Local drug delivery systems for the treatment of periodontal disease.

Filmy local drug delivery systems (LDDSs) were administered to periodontal pockets in beagles with induced periodontitis, and the in vivo-in vitro correlation of drug release from the LDDS and changes in the clindamycin (CLDM) concentration in the periodontal pocket fluid were studied. The in vitro drug release rate from the LDDS was determined by the dissolution study, without agitation, using phosphate buffer as the dissolution medium at 37 degrees C, and the in vivo drug release rate was determined according to the decrease in the drug load remaining in the LDDS after administration in periodontal pockets. The in vivo drug release rate from LDDSs was lower than the in vitro rate determined by the dissolution study, but the two rates showed a correlation in LDDSs that released drugs by diffusion. Therefore, the in vivo drug release rate was considered to be estimated from the results of the in vitro dissolution study. Changes in the drug concentration in the periodontal pocket fluid after administration of LDDS were dependent on the drug release properties of the LDDS. Also, when CLDM was administered as an aqueous solution in periodontal pockets, its concentration in the periodontal pocket fluid decreased according to a pseudo first-order equation. Therefore, the concentration in the periodontal pocket fluid after administration of a LDDS is considered to be simulated by the one compartment model based on a pseudo first-order elimination process.