Ultrasonication of chitosan nanoparticle suspension: Influence on particle size

- Ultrafine chitosan nanoparticles were prepared using an ionic gelation method.
- The stability of nanoparticles is highly dependent on freeze-drying.
- Cryoprotectant utilisation was not effective enough to prevent agglomeration.
- A critical ultrasonication time was determined to break down the agglomerates.
- Ultrasonication is effective even after 6 months storage of dried nanoparticles.