Poly(ethylene glycol)-modified proteins: implications for poly(lactide-co-glycolide)-based microsphere delivery.

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Protein Chemistry

Background:

• Poly(lactide-co-glycolide) (PLG) microspheres are used for sustained peptide delivery.
• Challenges exist in using PLG for chronic protein delivery, including initial burst release and protein adsorption/activity loss.

Purpose of the Study:

• To review techniques for improving protein delivery from PLG depot systems.
• To explore polyethylene glycol (PEG)ylation as a strategy to enhance protein release and stability in PLG microspheres.

Main Methods:

• Review of existing literature on PLG microsphere formulation and protein delivery.
• Discussion of protein modification techniques, specifically PEGylation, prior to encapsulation.

Main Results:

• Unmodified proteins suffer from burst release and adsorption to PLG, leading to activity loss.
• Covalent attachment of PEG to proteins shows promise for improving PLG depot performance.

Conclusions:

• PEGylation can potentially improve protein release kinetics from PLG microspheres.
• The shielding and stabilizing effects of PEG may lead to more complete release of active protein conjugates.