Drug release from chitosan beads

Abstract

In this study, chitosan beads containing sulphadiazine as a model drug were prepared by ionotropic gelation with tripolyphosphate ions. Beads containing up to 90% w/w drug loading could be prepared by this method. The efficiency of drug loading, as well as bead size, opacity and sphericity, increased with drug loading. A longer period of contact with the counterions, however, decreased bead size and efficiency of drug loading. Different drug release profiles were observed, depending on the drug loading in the beads and the dissolution medium used. In 0.1 M HCl, beads containing less than 34% w/w sulphadiazine showed a slower rate of drug release with increasing sulphadiazine content. For beads containing a drug load of more than 33% w/w, the release mechanism after 100 min in the acid medium was predominated by polymer erosion. There was no apparent erosion of the chitosan beads in simulated intestinal fluid.