One-step preparation of chitosan solid nanoparticles by electrospray deposition

Solid micro- and nanoparticles were prepared from chitosan/acetic acid solution in one-step by the electrospray procedure. The effects of various solution properties and processing parameters on particle formation were investigated. Solution viscosity and conductivity were the most important factors affecting electrospray behavior, i.e., stable electrospray was achieved only when viscosity was high and/or conductivity was low. Smaller particles could be obtained by decreasing acetic acid concentration, chitosan concentration, and/or flow rate. Furthermore, addition of ethanol could effectively stabilize the electrospray by decreasing the solution conductivity and increasing the solution viscosity. By optimizing the solution and operation parameters, the average diameter of the chitosan particles was reduced down to 124 nm, suggesting that electrospray is promising in producing solid micro- and nanoparticles for oral and pulmonary drug delivery systems.