• 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.

• Tuberculosis and Respiratory Diseases
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• v.69 no.2
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• pp.115-118
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• 2010

Paclitaxel has been widely used for treating many solid tumors. Although colonic toxicity is an unusual complication of paclitaxel-based chemotherapy, the reported toxicities include pseudomembranous colitis, neutropenic enterocolitis and on rare occasions ischemic colitis. $Genexol-PM^{(R)}$, which is a recently developed cremophor-free, polymeric micelle-formulated paclitaxel, has shown a more potent antitumor effect because it can increase the usual dose of paclitaxel due to that $Genexol-PM^{(R)}$ does not include the toxic cremophor compound. We report here on a case of a 57-year-old man with advanced non-small cell lung cancer and who developed ischemic colitis after chemotherapy with $Genexol-PM^{(R)}$ and cisplatin. He complained of hematochezia with abdominal pain on the left lower quadrant. Colonoscopy revealed diffuse mucosal hemorrhage and edema from the sigmoid colon to the splenic flexure. After bowel rest, he recovered from his symptoms and the follow-up colonoscopic findings showed that the mucosa was healing. Since then, he was treated with pemetrexed monotherapy instead of a paclitaxel compound and platinum.

• Polymer(Korea)
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• v.30 no.5
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• pp.437-444
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• 2006

Reactive hydroxypropyl methylcellulose phthalate (reactive HPMCP) was synthesized by using a stepwise urethane reaction with isophorone diisocyanate (IPDI) and 2-hydroxyethyl moth acrylate (HEMA). Molecular weight, acid number, and critical micelle concentration (CMC) of the synthesized reactive HPMCP and pristine HPMCP were measured and used as a polymeric surfactant in the emulsion polymerizations of styrene. In the preparation of HPMCP-hybrid poly styrene nanoparticles, 6, 9, 12, 18, and 24 wt% of HPMCPs were introduced, and the maximum rate of polymerization ($R_{p,max}$), the average number of radicals per particle (n), particle size distribution were investigated. In addition, core - shell morphology of the nanoparticles were observed by using TEM and their thermal stabilities were measured by using TGA. Reactive HPMCP showed higher $R_{p,max}$, smaller particle size, larger values of n and gel contents as compared with pristine HPMCP, due to the vinyl groups from HEMA, which can be reacted with styrene oligomers, in the reactive HPMCP.

• Journal of Pharmaceutical Investigation
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• v.38 no.6
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• pp.393-398
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• 2008

A propofol delivery system was prepared using two biocompatible polymeric surfactants, poloxamer 407 and PEG 400. The nanoparticular stability of the micellar system was evaluated in terms of temperature change, storage time and composition. The particle size of the system was slightly increased with elevating temperature from $4^{\circ}C$ to $25^{\circ}C$, but its distribution was unimodal. At $40^{\circ}C$, the system presented a bimodal particle size distribution and the increase in the fraction of particles larger than 15 nm. This result might be due to the expansion of the nanoparticles through micellar swelling at the high temperature. It was found that propofol was gradually come out of the system, stored for a month at three different temperatures (4, 25 and $40^{\circ}C$). The drug loss was apparently dependent on temperature and the system composition. Increasing temperature induced the acceleration of the drug loss of $7{\sim}10%$ at $4^{\circ}C$ and $14{\sim}16 %$ at $40^{\circ}C$. This may be owing to the high diffusivity resulting from the swelling of the hydrophilic surface of the nanoparticle at high temperature. However, the addition of PEG 400 to the system led to the reduction of the drug loss. This result is associated with the previous investigation that PEG coverage decreased diffusion coefficient because of the formation of the denser structure on the surface of nanoparticulate. Nevertheless, the limited amount of PEG, less than 2% (w/v), should be used to prevent the precipitation and discoloration of the system.

• Polymer(Korea)
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• v.34 no.3
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• pp.274-281
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• 2010

In this study, PEG-PLA(or PLGA) amphiphilic di-block copolymers were synthesized by ring opening polymerization of D,L-lactide(or glycolide) and applied to polymeric micelle system for solubilization of a rosiglitazone as diabetes drug. The drug could be efficiently loaded into the polymer micelle by solid dispersion technique, and the drug-loaded micelles were characterized and evaluated as a drug delivery carrier by fluorescence spectrometer, DSC, and DLS measurements. The colloidal stability of drug loaded micelles in aqueous media could be enhanced by addition of 2-hydroxy-N-picolylnitinamide as a hydrotropic agent. The polymer micelles also showed biocompatible and nontoxic properties in vitro cell viability using MTT assay, and the drug loaded micelles were observed to be more effective than free drug for decreasing glucose in blood of rats.

• Carbon letters
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• v.11 no.2
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• pp.96-101
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• 2010

Dispersion of the functionalized multiwalled nanotubes (MWNT) in the polyurethane (PU) matrix and DC conductivity of the MWNT/PU composites are investigated with the oxidation conditions, the kind of surfactants and their content. First, the most optimal surfactant type and its critical micelle concentration in the MWNT suspension are determined as a cationic surfactant, benzalkonium chloride (BKC) of 0.6 wt.% to the MWNT content from DEA and FESEM results. All the MWNT oxidized under several conditions are negatively charged and functionalized with carboxylic group, whereas the degree of damage is different from oxidation conditions. In addition, each MWNT/PU composite derived from several oxidation conditions shows different DC conductivity at a characteristic MWNT content. It is found that in order to enhance DC conductivity of the polymeric composites containing the oxidized MWNT the better dispersion of MWNT should be obtained by effective functionalities and surfactant adsorption with preserving the intrinsic geometry of pristine MWNT.

• Journal of the Korean Applied Science and Technology
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• v.6 no.1
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• pp.51-57
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• 1989

A series of four sodium ${\alpha}-sulfo$ fatty vinyl ester oligomers including sodium ${\alpha}-sulfo$ lauric acid vinyl ester oligomer, sodium ${\alpha}-sulfo$ myristic acid vinyl ester oligomer, sodium ${\alpha}-sulfo$ palmitic acid vinyl ester oligomer and sodium ${\alpha}-sulfo$ stearic acid vinyl ester oligomer were examined for surface activities such as surface tension, foaming power, foam stability, emulsifying power, dispersion effect, solubilization of orange OT. The critical micelle concentration(CMC) was also evaluated. Consequently, these sodium ${\alpha}-sulfo$ fatty acid vinyl ester oligomers were shown to have a good cohesive power and dispersion effect.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.275-280
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• 2008

The effects of the surfactant type, i.e., CTAB(cationic), SDS(anionic), and GA(polymeric), on the stability of 0.1 vol.% $Al_2O_3$ nanofluids were investigated. The changes in size and zeta potential of nanoparticles in nanofluids with pH, surfactant concentration, and time were experimentally observed. The nanofluids adding CTAB, which ionizes of the same charge with the bare particle surface, was found to have the best stability regardless of the surfactant concentration, whereas those with SDS became unstable under low surfactant concentration conditions, i.e. lower than the critical micellel concentration(CMC), before the charge reversal occurred. With higher SDS concentration over CMC, they became stable. Gum Arabic, which had been used often to stabilize the nanofluids, was also tested. In result, it was found that the type and concentration of surfactants to add should be selected considering pH and the sign of the bare particle surface charge.

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.15-20
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• 2009

In this study, solubilization experiments of n-octane oil were performed by micellar solutions of polymeric nonionic surfactant Pluronic L64 ($EO_{13}PO_{30}EO_{13}$) at room temperature. A single spherical drop of n-octane was injected into aqueous surfactant solution using an oil drop contacting technique and solubilization rate of n-octane was measured by observing the size of oil drop with time. It was found that solubilization rate was independent of initial oil drop size but inversely proportional to the initial surfactant concentration. These results revealed that solubilization of n-octane oil by L64 micellar solution is controlled by interface-controlled mechanism rather than diffusion-controlled mechanism. Dynamic interfacial tension measurements showed that interfacial tension decreases such as from $2.59{\times}10^{-2}$ to $2.45{\times}10^{-2}$, and further to $2.13{\times}10^{-2}mN/m$ as surfactant concentration increases from 8 to 9 and further to 10 wt% respectively. The equilibration time was also found to decrease slightly with an increase in surfactant concentration. All three systems reached an equilibrium within 7 minutes.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.24-30
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• 2009

In this study, solubilization experiments of n-decane, n-undecane and n-dodecane oil were performed by micellar solutions of polymeric nonionic surfactant Pluronic L64($EO_{13}PO_{30}EO_{13}$) at room temperature. A single spherical drop of hydrocarbon oil was injected into aqueous surfactant solution using an oil drop contacting technique and solubilization rate of hydrocarbon oil was measured by observing the size of oil drop with time. It was shown that solubilization rate decreased with the alkane carbon number(ACN) of the hydrocarbon oil. The solubilization rate was also found to be independent of initial oil dorp size and almost linearly proportional to the initial surfactant concentration. These results revealed that solubilization of n-decane, n-undecane and n-dodecane oils by L64 micellar solution is controlled by interface-controlled mechanism but not by diffusion-controlled mechanism. The equilibrium solubilization capacity(ESC) was measured by a turbidimeter and the result showed that EAC decreased with an increase in ACN but increased with both increases in surfactant concentration and solubilization rate. Dynamic interfacial tension measurements showed that interfacial tension and equilibrium time increased with an increase in ACN of hydrocarbon oil but decreased with an increase in surfactant concentration.