Preparation and characterisation of PLGA microspheres for sustained release of recombinant human granulocyte colony-stimulating factor

The purpose of this research was to develop a sustained micosphere for recombinant human granulocyte colony-stimulating factor (RHG-CSF). RHG-CSF was first incorporated into glassy sodium hyaluronate (HA) particle according to the freezing-induced phase separation method previously reported by the authors´ group. Once G-CSF was incorporated in the glassy HA particles, it gained resistance to organic solvents. The glassy HA particle containing G-CSF was subsequently encapsulated into polylactic-co-glycolic acid (PLGA) matrix to get HA-PLGA composite microspheres by the solid-in-oil-in-water multiple emulsion technique. The novel glassy HA particle and composite microsphere were characterised by scanning electron microscopy, particle and size distribution, size-exclusion HPLC. The in vitro release data indicate that continuous and sustained release profile was achieved for more than 30 days compared with microspheres prepared by the traditional water-in-oil-in-water method. Also the bioassay was assessed by proliferative ability of NSF-60 cell line and the result suggests that the bioactivity was preserved well in the process of formulation steps and in vitro release.