http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Enqi Wu (검색결과 9 건)
- 무료
- 기관 내 무료
- 유료
-
Enqi Wu,김경태,Sreenivas Kalyan Adidi,이영근,조종운,이원재,강종성 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.8
Capillary electrochromatographywas employed for enantioseparation ofa-amino acids and their derivatives. (-)-18-Crown-6-2,3,11,12-tetracarboxylic acid bonded on the silica was used as the chiral stationary phase and methanol/Tris-citric acid (20 mM, pH 3.0–4.5) (20:80, v/v) was used as mobile phase. The enantioseparation performance was discussed and structure-chiral separation relationship were tried to be explained. The enantiomeric resolution was increased when the pH of the mobile phase decreased or hydrogen of amino acid was substituted with halogen. The resolution of 4-bromophenylalanine was 2.37 at pH 4.5, however, this value was increased to 3.35 at pH 3.0. Bromoor chloro-substituted phenylalanine tended to show higher resolutionthanfluoro-substitutedone.Forfluoro-substituted phenylalanine the resolution was increased in order of 4-, 3and 2-substituted one. a-Methyltryptamine did not show reasonable separation. As the thermodynamic study is a useful tool to understand the chiral recognition, the temperature effect on the enantioseparation was studied and the thermodynamic parameters were calculated. The mostimportant mechanism of chiral recognition for the analytes tested could be barrier effects based on the thermodynamic calculations. The coefficient of determination between hydrophobicity and separation factor was found to be 0.87, indicating favorable separation with higher hydrophobicity of amino acids.
-
Ding, Yan,Wu, Enqi,Chen, Jianbo,Nguyen, Huu-Tung,Do, Thi-Ha,Park, Kyung-Lae,Bae, Ki-Hwan,Kim, Young-Ho,Kang, Jong-Seong Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.10
A simple high performance liquid chromatographic method was developed to evaluate the quality of Moutan Cortex Radicis based on chromatographic fingerprints that characterize eight pharmacological compounds, namely, gallic acid, paeoniflorin, galloyl paeoniflorin, benzoic acid, quercetin, benzoylpaeoniflorin, paeoniflorigenone, and paeonol. These compounds were identified by their characteristic UV profiles and the mass spectroscopy data, and their contents were determined by HPLC. The chromatographic separation was performed on a $C_{18}$ column by gradient elution with 0.05% formic acid in water and acetonitrile. The methodological validation gave acceptable linearities (r = 0.9996) and recoveries (ranging from 99.4∼103.1%). The limits of detection (LOD) of these compounds ranged from 10 to 30 $\mu$g/mL. The representative chromatographic fingerprints of Moutan Cortex Radicis were obtained by analyzing 20 batches of samples collected from markets in Korea and China. For the efficient evaluation of quality for the commercial Moutan Cortex Radicis it is recommended that the total content of the six characteristic compounds should contain more than a minimum of 2% and that the content of total paeoniflorin and paeonol should exceed a minimum of 1.5% of dry weight of Moutan Cortex Radicis.
-
키랄컬럼 쌍을 이용한 레보도파 제제 중의 l-도파와 d-도파의 HPLC 분석
주홍매,오은기,진건파,주반멘,이은주,이은실,강종성 충남대학교 약학대학 의약품개발연구소 2010 藥學論文集 Vol.25 No.-
Levodopa preparations are used for the treatment of Parkinson's disease, since it is capable of crossing the protective blood-brain barrier (BBB), whereas dopamine itself cannot. d-Dopa could be often contained to a pharmaceutical levodopa preparations as impurity, however, the Korean Pharmacopeia doesn't regulate the amount of d-dopa in levodopa preparations. A new, precise and simple HPLC method for determination of l-dopa and d-dopa from levodopa formulation was developed using a pair of chiral columns, SCA and RCA, for the purpose of quality control. The selected mobile phase was composed of methanol and water (80 : 20) containing 0.01% phosphoric acid. The flow rate was 1.0 mL/min and detection wavelength was 210 nm. The intraday precision of l-dopa and d-dopa analysed by developed method were 2.71~8.18% and 2.94~6.03%, respectively. Both dopa enantiomers were separated by SCA and RCA column, a pair of chiral columns. However, RCA column was useful for the analysis of l-dopa, while SCA column for d-dopa. The method was validated according to ICH Guidelines and the method was found to be simple, accurate, precise, economical and robust.
-
Jianbo Chen,Enqi Wu,Hongmei Zhu,이관준,Van Men Chu,조정원,김영호,박용기,이원재,강종성 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.8
High-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) were used to identify five active components in the modified herbal decoction Bo-Yang-Hwan-O-Tang (mBHT), i.e., amygdalin,decursin, paeoniflorin, salvianolic acid B, and calycosin-7-O-β-D-glycoside. These components were identified by comparing their retention times and mass spectra with those of reference compounds. The conditions of both analytical methods were optimized and validated. Sufficient separation of target analytes was achieved using a buffer consisting of 40 mM sodium borate and 60 mM sodium dodecylsulfate (SDS) containing 10% methanol (pH 9.5) at 250 nm for CE analysis and gradient elution with a water-methanol mobile phase and ultraviolet (UV) photodiode array detector (DAD) at 250 nm for HPLC analysis. The mBHT components were determined within 65 min by HPLC and 16 min by CE. All calibration curves showed high linearity (R > 0.999) within the ranges tested. Intra-day and inter-day precision were less than 1.6% and 1.8% for HPLC and 2.5% and 4.8% for CE, respectively. The accuracy of the methods ranged from 98.8% to 102.3% for HPLC and from 95.9% to 108.2% for CE.
-
Yan Ding,Enqi Wu,Jianbo Chen,Huu Tung Nguyen,Thi Ha Do,Kyung Lae Park,KiHwan Ba,Young Ho Kim,강종성 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.10
A simple high performance liquid chromatographic method was developed to evaluate the quality of Moutan Cortex Radicis based on chromatographic fingerprints that characterize eight pharmacological compounds, namely, gallic acid, paeoniflorin, galloyl paeoniflorin, benzoic acid, quercetin, benzoylpaeoniflorin, paeoniflorigenone, and paeonol. These compounds were identified by their characteristic UV profiles and the mass spectroscopy data, and their contents were determined by HPLC. The chromatographic separation was performed on a C18 column by gradient elution with 0.05% formic acid in water and acetonitrile. The methodological validation gave acceptable linearities (r = 0.9996) and recoveries (ranging from 99.4∼103.1%). The limits of detection (LOD) of these compounds ranged from 10 to 30 μg/mL. The representative chromatographic fingerprints of Moutan Cortex Radicis were obtained by analyzing 20 batches of samples collected from markets in Korea and China. For the efficient evaluation of quality for the commercial Moutan Cortex Radicis it is recommended that the total content of the six characteristic compounds should contain more than a minimum of 2% and that the content of total paeoniflorin and paeonol should exceed a minimum of 1.5% of dry weight of Moutan Cortex Radicis.
-
Zhu, Hongmei,Wu, Enqi,Chen, Jianbo,Men, Chuvan,Jang, Yu-Seon,Kang, Won-Ku,Choi, Jung-Kap,Lee, Won-Jae,Kang, Jong-Seong Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.6
Sibutramine enantiomers were separated successfully by capillary zone electrophoresis using substituted cyclodextrins as chiral selectors. The effects of cyclodextrin concentration, pH, voltage, buffer type, and electrolyte concentration on the migration time and resolution of enantiomers were examined. Separation of sibutramine enantiomers on an unmodified fused silica capillary (total length, 54 cm; effective length, 45 cm) was achieved using a mixed buffer of 20 mM phosphate/10 mM citrate containing either 5 mM methyl-${\beta}$-cyclodextrin (pH 4.3) or 5 mM carboxymethyl-${\beta}$-cyclodextrin (pH 6.5). Samples were injected with a pressure of 50 mbar for 5 s and were detected at a wavelength of 223 nm. The established method showed good precision and accuracy, with intra- and inter-day variations of less than 2.9 and 4.7%, respectively, and recoveries of 95.7 - 103.8%. The stability constants of (R)- and (S)-sibutramine demonstrated that the resolution of sibutramine enantiomers was attributable primarily to the difference in stability constants. When this optimized method was applied to the determination of sibutramine enantiomers in commercial drug formulations, it proved to be economical and convenient, affording sufficient accuracy, precision, and reproducibility as well as sensitivity and selectivity.
-
Hongmei Zhu,Enqi Wu,Jianbo Chen,Chuvan Men,장유선,Wonku Kang,Jung Kap Choi,이원재,강종성 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.6
Sibutramine enantiomers were separated successfully by capillary zone electrophoresis using substituted cyclodextrins as chiral selectors. The effects of cyclodextrin concentration, pH, voltage, buffer type, and electrolyte concentration on the migration time and resolution of enantiomers were examined. Separation of sibutramine enantiomers on an unmodified fused silica capillary (total length, 54 cm; effective length, 45 cm) was achieved using a mixed buffer of 20 mM phosphate/10 mM citrate containing either 5 mM methyl-β-cyclodextrin (pH 4.3) or 5 mM carboxymethyl-β-cyclodextrin (pH 6.5). Samples were injected with a pressure of 50 mbar for 5 s and were detected at a wavelength of 223 nm. The established method showed good precision and accuracy, with intra- and inter-day variations of less than 2.9 and 4.7%, respectively, and recoveries of 95.7 - 103.8%. The stability constants of (R)- and (S)-sibutramine demonstrated that the resolution of sibutramine enantiomers was attributable primarily to the difference in stability constants. When this optimized method was applied to the determination of sibutramine enantiomers in commercial drug formulations, it proved to be economical and convenient, affording sufficient accuracy, precision, and reproducibility as well as sensitivity and selectivity.
-
Chen, Jianbo,Wu, Enqi,Zhu, Hongmei,Lee, Kwan-Jun,Chu, Van Men,Cho, Cheong-Weon,Kim, Young-Ho,Park, Yong-Ki,Lee, Won-Jae,Kang, Jong-Seong Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.8
High-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) were used to identify five active components in the modified herbal decoction Bo-Yang-Hwan-O-Tang (mBHT), i.e., amygdalin, decursin, paeoniflorin, salvianolic acid B, and calycosin-7-O-${\beta}$-D-glycoside. These components were identified by comparing their retention times and mass spectra with those of reference compounds. The conditions of both analytical methods were optimized and validated. Sufficient separation of target analytes was achieved using a buffer consisting of 40 mM sodium borate and 60 mM sodium dodecylsulfate (SDS) containing 10% methanol (pH 9.5) at 250 nm for CE analysis and gradient elution with a water-methanol mobile phase and ultraviolet (UV) photodiode array detector (DAD) at 250 nm for HPLC analysis. The mBHT components were determined within 65 min by HPLC and 16 min by CE. All calibration curves showed high linearity (R > 0.999) within the ranges tested. Intra-day and inter-day precision were less than 1.6% and 1.8% for HPLC and 2.5% and 4.8% for CE, respectively. The accuracy of the methods ranged from 98.8% to 102.3% for HPLC and from 95.9% to 108.2% for CE.
-
최현수,진건파,오은기,이은주,이은실,박경래,강종성 충남대학교 약학대학 의약품개발연구소 2009 藥學論文集 Vol.24 No.-
Chirality plays an important role in biology, and many of the processes essential for life are stereospecific. Hence, the chiral chromatographic separation of drugs becomes more important for the pharmacologists and toxicologists to offer the appropriate tools to find the solution for many problems related with stereoisomers of drugs. This review discusses the clinical applications of chiral separation for meploquine salbutamol, omeprazole, ketamine and some fluorinated volatile inhalation anaesthetics. The chirality in clinical situations was illustrated by these drugs in the field of enantiospecific pharmacokinetics and therapeutic activities. The results indicated that the racemic switch to a single enantiomer for these drugs will promote the development of more effective and safe drugs.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
