Generation of quercetin/cellulose acetate phthalate systems for delivery by supercritical antisolvent process

Supercritical antisolvent process (SAS) has been used to precipitate microparticles of quercetin, a plant pigment found in many foods and used for medical treatments, pharmaceutical and cosmetic industries, together with nanoparticles of cellulose acetate phthalate (CAP), a polymer quite frequently used in drug delivery. Previously, precipitation of nanoparticles of CAP by the same process was studied at different conditions of pressure, temperature, CO₂ and solution flow rates, nozzle diameter and initial concentration of the solution. Morphologies of the precipitates were analyzed by scanning electron microscopy (SEM). A range between 84 and 145nm of diameter in spherical particle were achievement in CAP precipitation. A same range of semi-spherical particles of CAP around 145nm and needle-like particle of quercetin was obtained in the coprecipitation experiments. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were carried out to find out the possible loss of crystallinity of the coprecipitates and the possible interactions between the polymer and quercetin, respectively. Release profiles of quercetin were carried out in simulated gastric and intestinal fluids. Higher quercetin:polymer ratios in the coprecipitates are recommended to achieve faster release and higher solubilities of quercetin in the assayed time. This fact would allow its use in pharmaceutical, cosmetic or nutraceutical applications.