• KSBB Journal
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• v.23 no.6
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• pp.546-550
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• 2008

Basic characteristics of astaxanthin including solubility and stability were investigated. Astaxanthin showed a very poor solubility in water, but it was highly soluble in organic solvents such as acetone and acetic acid. The solubility of astaxanthin in acidic condition was 10-20 times higher than those in neutral and basic conditions. Astaxanthin was very unstable in acidic condition under UV irradiation and in the presence of oxygen. Also, heating even for a very short time accelerated the degradation of astaxanthin. In conclusion, it is required to enhance the water-solubility and stability of astaxanthin for industrial application in food and cosmetic area.

• Korean journal of food and cookery science
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• v.9 no.1
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• pp.43-51
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• 1993

Buckwheat protein isolate was tested for the effects of pH, addition of sodium chloride and heat treatment on solubility, emulsion capacities, emulsion stability, surface hydrophobicity, foam capacities and foam stability. The solubility of buckwheat protein isolate was affected by pH and showed the lowest value at pH 4.5, the isoelectric point of buckwheat protein isolate. The solubility significantly as the pH value reached closer to either ends of the pH, i.e., pH 1.0 and 11.0. The effects of NaCl concentration on solubility were as follows; at pH 2.0, the solubility significantly decreased when NaCl was added; at pH 4.5, it increased above 0.6 M; at pH 7.0 it increased; and at pH 9.0 it decreased. The solubility increased above $80^{\circ}C$, at all pH ranges. The emulsion capacity was the lowest at pH 4.5. It significantly increased as the pH approached higher acidic or alkalic regions. At pH 2.0, when NaCl was added, the emulsion capacity decreased, but it increased at pH 4.5 and showed the maximum value at pH 7.0 and 9.0 with 0.6 M and 0.8 M NaCl concentrations. Upon heating, the emulsion capacity decreased at acidic pH's but was maximised at pH 7.0 and 9.0 on $60^{\circ}C$ heat treatment. The emulsion stability was the lowest at pH 4.5 but increased with heat treatment. At acidic pH, the emulsion stability increased with the increase in NaCl concentration but decreased at pH 7.0 and 9.0. Generally, at other pH ranges, the emulsion stability was decreased with increased heating temperature. The surface hydrophobicity showed the highest value at pH 2.0 and the lowest value at pH 11.0. As NaCl concentrationed, the surface hydrophobicity decreased at acidic pH. The NaCl concentration had no significant effects on surface hydrophobicity at pH 7.0, 9.0 except for the highest value observed at 0.8 M and 0.4 M. At all pH ranges, the surface hydrophobicity was increased, when the temperature increased. The foam capacity decreased, with increased in pH value. At acidic pH, the foam capacity was decreased with the increased in NaCl concentration. The highest value was observed upon adding 0.2 M or 0.4 M NaCl at pH 7.0 and 9.0. Heat treatments of $60^{\circ}C$ and $40^{\circ}C$ showed the highest foam capacity values at pH 2.0 and 4.5, respectively. At pH 7.0 and 9.0, the foam capacity decreased with the increased in temperature. The foam stability was not significantly related to different pH values. The addition of 0.4 M NaCl at pH 2.0, 7.0 and 9.0 showed the highest stability and the addition of 1.0 M at pH 4.5 showed the lowest. The higher the heating temperature, the lower the foam stability at pH 2.0 and 9.0. However, the foam stability increased at pH 4.5 and 7.0 before reaching $80^{\circ}C$.

• Korean journal of food and cookery science
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• v.6 no.3 s.12
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• pp.9-15
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• 1990

Peanut prptein isolate was tested for the purpose of finding out the effect of pH, Sodium Chloride concentration and heat treatment on the solubility, surface hydrophobicity, foam expansion and foam stability. The solubility of peanut protein isolate was affected by pH and showed the lowest value at pH 4.5. When the peanut protein isolate was heated, the solubility decreased at pH 3 and pH 7 but at pH 9 solubility increased. At all pH range, solubility decreased as NaCl was added. The surface hydrophobicity of peanut protein isolate showed the highest value at pH 1.5. Generally, at acidic pH range the surface hydrophobicity was high, but at alkaline region, the surface hydrophobicity increased as the temperature increased. And when NaCl was added, the surface hydrophobicity was also increased. Foam expansion of peanut protein isolate was no significant difference among the values about pH. When the peanut protein was heated and NaCl was added, foam expansion was increased at pH 7. Foam stability was significantly low at pH 4.5 and foam stability was increased at acidic pH region below pH 4.5. At pH 7 and pH 9, heat treatment above $60^{\circ}C$ increased foam stability. When NaCl was added, foam stability was significantly increased at pH 3 and pH 7.

• Journal of Pharmaceutical Investigation
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• v.27 no.3
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• pp.199-205
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• 1997

In order to formulate biphenyl dimethyl dicarboxylate(DDB) aqueous solutions, the effects of various solubilizing agents such as cosolvents(PG, PEG 400, glycerin, ethanol), surfactants,$(poloxamer\;407,\;Cremophor^{\circledR}\; RH40,\;Solutol^{\circledR},\;Tween\;80,\;sodium\;lauryl\;sulfate)$, complexation agent$(CELDEX^{\circledR}\;CH-20)$ and others(urea, niacinamide, propylene carbonate, HPMC) on the solubility of DDB in water were evaluated. The solubility of DDB in water was about $0.21\;{\mu}g/ml\;at\;20^{\circ}C$, while its solubility in PEG 400 was 5,000 times higher than that in water. 60% PEG 400 aqueous solution was selected as an optimum solvent system, and surfactants or other solubilizing agents were added to prevent DDB from recrystalization. The addition of surfactants in water increased the solubility of DDB from 15- to 34-fold, however, $CELDEX^{\circledR}\;CH-20$ and other agents studied showed negligible effects on the solubility of DDB in water. The 60% PEG 400 aqueous solution containing 5% $Cremophor^{\circledR}$　RH40 was appeared as the formula of choice. It showed acceptable physical stability after stored for 7 days at $4^{\circ}C$.

• Journal of Pharmaceutical Investigation
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• v.18 no.4
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• pp.203-208
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• 1988

The stability and solubility of piroxicam in propylene glycol (PG), polyethylene glycol (PEC), and PG-water cosolvents have been studied by using high performance liquid chromatography. The degradation rate followed an apparent first-order kinetic and the reaction rate constants at 70, 80, and $90^{circ}C$ were determined. From these rate constants, the activation energy and the rate constant of piroxicam at $25^{circ}C$ in pure PG calculated by Arrhenius equation were 23.34 kcal/mole and $7.0\;{\times}\;10^{-4}\;day^{-1}$, respectively. Both of PG and PEG increased the solubility of the drug, but PEG was more effective.

• Korean journal of food and cookery science
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• v.7 no.3
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• pp.53-59
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• 1991

This study was carried out in order to investigate the change of protein functionalities such as foaming and emulsifying properties by succinylation of protein isolates. Succinylated and unsuccinylated munghean protein isolates were tested for finding out the effects of pH, heat treatment and sodium chloride concentration on the solubility, emulsion capacity, emulsion stability, foaming capacity, and foam stability. The results are summarized as follows: 1. Succinylation enhanced the solubility of MPI except at pH 4.5. When heated, succinylation greatly increased the solubility of succinylated MPI above $60^{\circ}C$. With the addition of NaCl, succinylation increased the solubility of MPI at acidic condition. 2. Emulsion capacity of succinylated MPI showed the lowest value at pH 7 and higher values at acidic and alkaine condition. when succinylated MPI was heated, emulsion capacity showed the highest at $80^{\circ}C$. With NaCl was added, emulsion capacity of succinylated MPI lincreased at pH 7, 9 or 11 decreased at pH 3 except addition of 1.0M NaCl. 3. Emulsion stability of MPI and succinylated MPI showed the highest at pH 4.5. Succinylation enhanced the emulsion stability of MPI at acidic condition. 4. The foaming capacity of MPI was increased at pH 3, 7 or 9 by succinylation. 5. When heated, foam stability of MPI and succinylated MPI showed the highest at pH 4.5 and at pH 11, respectively. When heated, both proteins showed the highest stability at $100^{\circ}C$.

• Journal of Pharmaceutical Investigation
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• v.40 no.spc
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• pp.97-102
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• 2010

A novel surface-attached solid dispersion is designed to improve the solubility and oral bioavailability of poorly water-soluble drugs without crystalline change. Accordingly, it draws increasing interest because of excellent stability and no pollution for accomplishing enhanced solubility and bioavailability, which have recently been highlighted in connection with a number of higher value-added poorly water-soluble drugs. In addition, excellent stability can be attained when the poorly water-soluble drugs are not dissolved but dispersed in water and provide no crystallinity change. This solid dispersion is given by means of attaching the dissolved carriers such as hydrophilic polymer and surfactant to the surface of dispersed drug particles followed by changing the hydrophobic drug to hydrophilic form. The aim of the present review is to outline the preparation, physicochemical property and bioavailability of novel surface-attached solid dispersion with improved solubility and bioavailability of poorly water-soluble drugs without crystalline change.

• Journal of Pharmaceutical Investigation
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• v.25 no.4
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• pp.283-289
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• 1995

The aim of this study is to increase the solubility and dissolution rate of clonixin by inclusion complex formation. Inclusion complexes of clonixin, a non-steroidal antiinflammatory drug, with ${\beta]-cyclodextrin$ were $2-hydrolrypropyl-{\beta]-cyclodextrin$ were prepared by freeze drying method. Inclusion complex formation of clonixin with cyclodextrins was determined by UV, IR and DSC. The apparent stability constants were calculated from the phase solubility diagrams. Dissolution rate and solubility of clonixin in water markedly increased by the complex formation.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1433-1436
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• 2000

The effect of addition of pectin on the stability of casein solution was studied to apply casein-pectin mixture to apple juice. The solubility of 0.1% casein solution was below 20% at pH 3-5. However, the solubility of 0.1% casein-0.1% pectin mixtures was over 70% at pH 2-10. The increase in the concentration of casein-pectin mixture showed adverse effect on the solubility. The apple juice (pH 3.4), containing 0.1-0.5% casein-pectin mixtures, remained stable without the precipitation of casein. The stability of apple juice including casein-pectin mixture was maintained upon heating at $100^{\circ}C$ for 10 minutes or refrigerating for a week. This study suggested the possibility of protein fortification to acidic beverages since casein-pectin mixture maintained stability in apple juice.

• The Korean Journal of Food & Health Convergence
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• v.5 no.4
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• pp.13-17
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• 2019

Amiodarone hydrochloride is an antiarrhythmic agent which has low aqueous solubility and presents bioavailability problem. These properties are a challenge for the pharmaceutical industry. Inclusion of lipophilic compound in the hydrophobic core of micelles, i.e. self-assembled structures based on surfactants in aqueous solution, is one way of increasing the solubility. Intravenous formulation of amiodarone hydrochloride with polysorbate 80 as a detergent and benzyl alcohol as a co-solvent is used in medical practice. This paper aimed to study the effect of polysorbate 80 and benzyl alcohol on the water solubility of amiodarone hydrochloride. Formation of mixed micelles consisting of nonionic surfactant polysorbate 80 and cationic amiodarone with chloride counterion was investigated by fluorescence spectroscopy. Benzyl alcohol was found to decrease the stability of the mixed micelles and lead to crystallization of amiodarone hydrochloride. The greatest amounts of crystals formed at 4℃ for 30 days in the model drug solutions with polysorbate 80 concentrations of 100.1 mg/mL and 97.9 mg/mL. A change of the polysorbate 80 concentration and avoidance the use of benzyl alcohol are recommended to improve the stability of the parenteral dosage form. These results can open new perspectives in the optimization of amiodarone intravenous formulations.