The effect of polymer and CaCl(2) concentrations on the sulfasalazine release from alginate-N,O-carboxymethyl chitosan beads

In this study, pH-sensitive blended polymeric beads were prepared by ionic gelation of mixed alginate and N,O-carboxymethyl chitosan (NOCC) solutions in aqueous media containing calcium chloride. To prepare drug-loaded beads, sulfasalazine (SA) as a model drug was added to the initial aqueous polymer solution. These beads were characterized and evaluated in vitro as potential carriers for colon-specific drug delivery. A 3(2) full factorial experimental design was employed to evaluate the effect of polymer and CaCl(2) concentrations on swelling and drug release behavior of the beads in simulated gastrointestinal tract fluid. It was found that the rate of swelling and drug release decreased significantly with increasing polymer and CaCl(2) concentrations, but polymer concentration was more effective than CaCl(2) concentration. The beads prepared using 4.5% polymer concentration and 4% CaCl(2) concentration retained approximately 60% of the loaded drug before approaching the simulated colonic fluid. Based on the results, the alginate-NOCC beads prepared with high polymer concentration could be potentially suitable polymeric carriers for colon-specific delivery of SA. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2194-0517-2-10) contains supplementary material, which is available to authorized users.