Preparation of microparticulate methylprednisolone acetate suspension

A sterile aqueous slurry consisting of methylprednisolone acetate, polysorbate 80 and water wherein the methylprednisolone acetate in the sterile aqueous slurry is in the form of particles having a D90 of between 7.93 microns and 17.30 microns, a D50 of between 3.87 microns and 6.92 microns, and a D10 of between 1.77 microns and 2.77 microns, the concentration of methylprednisolone acetate in the slurry is about 80 mg/ml or about 160 mg/ml, and the concentration of polysorbate 80 in the slurry is about 3.88 mg/ml or about 3.76 mg/ml, wherein the slurry is prepared in a process that includes the steps of:

• a) preparing an aqueous slurry of the methylprednisolone and polysorbate 80;
• and
• b) sterilizing the aqueous slurry by moist heat sterilization to form a sterile slurry, wherein the sterilization of the aqueous slurry is performed under homogenization and/or a nitrogen atmosphere and the moist heat sterilization comprises heating the aqueous slurry to a temperature of about 115° C. to about 128° C. for about 15 to 60 minutes.