抗癌药物柔红霉素的光谱电化学研究

采用现场光谱电化学技术,结合循环伏安和红外光谱等手段,研究了柔红霉素的电极过程,并提出了可能的还原机理.结果表明,柔红霉素的还原途径与其浓度存在一定的联系:稀溶液的还原经历一ECE过程--得到两个电子还原为柔红霉氢醌后,发生化学反应脱去7位上的糖基侧链,得到的7-去氧柔红霉醌继续被还原,生成的自由基中间体可发生歧化反应或通过分子间缔合而稳定;当溶液浓度较大时,柔红霉素分子在得到一电子生成半醌自由基中间体后,以其双分子缔合物的形式稳定存在.     

紫杉醇对柔红霉素与DNA作用影响的研究

采用紫外-可见光谱、荧光光谱、微分脉冲伏安法以及紫外-可见光谱电化学法等多种手段, 从分子水平研究了紫杉醇对柔红霉素与DNA作用的影响. 紫杉醇可以和柔红霉素形成分子间氢键; 紫杉醇的长链对柔红霉素糖环以及柔红霉素和DNA所形成加合物的外围有一定程度的缠绕作用, 最终使柔红霉素的药效增加毒副作用减小.     

抗癌药物4'-O-(α-L-夹竹桃糖基)柔红霉素与小牛胸腺DNA相互作用的荧光光谱法

在pH=7.4的Tris-HCl介质中,利用荧光光谱和紫外吸收光谱法,研究了一种新型蒽环类抗癌药物柔红霉素衍生物(4′-O-(α-L-夹竹桃糖基)柔红霉素,ODNR)与小牛胸腺DNA(ctDNA)的相互作用。 通过离子强度的影响、KI荧光猝灭实验和单双链ctDNA作用的比较实验,分析了ODNR与ctDNA的相互作用模式。 结果表明,ODNR通过嵌插方式与ctDNA发生作用。 ctDNA对ODNR的荧光有明显的猝灭作用,其机理属于静态猝灭。 通过Scatchard方程求得不同温度下的结合常数和结合位点数,由热力学参数确定分子间作用力为疏水作用,也可能存在静电作用。     

银盘电极盐酸柔红霉素电化学行为及其与BSA的相互作用

应用线性扫描伏安法和循环伏安法研究盐酸柔红霉素在银盘电极上的电化学行为及其与牛血清白蛋白(BSA)的相互作用.结果表明,在pH6.50的Britton-Robinson缓冲溶液中,盐酸柔红霉素有一灵敏的还原峰,峰电位Ep-0.64V(vs.SCE),缓冲液加入BSA后盐酸柔红霉素的还原峰峰电流下降,据此建立了BSA的电化学测定方法.在优化条件下,峰电流与BSA浓度于1.0×10-8～1.0×10-4mol·L-1(r=0.9965)范围内呈线性关系,检出限为5.0×10-9mol·L-1.同时还测定了盐酸柔红霉素与BSA的结合比和结合常数.     

柔红霉素在钴离子注入修饰玻碳电极上与DNA相互作用

用钴离子注入修饰电极研究了柔红霉素与DNA的相互作用.柔红霉素以嵌入方式与DNA发生作用,形成非电活性的结合物.加入DNA后,柔红霉素的电化学行为没有改变,仍为扩散控制.用非线性拟合得到柔红霉素与DNA的结合常数K=1.09×10⁸cm³/mol,结合数s≈4.DNA分子结构中的1个螺旋结合2个柔红霉素.     

2-(4-氨酰基-2-噻唑基)-1,4-脱水-L-木糖醇及其氟代衍生物的构象研究

用计算机分子模拟方法研究了2-(4-氨酰基-2-噻唑基)-1,4-脱水-L-木糖醇及其氟代衍生物的糖基构象.计算结果显示,6个碳核苷类似物的糖基构象均为S型.核磁共振谱和晶体x射线衍射结果与计算结果相吻合.     

柔红霉素发酵液的高效液相色谱分析

〕本文介绍柔红霉素和其同类物质以及它们的甙元的高效液相色谱法。色谱分离在C18烷基键合硅胶柱上以甲醇-0.01M醋酸铵水溶液(pH4.2)为流动相,流出液用紫外检测器检测波长为230毫微米。在两种牌号填料上考察了流动相组成对蒽环类化合物色谱分离的影响。发酵液经溶剂萃取后用高效液相色谱法测定主要代谢产物柔红霉素的含量,氯仿萃取发酵液中柔红霉素的平均回收率为99.79%,回收率的变异系数(C.V.)6.48%。     

红霉素分子印迹二维光子晶体水凝胶传感器的研究

以红霉素为印迹分子,聚苯乙烯二维光子晶体为模板,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸甲酯为交联剂,2,2-二乙氧基苯乙酮为引发剂,紫外光引发聚合,在甲醇-乙酸(9∶1, V/V)中洗脱印迹分子,得到能够特异性识别红霉素的分子印迹二维光子晶体水凝胶.通过测试德拜环直径变化,研究了此水凝胶在红霉素溶液中的响应性能.实验结果表明,当红霉素的浓度从0增加到1×10-6 mol/L时,德拜环直径增加6 mm, 相应的晶格间距减小30 nm.此外,水凝胶在1×10-6 mol/L红霉素的类似物罗红霉素、琥乙红霉素溶液中,德拜环直径仅分别增加1.5和2.0 mm,表明此光子晶体水凝胶具有良好的选择性,有望用于红霉素低成本的简易检测.     

柔红霉素发酵液的高效波相色谱分析

本文介绍柔红霉素和其同类物质以及它们的甙元的高效液相色谱法.色谱分离在C_8烷基键合硅胶柱上以甲醇—0.01M醋酸铵水溶液(pH4.2)为流动相.流出液用紫外检测器检测波长为230毫微米.在两种牌号填料上考察了流动相组成对蒽环类化合物色谱分离的影响。发酵液经溶剂萃取后用高效液相色谱法测定主要代谢产物柔红霉素的含量,氯访萃取发酵液中柔红霉素的平均回收率为99.79％,回收率的变异系数(C.V.)6.48％。     

快原子轰击和碰撞活化质谱法研究三萜皂苷结构

本文用快原子轰击(FAB)和碰撞活化(CA)相配合的方法测定了含3-5个糖基的三萜皂苷的结构.FAB谱能给出分子量信息,由质子化分子的CA谱可推测糖基连接序列.本法的优点在于难挥发,热不稳定的样品可直接进样分析不需制成挥发性衍生物,且样品中杂质经磁场进行质量分离后影响CA谱.本法的局限性在于不能区别糖的立体异构体和确定各糖基或糖基与苷元的连接位置.     

Study of the interaction between daunorubicin and human serum albumin,and the determination of daunorubicin in blood serum samples

The interactions between daunorubicin and human serum albumin (HSA) were studied using the spectrofluorimetric method. The binding constants of daunorubicin with HSA were obtained at different temperatures. The effects of various metal ions on the binding constants of daunorubicin with HSA were also studied. The optimum conditions of fluorometric determination of daunorubicin were studied and the developed method was successfully applied to the determination of daunorubicin in serum samples.     

DNA-binding Studies of Daunorubicin in the Presence of Methylene Blue by Spectroscopy and Voltammetry Techniques

The interaction of daunorubicin with calf thymus DNA has been investigated with the use of methylene blue dye as a spectral probe by the application of UV-Vis spectrophotometry, spectrofluorometry and voltammetry. The voltammetric behavior of daunorubicin has been investigated at a glassy carbon electrode using cyclic and differential pulse voltammetry. Both UV-vis spectrophotometry and cyclic voltammetry studies confirmed the intercalation reaction. The results showed that both daunorubicin and methylene blue molecules could intercalate into the double helix of DNA. The apparent binding constant of daunorubicin with DNA has been found to be 7.8 ×104 L•mol－1. The fluorescence signal of daunorubicin and methylene blue was quenched with DNA addition. The Stern-Volmer equation was plotted based on the quenching fluorescence signal of daunorubicin.     

Determination of free and liposome-associated daunorubicin and daunorubicinol in plasma by capillary electrophoresis

Liposomal daunorubicin (DaunoXome) is a formulation of the anticancer drug daunorubicin encapsulated into vesicles of about 45 nm diameter. To understand the pharmacodynamic relationships associated with the toxicity and efficacy of liposome-encapsulated daunorubicin in vivo and in vitro, it is essential to have a rapid method of separating the free and liposomal forms of the drug. We have developed and validated a method to quantify drug concentrations of liposomal daunorubicin, free daunorubicin and its main metabolite daunorubicinol that requires only 50 microl of plasma to conduct studies in children. The method involves the use of solid-phase extraction followed by capillary electrophoresis with laser-induced fluorescence (LIF) detection. With LIF detection a limit of quantification of 1 microg/l is obtained for the free form and the metabolite. Precision and accuracy are in accordance with the generally accepted criteria for bioanalytical methods. The method is rapid and allows for multiple samples to be processed simultaneously.     

Thin-Layer Chromatographic Separation and Quantitation of the Anti-Tumor Agent Daunorubicin in Fermentation Media

Abstract

Daunorubicin (1,2), an antibiotic produced by the microorganism Streptomyces penceticus, can be used in the treatment of both acute leukemia and solid tumors in human (3). Extensive clinical trails of this compound are being conducted by the National Cancer Institute. Production of daunorubicin by fermentation and its isolation from fermentation broth has been described elsewhere (4). In the course of producing sufficient daunorubicin for clinical trails, the Chemotherapy Fermentation Laboratory of the Frederick Cancer Research Center required a fast quantitative assay for daunorubicin in fermentation broth. This paper describes a one-dimensional thin-layer chromatographic system for the separation of daunorubicin and its in situ quantitation by densitometry.     

Development and validation of a high-performance liquid chromatography-tandem mass spectrometric method for quantification of daunorubicin in rat plasma

A high-performance liquid chromatography-tandem mass spectrometric method (LC-MS/MS) has been developed and validated for the determination of daunorubicin in K₃EDTA rat plasma. The 100 μL plasma samples were extracted by a methanol:acetone protein precipitation step in the presence of additional 50 μL of 70% (w/v) zinc sulfate, and subsequently analyzed by LC/MS/MS using positive turbo-ion spray ionization mode. The LC/MS/MS instrument was operated in the multiple-reaction-monitoring (MRM) mode. Doxorubicinol was better than doxorubicin as the internal standard because its recovery and absolute matrix effect data exactly matched with those for daunorubicin. In addition, HPLC gradient condition was optimized to thoroughly separate daunorubicin from the background interference. The validated concentration range was from 0.250 to 100 ng/mL. The true recoveries of daunorubicin and doxorubicinol were 93.2% and 93.6%, respectively. In addition, the ion-suppression data of daunorubicin and doxorubicinol were 78.2% and 78.4%, respectively. Absence of the relative matrix effect from six unique lots was confirmed. Results obtained from the GLP validation study demonstrated very good accuracy (95-105%) and precision (less than 10% CV).     

High performance liquid chromatography determination of doxorubicin and daunorubicin in plasma using UV detection and column switching

A method for the determination of doxorubicin and daunorubicin in plasma is described. The plasma is injected directly into a loop column and then washed with water. After switching the injection valve, the sample is separated on a phenyl column using detection at 254 nm. The detection limit is 10 ng/mL, the coefficient of variation is 7% for 100 ng/mL of doxorubicin and 4% for 200 ng/mL of daunorubicin.     

Novel nanocomposite of nano fe(3)o(4) and polylactide nanofibers for application in drug uptake and induction of cell death of leukemia cancer cells

Novel nanocomposites of polylactide (PLA) nanofibers and tetraheptylammonium-capped Fe3O4 magnetic nanoparticles have been prepared and utilized to realize the efficient accumulation of anticancer drug daunorubicin in target cancer cells. The observations of optical microscopy and confocal fluorescence microscopy indicate that the PLA nanofibers and Fe3O4 nanoparticles may contribute to their beneficial effects on intracellular drug uptake of leukemia K562 cell lines in which the efficiently enhanced accumulation of anticancer drug daunorubicin on the membrane of cancer cells could be observed. Meanwhile, the electrochemical detection and the microculture tetrazolium studies were also explored to probe the effect of the relevant nanomaterials on the drug uptake of cancer cells. The results illustrate that the nanocomposites could effectively facilitate the interaction of daunorubicin with leukemia cells and remarkably enhance the permeation and drug uptake of anticancer agents in the cancer cells, which could readily lead to the induction of the cell death of leukemia cells. This observation suggests a new perspective for the targeted therapeutic approaches of cancers.