• Proceedings of the PSK Conference
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• 2002.10a
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• pp.401.2-401.2
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• 2002

To study the pharmacokinetics of triflusal, more reliable and sensitive analytical method of triflusal in plasma sample was developed. Analytical method of triflusal in human plasma was developed using semi-microbore HPLC equipped with automated column switching system. p- Toluic acid, which is structural analogue of triflusal. was used as an internal standard and 2 M HCI was employed as a stabilizer. The load phase and mobile phase were prepared using acetonitrile and 20 mM $KH_{2}PO_{4}$ with the volume ratios of 10:90 (pH 2.5) and 43:57 (pH 2.3), respectively. (omitted)

• YAKHAK HOEJI
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• v.42 no.2
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• pp.149-152
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• 1998

A high performance liquid chromatographic method was developed for the determination of DA-6034 in biological fluids using internal standard. Plasma containing DA-6034 and inter nal standard was extracted by liquid-liquid extraction at an acidic pH. After evaporation of the organic layer, the drug and internal standard were reconstituted with mobile phase and injected into the column. They were separated by high performance liquid chromatography on inertsil ODS II column at 334 nm. The detection limit of DA-6034 in plasma was 0.02 ${\mu}$g/ml. In this method, the range of recovery and coefficients of variation were 96-110% and 0.40-3.78%, respectively. There was no interference from endogenous substances. Urine and bile were analysed using the deproteinization method and the detection limit of DA-6034 was 1${\mu}$g/l.

• Toxicological Research
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• v.29 no.3
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• pp.203-209
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• 2013

A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of ${\varepsilon}$-acetamidocaproic acid (AACA), the primary metabolite of zinc acexamate (ZAC), in rat plasma by using normetanephrine as an internal standard. Sample preparation involved protein precipitation using methanol. Separation was achieved on a Gemini-NX $C_{18}$ column ($150mm{\times}2.0mm$, i.d., 3 ${\mu}m$ particle size) using a mixture of 0.1% formic acid-water : acetonitrile (80 : 20, v/v) as the mobile phase at a flow rate of 200 ${\mu}l/min$. Quantification was performed on a triple quadrupole mass spectrometer employing electrospray ionization and operating in multiple reaction monitoring (MRM) and positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of AACA were linear over the concentration range of 20~5000 ng/ml in rat plasma. The coefficient of variation and relative error at four QC levels were ranged from 1.0% to 5.8% and from -8.4% to 6.6%, respectively. The present method was successfully applied for estimating the pharmacokinetic parameters of AACA following intravenous or oral administration of ZAC to rats.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.215-217
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• 2008

Crystallization behavior of the bulk metallic glass (BMG) during compression and tension was studied in the supercooled liquid region (SLR). Rod samples of the BMG alloy were produced by consolidating gas atomized powders of $Cu_{54}Zr_{22}Ti_{18}Ni_6$ using spark plasma sintering. The crystallization behavior in these samples was examined by tackling changes in thermal property during heating the samples in DSC. The present BMG alloy was firstly decomposed and then crystallized during annealing in the SLR. The phase decomposition from the original amorphous phase was retarded by the compressive stress, while it was accelerated by the tensile stress.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2760-2764
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• 2013

Geniposide is a biologically active ingredient of gardenia fruit. A liquid chromatography-tandem mass spectrometric method was developed and validated for the determination of geniposide in rat plasma. The plasma samples were pretreated by solid-phase extraction and introduced into a BDS Hypersil $C_{18}$ column ($50{\times}2.1mm$, $5{\mu}m$) for chromatographic separation. The mobile phase consisted of 0.1% formic acid and 0.1% formic acid in acetonitrile, and gradient elution was performed at a flow rate of 0.25 mL/min. For mass spectrometric detection, multiple reaction monitoring was performed via an electrospray ionization source in positive mode. The calibration curve for geniposide was linear ($r^2=0.997$) in the concentration range of $0.005-1{\mu}g/mL$. The intra- and inter-day accuracies and precisions fulfilled the required criteria (${\pm}15%$). The developed method was subsequently used for pharmacokinetic analysis of geniposide after oral administration to rats at a dose of 50 mg/kg. The mean maximum plasma concentration of geniposide was $0.68{\pm}0.29{\mu}g/mL$ at $0.44{\pm}0.13h$, and the mean area under the plasma concentration versus time curve was $1.46{\mu}g{\cdot}h/mL$.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.878-880
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• 2004

Revered-phase LC-electrospray ionization mass spectrometry was used to selectively determine enalapril from plasma with minimal sample preparation. Detection limit of the method was 1 ng/mL. Precision (within day and between days) and accuracy of the method at various concentrations were acceptable. The analytical technique was used for pharmacokinetic studies after administration of enalapril to human test subjects.

• Analytical Science and Technology
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• v.20 no.5
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• pp.424-433
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• 2007

An analytical method for the determination of thyroid hormones in plasma samples has been studied by solid-phase extraction and high-performance liquid chromatography/diode array detector (DAD)/electrospray ionization (ESI)-mass spectrometer. Seven thyroid hormones were successfully separated by gradient elution on the reverse phase Hypersil ODS column (4.6 mm I.D., 250 mm length, particle size $5{\mu}m$) with ammonium formate buffer and acetonitrile. In addition, these compounds were confirmed by UV spectra and ESI-mass Spectra. The extraction recoveries of thyroid hormones in the plasma sample (at pH 3) were in the range of 74.5-115.7 % with solid-phase extraction by C18, followed by elution with 4 mL of methanol. The calibration curves showed good linearity with the correlation coefficients ($r^2$) varying from 0.9939 to 0.9978 and the detection limits of all analytes were obtained in the range of 20-50 ng/mL (38.1-162.8 pmol/mL). As a result, thyroxine was found in the range of 50.98-112.97 ng/mL in normal plasma samples.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.4
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• pp.247-250
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• 2003

A simple and sensitive assay method was developed for cefepime in human plasma using high performance liquid chromatography (HPLC). Cefepime and cefadroxil (the internal standard) were extracted from heparinized human plasma by simple deproteination with perchloric acid. The extract was injected into an Atlantis dC18 column ($250{\times}4.6$ mm; particle size $5{\mu}m$, Waters) and the column was eluted with methanol and 0.01 M dihydrogen phosphate at pH 3.0 (15：85 v：v) as a mobile phase at a flow rate of 0.7 mL/min. Linearity was confirmed for the range 0.25 to $200{\mu}L/mL$ and the limit of quantitation was $0.25{\mu}L/mL$. The retention times were 10.2 min and 13.4 min for cefepime and cefadroxil, respectively. This method was successfully applied to a pharmacokinetic study of cefepime in plasma from bone marrow transplant patients.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.121.2-121
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• 2003

• Preventive Nutrition and Food Science
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• v.3 no.4
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• pp.379-381
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• 1998

An angiotensin converting enzyme (ACE) inhibitor was isolated and partially purified from bovine blood plasma. Bovine blood plasma was obtained after removing blood cells by centrifugation, followed by the addition of anticoagulant to whole bovine blood. To precipitate plasma proteins, bovine blood plasma was treated with 4% trichloroacetic acid (TCA) as a final concentration .An ACE inhibitor was isolated from TCA supernatnat, using ultrafiltration, gel permeation chormatography, and reverse-phase high pressure liquid chromatogrpahy. The ACE inhibitor purified from TCA supernatant had IC50 values of 9.4$\mu$M.