IN VIVO INVESTIGATIONS USING MICRODIALYSIS SAMPLING

这项提议的目标是开发微透析采样耦合到 作为一种能够连续监测的生物传感器的液体色谱 在生物微扰下体内的生化过程 系统。微透析取样由短时间的透析法组成 管路(外径约200微米)，溶液通过该管路缓慢泵送。小的 样品中的分子扩散到探针中，并被输送到 收集小瓶，而较大的分子被膜排除。 在此期间，将研究微渗析的四种应用 项目。首先，将开发微透析技术，用于 药代动力学研究。通过在一只实验动物体内植入几个探针 一种药物在多个部位的药代动力学是同时进行的 下定决心。例如，探头将被植入肝脏， 肌肉，并静脉注射，以研究血液水平与 全身分布和肝脏代谢。第二，微透析将 用于研究药物与血液蛋白的相互作用。只有 药物的游离部分通过微透析法取样，因为蛋白质结合 药物不能通过透析膜扩散。第三，多探头 也将被用来研究药物在血脑中的运输 障碍。最后，用探针植入皮下，透皮给药 将对交货情况进行调查。 该项目还将涵盖大众运输的基本方面 在微渗析条件下的跨膜。产品的质量 分析数据取决于对这些跨膜的了解 流程。分析物的参数、膜、探头设计和 将对样品矩阵进行研究。属性的效果，例如 电荷、疏水性和运输上的相对分子质量 下定决心。其他参数，如样品粘度和离子强度， 膜上的温度梯度以及透析管的长度和 直径也将被研究。 最后，微透析分析系统将实现自动化。一份特别的 设计的双进样阀将用于连续样品采集 还有注射。这将使实验者从处理样品中解脱出来 任务，这样所有的注意力都可以集中在生物方面 这个实验。为了进一步提高实验的分辨率， 微渗析将直接与质谱学相结合。这个 微透析探头将提供可直接注射的样本 将提供测定药物的选择性的质谱计 以及他们的代谢产物。

The goal of this proposal is to develop microdialysis sampling coupled to liquid chromatography as a biosensor capable of continuously monitoring biochemical processes in vivo with minimal perturbation of the biological system. Microdialysis sampling is consists of a short length of dialysis tubing (ca. 200 mum OD) through which solution is slowly pumped. Small molecules in the sample diffuse into the probe and are transported to a collection vial, while larger molecules are excluded by the membrane. Four applications of microdialysis will be investigated during this project. First, microdialysis techniques will be developed for pharmacokinetic studies. By implanting several probes into a test animal the pharmacokinetics of a drug at several sites will be simultaneously determined. For example, probes will be implanted in the liver, the muscle, and intravenously to study the relationship of blood levels to systemic distribution and hepatic metabolism. Second, microdialysis will be used to study the interaction of drugs with blood proteins. Only the free fraction of the drug is sampled by microdialysis because protein bound drug can not diffuse through the dialysis membrane. Third, multiple probes will also be used to study transport of drugs across the blood-brain barrier. Finally, using probes implanted subcutaneously, transdermal drug delivery will be investigated. The project will also encompass fundamental aspects of mass transport across membranes under microdialysis conditions. The quality of the analytical data depends on an understanding of these transmembrane processes. Parameters of the analyte, the membrane, the probe design and the sample matrix will be investigated. The effect of properties such as charge, hydrophobicity and molecular weight on transport will be determined. Other parameters, such as sample viscosity and ionic strength, temperature gradients across the membrane, and dialysis tubing length and diameter will also be studied. Finally, the microdialysis analysis system will be automated. A specially designed dual injection valve will be used for continuous sample collection and injection. This will relieve the experimenter from sample handling tasks so that total attention can be focused on the biological aspects of the experiment. To further enhance the resolution of the experiment, microdialysis will be directly coupled to mass spectrometry. The microdialysis probe will provide a sample amenable to direct injection into the mass spectrometer which will provide the selectivity to determine drugs and their metabolites.