Sustained release of ascorbate-2-phosphate and dexamethasone from porous PLGA scaffolds for bone tissue engineering using mesenchymal stem cells

The purpose of this research was to develop porous poly(D,L-lactide-co-glycolide) (PLGA) scaffolds from which ascorbate-2-phosphate (AsAP) and dexamethasone (Dex) are continuously released for a month for osteogenesis of mesenchymal stem cells for bone tissue engineering. Porous PLGA matrices containing AsAP and Dex were prepared by solvent casting/particulate leaching method. In vitro release and water uptake studies were performed in Dulbecco's phosphate buffered saline at 37 degrees C and 15 rpm. Drug loading and release rates were determined by high performance liquid chromatography. Release studies of Dex and AsAP showed that, after an initial burst release lasting 4 and 9 days, respectively, release rates followed zero order kinetics with high correlation coefficients at least until 35 days. Incorporation of AsAP into the scaffolds increased the release rates of Dex and AsAP, and the scaffold water uptake. When mesenchymal stem cells (MSCs) were cultured in the AsAP and Dex containing scaffolds in vitro, the amount of mineralization was significantly higher than in control scaffolds. In conclusion, AsAP and Dex were incorporated into porous PLGA scaffolds and continuously released over a month and osteogenesis of MSCs was increased by culture in these scaffolds.