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Traditional and supercritical CO2 assisted processes are frequently used to produce microparticles formed by a biopolymer containing an active principle to improve the bioavailability of the active principle. However, information about the internal organization of these microparticles is still scarce. In this work, a suspension of dextran + Fe3O4 nanoparticles (model system) and a solution of polyvinylpyrrolidone (PVP) + curcumin were used to produce spherical microparticles by supercritical CO2 processing. Periodic dynamic light scattering measurements were used to analyze the evolution of the microparticles dissolution, size, and size distribution of the guest active principle in the polymeric matrix. It was found that curcumin was dispersed in the form of nanoparticles in the PVP microparticles, whose size largely depended on its relative concentration. These results were validated by transmission electron microscopy and scanning electron microscopy of the PVP microparticles and curcumin nanoparticles, before and after the dissolution tests. [ABSTRACT FROM AUTHOR]

Supercritical CO2 (SC‐CO2) extraction is commonly used to eliminate caffeine from coffee beans. In this work, the feasibility of tryptamine elimination is considered as a further objective of the process. SC‐CO2 extraction process parameters (eg, pressure, CO2 flow rate, water content) were studied to obtain tryptamine reduction, starting from those used in supercritical decaffeination. A good compromise, in terms of tryptamine residue in coffee beans, and process feasibility and selectivity, was found operating at 280 bar and 0.8 kg/h CO2, at a starting H2O content in coffee beans of 20% w/w. Using these process conditions, a tryptamine residue of 218 ppm (ppm) was measured in coffee beans after 18 hours of processing. A negligible effect on process selectivity and tryptamine yield was obtained by changing the CO2 flow rate and the initial water content. However, working at an initial water content of 30% w/w and using wet CO2 (CO2 plus 3% w/w water), a tryptamine residue of 107 ppm in coffee beans was obtained, but industrial complexity and costs increased. [ABSTRACT FROM AUTHOR]

α-tocopherol (TOC), a poorly water-soluble vitamin, was impregnated using supercritical carbon dioxide in two different porous supports: an inorganic one (silica aerogel, SA) and a biopolymer one (maize starch aerogel, MSA). The composite systems can be used for the attainment of novel delivery systems with a rapid or controlled vitamin dissolution rate. TOC impregnation experiments on both the supports were carried out at a pressure of 15 MPa and a temperature of 60 °C. Impregnation equilibrium data were measured and represented as isotherms, whereas impregnation kinetic data were obtained by determining the TOC uptake on the two supports at various times. The TOC/aerogel composites were characterized by FESEM analysis and specific surface area determination. To study the properties of the adsorbed aerogels, as vitamin delivery systems, in vitro dissolution tests were performed. The dissolution rates of TOC charged in silica aerogel or maize starch aerogel using phosphate buffered saline solution (PBS) were compared with the one of the unprocessed vitamin. [ABSTRACT FROM AUTHOR]

BACKGROUND: Supercritical (SC)‐CO2 extraction of rotenoids from Derris elliptica roots was proposed using fractional separation of the extracts and operating at increasing pressure. RESULTS: The best processing conditions were found at 200 bar, 40 °C and 1.2 kg h−1 SC‐CO2 flow rate, obtaining a final product with a concentration of 93% w/w of rotenone and rotenoids, and a yield of active principles of 6.70% w/w with respect to the vegetable matrix. Very small quantities of waxes were found, up to 0.05% w/w; this result can be explained considering the reduced surface‐to‐volume ratio of this vegetable material. CONCLUSION: Extraction kinetics data confirmed that, in this case, the extraction process was controlled by solubility limitation of the active compounds in the supercritical solvent. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this work, Class 2 and Class 3 solvents contained in two corticosteroids, flunisolide (Fluni) and fluticasone propionate (Fluti), were reduced to a few ppm by supercritical CO2 extraction. The process was carried out at pressures from 80 to 200 bar, temperatures of 40 °C and 80 °C, and at a fixed CO2 flow rate of 0.7 kg/h. The results demonstrated that CO2 density is the key parameter influencing the extraction kinetics and the solvent final residue. In particular, in the range investigated, optimal pressure and temperature conditions for the extraction of residual organic solvents were found working at 200 bar and 40 °C, which corresponds to a CO2 density of 0.840 g/cm3. Operating in this way, total organic solvent residues were reduced from 13,671 ppm and 326 ppm to 12 ppm and 10 ppm for Fluni and Fluti, respectively. [ABSTRACT FROM AUTHOR]