Preparation of spherical and porous chitosan particles by suspension evaporation with O/W/O multiple emulsions

Porous spherical particles of chitosan were prepared by conventional suspen sion evaporation with modification. Aqueous chitosan solution was dispersed in decahydronaphthalene as the suspension medium with a nonionic surfactan t as the emulsifier. O/w/o multiple emulsions consisting of aqueous chitosa n particles containing decahydronaphthalene and dispersed in decahydronapht halene were obtained. Chitosan precipitated as insoluble spherical particle s by the gradual removal of water with heating. Particle porosity was relat ed to microemulsions formation, the cloud point of the emulsifier and chemi cal structure of the acid used.