• Journal of Pharmaceutical Investigation
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• 제25권1호
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• pp.9-17
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• 1995

To stabilize omeprazole(OMP), ethylenediamine(ED) complex of omeprazole(OMPED) was prepared by reaction between OMP and ED in methanol, and the complex formation was confirmed by the instrumental analysis, i.e., IR, DSC, EA, NMR, MS and XRD. The rates of decomposition of OMP and OMPED in aqueous solution and the shelf lives at standard temperature were measured by accelerated stability analysis. The results are summarized as follows; The mole ratio of OMP and ED in OMPED complex is 1:1, the energy of formation within OMPED might be combined between polar imidazole group of OMP with induced a dipole amine group in the readily polarizable ED molecule. At standard temperature the degradation rate constant of OMP in aqueous solution is $2.540{\times}10^{-2}\;hr^{-1}$ and the shelf life is 4.15 hrs, and in the case of OMPED the degradation rate constant is $7.986{\times}10^{-4}\;hr^{-1}$ and the shelf life is 131.96 hrs. So, the OMPED has about 31 times longer shelf life than OMP. The activation energy of OMP and OMPED are 5.23 and 18.55 kcal $mole^{-1}$ respectively. The stability of OMP is dependent chiefly on pH in the solutions and it decomposes readily in acidic medium by hydrogen ion catalized reaction but becomes stable beyond pH 9.0. In case of the ED-complex, OMPED is stable in neutral as well as in dilute acidic solutions even in pH 6, OMPED is very stable to light(UV), that is, the rate constant and shelf life of OMP are $k=1.0188{\times}10^{-2}\;day^{-1}$, $T_{90%}=4.5 \;days$, on the other hand, the those of OMPED are $k=7.138{\times}10^{-4}\;day^{-1}$, $T_{90%}=64.1\;days$, respectively. From the above results, it is thought that new dosage forms could be developed by using the OMPED as a potential OMP complex.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2325-2332
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• 2012

A series $[C_3Omim]$[X] of imidazolium cation-based ILs, with ether functional group on the alkyl side-chain have been synthesized and structure of the materials were confirmed by various techniques like $^1H$, $^{13}C$ NMR spectroscopy, MS-ESI, FTIR spectroscopy and EA. More specifically, the influence of changing the anion with same cation is carried out. The absorption capacity of $CO_2$ for ILs were evaluated at 30 and $50^{\circ}C$ at ambient pressure (0-1.6 bar). Ether functionalized ILs shows significantly high absorption capacity for $CO_2$. In general, the $CO_2$ absorption capacity of ILs increased with a rise in pressure and decreased when temperature was raised. The obtained results showed that absorption capacity reached about 0.9 mol $CO_2$ per mol of IL at $30^{\circ}C$. The most probable mechanism of interaction of $CO_2$ with ILs were investigated using FTIR spectroscopy, $^{13}C$ NMR spectroscopy and result shows that the absorption of $CO_2$ in ether functionalized ILs is a chemical process. The $CO_2$ absorption results and detailed study indicates the predominance of 1:1 mechanism, where the $CO_2$ reacts with one IL to form a carbamic acid. The $CO_2$ absorption capacity of ILs for different anions follows the trend: $BF_4$ < DCA < $PF_6$ < TfO < $Tf_2N$. Moreover, the as-synthesized ILs is selective, thermally stable, long life operational and can be recycled at a temperature of $70^{\circ}C$ or under vacuum and can be used repeatedly.

• 대한화학회지
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• 제33권1호
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• pp.97-105
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• 1989

CTABr 미셀용액 속에서의 2-alkylbenzimidazole(R-BI) 및 sodium 2-alkylbenzimidazole-5-sulfonate(R-BISO$_3$Na)에 의해 추진되는 p-nitrophenyl carboxylic esters(p-NPCE)들의 가수분해반응에 대한 미셀효과를 다루었다. 이들 반응은 각각 BI 및 BISO$_3$Na에 의해 추진되는 반응의 속도보다 현저히 감소하고, 알킬기가 methyl에서 heptyl로 길어질수록 감소의 정도가 더욱 크다. 이것은 CTABr을 포함하지 않는 수용액속에서의 BISO$_3$Na와 R-BISO$_3$Na에 의한 가수분해 반응속도가 별차이가 없음을 감안 할 때, 미셀의사층(micellar pseudophase) 내에서 이들 친핵체의 알킬기가 입체장해(steric hindrance)로 작용하기 때문이다. 이것은 수용액과 미셀용액 속에서의 반응의 측정된 홀성화에너지(${\Delta}H{\neq},\;{\Delta}G{\neq}$ 및 ${\Delta}S{\neq}$)의 값과도 정성적으로 일치하고 있다. 한편, nonyl기에서 pentadecyl기까지의 긴 알킬기를 갖고 있는 R-BISO$_3$Na는 그것의 imidazole 부분(BI moiety)이 친핵체로 작용할 뿐 아니라, 이들은 CTABr을 포함하지 않는 수용액속에서 미셀을 형성하고, 그 결과 기질인 p-NPCE를 쉽게 수용하여 반응속도를 촉진시키는 것으로 판단된다. R-BISO$_3$Na에 의한 이들 p-NPCE들의 가수분해반응의 mechanism을 알기위하여 중수소 동위원소효과(kinetic isotope effect)를 측정하였다. $k'_{H_2O}/K'_{D_2O}$값이 약 2.5∼3.2의 범위로서, 이 값은 R-BISO$_3$Na가 친핵체로만 작용한다고 보기에는 너무 높고, 일반염기로 작용한다고 보기에는 너무 낮다. 따라서 CTABr 미셀용액 속에서의 이 반응은 이 두 mechanism에 의해 동시적으로 진행된다고 생각된다.

• 센서학회지
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• 제27권5호
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• pp.345-351
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• 2018

We employed an unprecedented technique to synthesize porous $WO_3@SnO_2$ nanofibers exhibiting core-shell and fiber-in-tube configurations. Firstly, 2-methylimidazole was uniformly incorporated in as-spun nanofibers containing ammonium metatungstate hydrate and the sacrificial polymer (polyacrylonitrile). Secondly, the 2-methylimidazole on the surfaces of nanofibers was complexed with tin(II) chloride ($SnCl_2$) via simple impregnation of the as-spun nanofibers in ethanol containing tin(II) chloride dihydrate ($SnCl_2{\cdot}2H_2O$). The presence of vacant p-orbitals in tin (Sn) and the nucleophilic nitrogen on the imidazole ring allowed for the reaction between $SnCl_2$ and 2-methylimidazole, forming adducts on the surfaces of the as-spun nanofibers. The calcination of these nanofibers resulted in porous $WO_3@SnO_2$ nanofibers with a higher surface area ($55.3m^2{\cdot}g^{-1}$) and a better response to 1-5 ppm of acetone than pristine $SnO_2$ NFs synthesized using a similar method. An improved response to acetone was achieved upon functionalization of the $WO_3@SnO_2$ nanofibers with catalytic palladium nanoparticles. This work demonstrates the potential application of $WO_3@SnO_2$ nanofibers as sensing layers for chemiresistive sensory devices for the detection of acetone in exhaled breath.

• The Korean Journal of Physiology
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• 제8권1호
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• pp.55-65
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• 1974

The effect of ginseng on the ATPase activity of rabbit ref cell membrane has been investigated. The experiments were also designed to determine whether the components of ginseng could be attributed to the effect on ATPase activity which dependent upon sodium plus potassium and is sensitive to ouabain. The following results were observed. 1. The activity of the $Na^{+}-K^{+}-ATPase$ from red cell membrane is stimulated by ginseng, and the concentration of ginseng for half-maximal activity is about 15 mg%. The pH optimum for the ginseng sensitive component is 7.6. 2. The portion of the enzyme activity stimulated by ginseng is completely abolished by ouabain. 3. The activating effect of ginseng on the ATPase, with a given concentration of sodium in the medium, is increased by raising the potassium concentration but activity ratio is decreased. 4. The activating effect of ginseng on the ATPase, with a given concentration of potassium in the medium, is increased by raising the sodium concentration but the activity ratio is decreased. 5. The ATPase activity is increased by small amounts of calcium but inhibited by larger amounts and the rate of activity by ginseng is constant. 6. The action of ginseng on the ATPase activity was not related to the sulfhydryl group of cysteine, the amino group of lysine, the imidazole group of histidine, the quanidinium group of arginine, the carboxyl group of aspartic acid, or the hydroxyl group of threonine. 7. The activating effect of ginseng on the ATPase activity may be not due to a saponin which is contained in ginseng.

• 한국전기전자재료학회논문지
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• 제21권4호
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• pp.388-394
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• 2008

For purpose of anti-static film remaining unchanged in the condition of $160^{\circ}C$, organic solvent, acid and base solution $0.01\sim0.03{\mu}m$ particles of Sb doped tin oxide(ATO) were grafted by 3-Glycidyloxypropyltrimethoxysilane(GPTS) for improving interfere bonding force between ATO and epoxy resin. The particles were dispersed in 2-methoxyethanol with YD-I28(Bisphenol A type epoxy resin, Kukdo chemical) and 1-imidazole as hardener. The anti-static solutions were coated on PI film as thickness of $0.1{\mu}m$. Surface resistivity of anti-static film containing conductive polymer became $10^{12}\Omega/\Box$ after 32 hours in $160^{\circ}C$. The surface resistivity of ATO grafted by GPTS / Epoxy coating layer remained as $10^{7.6}\Omega/\Box$ in $160^{\circ}C$ for 7 days. ATO grafted by GPTS / Epoxy coating layer coated on PI film was dipped in acetone for 7 days. The surface resistivity remained unchanged as $10^{7.6}\Omega/\Box$. The anti-static layer dipped in water solutions containing each KOH 10 wt % and $H_2SO_4$ 2 wt% was ultra-sonicated for 10 minutes per once until 30th. The surface resistance of anti-static layer containing ATO grafted by GPTS remained unchanged.

• The Korean Journal of Physiology
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• 제10권1호
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• pp.25-34
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• 1976

The action of serotonin on the sodium plus potassium activated ATPase activity in the rabbit red cell membrane has been investigated. The experiments were also designed to determine the mechanism of action of serotonin on the ATPase activity. The following results were obtained. 1) The NaK ATPase activity of rabbit red cell ghosts is stimulated by low concentration of serotonin but inhibited by higher concentration, and the concentration of serotonin for maximal activity is about 2mM. The pH optimum for the serotonin sensitive component is 8.0. 2) The activating effect of serotonin on the ATPase, with a given concentration of sodium in the medium, is increased by raising the potassium concentration but the ratio of activity is decreased. 3) The activating effect of serotonin on the ATPase, with a given concentration of potassium in the medium, is increased by raising the sodium concentration but the ratio of activity is decreased. 4) The ATPase activity is increased by small amounts of calcium but inhibited by larger amounts and the ratio of activity by serotonin is decreased by small amounts of calcium but increased by larger amounts. 5) The action of serotonin on the ATPase activity was not related to the amino group of lysine, the hydroxyl group of threonine, the carboxyl group of aspartic acid, or the imidazole group of histidine. 6) The action of serotonin on the ATPase activity is due to sulfhydryl group of the enzyme of NaK ATPase.

• Parasites, Hosts and Diseases
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• 제28권2호
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• pp.71-78
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• 1990

세포내 cAMP의 농도 변화가 Toxoplasma의 성장 및 증식에 미치는 영향을 검토하기 위하여 끽접 cAMP와 cAMP의 analogue를 첨가하거나 간접적으로 세포내 cAMP의 합성이나 분해를 담당한 효소들의 활성을 변화시 킴으로써 CAMP의 농도를 조절하여 그 효과를 측정하였다. HL-60세포를 숙주 세포로 사용하여 동수의 Toxoplasma를 첨가하여 배양하였으며, 처리 효과는 배양 세포계에서 Toxoplnsma에만 특이하게 표지되는 $^3H-uracil$과 Toxoplasma및 HL-60세포에 공통으로 표지되는 $^3H-thymidine$을 각각 매 12시간마다 2시간씩 배양하여 그 표지량을 측정하여 비교 분석하였다. 직접 cAMP와 cAMP의 analogue인 dbcAMP 및 br-cAMP를 첨가하였을 때, 각각 특이한 농도에서, 즉 1 mM, 0.5~5mM 및 0.1mM에서 Toxoplasma의 성장 및 증식을 향상시켰다. 이때, 성장 및 증식을 유도하는 시기 및 그 증가도에서도 차이가 있는 것으로 나타났다. 이 결과들은 세포내 cAMP의 농도를 증가시키도록 cAMP의 합성 및 분해에 관여하는 효소들의 황성을 변화 시켰을 때에도 같은 양상으로 나타났다. cAMP의 합성 효소인 adenylate cyclase의 활성제인 pNHppG, cAMP의 분해 효소인 cAMP phosphodiesterase의 활성제인 A23187과 imidazole 및 억제제인 IBMX, compound 48/80 및 theophylline을 각각 처리하였는데, 세포내 cAMP의 농도가 증가되었을 대에는 Toxoplasmn의 성장 및 증식 을 향상시켰으나, cAMP의 농도를 감소시켰을 때에는 억제하였다. 이 때 배양계에 독성을 일으키는 농도 이하에서 농도 의존성의 경향을 보였으며, 유도 시기 및 그 증가도에는 차이가 있었다. 따라서 세포 내에서 향상된 수준의 cAMP가 어떤 기전을 활성화시키며, 그 결과 세포질에서의 Toxcplasma의 성장 및 증식을 자극하게 된다는 것을 시사하였다.

• Journal of Pharmaceutical Investigation
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• 제40권1호
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• pp.51-57
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• 2010

Losartan potassium, 2-butyl-4-chloro-1-[p-(o-1H-tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol mono-potassium salt, is a new class of antihypertensive agents, and is an antagonist in angiotensin receptor. The purpose of the present study was to evaluate the bioequivalence of two Losartan potassium tablets, Cozaar tablet (MSD Pharmaceutical Co., Ltd.) and Losata tablet (Kyung Dong Pharmaceutical Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The release of losartan from the two losartan potassium formulations in vitro was tested using KP VIII Apparatus II method with various dissolution media. Twenty eight healthy male subjects, $23.86{\pm}1.80$ years in age and $67.27{\pm}6.60\;kg$ in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After a single tablet containing 50 mg as losartan potassium was orally administered, blood samples were taken at predetermined time intervals, and the concentrations of losartan in serum were determined using HPLC with fluorescence detector. The dissolution profiles of two formulations were similar in all tested dissolution media. The pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated, and Equiv Test/K-BE Test 2002 was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, Cozaar, were -2.70%, 1.45% and 2.31% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 (e.g., log 0.8852~log 1.0655 and log 0.8319~log 1.2342 for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Losata tablet was bioequivalent to Cozaar tablet.

• 한국결정성장학회지
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• 제28권5호
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• pp.222-227
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• 2018

$Zn_{1-x}Co_x$ Zeolitic Imidazolate Framework-8(ZIF)(x = 0~0.05)를 2-methylimidazole을 사용하여 $Zn^{2+}$와 $Co^{2+}$를 공침시켜 합성하고, 이를 $600^{\circ}C$에서 2시간 열처리하여 순수한 ZnO 나노입자와 Co가 도핑된 ZnO 나노입자를 합성했다. x가 < 0.05일 경우, 2-methylimidazole 링커가 $Zn^{2+}$ 및 $Co^{2+}$ 모두에 강하게 배향되어 균질한 Zn/Co ZIFs가 합성되었으며, 열처리를 통해 Co가 균일하게 도핑된 ZnO를 합성할 수 있었다. 반면, $x{\geq}0.05$일 때는 불균질한 Zn/Co ZIFs가 합성되었으며, 열처리 이후 $Co_3O_4$ 이차상이 형성되었다. 합성된 나노입자들에 대한 가스감응특성 평가 결과, 3 at%의 Co가 도핑된 ZnO 센서는 순수한 ZnO와는 달리 trimethylamine에 대해 고감도, 고선택적 가스감응특성을 나타냈다. 본 연구의 bimetallic ZIF 유도 산화물 나노복합체 합성방법은 고성능 가스센서를 설계하는데 활용될 수 있을 것으로 기대된다.