Formulation and Evaluation of Bupivacaine-Loaded Glutaraldehyde-Crosslinked High Molecular Weight Chitosan Microspheres

Purpose: To develop a chitosan microsphere carrier system of bupivacaine for buccal administration. Methods: Chitosan microspheres loaded with bupivacaine were prepared by emulsification technique based on glutaraldehyde cross-linking and drug-loaded chitosan microsphere were coated with polyglycolic acid (PGA) film The formulated microspheres were characterized by x-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and in vitro release was performed in pH 7.4 phosphate buffer both in the presence and in absence of lysozyme. Results: Encapsulation yield was 83.1 %. SEM studies indicate that the microspheres were spherical and had a relatively smooth surface. XRD and DSC data indicate that there was no interaction between the drug and polymer. In vitro results show that in the presence of lysozyme, 39 % of the drug was released from the microspheres after 4.5 days while maximum drug release (42.5 %) was achieved on day 11. This compares with 31 % drug release on 4.5 day and 38 % on 11 day; maximum drug release occurred on day 11 in the absence of lysozyme. Conclusion: It is evident from this study that microspheres can potentially be used for controlled release of of bupivacaine for the management of dental pain in the buccal cavity.