Protein-loaded sodium alginate and carboxymethyl cellulose beads for controlled release under simulated gastrointestinal conditions

Abstract

Network characteristics of sodium alginate and carboxymethyl cellulose, in relation to the controlled release of bovine serum albumin under simulated gastrointestinal conditions, have been examined. Small-deformation dynamic oscillation in-shear, compression testing and optical microscopy were employed to monitor the structural characteristics of polysaccharide beads as excipients for protein entrapment. Work focused on gastrointestinal functionality and controlled release utilising variable acidity and counterion addition in preparations. Beads were found to shrink in gastric and swell in intestinal conditions, thus emphasising the disparate effect of experimental conditions. Changes in mechanical properties reflected alterations in gel microstructure, with beads becoming relatively strong in the gastric environment. In contrast, networks were weakened in the intestinal environment resulting in bead disintegration towards the end of digestion time. This type of structural behaviour allows the controlled delivery of the protein, as a model bioactive, in a particular part of the gastrointestinal tract