Abstract
Orteronel is newly identified as a selective 17,20-lyase inhibitor for an agent for
castration resistant prostate cancer. The absorption and disposition of [14C]orteronel were investigated in rats and monkeys. Orteronel was extensively excreted
into rat and monkey urine in an unchanged form after oral administration. The unbound
based renal clearances in rats and monkeys were greater than the respective glomerular
filtration rates (GFR), suggesting that urinary tubular secretion plays an important
role in the renal excretion of orteronel. Therefore, the uptake of [14C]orteronel was investigated using rat kidney slices to estimate the contribution
of carrier-mediated transport on the urinary tubular secretion. The uptake study using
rat kidney slices suggested that the transport of orteronel from the blood circulation
to the kidney was mediated by a digoxin sensitive transport system represented by
Oatp4c1 and non-saturable components. Furthermore, the saturable component accounted
for a limited fraction of the total renal uptake by rat kidney slices. These results
suggested that non-saturable uptake mainly contributed to the renal excretion of orteronel
in rats.
Key words
renal clearance - oatp4c1 - glomerular filtration rate