• Journal of Pharmaceutical Investigation
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• v.30 no.4
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• pp.279-282
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• 2000

Simple and precise high-performance liquid chromatographic (HPLC) assay was developed and validated for the determination of a HMG-CoA reductase inhibitor, $lovastatin^{TM}$ and its active metabolite (mevinolinic acid) in human plasma. The method involved solid phase extraction of mevinolinic acid and internal standard using Sep-Pak Cartridge. Samples were analyzed by reversed-phase HPLC using $Capcell-Pak\;C_{18}$ column with ultraviolet detection at 238 nm. The quantitation limit of mevinolinic acid was 2 ng/ml and the calibration curve was linear over the range of 2-50 ng/ml $(r^2>0.999)$ with human plasma. The analyses of quality control samples indicated that the normal values could be predicted with an accuracy >97%. The intra- and inter-day coefficients of variation for the analyses were <10%. The average recoveries were similar (79%) for mevinolinic acid and methylmevinolinic acid. The method described has been successfully applied to the quantification of mevinolinic acid in about 1,000 human plasma samples over six-month period.

• Analytical Science and Technology
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• v.20 no.3
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• pp.251-254
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• 2007

In this study, a convenient, fast and accurate inductively coupled plasma atomic emission spectrometry (ICP-AES) method has been optimized for the determination of osmium in aqueous solutions. The method makes use of the reaction of sulfurous acid with osmium to quantitative conversion of volatile Os(VIII) to non-volatile Os(IV) in the pH range 2-10. The response was found to be stabilized immediately after sulfurous acid reacted with osmium. The precision was calculated to be 0.5-4.5 % (RSD) under various ICP-AES conditions. The detection limit was 2.5-57.7 ng/g based on $3{\sigma}$ of the blank response (n=3) using a concentric flow nebulization.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1681-1685
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• 2012

A sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed to determine valproic acid in human red blood cell (RBC). It is important to measure the drug concentration of the RBC as well as that of the plasma because of drug partitioning for pharmacokinetic and pharmacodynamic study. The method was linear over the dynamic range of 1-100 ${\mu}g$/mL with a correlation coefficient $r$ = 0.9997. The linearity of this method was established from 1 to 100 ${\mu}g$/mL for valproic acid in red blood cell with accuracy and precision within 15% at all concentrations. The intra-run and inter-run assay accuracy and coefficient of variations are all within 15% for all QC samples prepared in plasma and red blood human samples. Then, valproic acid amount by protein precipitation in plasma was quantified by LC-MS/MS mass spectrometry. The distribution ratio of VPA in RBC and plasma was analyzed by clinical samples. Based on measurement of the valproic acid in human red blood cell, this method has been applied to clinical research for study of distribution ratio of valproic acid in blood.

• The Journal of Internal Korean Medicine
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• v.40 no.6
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• pp.1112-1121
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• 2019

Objectives: FDY003 is a raw material for medicine consisting of a natural product that is expected to have the advantages of low side effects and high efficacy. In this study, we predict the efficacy and the standardization of the drug by method validation of anticipated index compounds and the measurement of antioxidant activity. Methods: FDY003 is prepared by extracting and purifying 70% of ethyl alcohol (EtOH). The method validation of cordycepin and chlorogenic acid was determined by high-performance liquid chromatography-photo diode array (HPLC-PDA) and the content of FDY003 was calculated. In order to monitor the biological activity of FDY003, antioxidant activity was measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric-reducing antioxidant power (FRAP). The equivalent values of antioxidants such as trolox, ascorbic acid, gallic acid, and caffeic acid were measured by ABTS and FRAP. Results: Chlorogenic acid and cordycepin were both found suitable for method validation in HPLC and FDY003 containing 9.92±0.50 and 17.97±0.27 ㎍/g, respectively. In DPPH, the electron donating ability (EDA) value of FDY003 was increased in a concentration dependent manner. FDY003 confirmed antioxidant activity by ABTS and FRAP. Conclusions: FDY003 contains certain components including cordycepin and chlorogenic acid and has antioxidant ability by various mechanisms. Therefore, it is expected that FDY003 is capable of various physiological activities including anti-cancer activity.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.797-802
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• 2011

I assessed the B($a$)P content from the Ginseng extract, Red ginseng extract, and Ssangwha extract which have high viscosities. It wasn't easy to extract oil from these samples, consequently measuring of B($a$)P was difficult. In order to know the exact detecting contents, I injected standard material of B($a$)P to the above extractions and pre-treated for measurement but it was also difficult to measure of contents exactly. To improve of detecting method, I removed mucinous materials using a 85% phosphoric acid solution or 10% citric acid solution and then processed continuously with $60^{\circ}C$ hot water. The analysis revealed that extracting the samples contained B($a$)P determined the rate of each 70%, 55%, 67% could increase. As a result the detecting method of B($a$)P contents could be improved.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.568-574
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• 2016

In this study, the mixing method of positive paste and mixing temperature to improve the capacity of the lead-acid batteries has been investigated. The results show that the initial current capacity of lead acid battery depend on the mixing temperature and mixing method of positive paste. In the results of the capacity cycle repetition tests for estimating the life cycle, the 3BS showed the PCL. but the fine 4BS represented certain improved cycles compared to that of the coarse 4BS. It was considered that the fine 4BS showed higher bond strength between active materials than the coarse 4BS and represented large contact areas and that lead to prevent possible sulfation due to the suppression of insulating layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.11-14
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• 2001

We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 30[mN/m]. LB layers of Arac. acid deposited by LB method were deposited onto slide glass as Y-type film. The physicochemical properties of the LB films were examined by UV absorption spectrum, SEM and AFM. The structure of manufactured device is Au/arachidic acid/Al. the number of accumulated layers are 3~9. Also. we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from -3 to +3[V]. The insulation property of a thin film is better as the distance between electrodes is larger.

• Journal of Food Hygiene and Safety
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• v.7 no.2
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• pp.107.1-112
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• 1992

Free-, soluble- and insoluble phenolic acids were extracted from defatted Galla Rhois. The extracts were then dissolved in equal amounts of an soybean oil, and POV (peroxide value) of the resulting substrates, portion of the soybean oil (control) and 0.02% BHT were measured by AOM (active oxygen method) test at 97.8$^{\circ}C$ for 40 hours through Rancimat method. Induction period of control, BHT, free phenolic acids, soluble phenolic acids and insoluble phenolic acids by the Rancimat method were 4.8, 10.5, 23.9 and 30.5hr. The phenolic acids separated and tentati-vely identified by gas chromatography were catechol, gallic acid, vanillin, protocatechuic acid, syri-ngic acid, ferulic acid.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3239-3243
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• 2014

We have developed a simple method for tuning the morphologies of $Cu_2O$ microcrystals. $Cu_2O$ microcrystals were prepared by precipitation at room temperature from a mixture of $Cu(CH_3COO)_2{\cdot}H_2O$, N,N,N',N'-tetramethyl ethylenediamine (TMEDA), ascorbic acid, and polyethylene glycol (PEG). TMEDA was used to promote the formation of copper-TMEDA complexes. A variety of $Cu_2O$ microcrystal morphologies were obtained simply by varying the concentrations of TMEDA and ascorbic acid. Aggregated $Cu_2O$ microspheres are formed at higher concentrations of ascorbic acid in the absence of TMEDA. Aggregated $Cu_2O$ microcubes are formed at lower concentrations of ascorbic acid and higher concentrations of TMEDA. The crystal growth mechanism of these $Cu_2O$ morphologies is explained.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.547-551
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• 2001

The comparative activities of acetone, ethanol, and aqueous fractions extracted from fruit powder of Cudrania tricuspidata by different temperature were tested by in vitro experimental models; peroxidation of linoleic acid and autooxidation of rat hepatic and renal microsomes by using thiobarbituric acid (TBA) for assay of free malondialdehyde production, and scavenging activities of free radicals by DPPH (α, α'-diphenyl-β-picrylhydrazyl). In DPPH method, acetone fraction extracted at 30℃ showed the highest free radical scavenging activities and acetone fractions extracted at 30℃ and 60℃ and ethanol fraction extracted at 30℃ showed stronger than BHT (butylated hydroxitoluene) although used ten-fold lower concentrations. In thiocyanate method used linoleic acid an inhibitory effects of all fractions showed higher than control treatment. TBA method used linoleic acid showed the highest antioxidative activity in acetone fraction extracted at 30℃ and 60℃. an inhibition activity against lipid peroxidation in hepatic microsomes of rats showed the highest at acetone faction extracted at acetone fraction among extracted fractions was shown to be the most potent antioxidative properties and this action was more potent in fractions extracted at 30℃ than those extracted at 60℃.