• 생물정신의학
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• 제8권2호
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• pp.266-270
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• 2001

Objective : The purpose of this study was to compare the plasma amitriptyline and nortriptyline level between before and after fluoxetine addition with patients who were currently taking amitriptyline. Method : From the inpatient and outpatient unit of Soon Chun Hyang University Hospital, Chunan, fourteen subjects who were taking amitriptyline 25mg more than 1 week at least were given fluoxetine 20mg. Before and 2 weeks after fluoxetine addition, the plasma level of amitriptyline and nortriptyline are analyzed simultaneously by High Performance Liquid Chromatography(HPLC). At the same times, HAM-D(Hamilton Rating Scale for Depression) score and the UKU(Uldvalg for Klinske Unders${\Phi}$ gelser) side effect scale were checked. Results : After fluoxetine addition to the patients who were taking amitriptyline, the plasma level of amitriptyline, nortriptyline and sum of amitriptyline and nortriptyline had risen. The mean plasma amitriptyline level increased from $168.9{\pm}89.4ng/ml$ to $183.0{\pm}102.0ng/ml$ after fluoxetine addition(p=0.011), but the change was not statistically significant. The mean plasma nortriptyline level increased significantly from $114.3{\pm}70.2ng/ml$ to $168.0{\pm}86.2ng/ml$ after fluoxetine addition(p=0.011). In addition, the mean plasma level of total amitriptyline and nortriptyline increased significantly from $283.1{\pm}125.3ng/ml$ to $350.9{\pm}78.4ng/ml$ after fluoxetine addition(p=0.016). After fluoxetine addition, no significant change was noted in the UKU side effect scale score. Conclusion : As consequence of comparison of plasma amitriptyline and nortriptyline level before and after fluoxetine addition, mean amitriptyline, nortriptyline and total plasma level was increased after fluoxetine addition. This suggests that coadministration of amitriptyline and fluoxetine may induce improvement of depressive symptom in depressive patients by way of increased plasma level of amitriptyline.

• 한국진공학회지
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• 제17권6호
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• pp.544-548
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• 2008

반도체 공정에서 가장 많은 시간과 비용을 차지하는 공정 중 하나는 Photoresist strip 공정이다. 따라서 보다 빠르게 PR의 strip 공정을 단축하기 위한 연구가 계속 진행중에 있다. 하지만 기존 사용중인 strip용액을 대체하기 위한 물질을 찾는 것은 많은 비용을 수반한다. 본 연구에서는 PR의 strip 시간을 최대한 단축시키고 PR strip 잔여물의 빠른 제거를 위하여 기존 공정에서 사용 중인 strip 약액을 플라즈마에 의하여 활성화하는 방법(Plasma Liquid-Vapor Activation: PLVA)으로 PR strip 시간을 최대한 줄이는 방법에 대한 연구를 진행하였으며, 활성화된 strip용액이 더욱 빠른 strip율 성능을 나타내는 것을 확인하였다. 또한 PR strip에서 이온에 의한 영향을 받은 HDI-PR (high dose implanted photoresist)은 기존 strip용액으로 제거가 불가능하였다. 하지만 본 연구에서 제시한 PLVA 방법으로 활성화된 용액에서는 그 가능성을 확인하였고, 이러한 PLVA방법에 대한 물리적 연구를 위하여 HDI-PR 표면 내력의 변화를 측정하였다. 그 결과 PLVA 처리 전 후 HDI-PR의 표면 내력에 큰 변화를 확인하였다.

• 한국재료학회지
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• 제27권3호
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• pp.155-160
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• 2017

Doped-$LaCrO_3$ perovskites, because of their good electrical conductivity and thermal stability in oxidizing and/or reducing environments, are used in high temperature solid oxide fuel cells as a gas-tight and electrically conductive interconnection layer. In this study, perovskite $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC) coatings manufactured by atmospheric plasma spraying followed by heat treatment at $1200^{\circ}C$ have been investigated in terms of microstructural defects, gas tightness and electrical conductivity. The plasma-sprayed LCCC coating formed an inhomogeneous layered structure after the successive deposition of fully-melted liquid droplets and/or partially-melted droplets. Micro-sized defects including unfilled pores, intersplat pores and micro-cracks in the plasma-sprayed LCCC coating were connected together and allowed substantial amounts gas to pass through the coating. Subsequent heat treatment at $1200^{\circ}C$ formed a homogeneous granule microstructure with a small number of isolated pores, providing a substantial improvement in the gas-tightness of the LCCC coating. The electrical conductivity of the LCCC coating was consequently enhanced due to the complete elimination of inter-splat pores and micro-cracks, and reached 53 S/cm at $900^{\circ}C$.

• Journal of Pharmaceutical Investigation
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• 제38권4호
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• pp.235-240
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• 2008

A sensitive and simple method of determining the plasma levofloxacin (LFX, CAS 100986-85-4) concentrations in human volunteers by liquid-liquid extraction were developed and validated by using a high-performance liquid chromatography/diode array detector. The method was also applied to pharmacokinetic study of LFX. LFX was orally administered to 8 healthy male Korean volunteers at single lowest dose of 200 mg, compared to the published reports in which more than 500 mg of LFX was orally administered. LFX in human plasma was determined. The detection limit of LFX was $0.05\;{\mu}g/mL$. $C_{max}$ value was $2.48{\pm}0.67\;{\mu}g/mL$. $AUC_{0{\to}24\;hr$} and $AUC_{0{\to}{\infty}}$ were $14.52{\pm}3.35\;{\mu}g/mL$ and $16.00{\pm}3.66\;{\mu}g{\cdot}hr/mL$, respectively. The terminal half-life was $6.87{\pm}0.46\;hr$. Our pharmacokinetic parameters were very consistent with that previously reported, showing good correlation between LFX doses and AUC ($r^2=0.995$). This method can be useful for the pharmacokinetics and bioequivalence study with relatively low dose for reducing the main side effects of LFX.

• Mass Spectrometry Letters
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• 제8권4호
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• pp.109-113
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• 2017

Single analytical procedure including extraction, liquid chromatography, and mass spectrometric analysis was evaluated for the simultaneous measurement of lysophospholipids (LPLs). LPLs, particularly, lysophosphatidic acids (LPA) and sphingosine 1-phosphate (S1P) are lipid messengers ubiquitously found in various biological matrix. The molecular species mediate important physiological roles in association with many diseases (e.g. cancer, inflammation, and neurodegenerative disease), which emphasize the significance of the simple and reliable analytical method for biomarker discovery and molecular mechanistic understanding. Thus, we developed analytical method mainly focusing on, but not limited by those lipid species S1P and LPA using reverse phase liquid chromatography-tandem mass spectrometry (RPLC-ESI-MS-MS). Extraction method was modified based on Folch method with optimally minimal level of ionization additive (ammonium formate 10 mM and formic acid). Reverse-phase liquid-chromatography was applied for chromatographical separation in combination with negative ionization mode electrospray-coupled Orbitrap mass spectrometry. The method validation was performed on human blood plasma in a non-targeted lipid profiling manner with full-scan MS mode and data-dependent MS/MS. The proposed method presented good inter-assay precision for primary targets, S1P and LPA. Subsequent analysis of other types of LPLs identified a broad range of lysophosphatidylcholines (LPCs) and lysophosphatidyl-ethanolamines (LPEs).

• Journal of Ginseng Research
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• 제37권1호
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• pp.135-141
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• 2013

A rapid, sensitive and selective analytical method was developed and validated for the determination of compound K, a major intestinal bacterial metabolite of ginsenosides in human plasma. Liquid-liquid extraction was used for sample preparation and analysis, followed by liquid chromatography tandem spectrometric analysis and an electrospray-ionization interface. Compound K was analyzed on a Phenomenex Luna C18 column ($100{\times}2.00$ mm, 3 ${\mu}m$) with the mobile phase run isocratically with 10 mM ammonium acetate-methanol-acetonitrile (5:47.5:47.5, v/v/v) at a flow rate of 0.5 mL/min. The method was validated for accuracy (relative error <12.63%), precision (coefficient of variation <9.14%), linearity, and recovery. The assay was linear over the entire range of calibration standards i.e., a concentration range of 1 ng/mL to 1,000 ng/mL ($r^2$ >0.9968). The recoveries of compound K after liquid-liquid extraction at 1, 2, 400, and 800 ng/mL were $106.00{\pm}0.08%$, $103.50{\pm}0.19%$, $111.45{\pm}5.21%$, and $89.62{\pm}34.46%$ for intra-day and $85.40{\pm}0.08%$, $94.50{\pm}0.09%$, $112.50{\pm}5.21%$, and $95.87{\pm}34.46%$ for inter-day, respectively. The lower limit of quantification of the analytical method of compound K was 1 ng/mL in human plasma. The developed method was successfully applied to a pharmacokinetic study of compound K after oral administration in ten of healthy human subjects.

• Bulletin of the Korean Chemical Society
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• 제26권5호
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• pp.729-734
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• 2005

A sensitive and selective method for quantitation of sofalcone and its active metabolite in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Plasma samples were transferred into 96-well plate using an automated sample handling system and spiked with 10 $\mu$L of 2 $\mu$g/mL $d_3$-sofalcone and $d_3$-sofalcone metabolite solutions (internal standard), respectively. After adding 0.5 mL of acetonitrile to the 96-well plate, the plasma samples were then vortexed for 30 sec. After centrifugation, the supernatant was transferred into another 96-well plate and completely evaporated at 40 ${^{\circ}C}$ under a stream of nitrogen. Dry residues were reconstituted with mobile phase and were injected into a $C_{18}$ reversed-phase column. The limit of quantitation of sofalcone and its metabolite was 2 ng/mL, using a sample volume of 0.2 mL for analysis. The reproducibility of the method was evaluated by analyzing 10 replicates over the concentration range of 2 ng/mL to 1000 ng/mL. The validation experiments of the method have shown that the assay has good precision and accuracy. Sofalcone and its metabolite produced a protonated precursor ion ([M+H]$^+$) of m/z 451 and 453, and a corresponding product ion of m/z 315 and 317, respectively. Internal standard ($d_3$-sofalcone and $d_3$-sofalcone metabolite) produced a protonated precursor ion ([M+H]$^+$) of m/z 454 and 456 and a corresponding product ion of m/z 315 and 317, respectively. The method has been successfully applied to a pharmacokinetic study of sofalcone and its active metabolite in human plasma.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.850-853
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• 1992

A cryogenic electron cyclotron resonance plasma etching system has been built to study wafer-temperature in the silicon etching characteristics. The wafer temperature was controlled from -150 to +30 $^{\circ}C$ during etching using the liquid nitrogen cooled helium gas. Although silicon was etched isotropically in $SF_6$ plasma at room temperatures, we found that it is possible to suppress the etch undercut in Si by reducing a substrate temperature without side wall passivation. In addition, the selectivity of silicon to photoresist was improved considerably at a low wafer temperature. Etch rates, anisotropy and selectivity to photo resist are measured as a function of the wafer temperature in the region of -125 $\sim$ 25$^{\circ}C$ and rf bias power of 20W $\sim$ 80W.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.400.3-401
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• 2002

Levosulpiride is the levo-enantiomer from of racemic sulpride. abenzamide derivative selectively inhibition doparninergic D2 receptos at the trigger zone both in the central nervous system and in the gastrointestinal tract. We report a rapid and sensitive HPLC method using reverse phase C 18 column with fluorescence detection for separation and quantitation of levosulpiride in plasma. Tiapride was used as an internal standard. After adding an internal standard. levosulpiride in 800 ${\mu}l$ of plasma was extracted under basic conditions with ethyl acetate and methylene chloride. (omitted)

• 한국환경과학회지
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• 제27권3호
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• pp.219-225
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• 2018

This study was conducted to investigate the possibility of utilizing various types of nozzles and gas-liquid mixers to increase the dissolution rate of plasma gas containing ozone generated in a dielectric barrier plasma reactor. After selecting the air atomizing nozzle with the highest gas dissolution rate among the 13 types of test equipment, we investigated the influence of the operating factors on the air atomizing nozzle to determine the optimal plasma gas dissolution method. The gas dissolution rate was measured by a simple and indirect method, specifically, the measurement of KLa instead of direct measurement of ozone concentration, which requires a longer analysis time. The results showed that the KLa value of the simple mix of air and water was $0.372min^{-1}$, Which is 1.44 times higher than that ($0.258min^{-1}$) of gas emitted from a normal diffuser. Among the nozzles of the same type, the KLa value was highest for the nozzle having the smallest orifice diameter. Among the 13 types of devices tested, the nozzle with highest KLa value was the M22M nozzle, which is a gas-liquid spray nozzle. The relationship between water circulation flow rate and KLa value in the experimental range was linear. The air supply flow rate and KLa value showed a parabolic-type correlation, while the optimum air supply flow rate for the water circulation flow rate of 1.8 L / min is 1.38 times.