Polymer-Based Local Antibiotic Delivery for Prevention of Polymicrobial Infection in Contaminated Mandibular Implants

Antibiotic-releasing porous poly(methyl methacrylate) (PMMA) space maintainers, comprising PMMA with an aqueous porogen and a poly(DL-lactic-co-glycolic acid) (PLGA) antibiotic carrier, have been developed to facilitate local delivery of antibiotics and tissue integration. In this study, clindamycin-loaded space maintainers were used to investigate the effects of antibiotic release kinetics and dose upon bacterial clearance and bone and soft tissue healing in a pathogen-contaminated rabbit mandibular defect. Three formulations were fabricated for either high dose burst release (7 days) or with PLGA microparticles for extended release (28 days) at high and low dose. Although inoculated bacteria were not recovered from any specimens, the burst release formulation showed less inflammation and fibrous capsule formation and more bone formation close to the implant than the low dose extended release formulation by histologic analysis. These results suggest that local antibiotic release kinetics and dose affect soft and hard tissue healing independent from its ability to clear bacteria.