Objective: To prepare pH-dependent total alkaloids from Coptidis Rhizoma colon targeted pellets for treatment of ulcerative colitis and finish its in vitro and in vivo release performance evaluation. Method: Acrylic resin S100(eudragit S100) and eudragit L100-55 double-coated was adopted to prepare colon targeted pellets of total alkaloids from Coptidis Rhizoma.In vitro release and in vivo site-specific drug release of this preparation were evaluated with berberine hydrochloride as index. Result: In vitro release test showed that cumulative release rate of berberine hydrochloride was less than 0.1% in artificial gastric juice after 2 h and less than 10% in artificial intestinal fluid after 4 h

but cumulative release rate in artificial colon juice after 3 h was more than 90%.In vivo test showed that coated pellets could complete arrive to the cecum or colon in rats

and began to disintegrate and release. Conclusion: Colon targeted pellets of total alkaloids from Coptidis Rhizoma can achieve targeted release in the colon.