A process for forming microspheres is disclosed. The process includes contacting a solvent with a modified cellulose to form a solution； contacting the modified cellulose solution with at least one bioactive agent to form a discontinuous phase liquid； contacting the discontinuous phase liquid with a continuous phase liquid to form an emulsion； and contacting the emulsion with a third phase liquid to extract the solvent from the emulsion, thereby forming a plurality of modified cellulose microspheres.
