• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.3 s.47
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• pp.295-305
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• 2004

Colloid and surface chemistry have been focused on surface area and surface energy. Local surface properties such as surface density, interaction, molecular orientation and reactivity have been one of interesting subjects. Systems of such surface energy being important would be listed as association colloid, emulsion, particle dispersion, foam, and 2-D surface and film. Such nanoparticle systems would be applied to drug delivery systems and functional cosmetics with biocompatible and degradable materials, while nanoparticles having its size of several nm to micron, and wide surface area, have been accepted as a possible drug carrier because their preparation, characteristics and drug loading have been inves-tigated. The biocompatible carriers were also used for the solubilization of insoluble drugs, the enhancement of skin absorption, the block out of UV radiation, the chemical stabilization and controlled release. Nano/micro emulstion system is classified into nano/microsphere, nano/microcapsule, nano/microemulsion, polymeric micelle, liposome according to its prep-aration method and size. Specially, the preparation method and industrial applications have been introduced for polymeric micelles self-assembled in aqueous solution, nano/microapsules controlling the concentration and activity of high concen-tration and activity materials, and monolayer or multilayer liposomes carrying bioactive ingredients.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.376-383
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• 2011

The CMCs of LA and LA3 nonionic surfactants obtained from the reaction between glycidol and lauryl alcohol were found to be $0.97{\times}10^{-3}mol/L$ and $1.02{\times}10^{-3}mol/L$ respectively and the surface tensions for 1 wt% surfactant were 26.99 and 27.48 mN/m respectively. Dynamic surface tension measurements using a maximum bubble pressure tensiometer showed that the adsorption rate of surfactant molecules at the interface between the air and the surfactant solution was found to be relatively fast in both surfactant systems, presumably due to the high mobility of surfactant molecules. The contact angles of LA and LA3 nonionic surfactants were 27.8 and $20.9^{\circ}$ respectively and the dynamic interfacial tension measurement by a spinning drop tensiometer showed that interfacial tensions at equilibrium condition in both systems were almost the same. Also both surfactant systems reached equilibrium in 2~3 min. Both surfactant solutions showed high stability when evaluated by conductometric method and the LA nonionic surfactant system provided the higher foam stability than the LA3 nonionic surfactant system. The phase behavior experiments showed a lower phase or oil in water (O/W) microemulsion in equilibrium with an excess oil phase at all temperatures studied. No three-phase region was observed including a middle-phase microemulsion or a lamellar liquid crystalline phase.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.480-485
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• 1997

The absorption profile of phenytoin Na emulsion were examined compared to that of phenytoin suspension after oral administration in the rat. The corn oil-in-water emulsion, particle size of $184{\pm}$57.8 nm, was prepared using a microfludizer, and phenytoin Na added by shaft homogenizer. The phenytoin emulsion or suspension, 100 mg/kg, were intubated intragastrically using oral dosing needle and blood samples were withdrawn via an indwelling cannula from the conscious rat. Plasma concentrations of phenytoin were measured with HPLC using phenacetin as an internal standard. The plasma concentration versus time data were fitted to a one compartment open model and the pharmacokinetic parameters were calculated using the computer program, Boomer. The phenytoin plasma concentrations from the emulsion at each observed time were about 1.5-2 times higher than those from the suspension, significantly at time of 5, 6 and 7 hr after administration. The absorption $(k_a)$ and elimination rate constant $(k_e)$ were not altered significantly, however the AUC increased from 65.6 to $106.7{\mu}ghr/ml$ after phenytoin suspension or emulsion oral administration, respectively. From an equilibrium dialysis study, the diffusion rate constant $(k_{IE})$ was considerably higher from the phenytoin Na emulsion $(0.0439 hr{-1})$ than phenytoin suspension $(0.0014 hr{-1})$.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.517-519
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• 1991

The effect of glucose oxidase (GO) and superoxide dismutase (SOD) on the oxidative stability of fish oil was investigated from oxygen content and peroxide value determinations of oil samples stored in vial. GO could inhibit the oxidation of the oil by removing headspace oxygen. When SOD was solubilized in the oil, peroxide value was slightly lower than that of a control, indicating that the enzyme also had an effect on retarding the oxidation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.4
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• pp.277-281
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• 2006

Spherical micro silica sol-gel immobilized enzyme beads were prepared in an emulsion system using cyclohexanone and Triton-X 114. The beads were used for the in situ immobilization of transaminase, trypsin, and lipase. Immobilization during the sol to gel phase transition was investigated to determine the effect of the emulsifying solvents, surfactants, and mixing process on the formation of spherical micro sol-gel enzyme beads and their catalytic activity. The different combinations of sol-gel precursors affected both activity and the stability of the enzymes, which suggests that each enzyme has a unique preference for the silica gel matrix dependent upon the characteristics of the precursors. The resulting enzyme-entrapped micronsized beads were characterized and utilized for several enzyme reaction cycles. These results indicated improved stability compared to the conventional crushed form silica sol-gel immobilized enzyme systems.

• Journal of Powder Materials
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• v.16 no.3
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• pp.180-184
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• 2009

In this paper, the electrochemical non-enzyme immunosensor has been developed for the determination of salmonella antigen, using inverse voltammetry. For the estimation of salmonella antigen concentration, the $Fe_3O_4$ nanoparticles synthesized by microemulsion method were conjugated with salmonella antigen. Then, the immunocomplex between antibody immobilized on the transducer surface and antigen containing a magnetic nanoparticles was formed. From the linear relationship between the reduction peak current of Fe(III) and salmonella antigen concentration, it is suggested that the electrochemical non-enzyme biosensor is applicable to detect salmonella antigen in the concentration range of $10^1-10^5$ CFU/ml.

• Journal of Pharmaceutical Investigation
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• v.39 no.2
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• pp.111-115
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• 2009

The pharmacokinetics of cyclosporin A (CsA) after single and multiple oral dosing of new CsA self-micro-emulsifying drug delivery system (SMEDDS) in dogs were estimated. A single dose study was performed following a two-way crossover design against six dogs with reference SMEDDS. For a multiple dose study, three dogs were allocated for each drug, and 100 mg of drug was administered daily for 6 days. Whole blood concentration of CsA was analyzed by radio-immunoassay. Both drug showed identical blood concentration profiles in both studies, and no statistical difference was detected in pharmacokinetic parameters. The relative bioavailabilities of test SMEDDS were 91.4% and 89.1%, respectively, in the single dose study and the last day of multiple dose study. Especially, multiple dose study proved the good relationship between C-0/C-2 and AUC for reference SMEDDS, which is an indispensable part of therapeutic drug monitoring. These results suggest newly formulated CsA SMEDDS possibly shows identical pharmacokinetics and pharmacodynamic behaviors in clinical trials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1768-1772
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• 2010

Intra-molecular association is an important contribution to the overall hydrogen bonding in surfactant systems, especially in systems of colloidal and biological interest. Amphiphile systems, especially micelle and microemulsion systems, showed highly non-ideal behavior due to the intermolecular association and intra-molecular association. The objective of this research is to present a lattice fluid equation of state that combines the quasi-chemical nonrandom lattice fluid model with modified Veytsman statistics for intra + inter molecular association to calculate phase behavior for mixture containing surfactant systems. The lattice model could describe the literature data well for alkane and surfactant systems.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.60-65
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• 2006

In order to investigate the dependence of the particle size on the cation distribution in the spinel structure, Mossbauer spectra were taken in the presence of an external magnetic field f3r the magnetic nanoparticles prepared by using a microemulsion method. The crystals are found to have a cubic structure. The results show that as the particle sizes decrease, $Fe^{3+}$ ions migrate from the octahedral site to tetrahedral site.

• Journal of Powder Materials
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• v.17 no.3
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• pp.230-234
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• 2010

Homogenous silica-coated $CoFe_2O_4$ samples with controlled silica thickness were synthesized by the reverse microemulsion method. First, 7 nm size cobalt ferrite nanoparticles were prepared by thermal decomposition methods. Hydrophobic cobalt ferrites were coated with controlled $SiO_2$ using polyoxyethylene(5)nonylphenylether (Igepal) as a surfactant, $NH_4OH$ and tetraethyl orthosilicate (TEOS). The well controlled thickness of the silica shell was found to depend on the reaction time and the amount of surfactant used during production. Thick shell was prepared by increasing reaction time and small amount of surfactant.