Colon-specific delivery of resveratrol: optimization of multi-particulate calcium-pectinate carrier

This study aimed at devising multi-particulate calcium-pectinate (Ca-pectinate) bead formulations for colon-targeted delivery of resveratrol. As Ca-pectinate beads were not sufficient to endure the upper GI environment and premature release of resveratrol occurred before their arrival to the colon, the beads were hardened by adding polyethyleneimine (PEI) in the cross-linking solution. The effects of PEI concentration, cross-linking time, and pectin to resveratrol ratio were investigated on beads' characteristics, encapsulation efficiency, swelling-erosion, and resveratrol retention pattern of formulated beads. Proper conditions were optimized from these studies and optimized beads were further subjected to morphological examination. Formulated beads were spherical with approximately 1 mm diameter. Addition of PEI to the cross-linking solution and a minimum cross-linking time were found to be crucial factors for colon-specific release of resveratrol. As PEI was added in the cross-linking solution, hardening of the bead surface occurred simultaneously with bead formation. Observations from the present study revealed that optimized Ca-pectinate beads hardened with PEI can efficiently encapsulate resveratrol and have potential for colon-specific delivery to the lower GI tract.