Enantioseparation of vesamicol in human serum by capillary electrophoresis with solid phase extraction and sulfated-beta-cyclodextrin

An enantioseparation of racemic vesamicol in human serum by capillary electrophoresis with solid phase extraction and sulfated B-cyclodextrin (S-B-CD) is presented The separation was achieved on an uncoated 72 cm x 50 microm id fused silica capillary maintained at 30 degrees C and + 15 kV applied voltage using a run buffer of 128 micro-B-CD in 50 mM phosphate buffer at pH 5. The detection wavelength was 260 nm. Bond Elut C18 solid phase extraction cartridges were used in the sample preparation of the vesamicol samples from serum. Among the CDs studied, the migration order of the enantiomers was reversed in CM-B-CD compared to S-B-CD. Increases in migration time and differences in time between enantiomers was observed with increasing concentrations of S-B-CD. Baseline separation was achieved in the 2-20 microg/ml range of enantiomer concentration (r > .996). A sample stacking technique was used to improve peak shape and LOD. LODs were 0.5 microg/ml for each enantiomer. Studies of various factors and CE conditions showed the effect of CD type, CD concentration, buffer type, buffer concentration and pH on stability and resolution.     

Chiral separation of pemoline enantiomers by cyclodextrin-modified micellar capillary chromatography

Micellar electrokinetic chromatography (MEKC) was successfully applied to the chiral separation with the addition of cyclodextrins (CDs) as chiral selector to running buffer. Chiral separation depended on the type of CDs. Mono-3-O-phenylcarbamoyl-beta-CD was effective for the chiral separation of pemoline. We investigated the type and concentration of CD and other parameters such as buffer pH, the concentration of SDS and the effect of organic modifier. The conditions for enantiomeric separation of pemoline were as follows: 40 mmol/l borate buffer at pH 9.0 with 40 mmol/l SDS, 20 mmol/l mono-3-O-phenylcarbamoyl-beta-CD and 10% 2-propanol. Baseline separation (Rs=2.21) of pemoline can be achieved.     

Chiral separation of tamsulosin by capillary electrophoresis

Enantiomers of (+/-) 5-[2 (R,S)-{[2-(o-ethoxyphenoxy) ethyl] amino} propyl]-2-methoxy-benzenesulfonamide (tamsulosin, drug frequently used in the treatment of prostate diseases) were separated by capillary electrophoresis (CE). An acidic background electrolyte (BGE) with sulfated-beta-cyclodextrin (S-beta-CD) was used to create a chiral separation environment. Baseline separation of the isomers was achieved during 5 min using cathodic electro-osmotic flow (EOF) (countercurrent mode). The quantification limits were 5.3 x 10(-6) moll(-1) for R-isomer and 5.7 x 10(-6) moll(-1) for S-isomer. The R.S.D. values of peak area were 0.54% for R-isomer and 0.75% for S-isomer. The results achieved enable determination of 0.5% of optical impurity.     

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。     

胶束毛细管电泳法测定牛磺酸滴眼液中的羟苯乙酯

目的建立一种简便快速的胶束毛细管电泳法测定滴眼液中的抑菌剂羟苯乙酯的方法。方法采用未涂层石英毛细管柱(50μm×50 cm,有效分离长度41 cm)为分离通道,采用紫外检测器,检测波长254 nm,以20 mmol.L-1硼酸盐(pH7)-10mmol.L-1 SDS为运行缓冲液,运行电压20 kV,重力进样5 s(高度15 cm)。结果 25～400μg.mL-1羟苯乙酯线性关系良好,平均回收率97.9%,RSD=1.3%。结论所用方法准确、可靠且简便、易行。     

Separation of aceclofenac and diclofenac in human plasma by free zone capillary electrophoresis using N-methyl-D-glucamine as an effective electrolyte additive.

Aceclofenac (A) and diclofenac (D) are effective non-steroidal anti-inflammatory drugs (NSAIDs) derived from the phenylacetic acid with pronounced antirheumatic, anti-inflammatory, analgesic and antipyretic properties. Our work proposes a new, fast-free zone capillary electrophoresis method for the simultaneous determination of aceclofenac and diclofenac in human plasma. The effect of increasing concentrations of N-methyl-D-glucamine organic base on borate run buffer was investigated. A good separation was achieved using a 40 cm x 75 microm uncoated silica capillary, 300 mmol/l sodium borate buffer, 200 mmol/l N-methyl-D-glucamine, pH 8.9, in about 3 min. Moreover, the plasma sample pre-treatment procedure was examined: acidic precipitants such as trichloroacetic acid (TCA), metaphosphoric acid (MPA), perchloric acid (PCA) or 5-sulphosalicylic acid (SSA) cause a total loss of analytes while acetonitrile allows a recovery of 97-98% of both compounds. Its simplicity and rapidity and the low analysis costs demonstrate that our method is a reliable and efficient mean for the comprehensive determination of aceclofenac and diclofenac in human plasma when pharmacokinetics studies are required.     

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。     

毛细管区带电泳法同时测定冬虫夏草中多种核苷及其碱基成分含量

目的探讨毛细管电泳法研究天然冬虫夏草用不同溶剂提取的效果及测定其中核苷及其碱基含量的可行性。方法采用Unimicro毛细管电泳仪 ,石英毛细管柱 ( 6 0cm× 75 μmI D ) ,运行缓冲液分别为 36mmol/L硼砂 1 5mmol/L磷酸二氢钠 ( pH 8 9) ,分离温度 2 0℃ ,分离电压1 5kV ,测定波长 2 5 4nm ,虹吸进样 1 5s。结果基线分离冬虫夏草不同溶剂提取的样品。腺苷、尿苷、尿嘧啶和次黄嘌呤含量分别为 0 30 %、0 2 8%、0 1 4 %、0 0 5 % ;平均回收率分别为 96 4 %、98 2 %、94 3%、95 1 % ;RSD分别为 0 89%、1 2 %、1 4 %、1 8% (n =6 )。结论该法准确 ,快速 ,灵敏度高 ,对名贵药冬虫夏草的质量控制有较重要意义。     

盐酸肾上腺素注射液中S-对映体的测定及稳定性考察

目的:建立肾上腺素对映异构体中S-对映体的高效毛细管电泳检测方法。方法:采用未涂层熔融石英毛细管(50μm×42 cm,有效长度32 cm),以含13 mmol·L-1DM-β-CD pH 2.5的缓冲体系(含0.10 mol·L-1磷酸和0.07 mol·L-1三乙胺)为背景电解质溶液,在20 kV分离电压下,于214 nm波长处测定S-对映体。结果:肾上腺素R-对映体和S-对映体浓度分别在0.0026～0.1036 mg·mL-1范围内线性关系良好,相关系数分别为0.9995和0.9999(n=6);定量限分别为0.3和0.4μg·mL-1(S/N≥10),检测限分别为0.1μg·mL-1(S/N≥3)。结论:本方法灵敏度高,重复性好,可用于盐酸肾上腺素注射液中S-对映体的测定及稳定性研究。     

Chiral separation and quantitation of pentazocine enantiomers in pharmaceuticals by capillary zone electrophoresis using maltodextrins

The chiral separation of pentazocine was achieved by capillary electrophoresis using oligosaccharides. Enantiomers were separated on 100 mM Tris/H3PO4 buffer (pH 2.5) with 5% maltodextrin as a chiral selector, and migration behavior was monitored at 200 nm. Under these conditions, (-)- and (+)-pentazocine and dextromethorphan (internal standard) migrated within 9 min, and the resolution of pentazocine enantiomers was 2.54. Linear calibration curves were obtained in the range 5-50 microg/ml(-1) for each enantiomer. The detection limit of pentazocine enantiomers was 29 pg, and the recoveries of(-)- and (+)-pentazocine were 98.9 (R.S.D., 3.4%) and 101.4% (R.S.D., 4.3%) with 10 microg/ml(-1), respectively.     

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.     

Chiral separation of cefadroxil by capillary electrochromatography

In this paper, the chiral separation of cefadroxil was studied by capillary electrochromatography. Monolithic capillary column was prepared for the separation of cefadroxil enantiomers. The optimum buffer contained 28.5 mmol/L sodium acetate, 0.95% (v/v) acetic acid, 19 mmol/L beta-cyclodextrin (beta-CD) and 5% (v/v) isopropanol in formamide solution (pH 7.0), with the running voltage of 12 kV, the UV detector wavelength of 254 nm, the sample injected time of 8s and the temperature of 25 degrees C. Under these conditions, the column efficiency of cefadroxil enantiomers were N1=5324 and N2=23,768 with a selectivity factor (alpha) of 1.056 and resolution (Rs) of 0.978. The effect of buffer pH value, beta-CD concentration, organic modifier (isopropanol) concentration and voltage was also investigated for the separation by CEC.     

Chiral separation of bupivacaine hydrochloride by capillary electrophoresis with high frequency conductivity detection and its application to rabbit serum and pharmaceutical injection

Conductivity detection was employed to detect the enantiomers of bupivacaine hydrochloride (Bup), which were separated by high performance capillary electrophoresis. A computer-aided technique was used to calculate the binding energies, and the interaction between Bup enantiomers and cyclodextrins (CDs) is preliminarily discussed. Factors affecting the separation efficiency such as the types and concentration of chiral selectors, running buffer, pH value, separation voltage and capillary inside diameter and length were studied. Under optimized conditions, a baseline separation of Bup enantiomers was achieved in less than 15 min in 4mM NH4Ac-NaAc-HAc (pH 4.00) -0.48mM sulfobutyl ether-beta-cyclodextrin running buffer at a separation voltage of 12 kV. The lowest detectable concentration was 0.052 microg/mL. The proposed method was applied to chiral separation of Bup enantiomers in rabbit serum and pharmaceutical injections.     

高效毛细管电泳法测定川芎注射液中川芎嗪含量

目的建立测定川芎注射液中川芎嗪含量的高效毛细管电泳法.方法以15mmol/L磷酸盐缓冲液(pH=7.6)为电泳电解液,电压30kV(运行电流为25～30μA,检测波长280nm,内标为氨茶碱.结果川芎嗪迁移时间为2.70min,氨茶碱迁移时间为3.10min.川芎嗪含量在5.83～93.33μgm*l-1时,浓度与峰面积比呈良好线性关系,r=0.9999,日内、日间变异系数均＜2%.结论该方法简便,灵敏,特异性和重现性良好,具有较强的实用价值.     

Enantioselective determination of pheniramine in pharmaceuticals by capillary electrophoresis with charged cyclodextrin

Cyclodextrin (CD)-mediated capillary zone electrophoresis (CZE) in hydrodynamically closed separation system was developed for the separation and quantitation of pheniramine (PHM) enantiomers. Several parameters affecting the separation were studied, including the type and concentration of chiral selector, carrier cation and counterion, and the pH of the buffer. A high effectivity of oppositely migrating carboxyethyl-beta-cyclodextrin (CE-beta-CD) to separate the PHM enantiomers was demonstrated in detail. The optimized chiral analysis of the antihistamine drug was performed in a buffer consisted of 20 mmol/l epsilon-aminocaproic acid adjusted to pH 4.5 with acetic acid, containing negatively charged CE-beta-CD (2.5 mg/ml) as chiral selector and 0.2% (w/v) methylhydroxyethylcellulose (m-HEC) as an electro-osmotic flow (EOF) suppressor. Acceptable validation criteria for sensitivity, linearity, precision, accuracy/recovery were included. The proposed CZE method was successfully applied to the assay of PHM in pharmaceutical formulations using dioxopromethazine as an internal standard.     

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.     

Assay of terpene alcohols in pharmacopoeial essential oils by micellar electrokinetic capillary chromatography (MEKC)

Micellar electrokinetic capillary chromatography (MEKC) was used to separate and determine terpene alcohols of wide occurrence in herbal extracts and essential oils, namely eugenol, linalool, geraniol, citronellol and thymol. In the present paper sodium dodecyl sulfate (SDS) has been used as a micelle-forming additive to the CZE background electrolytes. Effects of SDS concentration, buffer type, its pH and concentration, addition of organic solvents on the migration times and separation efficiency were investigated. The optimal electrolyte system consisted of 20 mM TAPSO and 30 mM SDS in aqueous 10% (v/v) acetonitrile of pH 7.5 (adjusted by the addition of TRIS). The separation capillary was a fused silica tube (50 microm I. D., total length 75 cm, 42 cm effective length) maintained at 25 degrees C. The separations were performed at the applied voltage of 20 kV. Samples were injected hydrodynamically at a pressure of 50 mbar for 6 s. Detection was carried out at 200 nm. The calibration curves were rectilinear for 50-200 mg l(-1) (for eugenol, thymol and geraniol) and 100-400 mg l(-1) (for linalool and citronellol). The limits of detection varied between 5 mg l(-1) (for thymol) and 16 mg l(-1) (for linalool). The devised MEKC method was employed for the determination of the cited terpene alcohols as major quality-affecting constituents in commercial pharmacopoeial essential oils such as Geranii etheroleum, Caryophylli floris etheroleum, Lavandulae etheroleum and Thymi etheroleum. The results agreed well with those of a reference gas chromatographic method.     

水和非水毛细管电泳-电导检测法分离测定水杨酸类药物

目的建立水和非水毛细管电泳-电导法分离水杨酸类药物。方法用未涂层石英毛细管柱(55 cm×50 μm),以10 mmol·L^-1 Tris-30 mmol·L^-1 H₃BO₃(pH 8.0)为运行缓冲液,分离电压为24 kV,进样时间10 s,电导检测法。结果在非水实验条件下,水杨酸(SA)、乙酰水杨酸(ASA)和磺基水杨酸(SSA)得到很好的分离。SA,ASA和SSA的线性范围分别为0.05～100 mg·L^-1,5.0～250 mg·L^-1,0.08～100 mg·L^-1,r均大于0.995。结论应用于阿斯匹林制剂中水杨酸和乙酰水杨酸含量的测定,结果令人满意。与水介质相比,乙醇介质具有更高的灵敏度和分离效率。     

Separation and determination of clopidogrel and its impurities by capillary electrophoresis

Clopidogrel bisulphate, an anti-platelet drug, has been separated from its impurities, namely impurity A, B and C by capillary zone electrophoresis (CZE) using uncoated fused-silica capillary (50.0 μm internal diameter, 31.2 cm total length). Four factors affected the separation: buffer concentration, pH of the buffer, concentration of the chiral selector and the applied voltage. Optimization and robustness studies were performed with the aid of reduced central composite experimental design. The buffer used was triethylamine–phosphoric acid and the chosen chiral selector was sulphated β-cyclodextrin (SCD). The best separation was achieved by using 10 mM buffer, pH 2.3, containing 5% (mass/volume (m/v)) SCD. Reversed polarity mode was used with an applied voltage of −12 kV and the capillary temperature was maintained at 20 °C. The method was validated for quantitative determination of the drug. It offered a limit of detection (LOD) of 0.13 μg/ml, a limit of quantitation (LOQ) of 0.4 μg/ml, and a linearity range of 0.4–300 μg/ml. Commercial bulk samples were analyzed using the developed method.     

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。