Controlled release of bovine serum albumin using MPEG-PCL diblock copolymers as implantable protein carriers

MPEG-PCL cliblock copolymers consisting of methoxy polyethylene glycol (MPEG) and poly(epsilon-caprolactone) (PCL) as drug carriers were synthesized by ring-opening polymerization. It is possible to control the balance between hydrophilic and hydrophobic by changing the MPEG and the ratio of epsilon-CL to MPEG. Implantable wafers were easily fabricated by the direct compression method after physical mixing of diblock copolymers and bovine serum albumin-fluorescein isothiocyanate (BSA-FITC) as a model protein drug. The BSA release from wafers prepared by MPEG-PCL diblock copolymers were higher than that from PCL with the physical blending of MPEG. The wafers prepared by a variety of MPEG-PCL diblock copolymers exhibited the controlled BSA release profiles with a dependence on MPEG-PCL diblock copolymer compositions. In addition, the changing of MPEG and PCL molecular weights within MPEG-PCL cliblock copolymer controlled the initial burst of BSA. We confirmed that the diblock copolymers could be served as protein delivery carrier in implantable wafer form. (c) 2006 Wiley Periodicals, Inc.