羧甲基-β-环糊精为手性选择剂拆分托吡卡胺等4种手性药物对映体

目的以羧甲基-β-环糊精(CM-β-CD)为手性选择剂,建立毛细管区带电泳法分离托吡卡胺、文拉法辛、美托洛尔和瑞格列奈4种药物对映体。方法采用未涂壁熔融石英毛细管柱,磷酸盐缓冲液作为背景电解质溶液,分离电压为20 kV。考察了缓冲溶液的pH值、环糊精质量浓度、缓冲盐浓度对对映体分离的影响。结果在优化的分离条件下,4种手性药物均能达到完全分离。结论CM-β-CD适用于上述4种药物的对映体分离。     

Determination of the optical purity of (R)-terbutaline by H-NMR and RP-LC using chiral derivatizing agent, (S)-(−)-α-methylbenzyl isocyanate

A simple, convenient and precise ¹H-NMR and indirect HPLC methods were used for the determination of (S)-terbutaline in (R)-terbutaline. The enantiomers were converted to diastereomeric derivatives using (S)-(−)-α-methylbenzyl isocyanate and were successfully separated on an ODS column within 40 min with R_S=1.41 and α=1.09. Interaction between chiral solutes by the formation of the diastereomeric complexes also led to differentiations of the ¹H-NMR spectra of enantiomers and optical purities were determined on the basis of the peak area of the enantiomeric amine proton resonance. The effect of various experimental parameter, such as reaction time, reaction temperature and concentration of chiral derivatizing agent on the derivatization reaction and composition of mobile phase on the ODS column is discussed. Validation data such as recovery, linearity and detection limit are also presented. The results from ¹H-NMR and RP-HPLC methods were compared with those from chiral HPLC method and no racemization was found during the experiments. NMR results had agreed with those obtained by indirect HPLC method and two methods could be used as a quality control method for the enantiomeric purity determination of (R)-terbutaline.     

毛细管区带电泳法分离盐酸美沙酮对映体

目的:采用毛细管区带电泳法对盐酸美沙酮对映体进行了拆分。方法:比较了3种衍生化β-环糊精为手性添加剂的分离效果,对缓冲液的pH及浓度、手性添加剂的浓度、柱温、分离电压等方面进行了考察及优化。结果:确定采用75μm×75 cm未凃渍石英玻璃管柱,运行缓冲液为含50 mmol.L-1的Tris和10 mmol.L-1的HP-β-环糊精的水溶液(以磷酸调节pH至2.0),分离电压为25 kV,柱温25℃,检测波长为205 nm,结论:该方法简便、快速,在15 min内分离度可达到1.9。     

Enantiomeric purity determination of acetyl-l-carnitine by NMR with chiral lanthanide shift reagents

Enantiomer signal separation of acetyl-carnitine chloride was obtained on a 500 MHz Nuclear Magnetic Resonance (¹H NMR) analysis by fast diastereomeric interaction with chiral shift reagents such as chiral lanthanide-camphorato or chiral samarium-pdta shift reagents. Effects of the kinds of chiral shift reagents and the molar ratio of chiral shift reagent to acetyl-carnitine chloride on enantiomer signal separation were investigated and evaluated. Optimization of the experimental conditions provided two significant split signals for the enantiomers, leading to the successful quantitative analysis. Distinguishment of 0.5% of the minor enantiomer (d-form) in acetyl-l-carnitine chloride was found to be possible by ¹H NMR with tris[3-(heptafluoropropylhydroxymethylene)-d-camphorato] and praseodymium derivative, (Pr[hfc]₃), as chiral shift reagents.     

Stereospecific determination of citalopram and desmethylcitalopram by capillary electrophoresis and liquid-phase microextraction

A chiral capillary electrophoresis (CE) system allowing simultaneous enantiomer determination of citalopram (CIT) and its pharmacologically active metabolite desmethylcitalopram (DCIT) was developed. Excellent chiral separation was obtained using 1% sulfated-beta-cyclodextrin (S-beta-CD) as chiral selector in combination with 12% ACN in 25 mM phosphate pH 2.5. Samples were prepared by liquid-phase microextraction (LPME) based on a rodlike porous polypropylene hollow fibre. CIT and DCIT were extracted from 1 ml plasma made alkaline with NaOH, into dodecyl acetate impregnated in the pores of a hollow fibre, and into 20 mM phosphate pH 2.75, inside the hollow fibre. The acceptor solution was directly compatible with the CE system. Efficient sample clean-up was seen, and the recoveries were 46 and 29% for the enantiomers of CIT and DCIT, respectively, corresponding to 31 and 19 times enrichment. The limit of quantification (S/N=10) was <11.2 ng/ml, intra-day precision was <12.8% RSD, and inter-day precision was <14.5% RSD, for all enantiomers. The validated method was successfully applied to simultaneous determination of enantiomer concentrations of CIT and DCIT in plasma samples from nine patients treated with racemic citalopram. The results confirm LPME-CE as a suitable and promising tool for enantiomeric determination of chiral drugs and metabolites in biological matrices.     

磺化-β-环糊精为手性选择剂拆分文拉法辛等5种碱性药物

目的以磺化-β-环糊精(S-β-CD)为手性选择剂,建立毛细管区带电泳法分离文拉法辛、奥昔布宁、维拉帕米、萘哌地尔、氟西汀对映体。方法采用未涂壁熔融石英毛细管柱,磷酸二氢钠缓冲溶液为背景电解质,分离电压为-15 kV,考察了环糊精质量浓度、缓冲溶液的pH值、缓冲盐浓度对对映体分离的影响。结果在最优的电泳条件下5种药物均达到基线分离。结论 S-β-CD是一种具有较强分离选择性的手性选择剂。     

Determination of the optical purity of (R)-terbutaline by 1H-NMR and RP-LC using chiral derivatizing agent, (S)-(-)-alpha-methylbenzyl isocyanate

A simple, convenient and precise 1H-NMR and indirect HPLC methods were used for the determination of (S)-terbutaline in (R)-terbutaline. The enantiomers were converted to diastereomeric derivatives using (S)-(-)-alpha-methylbenzyl isocyanate and were successfully separated on an ODS column within 40 min with RS=1.41 and alpha=1.09. Interaction between chiral solutes by the formation of the diastereomeric complexes also led to differentiations of the 1H-NMR spectra of enantiomers and optical purities were determined on the basis of the peak area of the enantiomeric amine proton resonance. The effect of various experimental parameter, such as reaction time, reaction temperature and concentration of chiral derivatizing agent on the derivatization reaction and composition of mobile phase on the ODS column is discussed. Validation data such as recovery, linearity and detection limit are also presented. The results from 1H-NMR and RP-HPLC methods were compared with those from chiral HPLC method and no racemization was found during the experiments. NMR results had agreed with those obtained by indirect HPLC method and two methods could be used as a quality control method for the enantiomeric purity determination of (R)-terbutaline.     

氧氟沙星对映体的毛细管电泳手性分离

用高效毛细管电泳和二极管阵列检测器,以环糊精为拆分试剂对氧氟沙星进行手性分离(最大分离度可达2.18)。发现衍生化环糊精有较好的分离效果,用含DM-β-CD40mmol·L^-1,KH₂PO₄70mmol·L^-1,pH2.5的缓冲液,在25℃电泳,20kV分离电压下得到优化的分离结果。     

α_1酸性糖蛋白柱拆分西布曲明对映体

目的以α1酸性糖蛋白为固定相,建立了西布曲明的HPLC对映体拆分方法。方法考察了有机改性剂种类、比例、缓冲盐浓度、pH值、柱温以及流速等因素对西布曲明对映体拆分的影响,并对拆分机理进行了探讨。结果优化实验条件后,分离西布曲明的最佳色谱条件:流动相为异丙醇20 mmol.L-1NH4Ac(pH 5.0)(体积比为6∶94),柱温为20℃,流速为0.6 mL.min-1,在223 nm下检测。结论西布曲明对映体在α1酸性糖蛋白柱上能被完全分离。     

Enantioseparation of Flobufen with Cyclodextrins Studied by Capillary Electrophoresis and NMR

Purpose. The aim of this study was to obtain the resolution of flobufen enantiomers, an antiinflammatory active substance, by capillary electrophoresis with cyclodextrins. The mechanism of com- plexation and determination of the stoichiometry of the complexes were studied by NMR and the analytical method was developed and validated. Methods. Zone capillary electrophoresis coupled to direct ultraviolet detection was selected. The interaction between flobufen and the chiral selector was studied by NMR. Optimization of the separation was performed using a Box-Wilson Central Composite Design for three factors related to the composition of the electrolyte. Results. Heptakis (2,3,6-tri-O-methyl)--cyclodextrin (TM--CD) was found to be the most efficient selector via the formation of a 1:1 complex proved by NMR. Constants of complexation of flobufen enantiomers were determined by NMR and capillary electrophoresis. Optimal values for the critical factors of the analytical system were: pH (5.50), content in methanol (10% v/v), and TM--CD (30 mM). The ability of capillary electrophoresis to quantify as low as 0.1% (w/w) of R in S-flobufen or vice-versa was established. Conclusions. Capillary electrophoresis was shown to be a valuable method to control the enantiocomposition of flobufen by use of a chiral selector whose interactions with the analytes could be explored by NMR.     

高效毛细管电泳法拆分氧氟沙星对映体及其分析

目的：采用羧甲基-β-环糊精（CM-β-CD）为手性选择剂,建立测定氧氟沙星中对映体含量的毛细管电泳方法.方法：采用未涂层石英毛细管（50cm×50 μmn,41 cm）,在30 mmol·L-1的NaH2PO4缓冲溶液中加入（CM-β-CD）手性选择剂,调节不同的pH,分离电压为30 kV,得到优化的分离条件,在优化的分离条件下,对氧氟沙星对映体含量测定方法进行方法学验证,并采用该方法对3批样品进行检测.结果：在pH 4.0,30 mmol·L-1的NaH2PO4缓冲溶液,1.0％ CM-β-CD,分离电压为30 kV条件下,左氧氟沙星和右氧氟沙星线性范围为0.025 ～0.200 mg·ml1（r=0.999 3和0.999 2）,左氧氟沙星和右氧氟沙星的回收率分别为97.6％和97.8％,RSD分别为2.0和2.7％（n=9）.结论：羧甲基-β-环糊精对氧氟沙星有很高的对映体选择性,达到很好的分离效果.在不需要左、右氧氟沙星单纯对照品情况下,用于左氧氟沙星和右氧氟沙星的鉴别和含量测定.该方法重复性好,简便、快捷.     

毛细管电泳测定头孢曲松钠对映体含量

目的 :建立测定头孢曲松钠对映体含量的CD毛细管电泳方法。方法 :在不同电极性的条件下 ,运用 β-环糊精 (CD)手性添加剂毛细管电泳方法 ,同时考察了背景电解质pH值及 β-CD浓度对手性拆分的影响。结果 :拆分头孢曲松钠对映体的最佳条件 :缓冲液为50mmol/Lβ-CD ,3 0mmol/L三羟甲基氨基甲烷 ,分离电压为28kV ,pH为7 15。结论 :实验结果表明 ,在优化的实验条件下 ,头孢曲松钠对映体得到了基线分离。用该方法测定不同厂家的头孢曲松钠中两种对映体的含量 ,结果表明 ,不同厂家的头孢曲松钠中对映体的含量明显不同 ,故应建立控制头孢曲松钠对映体质量的方法。该方法可为药品质量控制及临床有效选择抗菌药物提供理论依据。     

2-甲基-β-环糊精作为手性选择剂对5种药物对映体的毛细管电泳拆分研究

目的以2-甲基-β-环糊精(2-O-methylated-β-cyclodextrin,2-O-M-β-CD)为手性添加剂,利用毛细管电泳法(capillary electrophoresis,CE)对消旋体药物甲溴后马托品、氧氟沙星、酮康唑、利阿唑和卡维地洛进行拆分研究。方法考察了背景电解质溶液的pH值、2-O-M-β-CD浓度、缓冲盐浓度对分离的影响,优化了分离条件。结果在最佳分离条件下,甲溴后马托品、氧氟沙星、酮康唑、利阿唑对映体达到完全分离,分离度分别为3.6、2.8、1.7、1.5;卡维地洛对映体分离度达到1.4。结论所建立的毛细管电泳法适于除卡维地洛外其余4种药物的对映体分离。     

Optimization of enantiomeric separation for quantitative determination of the chiral drug propranolol by 1H-NMR spectroscopy utilizing a chiral solvating agent

High-field 1H-NMR methodology for enantiomeric composition determination of the chiral drug propranolol utilizing a chiral solvating agent is reported. Optimal experimental conditions for the resolution of enantiomers were determined by studying the interaction of substrate concentration, chiral solvating agent concentration and temperature. The success of the method is based on the selection of a chiral solvating agent that has the following two characteristics. First, it possesses functional groups that are complimentary to those of the chiral substrate for significant interaction to occur. Second, it has a group of diamagnetic anisotropy near its stereogenic center for translating spatial environments of solute nuclei into different magnetic environments that are measurable by NMR spectroscopy. Optical purities were determined on the basis of the intensities of the methyl proton resonances. The analysis of synthetic enantiomeric mixtures of propranolol by the proposed NMR method resulted in assay values, which agreed closely with the known quantities of each enantiomer in the mixtures tested. The mean +/- SD recovery values for the (R)-(+)-enantiomer was 100.0+/-0.6% of added antipode (n = 7).     

Enantiomeric purity determination of acetyl-L-carnitine by NMR with chiral lanthanide shift reagents

Enantiomer signal separation of acetyl-carnitine chloride was obtained on a 500 MHz Nuclear Magnetic Resonance (1H NMR) analysis by fast diastereomeric interaction with chiral shift reagents such as chiral lanthanide-camphorato or chiral samarium-pdta shift reagents. Effects of the kinds of chiral shift reagents and the molar ratio of chiral shift reagent to acetyl-carnitine chloride on enantiomer signal separation were investigated and evaluated. Optimization of the experimental conditions provided two significant split signals for the enantiomers, leading to the successful quantitative analysis. Distinguishment of 0.5% of the minor enantiomer (D-form) in acetyl-L-carnitine chloride was found to be possible by 1H NMR with tris[3-(heptafluoropropylhydroxymethylene)-D-camphorato] and praseodymium derivative, (Pr[hfc]3), as chiral shift reagents.     

新型活性化合物Ⅱ-f对映体的毛细管电泳手性拆分研究

目的以羧甲基-倍他-环糊精(CM-β-CD)为手性选择剂,建立新型活性化合物Ⅱ-f对映体的毛细管电泳拆分方法,并对其左旋对映体的过量值(e.e.%值)进行测定。方法采用未涂层熔融石英毛细管柱,背景电解质为Tris-H3PO4缓冲溶液。考察了手性选择剂CM-β-CD浓度、pH值、缓冲溶液浓度、工作电压及温度对对映体分离的影响。结果在优化条件下,即20mmol·L-1CM-β-CD、40mmol·L-1Tris-H3PO4(pH4.4,50%甲醇v/v)的运行缓冲液,分离电压20kV,温度20℃,Ⅱ-f两对映体分离度达3.5,标记出峰顺序为右旋体杂质先出峰,左旋Ⅱ-f粗品与精制品样品的e.e.%值测定结果分别为72.50%和100%。结论该法简单快速,可用于Ⅱ-f对映体的质量控制。     

毛细管电泳法拆分盐酸安非他酮

目的:建立一种用毛细管电泳拆分盐酸安非他酮对映异构体的色谱方法。方法:以60 cm×75μm石英毛细管柱为分离通道,通过考察影响拆分的因素,如手性选择剂的种类、浓度,缓冲溶液的pH,分离电压和柱温,确定最佳拆分条件。结果:安非他酮拆分的最优条件为浓度15 mmol·L-1羟丙基-β-环糊精作手性添加剂,50 mmol·L-1的磷酸盐(pH 3.5)背景缓冲液,工作电压20 kV,柱温25℃。确定毛细管电泳中先出峰的是S-盐酸安非他酮。结论:该方法试样用量少、高效、快速、操作简单,环境污染少,可用于盐酸安非他酮的拆分,并为盐酸安非他酮的含量测定和单一对映体药理作用的研究奠定基础。     

Enantioselective pharmacokinetics of Carvedilol in human volunteers

Carvedilol is administered as a racemic mixture of the R(+)- and S(-)-enantiomers, although they exhibit different pharmacological effects. To investigate the stereoselective pharmacokinetics, the enantiomeric separation of carvedilol in human plasma was undertaken using capillary electrophoresis (CE). Resolution of the enantiomers was achieved using 2-hydoxypropyl-beta-cyclodextrin as the chiral selector. Phosphate buffer (50 mM, pH 4.0) containing 10 mM of 2-hydoxypropropyl-beta-cyclodextrin was used as electrolytic buffer. Achiral separation was carried out with the same electrolytic buffer without chiral selector. Following a single oral administration of 25-mg carvedilol to 11 healthy, male volunteers, stereoselective pharmacokinetic analysis was undertaken. The maximum plasma concentrations (Cmax) were 48.9 and 21.6 ng/mL for (R)-carvedilol and (S)-carvedilol, respectively, determined by the chiral method. The profiles of the plasma concentration of (RS)-carvedilol showed Cmax of 71.5, 72.2, and 73.5 ng/mL, as determined by the CE, HPLC/FD methods and calculations from the data of the chiral method, respectively.     

Reverse migration order of sibutramine enantiomers as a function of cyclodextrin concentration in capillary electrophoresis

The current study demonstrates the reversal of enantiomer migration order (EMO) in capillary electrophoresis (CE) based separations of sibutramines (SIB) as a function of the concentration of two types of cyclodextrin (CD), native β-CD and acetyl-β-CD. At normal working concentrations (<10mM) of either CD, (S)-SIB migrated first. However, at CD concentrations greater than 10mM, (R)-SIB was the first to migrate. This study describes factors involved in determining EMO for sibutramine enantiomers at low and high concentrations of CDs. The reversal of EMO could be explained in terms of the opposing effects of the stability and the limiting complex mobility of the SIB-CD complexes. The enantioseparation of SIB with methyl- and 2-hydroxypropyl-β-CD was possible based on differences in the binding constants of complexes. However, reverse EMO was not observed because of equal mobilities of SIB enantiomers complexed with methyl- and 2-hydroxypropyl-β-CD.     

Enantiomeric separation of glutethimide derivatives using a Ceramospher RU-2 column

The enantiomeric resolution of p-acetylaminoglutethimide and p-nitroglutethimide was achieved on a Ceramospher RU-2 column using methanol as the mobile phase. The flow rates of the mobile phase were 1.0 and 0.5 mL/min for p-acetylaminoglutethimide and p-nitroglutethimide, respectively, with UV detection at 254 nm. The values of alpha of the resolved enantiomers of p-acetylaminoglutethimide and p-nitroglutethimide were 1.63 and 1.24 while the values of Rs were 1.44 and 0.86 respectively. The possible chiral mechanism was the formation of transient diastereomeric intermediates between the enantiomers and the chiral selector (1,10-phenanthroline) ruthenium II complex which was stabilized by pi-pi interactions.