Abstract
In the study, we intend to design a suitable localized drug delivery system (LDDS) with chitosan and poly vinyl alcohol (PVA) for treating serve periodontitis. For that, a novel formulation based on the incorporation of chitosan‐based microspheres into PVA film was prepared. As the core parts of the novel formulation, chitosan‐based microspheres were prepared form chitosan and/or carboxymethyl‐chitosan (CM‐chitosan) by using water‐in‐oil emulsification method. Then basic in vitro and in vivo experiments focusing on biocompatibility and biodegradability of the two chitosan‐based microspheres were carried out to evaluate the feasibility of the novel LDDS. In vitro tests, besides having no hemolysis, chitosan microsphere (Cs1‐Ms), and CM‐chitosan microsphere (Cs2‐Ms) have adsorbed little proteins on their surfaces. Moreover, plasma proteins adsorbed on Cs2‐Ms, most of which can easily desorbed, are much less than that adsorbed on Cs1‐Ms. This indicates that Cs2‐Ms perhaps has better biocompatibility than Cs1‐Ms. In vivo tests, Cs1‐Ms and Cs2‐Ms were subcutaneously implanted in rat to investigate the host tissue inflammatory response. Implantations of Cs1‐Ms and Cs2‐Ms induced a little more severe inflammation when compared with the implantation of PVA film. However, the difference on in vivo biocompatibility between Cs1‐Ms and Cs2‐Ms could not be confirmed by the implantation model of our experiments. Both Cs1‐Ms and Cs2‐Ms had suffered bioerosion when they were subcutaneously implanted. The hard and compact matrixes of Cs1‐Ms were degraded very slowly, and only some trifling degradation had been found until 4 weeks of implantation. In contrast, Cs2‐Ms is soft and more hydrophilic, and can be quickly degraded in a form of diffluence by the physiological circumstance. All these results suggested that Cs2‐Ms had better potentials used as core parts of the novel designed LDDS in the future developments. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009