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.
