Objective: To prepare oxymatrine colonic localization tablets controlled by pH-dependent

colonic microflora-activated and time-dependent effects

and evaluated its release characteristics in vitro. Method: The oxymatrine colonic localization tablets were coated from inside to outside with isolated layer of HPMC and PEG6000

time-dependent layer of the mixed solution with Eudargit RS 30D and Eudargit RL 30D

enzyme-triggering layer of chitosan and Eudargit RS 30D/RL 30D

outermost enteric coating layer of Acryi-EZE.And investigated conditions of the coated tablets released in artificial gastrointestinal fluid in vitro. Result: The oxymatrine colonic localization tablets didn't release in simulated gastric fluid(pH 1.2) within 2 hours

the accumulative release was less than 10% in the simulated intestinal fluid within 6 hours

whereas it released mostly in the similated colon fluid(pH 6.0) within 8 hours. Conclusion: This study reveals that oxymatrine colon targeting tablets can delivery effectively in the specific location of colon.