Abstract: Objective: To prepare a sustained-release nanoparticles loaded with PMX-53. Methods: Nanoparticles loaded with PMX-53 were prepared by a two-step desolvation process. The morphology of the nanoparticles was observed by SEM. The encapsulation rate, drug content and the drug release were tested by HPLC. RAW264.7 cells were cocultured with gingipains to simulate inflammation environment and study the anti-inflammatory effects of drug-loaded microparticles in vitro. The experiment was divided into 4 groups: control group, gingipains group, gingipains+PMX-53 (1mg/L) group, and gingipains+nanoparticles loaded with PMX-53 (4.17g/L) group. The levels of IL-1β and IL-6 were detected after 48 hours by enzyme linked immunosorbent assay (ELISA). Results: SEM revealed that nanoparticles loaded with PMX-53 were spherical and 51.24% of them were 40~60nm in diameter. Drug content was 0.24mg/g. The encapsulation rate was 46.2%. The release cycle was up to seven days. The levels of IL-1β and IL-6 of gingipains group were higher than those of control group after 48 hours by ELISA. The levels of IL-1β and IL-6 of gingipains+nanoparticles loaded with PMX-53 group and gingipains+PMX-53 group were lower than gingipains group. Furthermore, there was a significant reduction in the secretion of IL-6 of gingipains+nanoparticles loaded with PMX-53 group. Conclusion: Nanoparticles loaded with PMX-53 showed good anti-inflammatory effects.