Aseriesofcross-linkedhydrogelsforcolon-specificdrugdeliveryweresynthesizedbygraftcopolymerizationofChitosanandacrylicacidusingN,N'-methylene-bis-(acrylamide)asacross-linker.TheirswellingbehaviorindifferentpHbuffersolutionsandcolonicenzymaticdegradabilitywerestudied.TheobtainedresultsshowthatthesehydrogelshavegoodpHsensitivitywhichcanavoiddrugreleaseinstomach,andtheirswellingkineticsinstimulantintestinalenvironmentfollowsecond-orderswellingkineticsequation.Thefactorsinfluencingtheswellingkineticsincludethedegreeofcross-linkingandthecomposition,whichmaycontrolnoreleaseoralittleamountreleaseofdruginsidethehydrogelsinthesmallintestinebytailoringthesefactors.Thegelsaredegradablebycolonicenzymesandthereisacorrelativitybetweenthedegradationofnetworksandtheswellingdegreeofthegels,whichmaytriggerthereleaseofdruginthecolon.Thehydrogelsshowagreatpotentialfortheirapplicationinoralcolon-specificdrugdeliverysystem.
