Enantioseparation and Determination of Sibutramine in Pharmaceutical Formulations by Capillary Electrophoresis

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.

Sex-related Differences in DNA Copy Number Alterations in Hepatitis B Virus-Associated Hepatocellular Carcinoma

Zhu, Zhong-Zheng,Wang, Dong,Cong, Wen-Ming,Jiang, Hongmei,Yu, Yue,Wen, Bing-Ji,Dong, Hui,Zhang, Xiao,Liu, Shu-Fang,Wang, Ai-Zhong,Zhu, Guanshan,Hou, Lifang Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.1

Background: Males have a higher prevalence of hepatocellular carcinoma (HCC) than females in general, but the reasons for the sex disparity are still obscure. DNA copy number alteration (CNA) is a major feature of solid tumors including HCC, but whether CNA plays a role in sex-related differences in HCC development has never been evaluated. Methods: High-resolution array comparative genomic hybridization (CGH) was used to examine 17 female and 46 male HCC patients with chronic hepatitis B virus (HBV) infection in Shanghai, China. Two-tailed Fisher's exact or ${\chi}^2$ tests was used to compare CNAs between females and males. Results: The overall frequencies and patterns of CNAs in female and male cases were similar. However, female HCC tumors presented more copy number gains compared to those in males on 1q21.3-q22 (76.5% vs. 37.0%, P = 0.009), 11q11 (35.3% vs. 0.0%, P = 0.0002) and 19q13.31-q13.32 (23.5% vs. 0.0%, P = 0.004), and loss on 16p11.2 (35.3% vs. 6.5%, P = 0.009). Relative to females, male cases had greater copy number loss on 11q11 (63.0% vs. 17.6%, P = 0.002). Further analyses showed that 11q11 gain correlated with 19q13.31-q13.32 gain (P = 0.042), 11q11 loss (P = 0.011) and 16p11.2 loss (P = 0.033), while 1q21.3-q22 gain correlated with 19q13.31-q13.32 gain (P = 0.046). Conclusions: These findings suggest that CNAs may play a role in sex-related differences in HBVassociated HCC development.

Enantioseparation and Determination of Sibutramine in Pharmaceutical Formulations by Capillary Electrophoresis

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.

On a class of Finsler metrics with isotropic Berwald curvature

Hongmei Zhu 대한수학회 2017 대한수학회보 Vol.54 No.2

In this paper, we study a class of Finsler metrics called general $\ab$-metrics, which are defined by a Riemannian metric $\a$ and a $1$-form $\b$. We show that every general $\ab$-metric with isotropic Berwald curvature is either a Berwald metric or a Randers metric. Moreover, a lot of new isotropic Berwald general $\ab$-metrics are constructed explicitly.

Microstructure and Properties of the LDEDed Cu-Bearing Martensitic Stainless Steel After a Single-Step Tempering Treatment

Hongmei Zhu,Li Zhao,Baichun Li,Longzhang Shen,Changjun Qiu 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.5

431 martensitic stainless steels (MSS) alloying with copper (Cu, 0–3.5 wt%) have been fabricated by a laser directed energydeposition technology and treated by a single-step tempering treatment. The microstructure and properties of the temperedMSS specimens have been carefully investigated by various advanced techniques, including XRD, SEM, EBSD, TEM, microhardnesstester, universal material testing machine, and electrochemical workstation. The results show that the Cu-free 431MSS is mainly composed of lath-shaped martensite, a few patches of austenite and carbide, while the martensite matrix isrefined with the increased austenite and nano-precipitates by increasing Cu content of the Cu-bearing MSS. Consequently, themicrohardness of the Cu-bearing 431 MSS specimens increases firstly and then decreases, reaching the maximum value (472HV0.2)at the Cu level of 2.5 wt%. In comparison to the Cu-free 431 MSS, the addition of 2.5 wt% Cu could lead to a strikingcomprehensive performance, including tensile properties with ultimate tensile strength (UTS) of 1576 MPa, yield strength(YS) of 1258 MPa and elongation (EL) of 16.1%, as well as improved corrosion resistance by an order of magnitude. Themechanisms behind the variation in the overall performance of the Cu-bearing 431 MSS specimens were discussed in detail.

ON A CLASS OF FINSLER METRICS WITH ISOTROPIC BERWALD CURVATURE

Zhu, Hongmei Korean Mathematical Society 2017 대한수학회보 Vol.54 No.2

In this paper, we study a class of Finsler metrics called general (${\alpha},{\beta}$)-metrics, which are defined by a Riemannian metric ${\alpha}$ and a 1-form ${\beta}$. We show that every general (${\alpha},{\beta}$)-metric with isotropic Berwald curvature is either a Berwald metric or a Randers metric. Moreover, a lot of new isotropic Berwald general (${\alpha},{\beta}$)-metrics are constructed explicitly.

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.

ON A CLASS OF LOCALLY PROJECTIVELY FLAT GENERAL (α, β)-METRICS

Mo, Xiaohuan,Zhu, Hongmei Korean Mathematical Society 2017 대한수학회보 Vol.54 No.4

General (${\alpha},{\beta}$)-metrics form a rich class of Finsler metrics. They include many important Finsler metrics, such as Randers metrics, square metrics and spherically symmetric metrics. In this paper, we find equations which are necessary and sufficient conditions for such Finsler metric to be locally projectively flat. By solving these equations, we obtain all of locally projectively flat general (${\alpha},{\beta}$)-metrics under certain condition. Finally, we manufacture explicitly new locally projectively flat Finsler metrics.

On a class of locally projectively flat general (α, β)-metrics

Xiaohuan Mo,Hongmei Zhu 대한수학회 2017 대한수학회보 Vol.54 No.4

General $(\alpha,\beta)$-metrics form a rich class of Finsler metrics. They include many important Finsler metrics, such as Randers metrics, square metrics and spherically symmetric metrics. In this paper, we find equations which are necessary and sufficient conditions for such Finsler metric to be locally projectively flat. By solving these equations, we obtain all of locally projectively flat general $(\alpha,\beta)$-metrics under certain condition. Finally, we manufacture explicitly new locally projectively flat Finsler metrics.

Quality Evaluation of Modified Bo-Yang-Hwan-O-Tang by Capillary Electrophoresis and High-performance Liquid Chromatography

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.