• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.295-301
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• 1997

Nitrendipine, a slightly soluble calcium channel blocking agent forms a solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$, which exhibits better dissolution characteristics than the uncomplexed drug. The dissolution rate of nitrendipine was markedly increased in solid dispersion system in pharmacopeial disintegration media at pH 1.2 and pH 6.8. Four different dosage forms of nitrendipine were administered to rats: (a) nitrendipine in the solution of PEG 400; (b) nitrendipine solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 by solvent evaporation method and administered in capsule form; (c) physical mixture of nitrendipine with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 and administered in capsule form; (d) nitrendipine alone administered in capsule form. Relative bioavailability after the oral administration of various dosage forms to rats with a dose of 10 mg/kg equivalent to nitrendipine was compared with that of nitrendipine in the solution of PEG 400. The AUC of solid dispersion was significantly bigger than that of nitrendipine powder. $T_{max}$ of solid dispersion was significantly shorter and $C_{max}$ was higher than that of nitrendipine powder. These results indicate that the bioavailability of nitrendipine could be improved markedly by inclusion complexation. An interesting correlation also appears to exist between the in vitro dissolution data and the area under the plasma concentration-time curves.

• Journal of Pharmaceutical Investigation
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• v.21 no.1
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• pp.23-32
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• 1991

Dissolution profiles of ketoconazole in solid dispersion system (SDS) were investigated in the second fluid (pH 6.8) for the dissolution test (KPV). PVP K-30 and methyl cellulose were used as carriers in SDS, and chloroform as a solvent. Computer optimization technique was applied to obtain an optimum formula of SDS, and the following results were obtained; 1) Dissolution rate of ketoconazole in SDS was larger than that of pure ketoconazole in the second fluid of pH 6.8. 2) PVP K-30 and methyl cellulosr were good carriers for SDS of ketoconazole. Moerover PVP K-30 was better than methyl cellulose. 3) The optimum formula of ketoconazole SDS obtained from computer optimization technique was chloroform 175 ml, PVP K-30 5g and methyl cellulose 0.2g per 1g of ketoconazole. 4) The experimental value of $A_{60}$ (Amount released from ketoconazole tablet during 60 minutes) obtained from SDS by optimum formula agreed well with the value calculated by polynomial regression equation.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.87.1-87.1
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• 2011

For commercial applications, MEA development must be optimized in order to achieve high performance and low cost. There are many factors that affect the performance of MEA. Especially, the optimization of the method for preparing catalyst layer has great effect on the performance of MEA. Various methods have been used to prepare the catalyst layer of MEA. Among them, spraying method has a merit in that catalysis lay can be prepared with very flexible changes in catalyst layer as well as in the solvent composition of catalyst ink. In addition, in order to reduce the time required for manufacturing catalyst layer, an effort has been made to change the nozzle size and injection pressure of spray system. Further, the operation condition of spray system was changed in various ways in an effort to prepare optimum catalyst layer of MEA. Having optimized the operation condition of spraying system, comprehensive and diverse experiments were carried out concerning various factors that affect the performance of MEA. The present research report describes the results of more sub-categorized and more detailed experiments about the important factors (Nafion$^{(R)}$ ionomer, Relative humidity) which have been shown in previous experiments to exert greater effect on the performance of MEA.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.490-494
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• 1985

The effect of organic solvents on the stability and catalytic activity of the microbial lipase from Rhizopus arrhizus for interesterification of fats and oils has been examined. The reaction system used was nonaqueous solvent system (two phase system). The solvents examined were 5 hydrocarbons (n-hexane, n-heptane, n-octane, isooctane, and cyclohexane) and 3 ethers (diethylether, diisopropylether, di-n-butylether). The results revealed that diisopropylether and isooctane are superior to the other solvents examined for interesterification of fats and oils in two phase systems.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.91-97
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• 2005

The research on the explosive limits is one of fundamental fields of combustion process, and information on the explosive limits of mixture of fuel and oxidant, with or without additives, is very important for the prevention in industrial fire and explosion accidents. Explosive limits of all compounds and solvent mixtures can be calculated with the appropriate use of the fundamental laws of Raoult, Batten, Le Chatelier and MRSM(modified response surface methodology) model. In this study, the reference values of lower explosive limits(LEL) of the ethanol+toluene+ethylacetate system were compared with the calculated values by using the solution thermodynamics and the MRSM model, respectively. The values calculated by the proposed equations were a good agreement with literature data within a few percent. By means of this methodology, it is possible to evaluate reliability of experimental data of the lower explosive limits of the flammable mixtures. Also, from given results, it is possible to predict explosive limits of the other flammable liquid mixtures used in the chemical process by the use of the proposed equations.

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.644-648
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• 2003

To investigate the feasibility of developing a new ondansetron transdermal system, the effects of vehicles and penetration enhancers on the in vitro permeation of ondansetron hydrochloride (OS) from a pressure-sensitive adhesive (PSA) matrices across dorsal hairless mouse skin were studied. Vehicles employed in this study consisted of various ratios of propylene glycol monocaprylate (PGMC)-diethylene glycol monoethyl ether (DGME) co-solvents and PGMC-propylene glycol (PG) co-solvents with 3% oleic acid. $Duro-Tak^\circledR$ 87-2100 and $Duro-Tak^\circledR$ 87-2196 were used as PSAs. The concentration of DGME in PGMC-DGME co-solvent system affected the release rate; as the concentration of DGME increased, the release rate decreased. The cumulative release amount of OS increased as the ratio of PSA to drug solution decreased. The permeation flux was also primarily affected by the amount of PSAs; as the amount decreased, the permeation flux increased. The overall fluxes from matrix formulations were significantly lower when compared to those obtained from solution formulations. The ratio of PG to PGMC did not affect permeation flux, while the lag time decreased significantly from $5.14\pm3.31 to 0.31\pm0.12$ h as the PG increased from 40% to 60%.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1244-1250
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• 2000

A method for simultaneous quantitative determination of plasticizers such as diethyl phthalate(DEP), di-n-propyl phthalate(DprP), di-n-butyl phthalate(DBP), di-n-pentyl phthalate(DPP), butylbenzyl phthalate(BBP), di-(2-ethylhexyl) phthalate(DEHP), dicyclohexyl phthalate(DCHP) and di-(2-ethylhexyl) adipate(DEHA), which are suspected as endocrine disruptors, in food was studied. A analysis method was optimized for the quantification of plasticizers in Jjambbong, which is a kind of fatty noodle, by using GC/FID. The detection limits of DEP, DprP, DBP, DPP, BBP, DEHP, DCHP and DEHA were 3.5, 5.3, 2.2, 2.2, 7.2, 1.7, 1.9 and 3.0 mg/kg, respectively. Much higher recovery was obtained by extraction with acetone/n-hexane(1:1) rather than hexane solvent system. The recovery of DEP, DprP, DBP, DPP, BBP, DEHP, DCHP and DEHA were 72.7, 85.9, 91.4, 97.1, 100.8, 103.2, 104.3 and 95.8% after 4 time extractions, respectively. The migration of plasticizers from PVC wraps into PVC wrap covered Jjambbong was conducted after shaking(120 rpm) for 30min at room temperature with chosen solvent system. It was found that the migration level of DEHA were 577, 706, 770 mg/kg into Jjambbong, respectively, while the other plasticizers were not observed.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.671-679
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• 2018

Glasswort has attracted an attention because of its interesting physiological actions. In this study, the effects of glasswort on inflammatory events including nitric oxide (NO) synthesis and arachidonic acid metabolism in cultured RAW264.7 macrophages were investigated. A series of solvent fractions, including fractions of hexane (Fr.H), ethyl ether (Fr.E), ethyl acetate, butanol, and water, were prepared from a 70% methanol extract of glasswort. Among the fractions, Fr.E showed the strongest inhibition of NO synthesis and inducible NO synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated macrophages. At a concentration of $80{\mu}g/mL$, Fr.E decreased the NO and iNOS levels by 73 and 77%, respectively, after 24 h. Fr.E showed the most potent inhibitory effects on the expressions of cytosolic phospholipase $A_2$ and cyclooxygenase-2 with $IC_{50}$ values of 33.4 and $27.9{\mu}g/mL$, respectively. Fr.H and Fr.E also significantly inhibited 5-lipoxygenase expression in LPS-stimulated macrophages. These results suggest that the hydrophobic fractions of glasswort possess anti-inflammatory activities through modulating the arachidonic acid metabolism and NO synthesis.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.103-108
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• 1998

A hydrophobic substrate triolein was hydrolyzed by lipase in a mono-phase reaction system containing cyclodextrin(CD) as emulsifier. The triolein was transformation to an emulsion-like state in the CD containing reaction system in contrast to the oil-droplet like state without CD due to the formation of an inclusion complex between the lipids and CDs. The hydyrolysis reaction increased substantially in the CD containing reaction system, and the optimum reaction conditions including the amount of lipase, ${\beta}$-CD concentration, and mixing ratio of triolein and ${\beta}$-CD, were determined. The performance of the enzyme reaction in a mono-phase reaction system was compared with that of a two-phase reaction system which used water immiscible hexane as the organic solvent. The role of a CD in the mono-phase reaction system was elucidated by comparing the degree of the inclusion complex formation with triolein and oleic acid, Km and Vmax values, and product inhibition by oleic aicd in aqueous and CD containing reaction systems. The resulting enhanced reaction seems to be caused by two phenomena; the increased accessibility of lipase to triolein and reduced product inhibition by oleic acid through the formation of an inclusion complex.

• Korean Journal of Agricultural Science
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• v.39 no.3
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• pp.395-405
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• 2012

Lipozyme TL IM-catalyzed esterification was carried out to produce functional hard fat (structured lipid, SL) using palm stearin (PS) and hydrolysate of pomegranate seed oil (HPSO) of 1:6 molar ratio. HPSO contained conjugated linolenic acid (CLnA, about 80%). The reaction was performed at non-solvent system and solvent (n-hexane) system using Lipozyme TL IM (10% of total substrates, w/w) for 12, 24, and 72 hr in a shaking water bath ($55^{\circ}C$ and 185 rpm), respectively. SL synthesized in non-solvent system (NH-SL) and SL synthesized in n-hexane system (H-SL) were refined after deacidification, respectively. Their physicochemical properties were compared to obtain desirable functional hard fat. The content of CLnA in NH-SL increased from 34.38% to 40.63% with increasing reaction time. Similar results also observed in H-SL resulting in 36.81~45.83% of CLnA. In triacylglycerol (TAG) composition, the main molecules of LnLnLn (Ln=linolenic acid, PN=36) and the LnLnP (P=palmitic acid, PN=40) were newly synthesized in NH-SL and H-SL with increasing reaction time. After 72 hr reaction, iodine values of NH-SL (136.49) and H-SL (140.37) showed high values because of the high content of CLnA. Solid fat index (SFI) in NH-SL was higher than that in H-SL at each measured temperature. The predominant polymorphic forms of NH-SL and H-SL obtained after esterification for 72 hr were the desirable crystalline structure of the ${\beta}$' form.