MUCOSAL CELL CARRIERS/ENZYMES IN ORAL DRUG ABSORPTION

拟议研究的目标是确定生物化学和 胃肠道吸收的分子遗传机制 类肽类药物，并开发改善口服 药物在人体内的传递。 快速药理筛选 方法学与组合合成方法相结合， 产生了多种具有潜在治疗效用的化合物。 然而，特别是对于肽和肽型抗体的治疗效用是不确定的。 药物的口服吸收率很低，这严重限制了药物的使用。 拟议 研究将利用新的分子生物学成果， 方法来推进我们对肽转运的理解。 这些 方法将与肠膜的测定相结合 在细胞、动物和人类系统中的渗透性允许交叉- 包括人类在内的物种之间的相关性。 最后，本提案 将开发利用肽的前药策略的扩展 转运蛋白发现是成功的改善口腔系统 极性化合物的递送。 拟议项目的具体目标 是：a. 确定肠和肝的结构要求 运输类肽型化合物，并延长机制 细胞、组织、动物和人体吸收之间的相关性。 B。 扩展了上皮细胞的结构-转运关系， 肝细胞转运作为口服药物前药设计的基础 交付和评估这一战略的有效性，在改善口腔 交付. C. 鉴定介导肽转运的基因并比较 从人结肠癌HT-29细胞中克隆的基因， 我们的实验室和建立转染细胞系的机制， 类肽转运的研究。 D. 确定亚细胞分布 肽转运蛋白基因和功能表达的细胞 细胞培养物、肠和肝组织中的表面， 免疫组织化学和运输试验，并确定要求 用于转运蛋白在质膜上的功能性表达 面 e. 识别肽转运蛋白的功能域 使用序列分析和定点突变，并开发一种 结构模型，以了解基板结合和运输在 分子水平。 F. 开发一个非线性吸收模型， 肠和肝渗透性，包括部位依赖性 渗透性、非线性吸收、酶水解和传输速率 可以用来预测人体口服吸收。 因此，拟议的研究项目将联合收割机分子生物学 通过综合细胞、动物和人体研究， 肽类药物吸收的机制基础。 经济社会发展呈现 分子和动力学信息，并利用这些知识来开发 并测试综合方法，以估计和改善 类肽药物的生物利用度。 这项研究合作使我们能够 在当前研究方法的最前沿工作， 提供了一个机会，真正影响口服药物输送的肽型 毒品

The goal of the proposed research is to determine the biochemical and molecular genetic mechanisms underlying the gastrointestinal absorption of peptoid-type drugs and to develop approaches to improving the oral delivery of drugs in humans. Rapid pharmacological screening methodologies combined with combinatorial synthetic approaches has produced a diverse array of compounds of potential therapeutic utility. However, the therapeutic utility particularly for peptide and peptide-type drugs is severely limited by their low oral absorption. The proposed research will take advantage of new molecular biological results and methodologies to advance our understanding of peptide transport. These approaches will be combined with the determination of intestinal membrane permeabilities in cell, animal and human systems allowing for cross- correlations between species including humans. Finally, this proposal will develop extensions of a prodrug strategy utilizing the peptide transporter found to be successful for improving the oral systemic delivery of polar compounds. The specific aims of the proposed project are: A. Determine the structural requirements for intestinal and hepatic transport of peptoid-type compounds and extend the mechanistic correlations between cell, tissue, animal and human absorption. B. Extend the structure-transport relationship for epithelial cell and hepatocyte transport as a basis for the design of prodrugs for oral drug delivery and evaluate the effectiveness of this strategy in improving oral delivery. C. Identified genes mediating peptide transport and compare with the cloned gene from human colon carcinoma HT-29 cells identified in our laboratories and establish transfected cell lines for mechanistic studies of peptoid transport. D. Determine the subcellular distribution of the peptide transporter genes and functional expression at the cell surface in cell culture, intestine, and liver tissue through immunohistochemistry and transport assays and determine the requirements for functional expression of the transporter at the plasma membrane surface. E. Identify the functional domains of the peptide transporters using sequence analysis and site-directed mutagenesis, and develop a structural model to understand substrate binding and transport at the molecular level. F. Develop a nonlinear absorption model incorporating intestinal and hepatic permeability, including site dependent permeability, nonlinear absorption, enzyme hydrolysis and transit rate that can be used to predict human oral absorption. Thus the proposed research project will combine molecular biological approaches with integrated cellular, animal and human studies to establish the mechanistic basis for peptide type drug absorption. It will develop molecular and kinetic information and utilize this knowledge to develop and test integrated approaches to estimating and improving the bioavailability of peptoid drugs. This research collaboration allows us to work at the very frontier of current research methodologies and provides an opportunity to truly impact oral drug delivery of peptide-type drugs.