Chitosan-based particles for protection of proteins during storage and oral administration.

Crosslinked chitosan particles have been developed to improve the storage stability of bioactive proteins and to ensure adequate bioavailability by targeting release to the colon. The characteristics of these chitosan-based particles, formed using different molecular weight chitosans and different anion cross-linkers, were demonstrated using small angle X-ray scattering, ζ-potential, particle size, and morphology. An in vitro release study showed that protein release from the particles in the upper gastrointestinal tract was <30%, suggesting the possibility for target release to the colon. Some of the particles were shown to retain colon-targeted protein delivery after storage in PBS buffer. By controlling the structure of the chitosan-based particles, it was possible to both reduce protein leakage during short-term storage and achieve colon-targeted delivery.