Chitosan solution with 1% w / v was prepared by using
a 2% (v / v) acetic acid aqueous solution as a solvent.
Chitosan microparticles were prepared by the waterin-
oil emulsion solvent diffusion method. The 0.5 mL of
0.5% w / v chitosan solution was added drop-wise to 200
mL of ethyl acetate with a stirring speed of 900 rpm for
1 h. The beaker was tightly sealed with aluminum foil
during the emulsification-diffusion process to prevent
ethyl acetate evaporation. The chitosan microparticles
suspended in ethyl acetate were collected by centrifuga