| Host-guest interaction plays particular important role in interpreting drug acting mechanism, constructing new drug releasing system and developing new drugs with high efficience. It has become one of the frontier reseach topics for scientists in chemistry, biology and pharmaceutical. In this dissertation, sulfobutylether-β-cyclodextrin (SBE-β-CD), a derivative of cyclodextrin widely used as solubilizer and sustained releasing agent, was utilized as a host molecule to establish a new flow injection-chemiluminescence (FI-CL) method based on the CL system formed by luminol/SBE-β-CD. Combined with the molecular spectrometric assays such as fluorescence spectrometry, the FI-CL method was further used to explore the host-guest interaction between SBE-β-CD and three kinds (phenolic acids, Borneol esters, antifungal agents) of pharmaceutical guests (eleven compounds). This dissertation was also designed to reveal the feasibility of applying the proposed FI-CL method in pharmacokinetic study of drugs using paclitaxel and matrine as probes. It is concluded that the proposed method is potential in supplying a new efficient assay for exploring host-guest interaction and has significance in constructing new drug delivering and releasing system. The dissertation was drafted as four chapters among which the author contributed greatly in following contents:1. Based on the properties of SBE-β-CD clear enhancing the CL intensity of luminol and pharmaceutical molecules decreasing the CL signal of luminol/SBE-β-CD in concentration-dependent manner, caffeic acid was used as a probe to establish the new FI-CL method on the basis of luminol/SBE-β-CD CL system. This FI-CL method was confirmed by fluorescence spectrometry and molecular docking. The results showed a good linear relationship between the loss of luminol/SBE-β-CD CL intensity and the concentration of caffeic acid during the range of5.0-1000.0pM, with a detection limit of2.0pM. The association constant of caffeic acid binding to SBE-β-CD was1.86×107/mol with a stoichiometric ratio of0.73. These results indicated that the proposed method provides methodology for investigating host-guest interactions between SBE-β-CD and other drugs.2. The proposed FI-CL method was used to investiagate the host-guest interaction between SBE-β-CD and five phenolic acids, three borneol esters and three antifungal agents. The association constants of protocatechuic acid, caffeic acid, vanillic acid, ferulic acid and gallic acid binding to SBE-β-CD were1.02×107/mol,1.86×107/mol,4.37×107/mol,4.79×107/mol and8.51×107/mol, respectively. For all the five phenolic acids, each molecule only binds to one molecule of SBE-β-CD. The association constants of yuanerchasuan bingpian zhi (YBZ), moshizisuan bingpian zhi (MBZ) and danshensu bingpian zhi (DBZ) targeting SBE-β-CD were determined to be2.5×103/mol,1.58×104/mol and3.98×104/mol, with a stoichiometric ratio approximately2.0. The binding of clotrimazole, ketoconazole and fluconazole gave association constants of1.6×105/mol,4.0×105/mol and1.26×106/mol and a stoichiometric ratio of1.0.All the aforementioned drugs approached and entered SBE-β-CD inner surface from its larger cavity to form inclusion complexation. This inclusion changed the micro-environment of the domain for luminol binding to SBE-β-CD and led to the clear quenching of luminol/SBE-β-CD intensity. Hydrogen bond confirmed to be the main driving force during the host-guest interaction between these drugs and SBE-β-CD.These results indicated that the proposed FI-CL method is feasible in determining the binding parameters of the host-guest interaction between drugs and SBE-β-CD as well as inverstigating the binding mechanism during the interaction. It is possible to provide methodology for revealing other host-guest interaction.3. Base on the advantages of the proposed luminol/SBE-β-CD/pharmaceutical FI-CL method such as high sensitivity, a new method for determining paclitaxel and matrine in rat plasma were established. This method was further used to investigate the pharmacokinetics of the two drugs after intravenous injection of paclitaxel or matrine through vena caudalis. Paclitaxel and matrine gave a linear relationship with their concentrations during the ranges of0.5-85.0ng/mL and0.28-560ng/mL, respectively. The low quantitation limits for the two drugs were0.5ng/mL and1.0ng/mL. Accuracy, precision and stability of the method met the requirements of bioanalytical methods for biological samples according to the guidelines of the Food and Drug Administration. The pharmacokinetic profiles of paclitaxel and matrine confirmed to be one compartment open models. Other pharmacokinetic parameters by the proposed FI-CL method were in line with the values by high performance liquid chromatography in previous reports. Taking abovementioned results together, the FI-CL method based on luminol/SBE-β-CD/pharmaceutical guest is believed to be feasibile in the inverstigation on the pharmacokinetics of paclitaxel and matrine. It will probably be an alternative for determining paclitaxel and matrine in other biological samples.During the study as a candidate for doctor degree, the author has accomplished and published seven papers related to this work. As a main participant, the author also contributed several experiments to a general project supported by National Natural Science Foundation. |
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