Polysaccharides-based spray-dried microspheres for maintained stability and controlled release of protein

Spray-dried microspheres based on polysaccharides were developed and the conformational stability and controlled release of incorporated protein were evaluated using bovine serum albumin (BSA) as a model protein. Microspheres composed of water soluble chitosan (WCS), hydroxypropyl-β-cyclodextrin (HP-β-CD) and polyethylene glycol (PEG) were prepared by spray dying. WCS was used as a mucoadhesive and biocompatible polymer. HP-β-CD and PEG were used as protein stabilizer during the spray drying process. Microspheres with 6–7 μm of mean diameter were successfully developed. Encapsulation efficiency of BSA in microsphere was over 70 %. Primary, secondary and tertiary structure of incorporated BSA in microsphere was analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, circular dichroism, and fluorescence intensity measurement, respectively. Conformational stability of BSA was maintained during the spray drying process. BSA release from microspheres was evaluated in in vitro model using the Transwell® insert, and showed a sustained release profile compared to naive BSA. Thus, these microspheres could possibly serve as an optimized delivery system for preserved stability and sustained release of protein.