Particle crystallization by supercritical antisolvent processing techniques: the case of Retama raetam powder for pharmaceutical purposes

In this work, the Supercritical AntiSolvent process has been used to generate micronized crystals of Retama raetam. The process was performed using ethanol and CO2 as solvent and antisolvent, respectively. Recrystallization was made at various temperatures (30-50 degrees C) and pressures (8-12 MPa) using a constant flow rate of supercritical CO2 (2 kg/h). We have been also varied the solution flow rate and its volume to identify conditions leading to spheroidal powder morphology. Size and morphology have been characterized by scanning electron microscopy and Image) software. The spraying of the supercritical solution directing the flow towards the precipitator results in the deposition of fine particles with uniform morphology at the bottom, and of a porous film adhering to the precipitator wall. For that reason, thermodynamic and hydrodynamic aspects are discussed so as to rationalize the powder and spongious film characteristics and provide a new way to control the SAS process applied to plant derivatives.