A process for forming microspheres is disclosed. The process includescontacting asolvent with a modified cellulose to form a solution: contacting, the modifiedcellulose solutionwith at least one bioactive agent to form a discontinuous phase liquid:contacting thediscontinuous phase liquid with a continuous phase liquid to form an emulsion；and contactingthe emulsion with a third phase liquid to extract the solvent from theemulsion, thereby forming aplurality of modified cellulose microspheres.
