A platelet derived growth factor delivery system for bone regeneration.

platelet derived growth factor (PDGF) was formulated in a calcium phosphate/biodegradable polymer system for local and controlled delivery to enhance bone regeneration. Implants with a porosity of 67 %, composed of hydroxyapatite, PLGA microspheres and Pluronic(®), were obtained by compression. An increase in porosity with time was expected due to Pluronic(®) dissolution and PLGA microsphere degradation. In vivo PDGF release and tissue distribution were monitored after system implantation into femurs of rabbits using (125)I-PDGF. Most of the PDGF was released within approximately 5 days and remained located around the implantation site with negligible systemic exposure. Compared with the reference groups, an important enhancement of bone regeneration was found with doses of 600 and 1,200 ng of PDGF, although no histological differences were observed between the two doses. In conclusion, the elaborated system exhibited good biocompatibility and offered a physiologically relevant PDGF profile that enhances bone formation compared to the non-treated bone defect.