Fabrication of injectable bone substitute loading porous simvastatin-loaded poly(lactic-co-glycolic acid) microspheres

An injectable bone substitute (IBS) with well-controlled release mechanism of simvastatin (SIM) was fabricated from SIM loaded-porous poly(lactic-co-glycolic acid) microspheres (PLGA MSs), biphasic calcium phosphates (BCP) and CaCO3 nano powder as the solid phase and gelatin, citric acid and hydroxypropyl methylcellulose as the liquid phase. The ratios of PLGA MSs and BCP were varied to obtain IBS with optimal mechanical properties, biocompatibility and bioactivity. In vitro test with MG-63 pre-osteoblast cells showed that IBS with higher amount of PLGA MSs yield better cell adhesion and proliferation. In vivo study on rabbit femoral defect also suggested that the IBS promoted osteogenesis.