简介：Thepresentresearcheffortwasaimedtodevelopcolontargeteddrugdeliverysystem(CTDDS)ofrhubarb,herbaldrugusingamixedfilmofpectinandethylcellulose(EC).Pectinandethylcelluloseweremixedinvariousproportionstocoatthecoretablettotargetcolon.Themethanolicextractofrhubarbwasusedandthedoseoftheextractineachformulationwasfinalizedbyestimatingtheemodincontentinitbyhighperformacethinlayerchromatography(HPTLC).Invitrodrugrelease,erosionstudyinpresenceandabsenceofpectinaseenzymeandreleaseconstant(K)ofzeroorderwasmeasuredforeachformulation.Theformulationwasoptimizedbyusing32fullfactorialdesign.Formulationhaving50%pectinasacoatingpolymerwith12%coatweightwasselectedasanoptimizedformulation(OF)onthebasisof%similaritywithmaximumdesirabilitybutthisformulationwasnotabletoretardthereleaseofdruginstomachandupperintestinefully.SoitwasfurthercoatedwithEudragitS100(ES)(3%coatweight).Theoptimizedformulation,coatedwithESindicatedsignificantlaxativeactivityonloperamideinducedconstipationinrats.TheresultsrevealedthatCTDDSofrhubarbusingtwocombinedapproachesofbiodegrablemicroflora-activatedsystemandpH-sensitivesystemexhibitedapromisingcolontargetingperformance.