The absorption characteristics of silybin in small intestine of rat

AimTo investigate the intestinal absorption of silybin (SLB) in male rats. Methods Single-pass intestinal perfusion (SPIP) technique was performed in each isolated region of the small intestine at a flow rate of 0.1 mL·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^effB at 190 μg·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 μg·mL^-1). The concentration dependent changes of k_a and P_{ere-1, ka and Peff were different from the values at either of the two higher concentrations (190 and 300 μg·mL^-1, P<0.05). However there was no difference between 190 μg·mL^-1 and 300 μg·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.}