• Applied Biological Chemistry
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• v.31 no.1
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• pp.52-57
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• 1988

The difference of absorbance before and after oxidation of L-ascorbic acid(AsA) from cucumber was directly proportional to the concentration of AsA. The effect of pH, enzyme concentration and reaction time on the AsA assay were examined. The values of AsA obtained by the present method and HPLC method agreed well in all cases.

• Analytical Science and Technology
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• v.33 no.6
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• pp.252-261
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• 2020

Currently, the potentiometric titration and the high pressure liquid chromatography (HPLC) method were utilized in Korean Pharmacopoeia XII (KP XII) as well as other pharmacopoeias (USP, EP, BP) for determination of loperamide hydrochloride in raw materials and capsules, respectively. The research objective is to overcome the remaining drawbacks from current methods such as solubility of mobile phase (KP XII), less scientific approach (USP 43) or using paired-ion chromatography reagent which shows some limitations (BP2017 and other formulation monographs). The proposed method was optimized by Design of Experiment (DoE) tool to obtain the satisfied method for determination of loperamide hydrochloride. The optimal condition was performed on the common C18 column (150 mm × 4.6 mm; 5 ㎛) using isocratic elution with the mobile phase containing 40 mM of potassium phosphate monobasic (pH 3.0) and acetonitrile (56:44), at a flow rate of 0.7 mL/min. The optimized method was validated and met the requirements of the International Conference on Harmonization. The developed method was applied to determine loperamide hydrochloride in capsules and can be used to update the current monograph in KP XII.

• Korean Journal of Food Science and Technology
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• v.48 no.1
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• pp.48-53
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• 2016

The objective of this study was to evaluate the accuracy and efficiency of different methods used for the fermentable sugar assay in the production of Makgeolli sul-dut. In the initial stage of fermentation, Ipguk treatment produced a higher alcohol content compared to the Nuruk treatment. However, the alcohol content was not significantly different between the two starters at the final stage of fermentation. Acidity in the Ipguk treatment was higher than that of Nuruk throughout the fermentation period. After analyzing the fermentable sugars using dinitrosalicylic acid (DNS), Fehling's method, refractometer, glucose kit, and high performance liquid chromatography (HPLC), it was confirmed that the HPLC method was the most accurate for fermentable sugar quantification. In both types of starters, DNS and Fehling's methods showed results comparable to HPLC in terms of fermentable sugar content, while the glucose kit and refractometer analyses showed relatively large discrepancies, indicating that the Fehling's method could also be effective for the analysis of fermentable sugars in the manufacture of Makgeolli.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.204-210
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• 1993

The distribution and excretion of DWC-751, a new cephalosporin, were examined in rats and mice following a single intravenous administration. DWC-751 in plasma and urine was determined by both HPLC and microbiological assay. The plasma concentration of the drug declined biexponentially. The initial and terminal half lives of the drug were 3.0 and 28.3 min, respectively. Binding of the drug to plasma proteins was 42.3%. The distribution volume at steacly-state ($Vd_{ss}$) was only 0.341 ι/kg, which is well correlated with the low n-octanol/water partition coefficient of the drug ($K_{o/w{\cong}0$) Actually, the drug was distributed to liver, kidney and lung with very low organ/plasma concentration ratio. The drug, was excreted mainly via renal excretion, i.e., the total($CL_T$) and apparent renal($CL_{R}$) clearances of the drug were 10.8 and 7.5 ml/min/kg, respectively.

• Journal of Pharmaceutical Investigation
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• v.24 no.1
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• pp.29-32
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• 1994

In order to improve the sensitivity of the current assay methods of selenium in dried-yeast preparations, atomic absorption spectrophotometry (AAS), high performance liquid chromatography (HPLC) and UV-Vis spectrophotometry were employed. The sample was prepared with the digestion by acid mixture of hydrochloric acid, nitric acid and perchloric acid after elimination of ether-soluble substances. The range of quantitation of selenium was $1.0{\sim}6.0\;{\mu}g/ml$ by UV-Vis spectrophotometry, $5.0{\sim}20.0\;{\mu}g/ml$ by HPLC and $0.03{\sim}0.10\;{\mu}g/ml$ by AAS.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.373-375
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• 2004

본 연구는 유황오리로부터 항종양 효과를 나타내는 물질을 용매추출과 각종 chromatography를 사용하여 분리 및 정제하였다. HPLC를 사용하여 정제한 항종양활성 성분의 수율은 유황오리 1Kg당 10mg이었다. HPLC를 이용하여 정제한 항종양활성 물질을 Clonogenic assay로 측정한 결과 $200{\mu}g/m{\ell}$의 농도에서 HEp-2, KB 및 SW-156에서 각각 26%, 28%및 30%의 생존율을 나타내어 항종양 효과가 나타났다. MTT assay에서는 $100{\mu}g/m{\ell}$의 농도는 Farrow, HEp-2 및 KB에 대해서 각각 56%, 58% 및 56%의 세포증식 억제 효과를 나타내었다. bovine normal kidney cell line인 MDBK는 $500{\mu}g/m{\ell}$, $200{\mu}g/m{\ell}$, $100{\mu}g/m{\ell}$에서 각각 48%, 34%, 28%로 증식억제 효과가 나타나 정상세포에 대한 세포독성은 강하지 않은 것으로 판단되어진다.

• Korean Journal of Clinical Pharmacy
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• v.10 no.1
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• pp.38-41
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• 2000

A high-performance liquid chromatographic method with fluorometric detection was evaluated for analysis of ofloxacin in plasma. Biological fluids (plasma, $200\;{\mu}L$) were prepared for assay by protein precipitation with chlorofurm. The detection of ofloxacin and triamterene as an internal standard were performed at 358 nm for excitation and 495 nm for emission. The HPLC separation was carried out on Ultrasphere ODS column (4.6 mm${\times}25\;cm,\;5\;{\mu} m$) with acetonitrile $(45\%)$-phosphoric acid $(1.5\%)\;containing\;0.3\%$ sodium laurylsulfate as the mobile phase. The flow-rate was 1.0 mL/min. The calibration graphs were linear from 3.0 to 80 ng/mL with r=0.998. The minimal detectable concentration in plasma was 1.5 ng/mL. The proposed technique is reproducible, selective, reliable and sensitive.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.181-187
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• 2000

The contents of organic acid in Korean apple juice were analyzed by HPLC using YMC-peak ODS-AQ column and enzymatic assay. Model apple juices were prepared at the laboratory and commercial apple juices were purchased from the market. Individual organic acid contents were as follows: DL-malic acid 62~402mg%, L-malic acid 48~360mg%, citric acid 1.81~15.74mg%, fumaric acid nd~0.50mg%. Together, these tests gave useful information about the quality and authenticity of a particular apple juice smaple. The presence of D-malic acid was a clear indication of adulteration because this isomer did not occur naturally. Fumaric acid and citric acid levels above trace amounts were also inconsistent with pure apple juice.

• YAKHAK HOEJI
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• v.40 no.2
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• pp.177-182
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• 1996

The contents of aloesin in aloe preparations were determined by HPLC. Aloesin was extracted 3 times with ethanol for 30 minutes. The ethanol extract was concentrated and suspend ed in saturated NaCl aqueous solution and successively partitioned with dichloromethane, n-butanol. Prepared samples were analyzed by HPLC on a reverse column(Inertsil ODS-2). In assay, internal standard was a puerarin and regression of calibration curve was 0.998. Recoveries of aloesin added to aloe preparation were 98~123(%).

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.205-205
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• 1994

동물, 곤충, 해조류 등으로 부터 얻어진 독소는 해로운 것으로 알려져 있지만 의학적으로 유용한 화합물을 내포하고 있다. 본 연구는 이러한 점에 착안하여 독사, 또는 곤충의 독 30여종을 대상으로 위암 세포인 SNU-1에 대해서 MTT assay에 의한 세포 독성 시험을 실시하였다. 이 중 세포 독성 활성이 가장 놓은 코브라 계통인 Ophiphagus hannah의 독으로 부터 세포 독성 물질의 정제를 시도하였다. HPLC-GPC와 HPLC-lEX 또는 RP-HPLC를 이용하여 정제하였고 각 분획들을 암세포주에 대해서 시험하였다. TSK-2000SW로 부터 2개의 분획을 얻어 분획 I에서 $IC_{50}$/ 의 값이 0.5 - 3 $\mu\textrm{g}$/ml의 범위 내에서 확인되었다. 분자량이 작은 분획 II에서는 세포독성이 작게 나타났지만 농축하여 성분 분석을 시도하였다. 분획 I을 RP-HPLC를 이용하여 TFA와 acetonitrile의 linear gradient에 의해 더욱 분리를 하였고, phopholipase $A_2$ 활성의 가능성도 측정하였다. 분획 II는 Mono S 칼람을 이용하여 ammonium acetate농도에 따른 pH gradient에 의한 분리를 시도하여 순도를 SDS-PAGE에 의해서 확인하였다. 각각의 크로마토그리피로 부터 얻은 분획에 대해서 세포 독성을 실시중에 있으며 성질도 동정중에 있다.