A novel osteotropic biomaterial OG‐PLG: Synthesis and in vitro release

Abstract Statins (e.g., simvastatin) have shown to induce expression of the bone morphogenic protein‐2 gene in bone cells, but they are not used clinically because of a lack of a suitable delivery device. The overall objective is to develop optimized statin delivery devices for bone regeneration. The specific objective was to determine the effect of grafting statins to biodegradable poly[lactide‐co‐glycolide] (PLG) on release kinetics. Simvastatin was grafted to PLG (OG‐PLG) and characterized using contact‐angle measurements, attenuated total reflectance–Fourier transform infrared, and ultraviolet–visible spectroscopy to determine success of the synthesis. An ultraviolet–visible assay for measuring release of statins and degraded OG‐PLG in media was also developed. In vitro release studies using films and scaffolds made with PLG, PLG blended with simvastatin (PLG + Sim), and OG‐PLG (simvastatin grafted to PLG) blended into PLG at different concentrations showed that release rate of OG‐PLG from films was significantly greater than that of PLG + Sim. However, release rate from scaffolds showed PLG + Sim to be significantly higher than that of OG‐PLG. The diffusion‐controlled release kinetics of simvastatin from PLG + Sim seems to be more heavily affected by device morphology, whereas the degradation‐controlled release kinetics seem to be less affected. In short, release kinetics can be modulated by grafting statins to PLG. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005