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

Abstract

MPEG-PCL diblock copolymers consisting of methoxy polyethylene glycol (MPEG) and poly(-caprolactone) (PCL) as drug carriers were synthesized by ringopening polymerization. It is possible to control the balance between hydrophilic and hydrophobic by changing the MPEG and the ratio of -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 diblock copolymer controlled the initial burst of BSA. We confirmed that the diblock copolymers could be served as protein delivery carrier in implantable wafer form.

Hydrogels for Protein Delivery

“…Several other thermosensitive copolymers of PEG with aliphatic polyesters were synthesized and applied for drug delivery. Some examples are AB, ABA, and BAB copolymers of PEG with caprolactone (PCL) and δ-valerolactone (PVL). − The in vitro and in vivo release of fluorescein isothiocyanate-labeled bovine serum albumin (BSA–FITC) was studied from PEG–PCL diblock copolymers gels and compared to that of Pluronic gels, and the studies demonstrated longer in vivo stability of PEG–PCL hydrogels and enhanced capability to provide sustained protein release over 10 days, as compared to Pluronic gels, where destabilization and drug release within 3 days was observed. , …”

Novel Biodegradable Blend Matrices for Controlled Drug Release

“…Improving and/or tailoring the properties of PCL commonly involve copolymerization of ε‐caprolactone with other suitable monomers. Hydrophilic segments such as poly(ethylene glycol) (PEG), methoxy poly(ethylene glycol) (MPEG) or poly(ethylene oxide)‐poly(propylene oxide)‐poly(ethylene oxide) (PEO‐PPO‐PEO) have been introduced into PCL chain to change the hydrophobicity and improve the biodegradability characteristic of PCL 11–13. Hydrophobic segments such as polylactide (PLA) or polyglycolide (PGA) have also been introduced into PCL chain to reduce its isotacticity so as to lower its crystallinity which is closely related to degradation/erosion rate 14.…”

Controlled release of peptide from biodegradable platforms for cardiovascular applications

“…And the presences of heat, moist and acidic environment would accelerate the degradation of polymers. in mPEG segment which resulted in improved water-penetration into the system [146].…”