AIMTo investigate the intestinal absorption of silybin (SLB) in male rats.

METHODSSingle-pass intestinal perfusion (SPIP) technique was performed in each isolated region of the small intestine at a flow rate of 0.1 mL x min(-1). The samples of perfusate and portal plasma were collected at the designated periods of time after rat intestinal perfusion and analyzed for drug by HPLC.

RESULTSThe absorption rate constant (k(a)) and the effective permeability (P(eff)) of SLB at 190 microg x mL(-1) were determined for each segment. These data indicated the absorption rate were duodenum > jejunum > ileum > colon. SPIP was also performed in duodenum with three concentrations of SLB (80, 190 and 300 microg x mL(-1)). The concentration dependent changes of k(a) and P(eff) were evident in the duodenum perfusion of silybin. At silybin perfusate concentrations of 80 microg x mL(-1), k(a) and P(eff) were different from the values at either of the two higher concentrations (190 and 300 microg x mL(-1), P < 0.05). However there was no difference between 190 microg x mL(-1) and 300 microg x mL(-1) groups. The drug mass appearing in the plasma further indicated the absorption were duodenum > jejunum > ileum > colon.

CONCLUSIONSLB can be absorbed in whole intestinal sections. When the concentration raises to a certain level, the uptake of SLB will not increase.