Pectin-Coated Curcumin-Chitosan Microparticles Crosslinked with Mg²⁺ for Delayed Drug Release in the Digestive System

Abstract

Curcumin-loaded chitosan-pectin microparticles based on polymeric microencapsulation were prepared by two methods to delay the release of curcumin in the digestive system, employing Mg 2+ as a pectin-crosslinking agent for the first time. Pectin-coated curcumin-chitosan microparticles (C-g-P Mg ) and curcumin-loaded chitosan-pectin composite microparticles (C-P Mg -g) were formulated, and their release profiles at pH 1.2 and at pH 6.8 were tested. The former (C-g-P Mg ) showed slower curcumin release profiles than the latter (C-P Mg -g) because the C-g-P Mg are composed of two layers, a chitosan-glutaraldehyde layer and a pectin-Mg 2+ layer, which together hold the curcumin for a longer duration. Of the pectin-coated microparticles, those crosslinked with Mg 2+ showed a slower release rate than those crosslinked with Ca 2+ , but the former showed a faster release rate at pH 6.8 in the presence of pectinase, acting as a promising drug delivery carrier for treating a colonic disease. The pectin layer and the pectin-crosslinking agent play a vital role in prolonging the release of curcumin until pectin is degraded by pectinase.