- Preparation of a β-cyclodextrin-based open-tubular capillary electrochromatography column and application for enantioseparations of ten basic drugs
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An open-tubular capillary electrochromatography column was prepared by chemically immobilized β-cyclodextrin modified gold nanoparticles onto new surface with the pre-derivatization of (3-mercaptopropyl)-trimethoxysilane. The synthesized nanoparticles and the prepared column were characterized by transmission electron microscopy, scanning electron microscopy, infrared spectroscopy and ultraviolet visible spectroscopy. When the column was employed as the chiral stationary phase, no enantioselectivity was observed for ten model basic drugs. So β-cyclodextrin was added to the background electrolyte as chiral additive to expect a possible synergistic effect occurring and resulting in a better separation. Fortunately, significant improvement in enantioselectivity was obtained for ten pairs of drug enantiomers. Then, the effects of β-cyclodextrin concentration and background electrolyte pH on the chiral separation were investigated. With the developed separation mode, all the enantiomers (except for venlafaxine) were baseline separated in resolutions of 4.49, 1.68, 1.88, 1.57, 2.52, 2.33, 3.24, 1.63 and 3.90 for zopiclone, chlorphenamine maleate, brompheniramine maleate, dioxopromethazine hydrochloride, carvedilol, homatropine hydrobromide, homatropine methylbromide, venlafaxine, sibutramine hydrochloride and terbutaline sulfate, respectively. Further, the possible separation mechanism involved was discussed.
- Fang, Linlin,Yu, Jia,Jiang, Zhen,Guo, Xingjie
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- Establishment and Evaluation of the Novel Tetramethylammonium-L-Hydroxyproline Chiral Ionic Liquid Synergistic System Based on Clindamycin Phosphate for Enantioseparation by Capillary Electrophoresis
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Much attention has been paid to chiral ionic liquids (ILs) in analytical chemistry, especially its application in capillary electrophoresis (CE) enantioseparation. However, the investigation of chiral ionic liquids synergistic systems based on antibiotic chiral selectors has been reported in only one article. In this work, a novel chiral ionic liquid, tetramethylammonium-L-hydroxyproline (TMA-L-Hyp), was applied for the first time in CE chiral separation to evaluate its potential synergistic effect with clindamycin phosphate (CP) as the chiral selector. As observed, significantly improved separation was obtained in this TMA-L-Hyp/CP synergistic system compared to TMA-L-Hyp or a CP single system. Several primary factors that might influence the separation were investigated, including CP concentration, TMA-L-Hyp concentration, buffer pH, types and concentrations of organic modifier, applied voltage, and capillary temperature. The best results were obtained with a 40 mM borax buffer (pH 7.6) containing 30 mM TMA-L-Hyp, 80 mM CP, and 20% (v/v) methanol, while the applied voltage and temperature were set at 20 kV and 20°C, respectively. Chirality 27:598-604, 2015.
- Xu, Guangfu,Du, Yingxiang,Du, Fan,Chen, Jiaquan,Yu, Tao,Zhang, Qi,Zhang, Jinjing,Du, Shuaijing,Feng, Zijie
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supporting information
p. 598 - 604
(2015/08/25)
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- Enantioselective absorption of enantiomers with maleic anhydride-β-cyclodextrin modified magnetic microspheres
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Multifunctional magnetic microspheres have enormous potential in diverse fields. In this work, surface chiral-modified magnetic microspheres as chiral selectors, are prepared by polymerizing maleic anhydride-β-cyclodextrin (MAH-β-CD) for the enantioselective absorption of four enantiomers. The successful grafting of MAH-β-CD onto the surface of magnetic microspheres is confirmed by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. The prepared functional microspheres have a three-ply structure with an average particle size of 550 nm and a high saturation magnetization of 60 emu g-1. The amount of MAH-β-CD modified on the P(MBAAm)@Fe3O4 was about 149.1 mg g-1. The analysis results of specific rotation and capillary electrophoresis reveal that the MAH-β-CD-modified Fe3O4 microspheres show stronger complexation of (-)-enantiomers than (+)-enantiomers. In addition, the MAH-β-CD-modified Fe3O4 microspheres have stronger enantioselective absorption for double-ring chiral compounds. These chiral-functionalized magnetic microspheres are therefore expected to be an efficient and economical chiral separation method for use in further research.
- Huang, Jun,Su, Ping,Wu, Jingwei,Yang, Yi
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p. 58514 - 58521
(2015/02/19)
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- Combined use of ionic liquid and hydroxypropyl-β-cyclodextrin for the enantioseparation of ten drugs by capillary electrophoresis
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In the present study, hydroxypropyl-β-cyclodextrin and an ionic liquid (1-ethyl-3-methylimidazolium-l-lactate) were used as additives in capillary electrophoresis for the enantioseparation of 10 analytes, including ofloxacin, propranolol hydrochloride, dioxopromethazine hydrochloride, isoprenaline hydrochloride, chlorpheniramine maleate, liarozole, tropicamide, amlodipine benzenesulfonate, brompheniramine maleate, and homatropine methylbromide. The effects of ionic liquid concentrations, salt effect, cations, and anions of ionic liquids on enantioseparation were investigated and the results proved that there was a synergistic effect between hydroxypropyl-β-cyclodextrin and the ionic liquid, and the cationic part of the ionic liquid played an important role in the increased resolution. With the developed dual system, all the enantiomers of 10 analytes were well separated in resolutions of 5.35, 1.76, 1.85, 2.48, 2.88, 1.43, 5.45, 4.35, 2.76, and 2.98, respectively. In addition, the proposed method was applied to the determination of the enantiomeric purity of S-ofloxacin after validation of the method in terms of selectivity, repeatability, linearity range, accuracy, precision, limit of detection (LOD), and limit of quality (LOQ). Chirality 25:409-414, 2013.
- Cui, Yan,Ma, Xiaowei,Zhao, Min,Jiang, Zhen,Xu, Shuying,Guo, Xingjie
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p. 409 - 414
(2013/07/26)
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- Method for preparing dexchlor tannate
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The invention pertains to a method for preparing dexchlorpheniramine (“dexchlor”) tannate by reacting dexchlorpheniramine free base at a temperature of about 75 to about 150° C. with tannic acid neat or as an aqueous slurry containing up to about 20 wt. % water. The dexchlorpheniramine free base may be obtained by reacting a commercially available dexchlorpheniramine salt such as dexchlorpheniramine maleate with a base such as aqueous sodium hydroxide. The resultant dexchlor tannate has extended release properties and is useful in pharmaceutical compositions as an antihistamine for human beings.
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- Method for preparing dexchlor tannate
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The invention pertains to a method for preparing dexchlorpheniramine (“dexchlor”) tannate by reacting dexchlorpheniramine free base at a temperature of about 75 to about 150° C. with tannic acid neat or as an aqueous slurry containing up to about 20 wt. % water. The dexchlorpheniramine free base may be obtained by reacting a commercially available dexchlorpheniramine salt such as dexchlorpheniramine maleate with a base such as aqueous sodium hydroxide. The resultant dexchlor tannate has extended release properties and is useful in pharmaceutical compositions as an antihistamine for human beings.
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- Dextrochlorpheniramine tannate
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The invention pertains to a novel composition comprising dextrochlorpheniramine tannate and to a method for preparing such tannate by reacting dextrochlorpheniramine free base at a temperature of about 60 to about 150° C. with tannic acid preferably neat or as an aqueous slurry containing about 5 to about 30 wt. % water. The dextrochlorpheniramine tannate has extended release properties and is useful in pharmaceutical compositions as an antihistamine for human beings.
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