Objective: To observe absorption characteristics of extract from Toosendan Fructus in duodenum

jejunum

ileum and colon segment by rat everted gut model. Method: Toosendanin(TSN) which was representative compositions of extract from Toosendan Fructus in rat everted gut test was detected by HPLC

and absorption rate parameter to describe absorption characteristics of TSN in different parts of intestine was calculated. Result: Absorption of TSN with different concentration was linearity in different intestines

square of coefficient correlation all exceed 0.95

which consistent with zero order absorption.K of TSN significantly increased along with raised the concentration of extract from Toosendan Fructus

indicated passive absorption.Absorption of TSN in duodenum

jejunum

ileum was quick with no significant differences

but absorption of TSN in colon was slow. Conclusion: Absorption of TSN at different sections of intestine conformed to zero order model with a pattern of passive absorption.