Effect of octacalcium phosphate on the release behavior of osteogenic factors from PLGA/PCL microspheres

The encapsulation and the release of ascorbate-2-phosphate (AsAP) and β-glycerophosphate (β-GP) in microspheres (MSs) consist of poly(lactide-co-glycolide) (PLGA) and poly(ε-caploractone) (PCL) with octacalcium phosphate (OCP) were studied. AsAP-loaded PLGA/PCL (50:50) MSs (AsAP-MSs) were prepared using a water-in-oil-in-water emulsion evaporation. β-GP-loaded PLGA/PCL MSs (β-GP-MS) were prepared similarly while β-GP was directly added in oil. The oil phase dichloromethane was evaporated producing pores in MSs. MSs were characterized by physical techniques such as Fourier transform infrared spectroscopy (FTIR). The drug encapsulation efficiency (E.E.) was evaluated by spectrophotometer after water-extracting. The drug releases into supernatant were analyzed after incubating in 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES)-NaCl buffer at 37°C for 36 days. E.E. was 89% for AsAP and 67% for β-GP, and AsAp was released immediately while β-GP was continuously released. OCP was hydrolyzed to hydroxyapatite, affecting β-GP release. PLGA/PCL MSc with OCP may be effective for the release of osteogenic factors.