• Food Science and Biotechnology
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• v.17 no.4
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• pp.833-838
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• 2008

Size effects of rice product powders on physical properties including suspension stability were investigated in this study. Endosperm, bran, and husk powders of rice with different size particles were prepared using the pin crusher or the ultrafine air mill. The physical properties of the powders were examined using particle size analysis, scanning electron microscopy, and spectrophotometry. The peak of the volume-weighted particle distribution of ultrafine endosperm particles was at $5.4\;{\mu}m$ whereas those of the bran and the husk appeared at 65 and $35\;{\mu}m$, respectively. Ultrafine particles of the endosperm and the husks dispersed better than larger-sized particles. As time elapsed, the dispersibility decreased, but the ultrafine particles were precipitated at the slowest rate. Our results suggest that ultrafine particles, including future nanosized particles, provide improved solubility and dispersibility resulting in better stability in the food colloidal suspension.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.116-116
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• 1997

Complex formation of practically insoluble dexamethasone dipropionate (DDP) with ${\beta}$-cyclodextrin (${\beta}$-CD), dimethyl-${\beta}$-cyclodextrin (DMCD), trimethyl-${\beta}$-cyclodextrin (TMCD), 2-hydroxypropyl-${\beta}$-cyclodextrin (HPCD) and sulfobutyl ether ${\beta}$-cyclodextrin (SBCD) in water was investigated by solubility method at various temperatures. Water solubility of DDP was found to be 1.78 $\mu\textrm{g}$/$m\ell$ at 37$^{\circ}C$. Propylene glycol (PG)-water cosolvent increased the solubility of DDP, but the solubilization was not sufficient (8.93 $\mu\textrm{g}$/$m\ell$ in 20% PG). The addition of CD markedly increased the solubility of DDP in water, and A$\sub$L/ type phase solubility diagrams were obtained with ${\beta}$-CD, TMCD, HPCD and SBCD, where the apparent stability constants of the soluble complexes at 25$^{\circ}C$ were determined to be 1388, 216, 1054, and 1992 M$\^$-1/, respectively. However, DMCD remarkably increased the solubility of DDP, and showed an A$\sub$P/ type diagram, suggesting that DMCD forms a soluble complex of high order with DDP. The stability constant for the DDP-DMCD complex at 25$^{\circ}C$ was determined to be 19132 M$\^$-1/. The thermodynamic parameters were calculated for the inclusion complex formation in aqueous solution. CD (1${\times}$10$\^$-2/M) remarkably decreased the partition coefficients of DDP between isopropyl myristate/water in the order of TMCD < ${\beta}$-CD < HPCD < SBCD < DMCD, and in squalane/water system in the order of HPCD < TMCD < ${\beta}$-CD < DMCD < DMCD $\leq$ SBCD. This finding represents that, in a o/w type cream, cyclodextrin complexation with DDP may result in high concentration of DDP in aqueous phase. The permeation of DDP through a cellophane membrane was highly suppressed by the addition of CD, and the degree of suppression was different among CDs, indicating that CD may control the skin permeation of DDP. The dissolution rates of solid dispersions with CDs were much faster than those of drugs alone and corresponding physical mixtures. All DDP-CD solid dispersions exceeded the equilibrium solubility. Consequently these results suggest that complex formation of DDP with CDs may provide useful means to markedly enhance the solubility, and CDs are useful in the semi-solid preparations such as creams and gels for topical application.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.642-644
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• 1999

We have prepared the plasma-polymerized membrane for pervaporation of organic-liquid mixtures by the plasma polymerization technique. Plasma polymerization techniques were utilized in the development of hydrophilic composite membranes having high hydrogen ion permeability and excellent dimensional stability. To develop an organic liquid permselective Membrane, suppressing membrane swearing as well as enhancing the solubility difference is impotant. the objectives of the present study are to disign a suitable membrane for an organic-mixture system by the control of the plasma-polymer solubility.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.80-86
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• 1997

Nine new solubility-increased container hosts having eight undecyl substituents were synthesized and characterized. 1H NMR spectral data showed integral inclusion state of carceplexes and their stability. 1H NMR chemical shifts of guest DMA were correlated to the host's cavity dimensions shrinked by constrictive binding. Carceplex and hemicarcerand showed their distinctive FD mass spectra.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1439-1446
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• 2009

The surfaces of different-sized endosperm, bran, and husk rice powders were modified using carboxymethylation. Carboxymethylation was carried out using aqueous alkalization and neutralization. After the carboxymethylation process, the centrifuged products were milled and classified by size: particles passed through sieves of 45, 106, and $300-{\mu}m$ width. The effect of carboxymethylation on physical properties such as solubility and dispersibility of endosperm, bran, and husk particles were studied. Overall, carboxymethylation increased solubility of the particles, while size reduction increased dispersibility. In particular, carboxymethylation created good aqueous suspensions by minimizing interparticle agglomeration. Our results show that the combination of size reduction and carboxymethylation improves solubility and dispersibility, resulting in better stability of the suspension. This study may be helpful for expanding the use of rice and its byproducts as ingredients in a variety of food and beverage applications.

• Macromolecular Research
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• v.14 no.1
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• pp.107-113
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• 2006

Processible norbornene copolymers were realized by judiciously designing norbomene comonomers, which were themselves prepared by the Diels-Alder reaction of cyclopentadiene and benzoquinone followed by the isomerization and alkylation of alcohols. The norbornene copolymers containing these derivatized comonomers, prepared by [Pd($x_{2}CH-{3} $)$_{4}$][$SbF_{6}$]$_{2}$ catalyst, exhibited excellent solubility in many organic solvents as well as good thermal stability, as evidenced by their high glass transition ($T_{g}$) and decomposition ($\∼$350$^{circ}C$) temperatures. In addition, fairly strong adhesion to substrates such as glasses and silicon wafers was also achieved with these copolymers to overcome the limitations experienced by polynorbornene homopolymers and to make them attractive for many important industrial applications.

• Food Science of Animal Resources
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• v.23 no.1
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• pp.63-69
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• 2003

This experiment was carried out to study changes in solubility and emulsifying properties of whey protein. Whey protein hydrolysates were obtained from tryptic hydrolysis of whey protein concentrate at pH 8.0 and 37$^{\circ}C$ for 6 hours. Emulsifying activity of whey protein hydrolysate was highest at 4 hours of hydroysis and at 5.50% of DH. During hydrolysis of whey protein concentrate with trypsin, ${\alpha}$-lactalbumin was not easily broken down. But ${\beta}$-lactoglobulin was hydrolysed rapidly from the early stage of hydrolysis, producing several low molecular weight peptides, which have to participate in increasing emusifying activity. The solulbility of hydyolysates tended to increase depending on hydrolysis time; however, there was a gradual decrease after 5 hours. The hydrolysate had a minimum solubility near the isoelectric point range (pH 4∼5). The more hydrolysed the whey protein concentrates, the more soluble they are near the pl. They aye also more soluble above pH 6. Emulsifying activity of hydrolysates showed similar results to solubility. Creaming stability gradually increased when hydrolysis increased, increasing rapidly above pH 8 after 4 hours of hydrolysis.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1089-1093
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• 1997

The physicochemical properties of erythritol were examined by measuring water absorption, solubility, water activity, heat stability, and viscosity compared to those of sucrose, xylitol, sorbitol and fructo-oligosaccharide. Erythritol showed the lowest water absorption and the highest water activity reducing capacity. In the solubility test of sweeteners, the saturation concentration of erythritol at $20^{\circ}C$ was 35.8%, which was the lowest solubility. Caramelization test and Maillard reaction test showed that erythritol was stabler than sucrose in heat treatment, while fructo-oligosaccharide showed the strongest reaction. The viscosity of erythritol was similar to that of other sweeteners at the same concentration (10%, 30% w/w). The viscosity of sweeteners increased exponentially with increasing concentration but decreased with increasing temperature following Arrhenius equation. The activation energy for flow of 30% erythritol solution was estimated to be 10.8 kcal/g mol.

• Journal of Pharmaceutical Investigation
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• v.40 no.1
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• pp.15-21
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• 2010

Sibutramine is an orally administered centrally-acting antiobesity agent and inhibits both noradrenaline(norephinephirine) and serotonin(5-HT) reuptake. These effects are contributed by its active metabolites, M1 and M2. However, as the free base form of sibutramine is an oil form in room temperature, it had the problem of handling and stability. Thus, this drug should be used in the form of acid salt form in the pharmaceutical application. Unfortunately, anhydrous sibutramine hydrochloride is highly hygroscopic and unstable. In order to solve the hygroscopicity of the anhydrous salt form, another sibutramine acid salt form must be developed as a hydrate form. In this study. to overcome these problems, various of sibutramine acid salt forms were prepared with the pharmaceutically available salts such as maleate, esylate, mandelate, camsylate, besylate, salicylate, tartrate, isethionate and malate forms, and their physicochemical properties were investigated. Sibutramine malate was selected for excellent solubility and stability among the listed salt forms above. Its pharmacokinetic parameters were evaluated in rats comparing with sibutramine HCl, resulting in similar parameters. In vitro dissolution study of sibutramine malate-loaded capsule was performed comparison with commercial product ($Reductil^{(R)}$) in pH 1.2, pH 4.0, pH 6.8 and water medium. Our results indicated that there were no significant differences in their dissolution profiles were similar in all tested medium. Thus, sibutramine malate-loaded capsule should be a potential candiate due to its excellent solubility, good stability and biosimilar absorption.

• Mass Spectrometry Letters
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• v.8 no.3
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• pp.59-64
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• 2017

In clinical diagnosis, it's well known that the abnormal level of uric acid (UA) in human body is implicated in diverse human diseases, for instance, chronic heart failure, gouty arthritis, diabetes, and so on. As a primary method, an isotope dilution mass spectrometry (IDMS) has been used to obtain the accurate quantity of UA in blood or serum and also develop the certificated reference material (CRM) so as to provide a SI-traceability to clinical laboratories. Due to the low solubility of UA in water, an ammonium hydroxide ($NH_4OH$) has been considered as a promising solvent to increase the solubility of UA that enables the preparation of both UA and its isotope standard solution for next IDMS-based absolute quantification. But, because of using this $NH_4OH$ solvent, it gives rise to the unwanted degradation of UA. In this study, we sought to optimize condition for the stability of UA in $NH_4OH$ solution by varying the mole ratios of UA to $NH_4OH$, followed by ID-LC-MRM analysis. In addition, we also inspected minutely the effect of the storage temperatures. Additionally, we also performed the quantitative analysis of UA in the KRISS serum certificated reference material (CRM, 111-01-02A) with diverse mixing ratios of UA to $NH_4OH$ and then compared those values to its certification value. Based on our experiments, adjusting the mole ratio of 1/2 ($UA/NH_4OH$) with the storage temperature of $-20^{\circ}C$ is an effective way to secure both the solubility and stability of UA in $NH_4OH$ solution for next IDMS-based quantification of UA in serum.