A method of preparing
polysaccharide glassy microparticles which are less than 10 μum in
diameter and contain structurally delicate agents, such as proteins, peptides,
gene materials, vaccines, antibodies, viruses and liposomes using low-temperature aqueous-aqueous emulsification (free of polyelectrolytes) and freezing-induced phase separation. When delicate agents are added to a
polysaccharide-PEG two phase
system followed by homogenization (or other shear adding process), the agents partition into the
polysaccharide dispersed phase preferentially. These processes help to avoid aggregation of proteins caused by interaction with charged polyelectrolytes used for stabilizing the polysaccharide dispersed phase in our previously reported aqueous-aqueous
emulsion. When this
system is frozen and lyophilized, glassy particles less than 10 μm in
diameter containing delicate agents can be formed. These fine polysaccharide particles protect proteins within their hydrophilic
glassy matrix, and can therefore be easily suspended in
hydrophobic polymer solutions and formulated to various forms of sustained release devices such
microsphere, sheets, fibers,
coating layers, and scaffolds. The particles can also be dispersed in hydrophilic gels to improve releasing
kinetics and to deliver vaccines and antibodies for
immune therapy.