• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.740-746
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• 2009

In the present study, the drowning-out crystallization of L(+)-calcium lactate was investigated in order to develop the crystallization separation process. The crystallization of the calcium lactate was induced by injecting the alcoholic anti-solvent into the aqueous solution of calcium lactate and the control of the calcium lactate crystal size during the crystallization was primarily investigated under the consideration of the anti-solvent species, anti-solvent composition and agitation speed as the key operating factors. Alcohols of methanol, ethanol, n-propanol and i-propanol were used as the anti-solvent for the drowning-out crystallization. Prior to the crystallization experiment, the solubility of calcium lactate in the water-alcohol mixture was measured along with the variation of the alcohol species and composition, which was necessary to estimate the supersaturation level of the crystallization. By the drowning-out crystallization, the calcium lactate crystals of the fabric shape were obtained. Using the ethanol as the antisolvent, the fabric crystals close to the needle shape were produced. However, the hairy crystals were obtained by using the propanol as the anti-solvent. Due to such morphological features, the crystals was highly apt to form the aggregates. The aggregation of the crystals was intensified as increasing the alcohol fraction in the water-alcohol mixture. Meanwhile, the agitation caused the breakage of crystals, resulting in the decrease of the crystal size. Therefore, the crystal size in the crystallization was predominantly determined by the competition between the crystal aggregation and breakage.

• Clean Technology
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• v.14 no.4
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• pp.242-247
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• 2008

Poly(N-vinyl-2-pyrrolidone) (PVP) has been used as biocompatible and biodegradable polymer in cosmetics, pharmaceuticals and electronics. Micro-particles of PVP were produced using an aerosol solvent extraction system (ASES). Dichloromethane (DCM) and supercritical carbon dioxide were used as solvent and antisolvent, respectively. The mean diameter of the obtained polymer particles ranged from 0.184 to $0.249\;{\mu}m$. The relationship between particle size and initial drop size was also considered.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.526-531
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• 2023

This study investigated the ingredients, anti-aging and anti-dementia activities of the Korean marine algae Silvetia siliquosa. The S. siliquosa solvent extracts were prepared with 70% ethanol, 80% methanol, and distilled water. The extraction yield range of various solvent extracts was 15.82-49.98%. The ethanol and methanol extracts had higher tyrosinase and collagenase inhibitory activities than those of the water extract. Meanwhile, all extracts exhibited high elastase inhibitory activity. Conversely, the methanol and water extracts exhibited the highest acetylcholinesterase inhibitory activity (IC₅₀, 0.40 mg/mL) and β-secretase inhibitory activity (IC₅₀, 0.81 ㎍/mL), respectively. These results indicate that S. siliquosa may be useful in food and pharmaceutical materials as a cosmetic and functional.

• Clean Technology
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• v.13 no.1 s.36
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• pp.34-45
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• 2007

Phase behavior of the ternary systems of water-insoluble simvastatin drug, which is well known to be effective drugs for hypercholesterolemia therapy, in solvent mixtures of dichloromethane and supercritical carbon dioxide was investigated to present a guideline of establishing operating conditions in the particle formation of the drugs by a supercritical anti-solvent recrystallization process utilizing dichloromethane as a solvent and carbon dioxide as an anti-solvent. The solubilities of simvastatin in the mixtures of dichloromethane and carbon dioxide were determined as functions of temperature, pressure and solvent composition by measuring the cloud points of the ternary mixtures at various conditions using a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The solubility of the drug increased as the dichloromethane composition in solution and the system pressure increases at a fixed temperature. A lower solubility of the drug was obtained at a higher temperature. The second half of this work is focused on the particle formation of the simvastatin drug by a supercritical anti-solvent recrystallization process in a cylindrical high-pressure vessel equipped with an impeller. Microparticles of the simvastatin drug were prepared as functions of pressure (8 MPa to 12 MPa), temperature (303.15 K, 313,15 K), feed flow rate of carbon dioxide, and stirring speed (up to 3000 rpm), in order to observe the effect of those process parameters on the size and shape of the drug microparticles recrystallized.

• KSBB Journal
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• v.30 no.4
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• pp.191-196
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• 2015

Blueberry juice possesses rich-procyanidins and - anthocyanidin, comprised a group of with numerous health benefits such as protection against coronary heart disease, detoxification, and obesity. Blueberry (Vaccinium virgatum) juice extracts were analyzed and separated by an HPLC method for the purpose of the separation and quantification in polyphenolic groups. In specific HPLC conditions, a binary mobile phase consisting of formic acid: water (10:90, v/v, solvent A) and formic acid: water: acetonitrile (10:60:30, v/v/v, solvent B) was utilized and it is detected at 546 nm wavelength. The phenolic contents of the extracts are determined using Folin-Ciocalteu phenol reagent. In order to test anti-inflammation activity assay, after producing nitric oxide (NO) in lipopolysaccharide activated RAW 264.7 cells, at concentration of $20-500{\mu}g/mL$ it reduced to NO production at a dose-dependent manner. Importantly, cytotoxicity assay with up to $500{\mu}g/mL$ of the extract from blueberry juice showed ~100% cell viability for RAW264.7 cell line. Therefore, Korean blueberry juice might have potential as anti-oxidant and antiinflammation agents.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.77-87
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• 2006

Micro- or nano-size particles are required to improve the combustion efficiency and stability in the case of solid explosives and propellants. The micro-structural properties of an energetic material strongly influence the combustion and explosion behavior. However, the traditional size reduction techniques, including milling, are not suitable for production of ultra-fine size particles. As an alternative to the traditional techniques, various re-crystallization processes based on supercritical fluids have recently been proposed. Supercritical fluids are fluids at temperatures and pressures above their critical point. In principle, they do not give problems of solvent contamination as they are completely released from the solute when the decompression occurs. Rapid Expansion Supercritical Solutions(RESS) and Supercritical Anti-Solvent Process(GAS/SAS) are representatives of a nano-size particle formation process of energetic materials using supercritical fluids. In this work, various fine particle formation processes using supercritical fluids are discussed and the results are presented.

• Clean Technology
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• v.13 no.4
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• pp.237-243
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• 2007

Phase behavior of the ternary systems of water-insoluble simvastatin drug, which is well known to be effective drugs for hypercholesterolemia therapy, in solvent mixtures of dimethyl ether (DME) and supercritical carbon dioxide was investigated to present a guideline of establishing operating conditions in the particle formation of the drugs by a supercritical anti-solvent recrystallization process utilizing DME as a solvent and carbon dioxide as an anti-solvent. The solubilities of simvastatin in the mixtures of DME and carbon dioxide were determined as functions of temperature, pressure and solvent composition by measuring the cloud points of the ternary mixtures at various conditions using a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The solubility of the drug increased as the DME composition in solution and the system pressure increases at a fixed temperature. A lower solubility of the drug was obtained at a higher temperature.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.413-416
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• 2010

In this research, root extracts of Nelumbo nucifera was tested to see the possibility for functional cosmetic agent. 70-100% ethanol was used as solvent and nuciferin was confirmed as active component. To test cosmetic effect of root extracts of Nelumbo nucifera, safety effect(MTT assay), anti-wrinkle effect(elastase inhibition assay) and antioxidation effect(DPPH free radical scavenging assay) were measured. When 100% ethanol was used as extracting solvent, cell viability was over 80% at $100{\mu}g/ml$, which indicated that root extract of Nelumbo nucifera was suitable for cosmetic agent. Root extract of Nelumbo nucifera showed 40~50% elastase inhibition at $100{\mu}g/ml$ so that it had good anti-wrinkle characteristics. 50% antioxidation capacity($FSC_{50}$) was $5.0{\sim}38{\mu}g/ml$ and root extract of Nelumbo nucifera showed excellent antioxidation effect. From the research, root extracts of Nelumbo nucifera showed strong possibility for anti-wrinkle functional cosmetic agent.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.730-736
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• 2015

Cyclotrimethylene trinitramine (RDX) is a high explosive commonly used for military applications. Submicronization of RDX particles has been a critical issue in order to alleviate the unintended and accidental stimuli toward safer and more powerful performances. The purpose of this study is to optimize experimental variables for drowning-out crystallization applied to produce submicron RDX particles. Effects of RDX concentration, anti-solvent temperature and anti-solvent mass were analyzed by the central composite rotatable design. The adjusted determination coefficient of regression model was calculated to be 0.9984 having the p-value less than 0.01. Response surface plots based on the central composite rotatable design determined the optimum conditions such as RDX concentration of 3 wt%, anti-solvent temperature of $0.2^{\circ}C$ and anti-solvent mass of 266 g. The optimum and experimental diameters of RDX particles were measured to be $0.53{\mu}m$ and $0.53{\mu}m$, respectively. The regression model satisfactorily predicts the average diameter of RDX particles prepared by drowning-out crystallization. Structure of RDX crystals was found to be ${\alpha}$-form by X-ray diffraction analysis and FT-IR spectroscopy.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.180-189
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• 2017

Pharmaceutical co-crystals primarily to improve the solubility as well as stability of insoluble drug are to be investigated more intensively for IMDs as US FDA has reclassified co-crystal as a special case of solvates in August this year. In this study, we proposed a mechanism of indomethacin-saccharin co-crystal formation and the creation of transient indomethacin meta-stable form using in-line monitoring tools with the addition rate of anti-solvent as a critical process parameter. Among various instruments, we combined PVM (particle vision measurement) and FBRM (focused beam reflectance measurement) for the in-line monitoring of anti-solvent co-crystallization process. The off-line characterization of resulting powders was carried out employing the PXRD (powder x-ray diffraction) and DSC (differential scanning calorimeter). It was observed that the pathway to the final IMC-SAC co-crystal was significantly dependent upon the anti-solvent addition rate. The process conditions to obtain high quality co-crystal powder effectively were established. Consequently, we concluded that in-line monitoring combing the PVM and FBRM should be useful for the in-line monitoring of pharmaceutical co-crystallization processes.