[CAS NO. 923604-59-5]  Simeprevir (TMC435)

In vivo, simeprevir has a relatively long absorption phase, reaching maximum concentration (Cmax) after 4-6 hours. It is extensively (99.9%) bound to plasma proteins, mainly to albumin. The absolute bioavailability is 44% after a single oral administration. In rats, The liver to blood ratio is 29:1, which means good distribution to the liver. For humans, in preclinical studies, the liver to plasma concentration ratio is really high (ratio of 39). The highest tissue/plasma AUC ratios are observed in the small intestine (ratio of 128). While tissue simeprevir concentrations reaches peak values within 4 hours postdosing, simeprevir concentrations in liver remains above the EC99 for up to 31 hours postdosing, and plasma concentrations are higher than the EC99 at 8 hours and around the EC50 at 24 hours postdosing. The AUC24h of simeprevir is increased by 61%-69% when administered with food. Simeprevir should therefore be taken with food. Simeprevir is also a substrate and inhibitor of P-glycoprotein. Simeprevir is metabolized by CYP3A4 and eliminated by biliary excretion. It is also an inhibitor of gut cytochrome 3A4 but not hepatic CYP3A4.