Investigation of pectin as a carrier for oral delivery of proteins using calcium pectinate gel beads

A novel oral delivery of protein to the colon based on the polysaccharide pectin has been investigated using bovine serum albumin (BSA) as a model protein. Calcium pectinate gel (CPG) beads were prepared by extruding BSA-loaded pectin solution into agitated calcium chloride solution. Subsequent drying produced matrix beads in which BSA were embedded. In vitro experiments were conducted on the release of BSA from the CPG beads under conditions pertaining to those in vivo. Monitoring of release gives a sensitive indication of the behavior of pectin under the different conditions. The type of pectin and the presence of enzymes in the medium influence release characteristics. By changing the type of pectin it is possible to protect BSA during conditions of mouth to colon transit and susceptibility to enzymatic attack. Additionally, the release of BSA from CPG beads was strongly affected by cross-linking time but not particularly affected by the amount of protein added. The investigated factors also influenced bead sizes and entrapment efficiency. The results suggest that calcium pectinate gel beads are promising as a carrier for oral delivery of protein by means of colonic delivery. (C) 1998 Elsevier Science B.V. All rights reserved.