The development of chemotherapoetic agents for periodontitis utilizing local drug delivery system.

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This study was conducted to establish the new chemotherapeutic agents for periodontal diseases utilizing the local drug delivery system. Sparfloxacin (SPFX) was selected as anti-bacterial agent for this new agent because of its superior anti-bacterial activity against periodontopathic bacteria. We examined the controlled release activity of various matrices in our preliminary studies. Among them, non-hydrated gel based on copoly{lactic/glycolic}acid showed the best characteristics for its purpose. According to this result, test reagent was prepared by mixing 2% SPFX with copoly {lactic/glycolic}acid. In vitro experiments to evaluate the persistence of this test reagent showed that the drug releasing lasted for 17 days until it was completely disappeared, following the initial burst and gradual decrease of releasing rate. The continuity of SPFX releasing in the periodontal pocket using this reagent was also examined. When the non-controlled reagent was applied, the SPFX concentration in … More the pockets was declined in 24 hours under MBC90(minimum bactericidal concentration) against clinically isolated A.a. and P.g.. In contrast, test reagont retained SPFX at the concentration of 4 mg/ml even 72 hours after application in the periodontal pocket and kept the drug level over MBC90 against A.a. and P.g.. These results suggested that this test reagent demonstrate the effective drug concentration in periodontal pocket for longer period than previously developed reagents. Then we evaluated the clinical effects of topical application of this reagent for pretreated periodontal pockets. The clinical parameters of the tested sites 1 week after the application, where the controlled release-drug was applied, was significantly improved in comparison with the sites where non-controlled release-drug or matrix alone was applied. However, when no further periodontal treatment was done, the clinical parameters of the tested sites got close to the value of the control sites and finally the value of both sites became similar 12 weeks after the application. On the other hand, the analysis of subgingival micro flora showed the decrease of both the positive rate of P.g. and Spirochete, and the frequency of P.g. positive sites at 1 and 4 weeks after the application. Finally, the combined effect of root plaining and drug application was studied. The clinical feature and the sub gingival micro flora did not show any significant change between the sites of combination therapy and root plaining alone. These data show that the new reagent established in this study demonstrates more effective antibacterial activity and longer persistence than any other known reagents and evaluated as one of the unique chemotherapeutic agents for periodontitis with the feature of local drug delivery system. Less