【作者】 董南；

【导师】 赵昱；

【作者基本信息】 浙江大学 ， 药物化学， 2008， 博士

【摘要】 瓜环是超分子化学中继冠醚、环糊精、杯芳烃之后备受瞩目的一类人工合成新型笼状大环主体分子。其在分子识别、超分子催化以及分子组装等领域得到了广泛的研究,但作为药物载体方面的研究还鲜见有报道,本论文致力于瓜环作为药物载体的基础性研究,选择两种作用机理不同的抗癌药物喜树碱、苯丁酸氮芥和消炎药物5-氨基水杨酸为模型药物,考察瓜环在药物载体方面的应用潜力。1.对瓜环同系物、衍生物的合成、分子识别、超分子催化、分子组装、实际应用等领域的新研究进行了较为详尽的综述。2.瓜环（Cucurbit（n）urils,CB[n]（n=6,7,8））的合成和分离纯化。首次利用高效液相色谱法（HPLC）研究瓜环与客体间的相互作用。结果表明HPLC法作为考察瓜环与客体相互作用的一种新尝试,具有直观、可靠的优点,特别是利用主客体配合物的容量因子k′_G·Q值及客体表观容量因子的变化研究主客体的相互作用模式是其特色。3.瓜环作为抗癌药物喜树碱（Camptothecin,CPT）载体的研究（1）急毒实验和体外细胞毒性实验表明瓜环的毒性小,使用安全,可作为一种潜在的药物新载体。（2）研究了瓜环在溶液中与喜树碱的两种存在形式（闭环内酯形式和开环羧酸盐形式）的相互作用。结果七、八元瓜环可与喜树碱闭环内酯形式形成2∶1的主客体配合物并利用JOB法计算了总的稳定常数,而只观察到八元瓜环与喜树碱的开环羧酸盐形式形成1∶1的主客体配合物。（3）利用相溶解度法考察了主客体配合物的形成对难溶化合物喜树碱的增溶作用,结果表明七元瓜环可使喜树碱的溶解度提高近70倍,而八元瓜环可提高近8倍。（4）红外（FTIR）、X-ray粉末衍射（XRD）、差热（DTA）的分析证实CB[n]（n=7,8）与CPT形成了主客体包合物,并结合¹H NMR技术提出了可能的包结模式,即CPT分子的喹啉环进入瓜环的空腔形成部分包结配合物。（5）包合物在不同pH介质中释放行为表明药物释放受介质的影响很大,在pH=2.0缓冲介质中,CB[n]-CPT固体包合物对CPT的溶出速度改善得最明显、其次是在纯水介质中,最差的是在pH=7.4缓冲介质中。（6）利用HPLC法考察了CB[n]-CPT固体包合物在模拟生理pH条件下对喜树碱内酯环的保护作用。结果表明瓜环包合物中的CPT在5h内有超过60%的保持其闭环形式,而单纯的CPT只有36%的比率,说明CB[n]对CPT的内酯环有一定的保护作用,可使其免受溶液的影响而转变成开环羧酸盐形式。（7）采用MTT法对CB[n]-CPT固态包合物进行了体外细胞毒活性测试,结果包合作用对喜树碱的抗癌活性影响不大。4.瓜环作为抗癌药物苯丁酸氮芥（Chlorambucil,CHB）载体的研究（1）利用荧光光谱法研究了在不同pH值条件下七、八元瓜环与苯丁酸氮芥的相互作用,并以β环糊精作对照。结果表明在酸性,弱酸性条件下,七、八元瓜环均与苯丁酸氮芥形成1∶1的包结配合物,而β环糊精还可在弱碱性条件下与苯丁酸氮芥形成1∶1的包结配合物。（2）三种载体与标示客体CHB的固体包合物经红外（FTIR）、差示扫描量热（DSC）、热重（TG）、¹H NMR的表征证实了固体包合物的形成;瓜环包合物的形成对CHB的热稳定性有所提高,但β-CD包合物对CHB的热稳定性没有改善作用。纯水介质中体外释放行为的研究表明包合作用能较好地改善苯丁酸氮芥的溶解度和溶出速度。（3）利用紫外光谱和¹H NMR技术研究了固体包合物与鸟苷的动力学反应,结果显示三种载体的包合作用都能使鸟苷与苯丁酸氮芥的反应速度降低2～3倍,这将可能导致降低苯丁酸氮芥的毒副作用。体外细胞毒活性测试表明包合作用对苯丁酸氮芥的细胞毒活性有一定的影响。5.七元瓜环作为5-氨基水杨酸（5-aminosalicylic acid,5-ASA）结肠给药载可行性考察（1）利用荧光光谱法和HPLC法考察了CB[7]和5-ASA在不同pH条件下的相互作用,结果表明在pH＜6.0时,CB[7]与5-氨基水杨酸可形成1∶1的包合物,而在pH＞6.0时未观察到两者之间有明显的相互作用。（2）热力学的研究表明包合反应的ΔG、ΔH、ΔS为负值,表明此种相互作用的主要驱动力是焓,疏水作用、范德华力和氢键等,包合反应是一个自发进行的过程。（3）结合人体胃,肠道的生理pH特征,利用¹H NMR技术进一步验证了CB[7]-5-ASA固体包合物在不同pH值的存在形式,得出当pH＜6.0,5-ASA以包合物的形式存在,而当pH＞6.0,5-ASA则以游离的药物分子形式存在的相同结论,说明CB[7]与5-ASA之间的相互作用依赖于体系的pH值。CB[7]有可能作为5-氨基水杨酸结肠给药的一种潜在载体。本论文还从雷公藤根皮95%乙醇提取物中分离、鉴定了17种化合物并首次建立了贵州产3种毛茛属植物石龙芮（Ranunculus sceleratus）,毛茛（R.japonicus）,禺毛茛（R.cantoniensis）的全草及不同部位中小麦黄素含量测定的HPLC方法和总黄酮含量测定的分光光度法。更多还原

【Abstract】 Cucurbituril（CB）,as a type of novel synthetic acceptor,has attracted considerable attentions of chemists.Studies in the field of their molecular recognition, supramolecular catalysis and molecular assembly have been widely carried out. However,the study for cucurbituril as the drug carrier is not sufficient,few papers have been reported.In present thesis,using Camptothecin,Chlorambucil and 5-aminosalicylic acid with different mechanism as model drugs,the potential utilization of CB[n]in the drug delivery were investigated.1.The recent research progress of cucurbituril including synthesis of cucurbituril and their derivatives,their molecular recognition,supramolecular catalysis,molecular assembly and application was reviewed.2.The synthesis and separation of CB[n]（n=6,7,8） have been studied,and the interaction between cucurbituril and guests has been firstly studied by HPLC method. The results reveal that the new attempt has the characteristic of credibility and direct-viewing,and the conclusions from HPLC method are consistent with that of absorption spectroscopy and ¹H NMR technique.Interaction model of host and guest by using the value of k′_G·Q and apparent K is also its feature.3.Study on cucurbituril as anti-cancer drug camptothecin（CPT） carrier（1） The experiments on cucurbti[n]uril（n=6,7,8） of acute toxicity and vitro cytotoxicity provided the evidences to be safe as potential carriers.（2） The interaction between cucurbit（n）uril（n=7,8）（CB[n]） with two forms namely lactone modality and carboxylate modality of anticancer drug camptothecin （CPT） was studied.The results revealed that the combination between CB[n]with the lactone form of CPT was observed by electronic absorption spectroscopy, fluorescence spectroscopy and ¹H NMR technique in the acid solution（pH=2） and the total stability constantsβwere also obtained by Job plot with a host:guest ratio of 2:1;while in the phosphate buffer solution（pH=7.4）,only CB[8]bound the carboxylate form of CPT in ratio 1:1,but no obvious interaction between CB[7]and the carboxylate form of CPT was observed.（3） The solubility of CPT was enhanced up to about 70 times and 8 times due to the formation of interaction complexes with CB[7]and CB[8]respectively by using phase solubility method.（4） Inclusion complexes of a slightly water soluble camptothecin（CPT） with cucurbit[n=7,8]uril prepared by co-evaporation method were characterized by Fourier transformation-infrared spectroscopy,differential thermal analysis,Power X-ray diffraction and ¹H NMR technique.The possible inclusion model was proposed that the quinoline ring of CPT was encapsulated into the cavity of the title CB[n]s.（5） The behavior of controllable drug release from CPT,CB[n]-CPT physical mixtures and inclusion complexes were investigated at buffer solutions with different pH values.The results revealed that the release rate for CB[n]-CPT inclusion complexes was the fastest at pH2.0,then in water,the least release rate was at pH7.4, which indicating that the rate of drug release can be effectively controlled by altering the pH values of the environment.（6） The potential of CB[7]or CB[8]for stabilizing lactone modality of CPT was also investigated by using HPLC method in simulated physiological environment （phosphate buffer solution,pH=7.4 at 37℃）.The results revealed that more than 60%CPT in presence of CB[7]or CB[8]remained in its lactone form for 5 h compared to only 36%CPT in absence of CB[7]or CB[8],indicating that CB[n] have a certain ability to protect the lactone form of CPT from influence of solvent to change into the carboxylate form.（7） A preliminary in vitro assay by using MTT method revealed that the anticancer activity of CPT was not affected remarkably by the inclusion interaction.4.Study on cucurbituril as anti-cancer drug chlorambucil（CHB） carrier（1） The interaction between cucurbit[n]uril（n=7,8） with chlorambucil at different values of pH was researched by using fluorescence spectroscopy andβ-CD was as contrapose.Cucurbit[n]uril（n=7,8） could bind chlorambucil in a ratio 1:1 at pH 2.0,4.0,6.0 buffer solution,however 1:1 formation of complexes withβ-CD were obtained in acid solution and weak basic solution.（2） The formation and physicochemical characterization of solid inclusion complexes were investigated by Fourier transformation-infrared spectroscopy（FTIR）, differential scanning calorimetry（DSC）,thermal gravity（TG） and ¹H NMR experiments.The results showed that the thermal stability of CHB was increased by cucurbit[n]uril（n=7,8） inclusion complexes,while no obvious reform was observed forβ-CD complex.The in vitro dissolution studies indicated that the dissolution rates were remarkably increased in inclusion complexes,compared with the physical mixture and drug alone.（3） The dynamics of solid inclusion complexes toward guanosine was studied by UV spectroscopy and ¹H NMR technique.The results revealed that the formation of mixtures could slow the rate of reaction by at least 2～3-fold and result in reducing the unwanted side effects of chlorambucil.A preliminary in vitro assay using various tumor cell lines（HL-60,Hela,Siha） revealed no decrease or moderate decrease in activity by encapsulation of three carriees.5.Investigation of CB[7]as 5- aminosalicylic acid（5-ASA） for Colon-specific drug delivery（1） The interaction between cucurbit（7）uril（CB[7]） and 5-aminosalicylic acid （5-ASA） at different values of pH was studied by fluorescence spectroscopy and HPLC method.The results revealed that CB[7]bound 5-ASA with a ratio of 1:1 at pH＜6.0,while no obvious interaction between CB[7]and 5-ASA was observed at pH＞6.0.（2） The thermodynamic parameters for the CB[7]-5-ASA complex were determined in temperature-dependent binding studies.From the temperature dependence of equilibrium constants,ΔG、ΔH andΔS have been negative in sign, indicating an enthalpic driving force for complexation and an energetically favored reaction.（3） According to the gastric and intestinal pH values,the forms of complexes in different buffer solutions were further confirmed by ¹H NMR technique.The results showed that the inclusion complex of CB[7]-5-ASA was dominant in acidic aqueous solution,while free 5-ASA drug molecules were released at pH＞6.0 due to the decomposition of the inclusion complex,indicating that the interaction between CB[7] with 5-ASA was dependent on the values of pH.CB[7]could be used as a potential 5-ASA colon-specific drug delivery.In present thesis,95%ethanolic extract from Tripterygium wilfordi was examined and 17 compounds were purified and identified.Moreover,the contents of tricin in total plant and in different plant parts from three kinds of Ranunculus plants namely R.sceleratus,R.japonicus and R.cantoniensis in Guizhou were first determined by HPLC method,and the contents of total flavones were also analyzed by UV-spectrophotometer.更多还原