Abstract
This study evaluated the sustained release effect of clarithromycin-loaded in PLGA microspheres in a rabbit calvaria defect model. Four bone defects (O5.0) were created in the calvaria of New Zealand White rabbits (n=21, n=7/time point). The defects were randomly designated to four groups. Group 1: No augmentation (sham), Group 2: beta-tricalcium phosphate (-TCP), Group 3: -TCP with 0.12 mu g clarithromycin, and Group 4: -TCP with 6.12 mu g PLGA microspheres loaded with 0.12 mu g Clarithromycin. After 2, 4, and 12 weeks of healing, bone regeneration was evaluated using micro-computed tomography (mu CT) and histology. Clarithromycin release from PLGA microspheres revealed sustained release for around 4 weeks with approximate to 50% release during the first week. Histologically, new bone formation was evident at 2 and 4 weeks of healing in all groups and bone formation increased as a function of healing time. At 12 weeks, Group 4 showed significantly higher amount of newly formed bone compared to Group 1. The mu CT showed that Group 4 expressed significantly higher bone formation compared to Group 1 at all time points. The in vivo findings showed that -TCP with clarithromycin-loaded microspheres can enhance bone formation in bone defects. (c) 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 201-208, 2018.