Objective: To simulate particle system of traditional Chinese medicine decoction and to investigate effect of chitosan particles (CS-Ps) with different size on in situ intestinal absorption properties of berberine. Method: Chitosan particles with different particle size were prepared by high-voltage electrostatic spray method

its particle size and Zeta potential were evaluated by laser granularity analyzer.Intestinal absorption rate constant (Ka) and average apparent permeability (P < sub>app) of berberine were assayed by in situ intestinal perfusion model. Result: Particlesizes of CS-P1

CS-P2

and CS-P3 were (163.9±2.3)

(456.0±76.6)

(903.4±131.1) nm

Zeta potentials of them were (25.2±7.0)

(27.9±4.3)

(28.4±5.7)mV

respectively.There was no significant difference of surfacepotential value between different groups.Compared with the blank group

particlesize of CS-P1 and CS-P2 could promote intestinal absorption of berberine significantly (P < 0.05);however

CS-P3 group had no significant effect. Conclusion: Chitosan particles can promote intestinal absorption of berberine

which associated with its particle size.