Colon-targeted dexamethasone microcrystals with pH-sensitive chitosan/alginate/Eudragit S multilayers for the treatment of inflammatory bowel disease.

•Dexamethasone microcrystals with colon-targeted chitosan/alginate/Eudragit S multilayers were fabricated.•Unwanted burst release of dexamethasone was prevented in the upper gastrointestinal tract pH.•Dexamethasone was released in a sustained manner after reaching the colonic pH.•Excellent therapeutic activity was found in a mouse model of colitis.