Nanoparticulation of curcumin by liquefied dimethyl ether feed solution assisted supercritical carbon dioxide anti-solvent with coaxial nozzle

Abstract

Curcumin is a hydrophobic polyphenolic compound with various pharmacological effects. However, its poor water solubility and bioavailability limit its clinical application. In this study, curcumin nanoparticles were successfully prepared by the supercritical CO₂ anti-solvent (SAS) technique using liquefied dimethyl ether (DME) as the solvent and a coaxial nozzle to promote particle formation. For comparison, curcumin particles were prepared under the same conditions using ethanol as the solvent. The effects of the process parameters, including pressure and temperature, were investigated on the curcumin nanoparticles. Field-emission scanning electron microscopy (FE-SEM) images showed that curcumin nanoparticles with a uniform spherical morphology and an average diameter of < 100 nm were obtained from liquefied DME at 10 MPa and 60 °C. In comparison, curcumin particles precipitated from ethanol at 14 MPa and 50 °C had a larger average size of > 100 nm and broader, less uniform particle size distribution. The smallest nanoparticles precipitated from liquefied DME required a lower pressure than those precipitated from ethanol. X-ray diffraction (XRD) analysis confirmed that the nanoparticles obtained from both liquefied DME and ethanol solutions had an amorphous structure, indicating complete transformation from the crystalline form of the original curcumin. Furthermore, Fourier-transform infrared (FT-IR) spectroscopy revealed no detectable residual solvent in the DME-precipitated nanoparticles, whereas the spectra of the ethanol-precipitated particles showed characteristic peaks corresponding to residual ethanol. This approach provides a promising strategy to improve the solubility and bioavailability of curcumin for pharmaceutical applications.