep 01
TA  - Drug Metabolism and Disposition
PG  - 1734--1746
VI  - 39
IP  - 9
4099  - http://dmd.aspetjournals.org/content/39/9/1734.short
4100  - http://dmd.aspetjournals.org/content/39/9/1734.full
SO  - Drug Metab Dispos2011 Sep 01; 39
AB  - The metabolism and disposition of eltrombopag, the first-in-class small molecule human thrombopoietin receptor agonist, were studied in six healthy men after a single oral administration of a solution dose of [14C]eltrombopag (75 mg, 100 μCi). Eltrombopag was well tolerated. The drug was quickly absorbed and was the predominant circulating component in plasma (accounting for 63% of the total plasma radioactivity). A mono-oxygenation metabolite (M1) and acyl glucuronides (M2) of eltrombopag were minor circulating components. The predominant route of elimination of radioactivity was fecal (58.9%). Feces contained approximately 20% of dose as glutathione-related conjugates (M5, M6, and M7) and another 20% as unchanged eltrombopag. The glutathione conjugates were probably detoxification products of a p-imine methide intermediate formed by metabolism of M1, which arises through cytochrome P450-dependent processes. Low levels of covalently bound drug-related intermediates to plasma proteins, which could result from the reaction of the imine methide or acyl glucuronide conjugates with proteins, were detected. The bound material contributes to the longer plasma elimination half-life of radioactivity. Renal elimination of conjugates of hydrazine cleavage metabolites (mostly as M3 and M4) accounted for 31% of the radiodose, with no unchanged eltrombopag detected in urine.