Encapsulation and stabilization of nerve growth factor into poly(lactic-co-glycolic) acid microspheres

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Neuroscience

Background:

• Recombinant human nerve growth factor (rhNGF) holds therapeutic potential for neuronal diseases.
• Achieving stable, sustained release of rhNGF has been a significant challenge.
• Previous attempts using common excipients led to protein aggregation during release.

Purpose of the Study:

• To develop a stable, sustained-release formulation of rhNGF.
• To overcome protein degradation during microencapsulation and in vitro release.
• To achieve controlled release of rhNGF for potential neuronal disease therapy.

Main Methods:

• rhNGF was encapsulated into poly(lactic-co-glycolic) acid (PLGA) microspheres via spray freeze-drying.
• An insoluble rhNGF-zinc complex was formed prior to encapsulation to enhance stability.
• Zinc carbonate was incorporated into the polymer phase to control release kinetics.

Main Results:

• The rhNGF-zinc complex formation significantly stabilized the protein during microencapsulation and release.
• A formulation using 10% rhNGF in 12 kDa PLGA (50:50) achieved 14 days of continuous release.
• Addition of zinc carbonate resulted in a low initial burst (approx. 1%) and controlled release rate.

Conclusions:

• Zinc complexation is an effective strategy to stabilize rhNGF in PLGA microspheres.
• The developed formulation provides sustained release of rhNGF for 14 days.
• This approach offers a promising method for delivering rhNGF for neuronal disease treatment.