Tailored protein release from biodegradable poly(ε-caprolactone-PEG)-b-poly(ε-caprolactone) multiblock-copolymer...

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Biodegradable polymers are crucial for controlled drug release.
• Poly(ε-caprolactone)-based copolymers offer tunable properties for biomedical applications.
• Phase-separated multiblock copolymers present unique characteristics for protein encapsulation.

Purpose of the Study:

• To investigate in vitro protein release from novel [PCL-PEG]-b-[PCL] multiblock copolymers.
• To evaluate the impact of polymer block ratio and polyethylene glycol (PEG) content on protein release kinetics.
• To determine the influence of protein molecular weight on release profiles from these biodegradable implants.

Main Methods:

• Synthesis of poly(ε-caprolactone-PEG)-block-poly(ε-caprolactone) ([PCL-PEG]-b-[PCL]) multiblock copolymers with varying PEG content (22.5-52.5 wt%).
• Spray-drying of proteins (goserelin, insulin, lysozyme, carbonic anhydrase, albumin) with inulin stabilizer.
• Incorporation of spray-dried proteins into polymeric implants via hot melt extrusion.
• In vitro release studies of proteins with molecular weights ranging from 1.2 to 66 kDa.

Main Results:

• All incorporated proteins maintained structural integrity post-extraction.
• Protein release rate increased with decreasing protein molecular weight.
• Higher PEG content in the [PCL-PEG]-b-[PCL] copolymer led to increased protein release rates.
• Increased PEG content also enhanced copolymer swelling and degradation rates.

Conclusions:

• The release rate of proteins from [PCL-PEG]-b-[PCL] copolymers is significantly influenced by protein molecular weight and polymer PEG content.
• Tailoring the PEG content in these biodegradable multiblock copolymers allows for controlled release of proteins with varying molecular weights.
• These findings support the potential of [PCL-PEG]-b-[PCL] copolymers as versatile platforms for advanced protein delivery systems.