Porous and spherical ethyl cellulose fine particles produced by ternary system-based emulsion castings

Abstract Biocompatible polymer fine particles would be promising carriers for a drug delivery system. Although biocompatible polymer fine particles containing active pharmaceutical ingredients are typically produced by oil in water (O/W) emulsion castings, this method has several limitations, such as the significant solubility of both the polymer and API being studied in typical less-polar solvents that are immiscible with aqueous media is required to form O/W emulsions. Herein, we demonstrate that ternary system-based oil in oil emulsion castings can produce porous and spherical fine particles of biocompatible ethyl cellulose (EC) with a narrow size distribution. The fine particles possess macropores with average diameter of 0.43 μm and are quantitatively obtained from commercial EC. Several analytical techniques, including transmission electron microscopy, scanning electron microscopy in combination with energy dispersive X-ray spectroscopy, and X-ray computed tomography scan have revealed that pore networks are constructed throughout the particles, which provides the large pore volumes.