Enhancing the Stabilization Potential of Lyophilization for Extracellular Vesicles

Area of Science:

• Biotechnology
• Materials Science
• Pharmaceutical Sciences

Background:

• Extracellular vesicles (EVs) show promise as immune therapeutics and drug delivery vehicles.
• Current storage at -80°C limits clinical applicability.
• Developing stable, long-term formulations for EVs is crucial.

Purpose of the Study:

• To identify optimal formulation parameters for freeze-drying EVs.
• To evaluate the stability of lyophilized EV formulations.
• To enable long-term storage and clinical use of EVs.

Main Methods:

• Freeze-thawing studies with two EV types to assess colloidal stability.
• Freeze-drying feasibility study.
• Storage stability testing of lyophilized formulations for up to 6 months at 40°C.
• Analysis of particle size, concentration, and biological activity.

Main Results:

• Sucrose or potassium phosphate buffer improved colloidal EV stability compared to sodium phosphate buffer or PBS.
• Neutral pH was optimal for EV stability, minimizing aggregation and fusion.
• Poloxamer 188 effectively preserved EV colloidal stability; polyvinyl pyrrolidone did not.
• Lyophilizates with 10 mm K-/Na-phosphate buffer, 0.02% poloxamer 188, and 5% sucrose retained EV particle size and concentration for 6 months at 40°C.
• Biological activity of associated beta-glucuronidase was maintained for 1 month but decreased after 6 months.

Conclusions:

• Optimized lyophilization parameters, including specific excipients and pH, are essential for creating stable EV formulations.
• Freeze-dried EVs stored under optimized conditions demonstrate good physical stability for up to 6 months.
• Further research is needed to enhance the long-term preservation of EV biological activity post-lyophilization.