Enhancement of absorption and bioavailability of echinacoside by verapamil or clove oil.

Purpose: This present study investigated the absorption kinetics of echinacoside (ECH) in situ and in vitro and its oral bioavailability in rats. Additional aim was to find an agent(s) to promote ECH absorption and oral bioavailability among two efflux proteins and three absorption promoters.

Methods: ECH absorption behaviors were investigated by everted gut sac model in vitro and single-pass intestinal perfusion model in situ.