Protein encapsulation in and release from monodisperse double-wall polymer microspheres

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Polymer Chemistry

Background:

• Biodegradable polymer double-wall microspheres (DWMS) are advanced carriers for macromolecular therapeutics like proteins and peptides.
• Precision Particle Fabrication (PPF) technology enables the creation of uniform microspheres with controlled structures.

Purpose of the Study:

• To fabricate and characterize biodegradable polymer double-wall microspheres (DWMS) for enhanced macromolecular therapeutic delivery.
• To investigate the impact of a drug-free poly(lactic acid) (PLA) shell on protein encapsulation and release kinetics.

Main Methods:

• Fabrication of uniform DWMS (approx. 55 μm outer diameter) using PPF technology, with poly(lactide-co-glycolide) cores encapsulating bovine serum albumin (BSA) and PLA shells.
• Utilized differential solvent extraction (ethyl acetate for shell, dichloromethane for core) to achieve distinct core-shell structures.
• Analyzed initial protein distribution, particle erosion, and in vitro protein release profiles for both DWMS and single-wall microspheres (SWMS).

Main Results:

• DWMS exhibited well-defined core-shell structures, high BSA encapsulation efficiency, and successful protein localization within the core.
• The presence of a drug-free PLA shell significantly reduced the protein release rate compared to SWMS.
• Protein release duration was extended from approximately 50 days to 70-80 days with the DWMS formulation.

Conclusions:

• Biodegradable polymer DWMS fabricated with PPF technology provide effective encapsulation and controlled release of protein therapeutics.
• The drug-free shell in DWMS acts as a barrier, significantly extending the release duration and improving therapeutic delivery control.
• These findings highlight the potential of DWMS for developing sustained-release formulations for protein and peptide drugs.