Chitosan Beads as Templates for Layer-by-Layer Assembly and their Application in the Sustained Release of Bioactive Agents

Uncoated chitosan beads and chitosan beads coated with hyaluronic acid/chitosan (HA/Ch) multilayers, were used to investigate the controlled release of gentamicin sulphate (GS). Greater encapsulation efficiency was observed for the layer—by-layer multilayer coated beads. The in vitro drug release was in a slower sustained manner compared with noncoated chitosan beads. The differences in in vitro drug release results may be explained by the barrier effect of the coating that impedes diffusion of GS and supporting complementary water uptake. These findings indicated that a slower sustained release of gentamicin can be obtained using multilayer coatings of HA/Ch on chitosan beads and that this process could be used as a drug delivery system. In addition, agglomerates of these bead could provide a porous support in tissue engineering applications.