Pharmacokinetic properties of crocin (crocetin digentiobiose ester) following oral administration in rats

This study investigated the pharmacokinetic properties of crocin following oral administration in rats. After a single oral dose, crocin was undetected while crocetin, a metabolite of crocin, was found in plasma at low concentrations. Simultaneously, crocin was largely present in feces and intestinal contents within 24 h. After repeated oral doses for 6 days, crocin remained undetected in plasma and plasma crocetin concentrations were comparable to the corresponding data obtained after the single oral dose. Furthermore, the absorption characteristics of crocin were evaluated in situ using an intestinal recirculation perfusion method. During recirculation, crocin was undetected and low concentrations of crocetin were detected in plasma. The concentrations of crocin in the perfusate were reduced through different intestinal segments, and the quantities of drug lost were greater throughout the colon. These results indicate that (1) orally administered crocin is not absorbed either after a single dose or repeated doses, (2) crocin is excreted largely through the intestinal tract following oral administration, (3) plasma crocetin concentrations do not tend to accumulate with repeated oral doses of crocin, and (4) the intestinal tract serves as an important site for crocin hydrolysis.