Ionotropically Gelled Chitosan-alginate Complex Hydrogel Beads: Preparation, Characterization and In-vitro Evaluation

Prolonged release drug delivery system of stavudine was made by ionotropic gelation and polyelectrolyte complexation technique. Cross-linking reinforced chitosan-Alginate complex beads were prepared by gelation of anionic sodium alginate, the primary polymer, with oppositely charged counter ion to form beads which were further complexed with chitosan as a polyelectrolyte. The effect of this polymer on release profile of drug was studied. Beads without chitosan complexation were also made. The reaction of chitosan-alginate complex dominates the formation of skin layer on the surface of beads. Stavudine an anti-retroviral drug was selected as novel drug for the experiment. The final formulations were subjected to in-vitro evaluation and several characterization studies. Batches with alginate alone showed Higuchi model and while chitosan-alginate showed zero order release. All the batches with copolymer showed sustained the drug release more than 12 hrs whereas with alginate alone showed up to 10 hrs. Batches with chitosan coating showed maximum drug encapsulation efficiency.