Precipitation of submicron particles of rutin using supercritical antisolvent process

• Submicron particles of rutin have been obtained for the first time by SAS process.
• The negligible and stronger effects on particle size were identified.
• Election of solvent is the key parameter in the success of SAS process.
• Rutin was amorphizated in the process.
• Submicron particles of rutin dissolve ten times faster than commercial in simulated fluids.

Spherical submicron particles of rutin were prepared by a supercritical antisolvent process (SAS). Selection of the appropriate solvent determined the success of the precipitation process. A mixture of acetone and DMSO in a 9:1 ratio was selected in order to study the main parameters that influence the SAS process in terms of particle size, size distribution and particle morphology. Smaller particles were produced at higher temperature and pressure, and with a lower initial concentration of the solution. A lower liquid solution flow rate is recommended to obtain submicron particles but the CO2 flow rate and nozzle diameter had a negligible effect on particle size, at least at the levels evaluated. The precipitated powders were analysed by Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The SAS process contributed to the dehydration of rutin, thus conferring higher added value. Moreover, amorphization of the processed samples was produced during the process. Processed rutin particles dissolved more rapidly than commercial rutin in simulated fluids and this is related to the particle size reduction and the loss of crystallinity due to amorphization. This effect was more pronounced in simulated intestinal fluids than in gastric fluids.

SEM images of (a) commercial and (b) spherical microparticles of rutin processed by SAS. P: 100 bar, T: 50 °C, QCO2: 10 g/min, QL: 6 mL/min, cc: 20 mg/mL, Øn: 200 μm and tw: 60 min.Figure optionsDownload as PowerPoint slide