Preparation of Emodin‐Polyethylene Glycol Composite Microparticles Using a Supercritical Antisolvent Process

Emodin-polyethylene glycol (PEG) composite microparticles were obtained from a dichloromethane-methanol mixture via the solution-enhanced dispersion by supercritical fluids through prefilming atomization (SEDS-PA) process. Morphologies, particle sizes (PSs), and emodin contents of the composite microparticles were analyzed by scanning electron microscopy and UV-visible spectrophotometry. The crystallinity change of emodin before and after the SEDS-PA process was demonstrated by X-ray powder diffraction (XRD). The composite microparticles present nubbly, rod-like emodin dispersed in PEG or a nubbly, sheet emodin inlay on PEG, with PSs ranging between 3 and 12 μm. The PSs of the composite microparticles increase with the increase of temperature, decrease with the increase of pressure, and do not seem to depend on the emodin content of the initial solute and on the solution flow rate. The emodin contents of the composite microparticles increase with the increasing emodin content in the initial solute and temperature and decrease with increasing solution flow rate.