Supercritical Fluid Extraction and Micronization of Ginkgo Flavonoids from Ginkgo Biloba Leaves

Ginkgo flavonoids were extracted from Ginkgo biloba leaves using supercritical carbon dioxide extraction technology (SFE) with ethanol as the entrainer. The effects of important process parameters on SFE were examined, and the crude extracts were further refined. At optimized experimental conditions, i.e., 20 MPa of extraction pressure, a 40 °C extraction temperature, a 10 g/min CO2 flow rate, and a 6 mL/min ethanol flow rate, the extraction yield could reach 0.36%. Supercritical fluid assisted atomization introduced by a hydrodynamic cavitation mixer (SAA-HCM) was used to obtain microparticles of Ginkgo flavonoids. The influences of the solute concentration as well as the mass flow ratio of the CO2/liquid solution on particle size (PS) and particle size distribution (PSD) were investigated. Well-defined, spherical, and separated particles with a controlled particle size ranging between 0.2 and 3.0 μm were successfully obtained in this work. The micronization of Ginkgo flavonoids can improve the drug absorption in the body and has great potential for use in drug delivery systems.