In this study, we attempted to prepare chlorophyll-free young barley leaf extract powders using three different supercritical carbon dioxide (SCCO2) drying processes. The pure SCCO2 drying process for a methanolic extract solution resulted in a ~30% increase in the antioxidant (saponarin and isovitexin) content and a ~75% decrease in the chlorophyll content compared to a solvent evaporation method. The drying process with ethanol-modified SCCO2 increased the antioxidant content considerably and completely removed the chlorophylls. However, this process could not dry an aqueous ethanolic extract solution with a more than 30% water content. The ethanol-modified SCCO2 drying process that employed a periodic flush with pure SCCO2 was found to effectively dry an aqueous ethanolic extract solution with more than 30% water content.

Supercritical fluid extraction (SFE) using cosolvent-modified supercritical carbon dioxide and a two-step separation/purification method was investigated as a way to improve the purity of glabridin, one of the many bioactive components of Glycyrrhiza glabra (licorice). The SFE parameters were optimized using an analytical-scale SFE system in the temperature range 40–80°C and the pressure range 10–50 MPa. The extraction was then scaled up by 100 times using a preparative SFE system under the following set of optimized conditions: 40°C, 30 MPa, and SCCO 2 modified with ethanol equivalent to its 25% (v/v) concentration. The glabridin purity obtained through the scaled-up SFE system was 6.2%, a much higher level than that obtained through organic solvent extraction. The licorice extract obtained by scaling up the SFE system was isolated and purified by applying alcohol precipitation/ filtration and adsorption chromatography with 80% aqueous ethanol to obtain a purer product. It was confirmed that the glabridin purity of the final extract product was increased by up to 37%, without significant loss of glabridin after two separation/purification steps.

We synthesized 3–16 armed methyl-β-cyclodextrin-poly(l-lactide) (MCD-PLLA) polymers, and then blended them with PLLA. The addition of MCD-PLLA with 9 or 12 arms to PLLA dramatically increased the elongation at break (E) and toughness (UT) of PLLA with little affecting its Tg and tensile strength. The highest E and UT were obtained to be 127% and 6.85 GJ/m3, respectively, for PLLA blends containing these MCD-PLLAs. It was confirmed that the MCD-PLLA served as a nucleation agent for PLLA, inducing PLLA chains to form smaller and more uniform-sized crystallites compared with pure PLLA. The homogeneous fragmentation of these small and uniform-sized crystallites during tensile deformation consequently resulted in such a remarkable increase in E and UT. In contrast, the addition of MCD-PLLAs with more than 12 arms to PLLA decreased its E and UT mainly due to preferential crystallization by themselves.

Nanocellulose and microcellulose have been widely investigated as a next-generation core material in various fields due to its excellent properties such as low density, high modulus, heat resistance, and transparency. Depending upon its resources, cellulose shows different structural properties such as degree of crystallinity, crystal size, morphology, and molecular weight. In this study, various micro- and nano-celluloses were prepared from red pine, ramie and cotton using physical and/or chemical processes. By employing high-pressure homogenization as a physical method and sulfuric acid hydrolysis as a chemical method, four different treatments were carried out. From cotton, microfibrillated cellulose with a uniform network structure and nanowisker cellulose were prepared by homogenization and homogenization/hydrolysis/homogenization/hydrolysis, respectively. On the other hand, microwhisker cellulose was obtained from red pine by hydrolysis/homogenization. It was observed that homogenization with β-cyclodextrin, which have the same monomer structure to cellulose, could lead to a significant reduction in the size of micro- and nano-celluloses.

In this study, gemcitabine (Gem)-Poly(L-lactic acid) (PLLA) conjugates were synthesized through an amide linkage reaction. Then, the microparticles of Gem-PLLA/PLLA blends containing gemcitabine were prepared using a supercritical fluid process, called aerosol solvent extraction system (ASES). Gemcitabine-loaded Gem-PLLA/PLLA microparticles obtained from the ASES process showed a spherical shape. The amount of gemcitabine released after 30 day incubation in a phosphate buffer solution of pH 7.4 was about 90% of the total amount of gemcitabine present in the product.

In this study, peptide-loaded microparticles were prepared using an aerosol solvent extraction system (ASES) by employing supercritical carbon dioxide as an antisolvent. The effects of the molecular weight of poly(Llactide) (PLLA), poly(ethylene glycol) (PEG), the block length of methoxy poly(ethylene glycol)- b -poly(L-lactide) (mPEG-PLLA), the blending of PLLA and PEG, and the drug-to-polymer feed ratio on the formation of leuprolide acetate (LA)-loaded microparticles and their release characteristics were investigated. Scanning electron microscope observations showed that the LA-loaded polymer particles had a spherical morphology with a smooth surface. The entrapment efficiency of LA in the ASES-processed microparticles was found to be extremely high (about 99%), whereas the initial release rate of the LA-loaded microparticles was very low for PLLA. The release rate of LA was observed to increase as the PEG block length of mPEG-PLLA and/or the drug content in the microparticles increased. When PLLA was blended with PEG, the release rate of LA from the PLLA/PEG microparticles was significantly faster compared with the corresponding mPEG-PLLA copolymer.

In this study, we employed hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as an excipient to produce poly(lactic-co-glycolic acid) (PLGA) fine particles by a supercritical fluid process, called aerosol solvent extraction system (ASES), and investigated the effect of HP-beta-CD content on the morphology of the particles. The influence of HP-beta-CD on the drug release characteristics of paclitaxel-loaded PLGA particles was also evaluated. Fine particles were obtained when the HP-beta-CD content in PLGA/HP-beta-CD mixtures was greater than 40% and 30%, respectively, for PLGA(75:25) and PLGA(50:50), whereas a film-like precipitate was obtained for lower HP-beta-CD content. The release rate for paclitaxel loaded PLGA(75:25)/HP-beta-CD particles was found to increase with HP-beta-CD content.

The dyeing of polyester fiber with two different disperse dyes (Disperse Red 60 and Disperse Yellow 54) was carried out using supercritical carbon dioxide (SCCO2) as a dyeing medium at temperatures ranging from 50 ℃ to 90 ℃ and at pressures from 15 MPa to 30 MPa. The dye uptake of Disperse Red 60 on polyester fiber was found to increase with temperature at constant pressure and SCCO2 density (700 kg/m 3 ). At 90 ℃ and 30 MPa, the dye uptake on polyester fiber increased with dyeing time and the saturation concentration of Red 60 was attained within 240 min, while a longer dyeing time was required for Yellow 54 to reach its saturation concentration. When dyestuff mixtures with mixing ratios of 0.01 to 9.0 (Red 60/Yellow 54) were used, the uptake ratio of the two dyes was found to be proportional to 0.26 power of their mixing ratio. Dyed fibers showed an orange color and the depth of the color depended upon the mixing ratio of the dyestuffs.

Methoxy poly(ethylene glycol)-b-poly(L-lactide) (MPEG-PLLA) diblock copolymer was synthesized via ring-opening polymerization, and MPEG-PLLA microparticles were then prepared using an aerosol solvent extraction system (ASES) technique with compressed carbon dioxide as antisolvent. The MPEG-PLLA microparticles were prepared at temperatures ranging from 25 °C to 55 °C and at pressures from 85 bar to 150 bar. The concentration of MPEG-PLLA copolymer, solution flow rate, and CO2 flow rate were adjusted to be 0.5–3.0% (w/v), 0.3–1.0 mL/min, and 19 g/min, respectively. Relatively small spherical microparticles were prepared in the subcritical region at 25 °C, while agglomerated particles were obtained at temperatures above the critical point. The mean particle sizes of the MPEGPLLA microparticles prepared by the ASES varied from 9.53 μm to 46.9 μm depending upon the operating conditions.

In this study, two different extraction techniques, organic solvent extraction and supercritical carbon dioxide ($SCCO_2$) extraction, were employed to evaluate the extraction efficiency of oil from Chlorella vulgaris. In the organic solvent extraction, the effects of various organic solvent on the extraction yield were investigated. The $SCCO_2$ extraction was carried out while varying such operating parameters as temperature, pressure, $SCCO_2$ flow rate, and cosolvent. About 4.9 wt% of oil was extracted from ground Chrollera vulgaris for 18 h when dichloromethane/methanol (2：1, v/v) was used as an extraction solvent. The oil yield of the $SCCO_2$ extraction was found to be very low (0.53 wt%) and to increase up to about 0.86 wt% with the addition of cosolvent.