• The Plant Pathology Journal
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• v.37 no.6
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• pp.533-542
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• 2021

Chitosan has been considered an environmental-friendly polymer. However, its use in agriculture has not been extended yet due to its relatively low solubility in water. N-Methylene phosphonic chitosan (NMPC) is a water-soluble derivative prepared by adding a phosphonic group to chitosan. This study demonstrates that NMPC has a fungicidal effect on the phytopathogenic fungus Fusarium solani f. sp. eumartii (F. eumartii) judged by the inhibition of F. eumartti mycelial growth and spore germination. NMPC affected fungal membrane permeability, reactive oxygen species production, and cell death. Also, this chitosan-derivative exerted antifungal effects against two other phytopathogens, Botrytis cinerea, and Phytophthora infestans. NMPC did not affect tomato cell viability at the same doses applied to these phytopathogens to exert fungicide action. In addition to water solubility, the selective biological cytotoxicity of NMPC adds value in its application as an antimicrobial agent in agriculture.

• KSBB Journal
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• v.16 no.3
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• pp.253-258
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• 2001

Recently, there were many studies not only to enhance drug delivery effect but to reduce side effect. Drug delivery system(DDS) is able to improve efficiency with decreasing side effect of drug dosage. Among these application fields, DDS is often used as the method of drug dosage into the epidermic skin. We investigated characters of transdermal therapeutic system(TTS) and the skin permeability of that with applying DDS. We investigated the permeation of xanthan gum containing drug in rat skin using borizontal membrane cell model. Permeation properties of materials were investigated for water-soluble drug with oxiniacic acid and also for lipophilic drug with clofibrate. The permeation rate of lipophilic drug was found to be faster than that of water-soluble drug in vitro. The rate differences of both water-soluble drug and lipophilic drug according to drug content were negligible. We used glycerin, PEG 600 and oleic acid as enhancers. These results showed that skin permeation rate of each drug across the composite was mainly dependent on the property of base and chemical property of drug etc.. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate. This result suggests a possible use of natural polymer base as a transdermal delivery system of antihyperlipoproteinemic agent.

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.379-386
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• 1996

Photosensitive compound, 1-methyl-4-[2-(4-diethylacetylphenyl)ethenyl] pridinium methosulfate(SbQ-A salt), was synthesized from dimethyl sulfate, terephthalaldehyde mono-(diethylacetal) and 4-picoline. SbQ-A salts were reacted with poly(vinyl alcohol)s, (PVA) in aqueous solution with phosphoric acid as catalyst to give photosensitive PVA-SbQ with different SbQ content and molecular weight. Relative photosensitivity of PVA-SbQ was determined by gray scale(GS) method. The rotative sensitivity of PVA-SbQ increased with increasing amount of bound SbQ in the case of high molecular weight(MW=77,000-79,000g/mol) as substrate and decreased with decreasing molecular weight of PVA with about constant(1.3mol%) amount of bound SbQ. The most sensitive polymer was obtained when SbQ group content in PVA-SbQ reached about 2.63mol% in the case of high molecular weight(77,000-79,000g/mol) PVA. This sample showed 90 times greater sensitivity than dichromated PVA as reference photosensitive system. PVA-SbQ photosensitive polymer synthesized was applied to the photolithographic screening process of phosphor on the panel of cathode ray tube(CRT). Phosphor slurry was made with PVA-SbQ, phosphor, a small amount of surfactant and other additives using water as medium. The slurry was coated onto panel, dried by heater, exposed to UV light and then developed by distilled water. When a small amount of cationic surfactant such as cetyltrimethylammonium chloride was used in the slurry formulation, the sharpness of phosphor pattern was equal to or better than that of dichromated PVA photosensitive polymer system used currently.

• Polymer(Korea)
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• v.38 no.4
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• pp.434-440
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• 2014

We prepared nanoparticles containing insoluble celecoxib by the method of solid dispersions using a spray dryer to improve solubility of celecoxib. We used PVP K30 and Eudragit EPO as water-soluble carriers for the solid dispersion, and poloxamer 407 as a surfactant. Characterization of celecoxib solid dispersion was performed by scanning electron microscope (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The results of SEM, DSC and XRD demonstrated that celecoxib is amorphous in solid dispersion. The dissolution rate measured in intestinal juice showed that the method of solid dispersion improved celecoxib solubility as compared with a conventional drug (Celebres$^{(R)}$). In conclusion, solid dispersion formulation prepared by a spray dryer would improve the solubility of celecoxib in oral administration.

• Polymer(Korea)
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• v.31 no.6
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• pp.505-511
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• 2007

Poly(lactide-co-glycolide)(PLGA) and hyaluronic acid (HA) has been widely used as biocompatible scaffold materials to regenerate tissue. In this present study, we fabricated microporous PLGA and HA loaded PLGA scaffolds by a emusion freeze-drying method. In order to confirm that the release profile of cytokine or water-soluble drugs, we manufactured the granulocyte macrophage colony stimulating factor(GM-CSF) loaded PLGA and HA-PLGA scaffold. All scaffolds were characterized using scanning electron microscope(SEM), mercury porosimeter and wettability measurement. Cell proliferation and viability were assessed by a 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) test. The porosity of HA-PLGA scaffold was greater than 95% with the total pore area of $261\;m^2/g$. The HA-FLGA scaffold exhibited well interconnected pores to allow greater cell adhesion and prolixferation. It was proven by higher cell viability in the HA-PLGA scaffold than PLGA alone. This may be due to the enhanced natural properties and higher water retention capacity of HA.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.305-312
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• 1994

The fed-batch process which combinded high selectivity of affinity chromatography and membrane process was developed. The mixture of trypsin and chymotrypsin, having almost the same molecular weight and the chemical structure, were used as model enzymes. The water soluble polymer having more affinity for trypsin and celluose acetate membrane gelated in 50vol.% ethanol for removing free enzymes and retentating trypsin-affinity polymer complex simutaneously were used in this system. The membrane pore size was controlled by ethanol concentration in the gellation bath, and the affinity polymer was prepared by polymerization of acrylamide with N-acryloyl-m-aminobenzamidine at $4^{\circ}C$. The trypsin could be effectively concentrated by utilizing an affinity polymer and a prepared UF-50 ultrafiltration membrane. As a result, 86% purity trypsin was recovered by the current purification process.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.314-321
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• 1999

This study was performed to test application possibility of electronic nose with 32 conducting polymer sensor arrays for aroma analysis of persimmon vinegar. The 20, 30, 40, 50, 60, and $70^{\circ}Bx$ persimmon vinegar concentrates were prepared by vacuum concentration at $55^{\circ}C$. The recovery yield of water soluble solid to concentrates was 55.5% on $20^{\circ}Bx$ persimmon vinegar concentrate. As the concentration of persimmon vinegar concentrates increased, pH of concentrates increased and acidity as acetic acid decreased. From sensory evaluation for persimmon vinegar concentrates, as the concentration of persimmon vinegar concentrates increased, their cooking odor and umami taste increased, sour taste and acidic odor decreased, salty odor and astringency were not changed. Aroma analysis by electronic nose (AromaScan) showed no difference in normalized pattern and odor intensity among persimmon vinegar concentrates. All quality factors among concentrates also were less than 1.042. And so the electronic nose with conducting polymer sensor was not suitable for aroma analysis of persimmon vinegar concentrate.

• Polymer(Korea)
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• v.35 no.6
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• pp.558-564
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• 2011

The biocompatibility and biodegradability of poly(amino acid) make them ideal candidates for many bio-related applications. Poly(aspartic acid), PASP, is one of synthetic water-soluble polymers with proteinlike structure, and has been extensively explored for the potential industrial and biomedical applications due to its biodegradable, biocompatible and pH-responsive properties. In this work, amino acid-conjugated PASPs were prepared by aminolysis reaction onto polysuccinimide (PSI) using ${\gamma}$-aminobutylic acid(GABA) and ${\beta}$-alanine methyl ester and a subsequent hydrolysis process. Their chemical gels were prepared by crosslinking reaction with ethylene glycol diglycidyl ether (EGDE). The hydrogels were investigated for their basic swelling behavior, hydrolytic degradation and morphology. The crosslinked gels showed a responsive swelling behavior, which was dependent on pH and salt concentration in aqueous solution, and relatively fast hydrolytic degradation.

• Journal of Pharmaceutical Investigation
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• v.6 no.3
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• pp.48-57
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• 1976

An enhancement in the dissolution rate of the drug should facilitate its GI absorption if the absorption process is dissolution rate limited. One of the need for the techniques that can potentially enhance the dissolution rate and extent of absorption of hydrophobic drugs is the formation of coprecipitates with pharmacologically inert, polymeric materials. The physicochemical modification offers the advantage of possibly enabling one to administer the drug orally in a form from which it is most available for GI absorption. Several $investigation^{1-15)}$ demonstrated that the formation of solid dispersions or coprecipitates of relatively water-insoluble drugs with various pharmacologically inert carriers can increase singnificantly their in vitro dissolution rates. However, little information is available in the literature related to the dissolution rate patterns of furosemide, a water-insoluble diurectices, with respect to the sort of copolymer and the ratio of coprecipitates as a function of time, respectively. The purpose of the present investigation was to ascertain, the general applicability of the copolymers to use fore more fast, enhanced dissolution techniques of furosemide. To accomplish the need for enhancement in the dissolution rate of furosemide, varying ratio coprecipitates with different water-soluble polymers, such as polyvinylpyrrolidone (PVP), polyethylene glycol 4000(PEG 4000), and polyethylene glycol 6000 (PEG 6000), were quantitatively studied by comparing their dissolution characteristics of furosemide. The dissolution patterns of pure furosemide, varying ratio furosemide-PVP coprecipitates, (1:2, 1:5, and 1:9(w/w)), furosemide-PEG 4000 coprecipitates (1:4, 1:9, and 1:19(w/w), furosemide-PEG 6000 coprecipitates(1:4, 1:9, and 1:19(w/w)), and the same ratio physical mixtures, respectively, were compared by the amount dissolved as a function of time.

• Composites Research
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• v.24 no.6
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• pp.1-6
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• 2011

A new water-soluble and self-doped poly(styrenesulfonic acid-graft-aniline), PSSA-g-PANI, for dispersing carbon nanotubes (CNTs) in water was synthesized and its ability to stabilize aqueous CNT dispersions was examined. It was observed that the PANI in PSSA-g-PANI, which has benzoid and quinoid structure, was strongly adsorbed onto the nanotube surface via a strong ${\pi}-{\pi}$ interaction, and thus only gentle sonication causes exfoliation of CNT ropes to small bundles and the long-term stability of their resulting dispersions was much better than commercial surfactants. Furthermore, when thin films of PSSA-g-PANI/CNT are prepared from aqueous dispersion and their electrical conductivities are measured by the four probe technique, it is observed that their conductivities are in the range of 1.5-2.5 S/cm.