• Archives of Pharmacal Research
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• v.5 no.2
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• pp.87-91
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• 1982

In order to develop an analytical method for amikacin and butirosin in presence of their parent antibiotics, kanamycin A and ribostamycin, high-performance liquid chromatographic technique and microbioassay method were evaluated and compared. Using high performance liquid chromatography, two acylated antibiotics, amikacin and butirosin was partially separated from their parent antibiotics, to provide a qualitative analytical method. In microbioassay using Pseudomonas aeruginosa TI-13, a producer of aminoglycoside-3-phosphotransferase I, only acylated antibiotics were selectively analyzed when paper disc-susceptibility assay was used. The standard curve showed a good correlation between the response and odse in semilogarithmic plat with correlation coefficients above 0.96, and analytical deviation from expected dose was within 10%.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.389.1-389.1
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• 2002

A high-performance liquid chromatographic method was developed to determine the quantities of curcumin and glycyrrhizin in two different oriental herbal preparations of Kamijadowhan (KMD. NKMD). Two compounds were separated in less than 10 min with a Nova-Pak $C_{18}$ column ($3.9{\times}150$ mm ($5{\mu}$ particle size) by linear gradient elution using 0.03% (v/v) phosphoric acid-acetonitrile (60:40. v/v% at 0 min; 40:60 v/v% at 6 mini as the mobile phase at a flow-rate of 0.8 ml $min^{-1}$. (omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.283.1-283.1
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• 2003

This study was designed to develop and validate an isocratic reversed phase high performance liquid chromatographic(HPLC) method for the quantitation of sobrerol in drug preparations, and obtain the data pool that can be used in the revision of pharmacopoeia. The separation of sobrerol and the other compounds (S-carboxymethylcysteine, acetaminophen, methyl paraben, propyl paraben, and sobrerol degradants) was achieved in a C18 column with an acetonitrile-methanol-water(24.5:10.5:65.0) mobile phase. (omitted)

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.1
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• pp.208-222
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• 2000

This study was conducted to supplement limit of previous study, The objectives of this study were to select optimal conditions of high performance liquid chromatography(HPLC) operation for detecting urinary 2-thiothiazolicline-4-carboxylic acid(TTCA) and thiocarbamide simultaneously, and to evaluate recovery rates for various liquid-liquid extration method of these metabolites, The results are as follows : 1. The urinary TTCA and thiocarbamide were separate sharply when flow rate is $0.7m{\ell}/min$, using a series $C_8$ and $C_{18}$ column, 50 mM $KH_2PO_4$ : acetonitrile (93.5 : 6.5) and pH 3.5 as a mobile phase. The retention time was TTCA, $12.07{\pm}0.11$(mean${\pm}$SD, n=06), thiocarbamide, $7.85{\pm}0.01$ (mean${\pm}$SD, n=6), respectively. The calibration curve for TTCA and thiocarbamide was linear within the range 0.05 to $30{\mu}g/m{\ell}$. 2. By the liquid-liquid extration, butanol extration with $(NH_4)_2$ as a salting-out reagent was used as a simultaneous extration method for these metabolites in acid state, and recovery rates of this method are urinary TTCA, $49.6{\pm}17.7$ (mean${\pm}$SD, n=16), thiocarbamide, $43,9{\pm}5.50$ (mean${\pm}$SD, n=16), respectively 3. The precision(pooled coefficients of variation for 4 concentration) of the urinary thiocarbamide analysis was 0.03754 by butanol liquid-liquid extraction with $(NH_4)_2$ as a salting-out reagent, and TTCA was 0.04082 by ethyl acetate liquid-liquid extration with $(NH_4)_2$ as a salting out reagent The above results show that the butanol liquid-liquid extraction with $(NH_4)_2$ as a salting-out reagent in acid state, and using a series $C_8$ and $C_{18}$ column, 50 mM $KH_2PO_4$ : acetonitrile (93.5 : 6.5) and pH 3.5 as a mobile phase are suitable for the analysis of urinary TTCA and thiocarbamide simultaneously. The detection limit of TTCA and thiocarbamide was about $0.17{\mu}g/m{\ell}$, $0.07{\mu}g/m{\ell}$.

• Korean Journal of Pharmacognosy
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• v.16 no.4
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• pp.214-220
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• 1985

The preservatives in 32 commercial liquid preparations of crude drugs have been analyzed by using high performance liquid chromatography. Benzoic acid (BA) and p-hydroxybenzoates were separated with mobile phase of $MeOH-H_2O$ (70:30) (pH 7.0) at a flow rate of 0.9ml/min. BA, sorbic acid and dehydroacetic acid were separated with mobile phase of $MeOH-H_2O$ (40:60) (pH 4.5) at a same flow rate. In addition, the pH values of the preparations were investigated. It was found that BA was used in most of the preparations.

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.211-226
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• 1988

Liquid chromatographic behavior of several metal ions in dithiocarbamate(DTC) chelates were investigated by reversed phase high performance liquid chromatography on Novapak $C_{18}$ and ${\mu}$-Bondapak $C_{18}$ columns. The optimum conditions for the separation of DTC-metal chelate were examined with respect to the pH, shaking time, flow rate, extraction solvent, and mobile phase strength. The metal ions in mixtures at trace level, chelated with some dithiocarbamate derivatives were separated successfully on Novapak $C_{18}$ column using acetonitrile/methanol/water or acetonitril/water mixtures as mobile phases. It was found that all DTC metal chelates studied were eluted in an acceptable range of capacity factor values ($0{\leqq}log\;k'{\leqq}1$). Although several foreign metal ions were coexisted, high recovery and good precision were attained ; 97.0-106.7 % for the recovery and 0.98-3.41% for the coefficient of variation. Under the optimum analytical conditions, trace metal ions in the composite water samples were determined sucessfully with in relative error of about {\pm}$6.7 %.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2663-2670
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• 2013

The purpose of stability testing is to provide evidence about how the quality of a drug varies with time under the influence of a variety of environmental factors. In this study, erythropoietin (EPO) was analyzed under different pH (pH 3 and pH 9) and temperature ($25^{\circ}C$ and $40^{\circ}C$) conditions according to current Good Manufacturing Practice (cGMP) and International Conference on Harmonisation (ICH) guidelines. The molecular weight difference between intact EPO and deglycosylated EPO was determined by SDS-PAGE, and aggregated forms of EPO under thermal stress and high-pH conditions were investigated by size exclusion chromatography. High pH and high temperature induced increases in dimer and high molecular weight aggregate forms of EPO. UPLC-ESI-TOF-MS was applied to analyze the changed modification sites on EPO. Further, normal-phase high-performance liquid chromatography was performed to identify proposed glycan structures and high pH anion exchange chromatography was carried out to investigate any change in carbohydrate composition. The results demonstrated that there were no changes in modification sites or the glycan structure under severe conditions; however, the number of dimers and aggregates increased at $40^{\circ}C$ and pH 9, respectively.

• ALGAE
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• v.28 no.3
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• pp.289-296
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• 2013

For the quantitative detection of algal toxin, microcystin, a chemiluminescence immunochromatographic assay method was developed. The developed system consists of four parts, chemiluminescence assay strip (nitrocellulose membrane), horse radish peroxidase labeled microcystin monoclonal antibodies, chemiluminescence substrate (luminol and hydrogen peroxide), and luminometer. The performance of the chemiluminescence immunochromatographic assay system was compared with high performance liquid chromatography (HPLC) detection. The detection limit of chemiluminescence immunochromatographic assay system is several orders of magnitude lower than with HPLC. The chemiluminescence immunochromatography and HPLC results correlated very well with the correlation coefficient ($r^2$) of 0.979.

• Proceedings of the Korean Society of Toxicology Conference
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• 2006.11a
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• pp.65-74
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• 2006

Modem drug discovery requires rapid pharmacokinetic evaluation of chemically diverse compounds for early candidate selection. This demands the development of analytical methods that offer high-throughput of samples. Naturally, liquid chromatography / tandem mass spectrometry (LC-MS/MS) is choice of the analytical method because of its superior sensitivity and selectivity. As a result of the short analysis time(typically 3-5min) by LC-MS/MS, sample preparation has become the rate- determining step in the whole analytical cycle. Consequently tremendous efforts are being made to speed up and automate this step. In a typical automated 96-well SPE(solid-phase extraction) procedure, plasma samples are transferred to the 96-well SPE plate, internal standard and aqueous buffer solutions are added and then vacuum is applied using the robotic liquid handling system. It takes only 20-90 min to process 96 samples by automated SPE and the analyst is physically occupied for only approximately 10 min. Recently, the ultra-high flow rate liquid chromatography (turbulent-flow chromatography)has sparked a huge interest for rapid and direct quantitation of drugs in plasma. There is no sample preparation except for sample aliquotting, internal standard addition and centrifugation. This type of analysis is achieved by using a small diameter column with a large particle size(30-5O ${\mu}$m) and a high flow rate, typically between 3-5 ml/min. Silica-based monolithic HPLC columns contain a novel chromatographic support in which the traditional particulate packing has been replaced with a single, continuous network (monolith) of pcrous silica. The main advantage of such a network is decreased backpressure due to macropores (2 ${\mu}$m) throughout the network. This allows high flow rates, and hence fast analyses that are unattainable with traditional particulate columns. The reduction of particle diameter in HPLC results in increased column efficiency. use of small particles (<2 urn), however, requires p.essu.es beyond the traditional 6,000 psi of conventional pumping devices. Instrumental development in recent years has resulted in pumping devices capable of handling the requirements of columns packed with small particles. The staggered parallel HPLC system consists of four fully independent binary HPLC pumps, a modified auto sampler, and a series of switching and selector valves all controlled by a single computer program. The system improves sample throughput without sacrificing chromatographic separation or data quality. Sample throughput can be increased nearly four-fold without requiring significant changes in current analytical procedures. The process of Bioanalytical Method Validation is required by the FDA to assess and verify the performance of a chronlatographic method prior to its application in sample analysis. The validation should address the selectivity, linearity, accuracy, precision and stability of the method. This presentation will provide all overview of the work required to accomplish a full validation and show how a chromatographic method is suitable for toxirokinetic sample analysis. A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method developed to quantitate drug levels in dog plasma will be used as an example of tile process.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1386-1391
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• 1999

The methanol extract of Gardenia jasminoides Ellis showed antimicrobial activity against bacteria and yeasts. The extract was successively purified with solvent fractionation, silica gel adsorption column chromatography, Sephadex LH-20 column chromatography, octadecylsilane column chromatography. The purified active substance was isolated by high performance liquid chromatography. The isolated compound was 3,4-dihydroxybenzoic acid which was determined by mass spectrometer, gas chromatograph-mass spectrometer, $^{1}H-nuclear$ magnetic resonance, $^{13}C-nuclear$ magnetic resonance and two-dimensional nuclear magnetic resonance. The content of 3,4-dihydroxybenzoic acid was $32.7\;{\mu}g/g$ in dried fruits of Gardenia jasminoides Ellis.