• Journal of Pharmaceutical Investigation
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• v.35 no.1
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• pp.7-16
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• 2005

Gardeniae Fructus is consisted of geniposide and it's derivatives. For the purpose of treatment of skin disease, geniposide and hydrolyzed products (HP) of Gardeniae Fructus were studied on skin permeation and cross1inking with biological tissue. The hydrolyzed products (HP) and active ingredients of Gardeniae Fructus were identified and investigated about skin permeability. Genipin has provided low cytotoxic cross1inking reagents and formed stable and biocompatible crosslinked products. The permeation enhancing effects of geniposide and genipin under the hydrolyzed products of cream and hydrogel preparations were tested using Franz type diffusion cell and the skin of hairless mouse. The remaining proportions of geniposide and genipin were measured in the hydrolyzed products of cream and hydrogel preparations. The crosslinking of epidermic and endodermic tissue with genipin under the hydrolyzed prodcuts of cream and hydrogel preparation was observed using light microscopy. Increased absorption ratio of the skin of hairless mouse about genipin was higher than that of geniposide. Loads at break, tensile strengths and skin permeation rate of the hydrolyzed products (HP) of cream and hydrogel preparations were higher than the nonhydrolyzed products (NHP). The hydrolyzed products (HP) of cream and hydrogel of Gardeniae Fructus Extracts were proper preparations and crosslinking agents to increase the transdermal absorption with epidermic and endodermic tissue.

• Polymer(Korea)
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• v.29 no.6
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• pp.599-604
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• 2005

The hyaluronic acid (HA) with excellent biocompatibility has been combined with lactide, the ester dimer of polylactide, with good biodegradability to produce biocompatible materials which can control the period of degradation in a human body. By freeze frying method, HA and lactide were crosslinked with crosslinking agent, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC). Degree of lactide and EDC reaction was determined by the analysis of nuclear magnetic resonance spectroscopy. Both lactyl group and EDC conversion increased as the mole ratio of lactide to HA increased from 5 to 13. The membrane swelled less and became more brittle with the more addition of lactyl group resulting from the higher mole ratio of lactide to HA. Swelling ratio decreased and tensile modulus increased due to the more addition of lactyl group as the EDC concentration increased or reaction temperature decreased. Drug release experiment from various membranes with different degree of crosslinking showed that permeability decreased with increasing degree of crosslinking. The degradation became slower with the more addition of lactyl group. Mechanical property and degradation rate of the synthesized membrane were shown to be controlled through adjusting operation parameters such as mole ratio, temperature, and crosslinking agent concentration.

• Archives of Pharmacal Research
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• v.27 no.11
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• pp.1183-1187
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• 2004

This study was designed to develop crosslinking of $\beta$-cyclodextrin ($\beta$-CD), and determine the optimum conditions of different factors (mixing time, mixing temperature, and mixing speed) on cholesterol reduction from milk. Crosslinked $\beta$-CD was prepared with epichlorohydrin. When milk was treated with different conditions, the cholesterol removal rate was in the range of 79.4 to 83.3% with 1 % crosslinked $\beta$-CD addition, which were not significantly different among treatments. After cholesterol removal from milk, the used crosslinked $\beta$-CD was washed for cholesterol dissociation and reused. For recycling study, the cholesterol removal rate in first trial was 81.8%, which was mostly same as that using new crosslinked $\beta$-CD. With five trials repeatedly using the same sample, the mean cholesterol removal rate was 81.2%. The present study indicated that the optimum conditions on cholesterol removal using crosslinked $\beta$-CD were 10 min mixing with 400 rpm speed at $5^{\circ}C$ with about 80% cholesterol removal. In addition, crosslinked $\beta$-CD resulted in the effective recycling efficiency almost 100%.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.5 s.142
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• pp.671-679
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• 2005

Chitosan is the affinitive finishing agent and gives susceptible effect in textile finishing. In order to examine the modification of polyester fabric treated with chitosan, we observed the characteristic of polyester fabric surface and measured its physical properties. For the purpose of confirming the adhesion of cationic material, we made a comparative study on anionic acid dye. The fabric was treated with crosslinking agent after chitosan finishing. Glutardialdehyde as crosslinking agent was used to improve the fixation rate of chitosan on the polyester fabric. And the US value was increased according to increasing of chitosan concentration. As the concentration of crosslinking agent was increased, whiteness index of the fabric chitosan treated was increased. Moisture regain of the fabric treated with $1\%$ chitosan was doubled and that treated with $2\%$ chitosan was tripled comparing with original fabric. Tensile strength of the chitosan treated fabric had been an increase of $10\%$ compared with alkali treated fabric and crease resistance decreased regardless of chitosan concentration.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.435-438
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• 1991

This work is aimed to clarify the effect of only crosslinking of polyethylene on the water tree propagation and thus the crosslinking of LDPE was made by use of $Co^{60}$ $\gamma$-ray irradiation at room temperature. For this purpose, before water tree testing under same test conditions, injection molded samples were made of LDPE using CNRS laboratory model and also some of them were irradiated under different dose rate for crosslinking. Afterwards, the aged specimens were put into microscopic investigation as a mean to compare their different morphological aspects by use of SEM for the fractured surface. The SEM observation points out that the untreed region in the irradiated PE shows the densed structure whereas that in the LDPE is not closely packed. Also in the water treed region of LDPE, the density and the dimension of voids are higher than those in irradiated PE. Based on our results, it seems that the difference in the PE structure could sufficiently contribute to cause the different water tree propagation of these materials.

• Food Science of Animal Resources
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• v.26 no.4
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• pp.540-547
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• 2006

This review highlights areas of interest in the cholesterol removal of milk and dairy products. The demand for cholesterol removal has increased due to consumer demand for cholesterol-reduced products. At present the best method for producing without changing flavor, taste and texture of the products is entrapping cholesterol by ${\beta}-cyclodextrin({\beta}-CD)$. Especially, crosslinking of ${\beta}-CD$ is important due to recycling that could be separated the ${\beta}-CD$ from treated cream or milk. The recycling can be up to 10 times with keeping the rate of cholesterol removal. Various functional milk and dairy products can be produced in this manner. This report reviews general information including methods of cholesterol removal, crosslinking of ${\beta}-CD$, and recycling of the ${\beta}-CD$ in milk and dairy products.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.3
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• pp.191-195
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• 2004

Drug delivery systems that are based on pectin have been studied for colon specific delivery using the specific activity of colon microflora. The aim of this study was to design a novel method of manufacturing pectin microspheres without oils and surfactants and to investigate the potential use of the pectin microspheres as an oral colon-specific drug carrier. The pectin microspheres were successfully formed using the spray drying method and crosslinking with calcium chloride. From the crosslinked pectin microspheres, indomethacin (IND) release was more suppressed than its release from non-crosslinked microspheres. In a low pH (pH 1.4) environment, the pectin microspheres released IND at an amount of about 18${\pm}$2% of the total loaded weight for 24 h while the release rate of IND was stimulated at neutral pH (pH 7.4). IND release from the pectin microspheres was increased by the addition of pectinase. The results clearly demonstrate that the pectin microspheres that were prepared by the spray drying and crosslinking methods are potential carriers for colon-specific drug deliveries.

• Membrane Journal
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• v.15 no.1
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• pp.8-14
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• 2005

The hyaluronic acid (HA) with excellent biocompatibility can be combined with the monomer polylactide with good biodegradability to produce biocompatible materials which can control the period of degradation in a human body. By freeze drying method, HA and the lactic acid, monomer of polylactide, or lactide, the ester dimer of polylactide, were crosslinked with crosslinking agent, l-ethyl-3-(3-dimethyl aminopropyl) carbodiimide. The analysis of infrared spectroscopy showed that the ester linkage was formed and the analysis of nuclear magnetic resonance (NMR) spectroscopy showed that the ester linkage was due to the reaction of lactic acid and HA. The conversion (6∼32%) and degree of crosslinking (4∼19%) increased but the selectivity was almost constant at 62% as the mole ratio of LA to HA increased from 1 to 10 in the crosslinking reaction. The brittleness became more pronounced and the rate of degradation became faster with more addition of lactic acid resulting from the higher ratio of LA to HA, and the swelling ratio was in the range of 500 to 2000%.

• Journal of Pharmaceutical Investigation
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• v.23 no.3
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• pp.145-153
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• 1993

Retaining a drug in the stomach by some means is sometimes necessary to extend the G1 absorption time of the drug more than 6-8 hrs. Hydrogel has often been examined for its feasibility as a dosage form, so called platform, that could be retained in the stomach due to its excellent swelling properties in the gastric fluid. In this study, polyvinylpyrrolidone (PVP) hydrogel crosslinked by albumin or acrylated albumin was synthesized in a tablet form and evaluated for its possibility as the platform. The synthesis of the hydrogel was performed by $^{60}Co\;{\gamma}-ray$ irradiation of N-vinyl-2-pyrrolidone (monomer) in the presence of a crosslinking agent: aqueous solution of albumin or acrylated albumin. Synthetic conditions such as radiation dose, dose rate and concentration of crosslinking agent were varied in order to optimize the swelling and mechanical properties of the hydrogels. Degree of swelling of albumin-crosslinked PVP (Al-PVP) was highly dependent on radiation dose, dose rate and albumin concentration: it was decreased as they increased. On the other hand, that of acrylated albumin-crosslinked PVP (Acryl-PVP) was almost independent on them except dose rate: it was decreased as the radiation dose rate increased. The compressive strength of the two hydrogels was decreased as the dose rate increased. Digestion of both PVP in artificial gastric fluid containing pepsin was delayed by the ${\gamma}-ray$ irradiation. In conclusion, Al-PVP and Acry-PVP with diverse swelling and mechanical properties could be obtained by controlling synthetic conditions, mainly the irradiation dose rate.

• KSBB Journal
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• v.6 no.3
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• pp.249-254
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• 1991

Permeabilization of Zymomonas mobilis with CTAB(Cetyltrimethylammoniumbromide) was investigated in order to obtain stable process for sorbitol production in the immobilized system. The optimum conditions for sorbitol formation were obtained in the case of using cells treated with 0.2% CTAB at$ 4^{\circ}C$ for 10 min. Permeabilized cells were treated with glutaraldehyde to cross-link the internal enzyme for the improvement of the enzyme stability. In this way, no significant loss of enzyme activity was apparent during 30-day operation in a continuous process. The productivity of the continuous process at dilution rate 0.2h-1 was 6.51g/1/h for sorbitol. The CTAB permeabilized cells could be used to produce sorbitol in the long term continuous process.