Formation of curcumin nanoparticles via solution-enhanced dispersion by supercritical CO₂

Abstract

In order to enhance the bioavailability of poorly water-soluble curcumin, solution-enhanced dispersion by supercritical carbon dioxide (CO₂) (SEDS) was employed to prepare curcumin nanoparticles for the first time. A 2⁴ full factorial experiment was designed to determine optimal processing parameters and their influence on the size of the curcumin nanoparticles. Particle size was demonstrated to increase with increased temperature or flow rate of the solution, or with decreased precipitation pressure, under processing conditions with different parameters considered. The single effect of the concentration of the solution on particle size was not significant. Curcumin nanoparticles with a spherical shape and the smallest mean particle size of 325 nm were obtained when the following optimal processing conditions were adopted: P =20 MPa, T =35°C, flow rate of solution =0.5 mL·min⁻¹, concentration of solution =0.5%. Fourier transform infrared (FTIR) spectroscopy measurement revealed that the chemical composition of curcumin basically remained unchanged. Nevertheless, X-ray powder diffraction (XRPD) and thermal analysis indicated that the crystalline state of the original curcumin decreased after the SEDS process. The solubility and dissolution rate of the curcumin nanoparticles were found to be higher than that of the original curcumin powder (approximately 1.4 μg/mL vs 0.2 μg/mL in 180 minutes). This study revealed that supercritical CO₂ technologies had a great potential in fabricating nanoparticles and improving the bioavailability of poorly water-soluble drugs.

Keywords:

• curcumin
• crystalline sate
• dissolution rate
• solubility

Acknowledgments

We thank the Hong Kong Research Grant Council and the Hong Kong Polytechnic University through projects PolyU5242/09E and G-YM63. We would also like to thank the support provided by the Natural Science Foundation of Hubei Province through project 2014CFB839, Doctoral Research Fund of Wuhan University of Technology through project 471-40120093, Guangdong Provincial Department of Science and Technology through projects 2012B050800002 and 2012B091000143.

Disclosure

The authors report no conflicts of interest in this work.