• Asian Journal of Atmospheric Environment
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• v.11 no.4
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• pp.283-299
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• 2017

An analytical method using high-performance liquid chromatography (HPLC) with fluorescence (FL) detection was developed for simultaneously analyzing 10 polycyclic aromatic hydrocarbons (PAHs) and 18 nitro-derivatives of PAHs (NPAHs). The two-dimensional HPLC system consists of an on-line clean-up and reduction for NPAHs in the 1st dimension, and separation of the PAHs and the reduced NPAHs and their FL detection in the 2nd dimension after column-switching. To identify an ideal clean-up column for removing sample matrix that may interfere with detection of the analytes, the characteristics of 8 reversed-phase columns were evaluated. The nitrophenylethyl (NPE)-bonded silica column was selected because of its shorter elution band and larger retention factors of the analytes due to strong dipole-dipole interactions. The amino-substituted PAHs (reduced NPAHs), PAHs and deuterated internal standards were separated on polymeric octadecyl-bonded silica (ODS) columns and by dual-channel detection within 120 min including clean-up and reduction steps. The limits of detection were 0.1-9.2 pg per injection for PAHs and 0.1-140 pg per injection for NPAHs. For validation, the method was applied to analyze crude extracts of fine particulate matter ($PM_{2.5}$) samples and achieved good analytical precision and accuracy. Moreover, the standard reference material (SRM1649b, urban dust) was analyzed by this method and the observed concentrations of PAHs and NPAHs were similar to those in previous reports. Thus, the method developed here-in has the potential to become a standard HPLC-based method, especially for NPAHs.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.353-357
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• 2012

The new qualitative and quantitative analytical method for hydrocarbon compounds in DME-LPG blending fuel, mixing dimethyl ether (DME) with liquefied petroleum gas (LPG), by using gas chromatography (GC) was investigated. It is difficult to analyze all components of DME-LPG blending fuel by using single column in GC due to consisting of the non-polar LPG and the polar DME which is oxygen-containing compound. Therefore, it has been introduced the Deans switching system, which are useful for analyzing mixtures of a very different nature and/or target analytes in very complex matrix. This technique is to control the pressure between two columns and to selectively change the path of effluent flows to either one of two columns. As a result, we found that DME and LPG can be completely separated at the different columns and the determination of all hydrocarbon compounds in DME-LPG blending fuel can be achieved to this method qualitatively and quantitatively during the operation of one injection. In addition, this method can be applied to the determination of trace components of by-product, such as methanol, methyl formate and ethyl methyl ether, which will be derived from DME synthesis process.

• Archives of Pharmacal Research
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• v.12 no.2
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• pp.108-113
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• 1989

A new column-switching high performance liquid chromatographic method was developed for the determination of lonazolac in plasma. This method was based on the on-line trace enrichment of lonazolac using a precolumn packed with Amberlite XAD-2. The analysis was complete in 20 min. between injections and the limit of detection was $0.1{\mu}g/ml$ using $100{\mu}l$ of plasma. The method was linear in range of $0.1-10{\mu}g/ml$ with a correlation coefficient of 0.9991. Absolute recovery of lonazolac from the spiked plasma samples ranged from 95.6% to 97.1%. The method was shown to be reproducible over the concentration range studied.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.402.3-403
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• 2002

Cilostazol. a quinolinone derivative that inhibits phosphodiesterase. is used for the treatment of intermittent claudication resulting from peripheral arterial disease. In order to perform pharmacological and pharmacokinetic studies of cilostazol, specific. sensitive and reproducible analysis methods are demanded. Therefore. in the present study. an analytical method of cilostazol in human plasma was developed using semi-microbore HPLC equipped with automated column switching system. (omitted)

• YAKHAK HOEJI
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• v.34 no.5
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• pp.334-340
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• 1990

The bioequivalence of Mandol and Mancef (cefamondole nafate injection preparation) was investigated for 8 healthy human volunteers. Cefamandole nafate hydrolysis to cefamandole base in the blood and shows antibacterial activity. As the rate of the hydrolysis can be varied according to the buffer used in the preparation, the bioequivalence of cefamandole nafate I.V. was studied. A new HPLC method, the column switching technique, was developed and used for the simultaneous determination of cefamandole and cefamandole nafate in the plasma and in the urine. There were no statistically significant difference in between Mandol and Mancef for the parameters of AUC and Cp 0.25 hr even through the power of the test was not enough.

• Analytical Science and Technology
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• v.8 no.4
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• pp.539-543
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• 1995

The on-line SPE-HPLC coupling system was developed for the efficient separation and determination of trace pesticides, such as phenoxyacetic acids and esters, and triazines in aqueous solutions. By using the developed SPE-HPLC on-line system, the band broadening usually observed in single precolumn switching mode was greatly reduced, consequently, the quantitative determination of trace pesticides could be achieved, Besides, since most of the analytes preconcentrated by SPE column could be injected directly into HPLC system, the limit of detection can be improved down to ppt level.

• Journal of ILASS-Korea
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• v.23 no.1
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• pp.9-15
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• 2018

Breakup lengths of circular and elliptical liquid jets in a subsonic crossflow were experimentally studied. Two circular-shaped and four elliptical-shaped plain-orifice injectors, which had different aspect ratios and orifice length to diameter ratios, were used to provide various liquid jet conditions such as steady, cavitation, and hydraulic flip. By varying the injection pressure drop from 1 bar to 6 bar, spray images were taken using a shadowgraph technique. Breakup lengths were measured and analyzed. As the aspect ratio in orifices increased, liquid column breakup lengths normalized by the equivalent diameter were reduced irrespectively of the switching of the major or minor axis to the crossflow. It was also found that when hydraulic flip developed inside the orifice, x-directional breakup lengths more decreased for both circular and elliptical liquid jets.

• Journal of Pharmaceutical Investigation
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• v.33 no.4
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• pp.311-317
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• 2003

Felodipine is a calcium antagonist that lowers blood pressure by reducing peripheral resistance by meas of a direct, selective action on smooth muscle in arterial resistance vessels. Futhermore, it have been approved for the effective in angina pectoris and cardiac failure. The purpose of the present study was to evaluate the bioequivalence of two felodipine extended release (ER) tablets, Splendil (YuHan Corporation) and Stapin (Hana Pharmaceutial Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). The felodipine release from the two felodipine formulations in vitro was tested using KP VIII Apparatus II method at pH 6.5 buffer solution. Twenty six healthy male subjects, $22.73{\pm}1.78$ years in age and $66.66{\pm}7.28\;kg$ in body weight, were divided into two groups and a radomized $2{\times}2$ cross-over study was employed. After two tablets containing 5 mg as felodipine were orally administered, blood sample was taken at predetermined time intervals and the concentrations of felodipine in serum were determined using column-switching HPLC method with UV detector. The dissolution profiles of two formulations were similar at pH 6.5 buffer solution. Besides, the pharmacokinetic parameters such as $AUC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t\;and\;C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the Splendil were 2.53%, 1.32% and 18.32% for $AUC_t,\;C_{max}\;and\;T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance rage of log(0.86) to log(1.25) $(e.g.,\;log(0.86){\sim}log(1.20)\;and\;log(0.89){\sim}log(1.23)\;for\;AUC_t,\;C_{max},\;respectively)$. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Stapin ER tablet and Splendil ER tablet are bioequivalent.

• Journal of Pharmaceutical Investigation
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• v.41 no.2
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• pp.117-123
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• 2011

Loxoprofen sodium, a 2-phenylpropionate non-steroidal anti-inflammatory drug (NSAID), has marked analgesic and antipyretic activities and relatively weak gastrointestinal ulcerogenicity. The purpose of the present study was to evaluate the bioequivalence of two loxoprofen sodium tablets, Hana loxoprofen sodium tablet (Hana Pharm. Co., Ltd.) and Dongwha Loxonin$^{(R)}$ tablet (Dongwha Pharm. Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The in vitro release of loxoprofen from the two loxoprofen sodium formulations was tested using KP IX Apparatus II method with various dissolution media. Twenty four healthy Korean male volunteers, $22.83{\pm}1.862$ years in age and $69.92{\pm}9.14$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ crossover study was employed. After a single tablet containing 60 mg as loxoprofen sodium was orally administered, blood samples were taken at predetermined time intervals and the concentrations of loxoprofen in serum were determined using a online column-switching HPLC method with UV/Vis detection. The dissolution profiles of two formulations were similar in all tested dissolution media. The pharmacokinetic parameters such as $AUC^t$, $C_{max}$ and $T_{max}$ were calculated, and computer programs (Equiv Test and K-BE Test 2002) were utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and un-transformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, Dongwha Loxonin$^{(R)}$ tablet, were 2.03, 2.99 and -9.49% for $AUC_t$, $C_{max}$, and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log0.8 to log1.25 (e.g., log0.9831~log1.0535 and log0.9455~log1.1386 for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Hana loxoprofen sodium tablet was bioequivalent to Dongwha Loxonin$^{(R)}$ tablet.

• Korean Journal of Clinical Pharmacy
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• v.20 no.3
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• pp.235-241
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• 2010

Bambuterol hydrochloride, dimethylcarbamic acid 5-[2-(1,1-dimethylethyl)amino-1-hydroxyethyl]-1,3-phenylene ester hydrochloride, is the prodrug of active ${\beta}_2$-adrenergic metabolite terbutaline. The purpose of the present study was to evaluate the bioequivalence of two bambuterol hydrochloride tablets, $Bambec^{(R)}$ tablet 10 mg (Yuhan Co., Ltd.) and Bambucol tablet 10 mg (Sam Chun Dang Pharm. Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). In vitro release of bambuterol from two bambuterol hydrochloride formulations was tested using KP VIII Apparatus II method with various dissolution media. Twenty eight healthy male Korean volunteers, $23.86{\pm}1.65$ years in age and $68.98{\pm}9.58$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After two tablets containing 10 mg as bambuterol hydrochloride were orally administered, blood samples were taken at predetermined time intervals, and the concentrations of bambuterol in serum were determined using column switching HPLC with UV detector. The dissolution profiles of two formulations were similar in all tested dissolution media. The pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated, and ANOVA test with K-BE Test 2002 was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, $Bambec^{(R)}$, were -8.10%, -3.82% and 12.65% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 (i.e., log 0.8093~log 1.0302 and log 0.8564~log 1.1280 for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Bambucol tablet 10 mg was bioequivalent to $Bambec^{(R)}$ tablet 10 mg.