Preparation of cefpodoxime proxetil fine particles using supercritical fluids

Fine particles of cefpodoxime proxetil (CPD) were prepared using an Aerosol Solvent Extraction System (ASES) with supercritical CO 2 . The resulting primary particles were approximately 0.1–0.2 μm in size and were almost spherical in shape. The secondary particles were approximately 0.2–0.6 μm in size and had irregular shapes. The larger particle size and irregular shapes were due to the agglomeration of the primary particles. The effects of solvent type, CO 2 -to-CPD solution weight ratio, and CPD solution concentration on the extent of agglomeration were investigated. As a result, the use of ethyl acetate and acetone as solvents also reduced the degree of agglomeration. The degree of agglomeration was reduced with the use of a high CO 2 -to-solution weight ratio, and a low solution concentration. In particular, spherical particles, approximately 0.1–0.4 μm in size, were obtained when a 10.0 wt% CPD solution was used. As a result of dissolution study, almost 90% of the processed CPD had dissolved within 10 min. The recovery yield of the CPD powder reached approximately 80% using a membrane filter.