胶束电动毛细管色谱法测定穿心莲中穿心莲内酯和脱水穿心莲内酯

采用胶束电动毛细管色谱法分离测定了中药穿心莲中穿心莲内酯和脱水穿心莲内酯。电泳条件 :以2 0mmol L磷酸缓冲溶液 1 0mmol LSDS(含 5 %甲醇 ,V/V ,pH 6.8)为电泳介质 ,未涂层石英毛细管 (75 μmi.d.× 5 0cm ,有效分离长度 4 2 .2cm)为分离通道 ,压力进样 (2 5 0kPa·s) ,2 0kV恒压电泳 (2 5℃ )分离 ,检测波长 2 4 0nm。在 1 0 .4～93 .5mg/L ,和 1 0 3～ 92 .7mg L范围内 ,对两种内酯分别进行了定量分析。加样回收率穿心莲内酯为 1 0 2 % ,脱水穿心莲内酯为 1 0 2 %。     

胶束毛细管电泳在线扫集技术同时分离测定穿心莲内酯和脱水穿心莲内酯的研究

采用胶束毛细管电泳在线扫集技术分离测定了中药穿心莲中脱水穿心莲内酯和穿心莲内酯.电泳条件:以20 mmol/L H3BO310 mmol/L NaH2PO4-50mmol/L SDS(含体积分数20%甲醇,pH 2.4)为电泳运行缓冲溶液,未涂层石英毛细管(58 cm×50 μm i.d.,有效长度为41.2 cm)为分离通道,重力进样,进样高度为11 cm,-20 kV恒压,检测波长为246 nm.富集倍数可以达到200倍以上.在5.70～91.20 mg/L,和3.96～31.68 mg/L范围内呈良好的线性关系,对两种内酯分别进行了定量分析.加标平均回收率脱水穿心莲内酯为100.80%,穿心莲内酯为98.06%.     

反相高效液相法测定穿心莲药材及其制剂中的穿心莲内酯和脱水穿心莲内酯

 发展了穿心莲药材及其中成药中两种主要成分穿心莲内酯和脱水穿心莲内酯的反相高效液相测定方法。采用甲醇振荡提取法进行样品前处理 ,在以乙腈 水为流动相作梯度洗脱、ODS柱、检测波长为 2 2 5nm的条件下 ,穿心莲内酯和脱水穿心莲内酯在 1 5min内可达到基线分离。两种内酯在 1 0mg/L～ 1 0 0mg/L时其浓度与峰面积成良好的线性关系 ,加标回收率为 96 %～ 1 0 4 %。     

穿心莲内酯的溶剂浮选

应用溶剂浮选法对穿心莲乙醇提取液中的穿心莲内酯进行分离富集,优化了穿心莲内酯的浮选条件.实验表明:浮选溶剂为乙酸乙酯,水相与有机相体积比为2: 1,加入水相体积4%的乙醇,溶液pH 7,氮气流速200 mL/min,浮选时间40 min为最佳浮选条件.在最佳实验条件下,穿心莲内酯平均收率为94.1%; RSD为1.1%,平均标准加入回收率95.1%; 富集倍数为9.7倍.溶剂浮选法分离穿心莲内酯不仅能得到满意的回收率和富集倍数,并能有效地除去水溶性杂质,提高目标物纯度.与溶剂萃取法相比, 溶剂浮选法能节约有机溶剂和操作时间.     

15-二氘脱水穿心莲内酯的合成和氢-氘交换速率考察

以脱水穿心莲内酯为原料,氧化氘作为氘源,四氢呋喃为助溶剂,三乙胺催化反应,分离纯化得到反应产物,其结构经¹H NMR、 ¹³C NMR和HR-MS(ESI-TOF)确证,并考察了产物在不同pH值的氢氘交换速率。结果显示,产物表征鉴定为15-二氘脱水穿心莲内酯,15位H-D交换速率在pH 分别为6, 7和8时较慢,随pH值升高加快。     

两个穿心莲内酯苷的波谱学研究

利用柱色谱对穿心莲地上部分的提取物进行分离,得到3,14-二去氧穿心莲内酯苷和14-去氧穿心莲内酯苷。利用核磁共振氢谱(1H-NMR)、碳谱(13C-NMR)以及双量子滤波相关谱(DQFCOSY)、总相关谱(TOCSY)、异核多量子相干谱(HMQC)、异核多键相关谱(HMBC),解析这两个化合物的结构。确定了1H-NMR的氢信号和13C-NMR的碳信号的归属,并且用NOESY对3,14-二去氧穿心莲内酯苷的立体结构进行了研究。     

穿心莲内酯衍生物的合成研究进展

穿心莲内酯是中药穿心莲的主要二萜类活性成分之一. 近年来药物及有机化学工作者发现穿心莲内酯及其衍生物具有抗肿瘤, 抗HIV, α-葡萄糖苷酶抑制等活性, 由于其广泛的药理活性而倍受人们的关注. 作者对穿心莲内酯衍生物的合成进行了综述.     

大孔吸附树脂提取穿心莲总内酯的研究

研究了大孔吸附树脂提取和纯化穿心莲总内酯的方法，采用HPLC法测定了穿心莲内酯的含量；考查了乙醇浓度对浸提效果的影响，并经动态吸附筛选了4种树脂；最后确定以ADS－7作为提取分离穿心莲总内酯的树脂，此树脂吸附量较高，脱附容量且能与杂质分离，有利于得到质量较好的穿心莲总内酯产品。     

19-O-β-D-吡喃葡萄糖基脱氧穿心莲内酯的晶体结构

19—O-β-D-吡喃葡萄糖基脱氧穿心莲内酯是从中草药爵床科须药草属穿心莲植物中分离而得的一种甙类化合物,具有抗菌、消炎、解毒等性能本文测定其晶体结构,证明葡萄糖以β-甙键的形式与脱氧穿心莲内酯的C_(19)羟基连接.单晶由南京药学院提供.     

新型脱水穿心莲内酯环磷酸酯类衍生物的合成及其抗肿瘤活性

以穿心莲内酯为先导化合物,在其3-位和19-位进行结构修饰,设计并合成了3个新型的脱水穿心莲内酯环磷酸酯类衍生物(1a～1c),其结构经1HNMR,IR和MS表征。体外抗肿瘤活性测试结果表明,1a～1c对舌癌Tca-8113细胞具有较好的体外抑制活性。     

Rapid Determination of Diterpenoids in Andrographis paniculata by Microemulsion Electrokinetic Capillary Chromatography with Short-End Injection

A rapid, simple, and reliable method has been developed for routine capillary electrophoretic analysis of two diterpenoids, andrographolide and dehydroandrographolide, in Andrographis paniculata. For this system, using ethyl acetate oil-based microemulsion electrokinetic chromatography (MEEKC) and the short-end injection technique, analysis was complete in less than 2.5 min. In method validation the relative standard deviations of migration time and peak area of the two constituents were, respectively, 0.54% and 1.70% for andrographolide and 0.45% and 2.11% for dehydroandrographolide. Regression equations revealed linear relationships (correlation coefficients 0.9994 for andrographolide and 0.9993 for dehydroandrographolide) between peak area and concentration. The effects of buffer pH, borate concentration, SDS concentration, co-surfactant type and concentration, injection time, and running potential were systematically investigated. The method can be successfully implemented in routine quality-control testing.     

Rapid determination of water- and fat-soluble vitamins with microemulsion electrokinetic chromatography

A rapid, reliable and reproducible method based on microemulsion electrokinetic chromatography (MEEKC) for simultaneous determination of 13 kinds of water- and fat-soluble vitamins has been developed in this work. A novel microemulsion system consisting of 1.2% (w/w) sodium lauryl sulphate (SDS), 21% (v/v) 1-butanol, 18% (v/v) acetonitrile, 0.8% (w/w) n-hexane, 20mM borax buffer (pH 8.7) was applied to improve selectivity and efficiency, as well as shorten analysis time. The composition of microemulsion used as the MEEKC running buffer was investigated thoroughly to obtain stable separation medium, as well as the optimum determination conditions. Acetonitrile as the organic solvent modifier, pH of the running buffer and 1-butanol as the co-surfactant played the most important roles for the separation of the fat-soluble vitamins, water-soluble vitamins and stabilization of system, respectively. The 13 water- and fat-soluble vitamins were baseline separated within 30 min. The system was applied to determine water- and fat-soluble vitamins in commercial multivitamin pharmaceutical formulation, good accuracy and precision were obtained with recoveries between 97% and 105%, relative standard derivations (RSDs) less than 1.8% except vitamin C, and acceptable quantitative results corresponding to label claim.     

微乳液毛细管电动色谱-场放大富集法灵敏分析尿液中的9种麻醉剂类药物

建立了一种微乳液毛细管电动色谱(MEEKC)-场放大富集(FASI)分析尿液中多种麻醉剂(吗啡、可待因、纳洛酮、海洛因、蒂巴因、可卡因、哌替啶、芬太尼、美沙酮)的方法。考察了微乳液组成、分离电压等因素的影响,得到的最佳微乳液组成(质量分数)为0.6%十二烷基硫酸钠、1.2%正丁醇、0.6%乙酸乙酯和97.6% 10 mmol/L硼砂缓冲液(pH 9.5);分离电压为25 kV。在上述微乳体系中,9种化合物在15 min内得到了基线分离。采用场放大在线富集技术提高了分析灵敏度,检出限(S/N=3)低至0.3 μg/L。模拟尿样样品中9种麻醉剂的加标回收率介于79.4%～119.9%之间,日内相对标准偏差小于5.5%。将该方法应用于美沙酮大鼠体外代谢样品的测定,结果令人满意。     

微乳液毛细管电动色谱快速分析解热镇痛药中的有效成分

建立了微乳液毛细管电动色谱快速测定解热镇痛药中非那西丁、氨基比林和咖啡因的新方法。采用由乙酸乙酯-十二烷基硫酸钠(SDS)-正丁醇-硼砂缓冲液组成的微乳液体系,以氯霉素为内标,3种有效成分在2.5 min内完成分离,峰面积相对标准偏差(RSD)在1.2%～1.6%之间,回收率在95.6%～104.0%之间。实验考察了缓冲溶液的浓度、pH值、SDS浓度以及助表面活性剂的种类、含量对分离测定的影响。该法可用于实际样品分析。     

Separation of seven fluoroquinolones by microemulsion electrokinetic chromatography and application to ciprofloxacin, lomefloxacin determination in urine

A simple, reliable microemulsion electrokinetic chromatography (MEEKC) method is developed for the simultaneous separation of seven fluoroquinolones (FQs). The best separation is achieved in a carrier electrolyte containing 1% (v/v) heptane, 100 mmol/L sodium dodecyl sulfate (SDS), 10% (v/v) 1-butanol, and 8 mmol/L phosphate-sodium tetraborate buffer at pH 7.30. The proposed method was directly applied to the determination of ciprofloxacin (CPF) and lomefloxacin (LMF) in urine samples of subjects administered either with CPF or LMF.     

Migration mechanism of bases and nucleosides in oil-in-water microemulsion capillary electrophoresis.

The electrophoretic behaviors of five bases and corresponding nucleosides in the oil in water (o/w) microemulsion capillary electrophoresis, microemulsion electrokinetic chromatography (MEEKC), were examined in comparison with those in normal capillary zone electrophoresis (CZE). The microemulsion systems were composed of heptane, sodium dodecyl sulfate (SDS), 1-butanol and 10 mM phosphate buffer (pH 7.0) or toluene, SDS, 1-butanol and 5 mM carbonate buffer (pH 10.0). CZE was carried out in the range of pH 9.7-10.9, and the dissociation constants, pKa, of the bases and nucleosides and the electrophoretic mobilities of the anionic forms were determined. The electrophoretic behaviors of the solutes in the microemulsion systems were analyzed from their pKa, the electrophoretic mobilities of the anions determined by CZE, and the distribution constants, K(D), of the neutral forms between the microemulsion droplets and the outer aqueous phase. The importance of adsorption mechanism in MEEKC system was suggested from the correlation between log K(D) and log P.     

Simultaneous determination of natural and synthetic estrogens by EKC using a novel microemulsion

A novel microemulsion based on sodium bis(2-ethylhexyl) sulfosuccinate (AOT) was developed for the simultaneous determination of natural and synthetic estrogens by microemulsion EKC (MEEKC). The microemulsion system consisted of 1.4% w/w AOT, 1.0% w/w octane, 7.0% w/w 1-butanol and 90.6% w/w 20 mM sodium salt of 3-(cyclohexylamino)-2-hydroxy-1-propanesulfonic acid (CAPSO) and 10 mM phosphate buffer at pH 12.5. A baseline resolution in the separation of estrone, 17beta-estradiol, estriol, estradiol 17-hemisuccinate, etinilestradiol, estradiol 3-benzoate, and estradiol 17-valerate was achieved in comparison to the traditional MEEKC system with SDS in less than 15 min. The optimized electrophoretic conditions included the use of an uncoated-silica capillary of 60 cm of total length and 75 microm id, an applied voltage of 25 kV, a temperature of 25 degrees C and 214 UV-detection. Parameters of validation such as specificity, linearity, accuracy, LOD, LOQ and robustness were evaluated according to international guidelines. Due to its simplicity, accuracy, and reliability, the proposed method can be an advantageous alternative to the traditional methodologies for the analysis of natural and synthetic estrogens in different pharmaceutical forms.     

Comparing micellar electrokinetic chromatography and microemulsion electrokinetic chromatography for the analysis of preservatives in pharmaceutical and cosmetic products

In this study, separation and determination of nine preservatives ranging from hydrophilic to hydrophobic properties, which are commonly used as additives in various pharmaceutical and cosmetic products, by micellar electrokinetic chromatograpy (MEKC) and microemulsion electrokinetic chromatography (MEEKC) were compared. The effect of temperature, buffer pH, and concentration of surfactant on separation were examined. In MEKC, the separation resolution of preservatives improved markedly by changing the sodium dodecyl sulfate concentration. Temperature and pH of running buffers were used mainly to shorten the magnitude of separation time. However, in order to detect all preservatives in a single run in a MEEKC system, a microemulsion of higher pH was needed. The separation resolution was improved dramatically by changing temperature, and a higher concentration of SDS was necessary for maintaining a stable microemulsion solution, therefore the separation of the nine preservatives in MEEKC took longer than in MEKC. An optimum MEKC method for separation of the nine preservatives was obtained within 9.0 min with a running buffer of pH 9.0 containing 20 mM SDS at 25 degrees C. A separation with baseline resolution was also obtained within 16 min using a microemulsion of pH 9.5 which composed of SDS, 1-butanol, and octane, and a shorter capillary column at 34 degrees C. Finally, the developed MEKC and MEEKC methods determined successfully preservatives in various cosmetic and pharmaceutical products.     

Microemulsion electrokinetic chromatography for the analysis of acrylamide in food

The influence of microemulsion electrokinetic chromatography (MEEKC) operating conditions, such as the type of water-immiscible alcohol, aqueous phosphate buffer concentration, pH, as well as the addition of methanol and 2-propanol, on acrylamide migration has been studied. These parameters have been optimized taking into account the presence of matrix signals, in order to avoid the interference of these peaks in acrylamide determination. The best separations were achieved using a microemulsion consisting of 0.8% m/v n-amyl alcohol, 3.3% m/v sodium dodecyl sulfate (SDS), 6.6% m/v 1-butanol, and 89.3% m/v 40 mM phosphate buffer at pH 6.5 working at 15 kV in uncoated silica capillaries. Linear calibration curves over the range studied (1.25-125 microg x mL(-1)), the detection limit (0.70 microg x mL(-1)), and both run-to-run (up to 3.4% for concentration and 1.6% for time values) and day-to-day precision (lower than 11.6% for concentration) have been established. Finally, the applicability of the MEEKC method developed has been demonstrated by analyzing levels of acrylamide present in samples of home-made French fries.     

Microemulsion electrokinetic chromatography for separation and analysis of curcuminoids in turmeric samples

Microemulsion EKC (MEEKC) was developed for quantitative analysis of curcuminoids, such as curcumin (C), demethoxycurcumin (D), and bis-demethoxycurcumin (B). MEEKC separation of curcuminoids was optimized, and a change in resolution was explained using a modified equation for resolution in MEEKC without electroosmosis. The suitable MEEKC conditions for separation of curcuminoids were obtained to be the microemulsion buffer containing 50 mM phosphate buffer at pH 2.5, 1.1% v/v n-octane as oil droplets, 180 mM SDS as surfactant, 890 mM 1-butanol as cosurfactant, and 25% v/v 2-propanol as organic cosolvent; applied voltage of -15 kV; and separation temperature 25 degrees C. Achieved baseline resolution of C:D and D:B was obtained with R(s) -2.4 and analysis time within 18 min. In addition, high accuracy and precision of the method were obtained. This MEEKC method was used for quantitative determination of individual curcuminoids in medicinal turmeric capsules and powdered turmeric used as coloring additive in food, with simple sample preparation such as solvent extraction, dilution, and filtration, and without cleaning up by SPE.