Chirality in Drug Design and Development 第4章.pdfVIP

4 Stereoselective Drug Delivery Through Prodrug Approach Teruko Imai and Masaki Otagiri Kumamoto University, Kumamoto, Japan 1. INTRODUCTION The goal in most drug development processes is the design of agents that are optimally effective in curing a defined illness with minimum or no side effects. For a traditional (nontargeted) delivery system, only a minor fraction of the total administered drug reaches the target site. Therefore a considerable portion of the administered therapeutic agent may interact with nontarget sites, resulting in inefficient drug delivery and/or undesirable side effects. A drug delivery system that has the ability to target a drug to a particular site (such as a specific tissue, organ, cell, enzyme, bacterium, or virus) would optimize therapy and minimize or eliminate possible drug toxicity. One approach to the site-specific delivery of a parent drug to a certain tissue involves the design of drug delivery systems targeted to specific drug carrier proteins and/or enzymes. Among molecular modification strategies, the prodrug approach would be useful for site-specific delivery of the drug. The prodrug approach has been recognized as an integral part of the new drug design process. This approach matu