Preparation of Alginate/Poly(L-Arginine)-Chitosan Ternary Complex Microcapsules

Following a polyelectrolytical complex reaction, alginate/poly(L-Arginine)-chitosan ternary complex microcapsules were prepared by coating poly(L-Arginine) and chitosan as membrane materials on calcium alginate beads, which were produced by a high-voltage electrostatic droplet generator. The influences on the diameter and uniformity of the calcium alginate beads were studied, and the optimum operating parameters were selected to produce microcapsules. The in vitro drug release behavior and pH stimuli-response of alginate/poly(L-Arginine)-chitosan ternary complex microcapsules were investigated. In comparison with alginate/chitosan microcapsules, alginate/poly(L-Arginine) microcapsules and their corresponding double-membrane microcapsules, alginate/poly(L-Arginine)-chitosan microcapsules released the macromolecular drug in a more sustained and stable way. It was found that they released 85.7% of the bovine erythrocytes hemoglobin (Hb) in 85 hours by approximate first-order kinetics in pH 6.8 PBS. While in a pH 1.0 HCl solution, only 9.6 % of the Hb was released in the first half hour and then the drug release shifted to a flat stage, which indicated that the alginate/poly(L-Arginine)-chitosan microcapsules possessed a pH stimuli-response property. The results suggest that the alginate/poly(L-Arginine)-chitosan ternary complex microcapsules might be a potential colon-targeted drug delivery system for the encapsulation of proteins.