Zero-order delivery with periodontal placement of tetracycline-loaded ethylene vinyl acetate fibers.

The concentration of tetracycline in the gingival fluid was measured in the periodontal pocket following placement of controlled drug delivery monolithic fibers and subgingival irrigation. Following subgingival irrigation with 1% and 10% tetracycline HCl solution, concentrations decayed exponentially with half times of 4.2 and 12.2 h, respectively. Tetracycline fibers maintained a constant average concentration of 1590 micrograms/ml in periodontal pockets over a 10-day period. The observed concentrations were in agreement with those expected from a steady-state model based on release rate characteristic of the fibers and gingival fluid flow rate. After removal of the delivery system, tetracycline concentrations decreased exponentially with half time of 4.5 h. These data describe the delivery characteristics of tetracycline-loaded ethylene vinyl acetate fibers as zero-order for 10 d; following removal, an exponential washout was observed.