New Delivery Systems for Controlled Drug Release from Naturally Occurring Materials

Controlled drug delivery systems are prepared from synthetic or natural materials and combined with a drug or an active ingredient allowing its release in a predetermined fashion. The release can be constant, cyclic, or triggered by changes in physiological environment or an external event. The development of novel drug delivery systems that are capable of controlling the release of drugs to specific sites in the body has attracted considerable attention.

Early biomaterials were selected primarily for their desirable physical properties and not for delivery of active ingredients in biological systems. In recent years, however, new systems have been prepared from naturally occurring materials that are biocompatible and resistant to enzymatic and chemical attack in the in vivo environment.

Today, microencapsulation and controlled-release technologies are finding broad application not only in the pharmaceutical industry but also for transplantation and regeneration medicine, for example, scaffoldbased drug delivery for tissue engineering. The advantages of using controlled delivery systems in the aforementioned applications is primarily the maintenance of drug levels within defined ranges, in a localized manner while maintaining overall biocompatibility. Possible disadvantages, however, include the high cost of controlled-release systems, potential toxicity, or non-biocompatibility of the materials used.

This book is targeted toward scientists and engineers in industry, government, and academia who are interested in the development of novel drug delivery systems and regeneration technologies from natural materials. An understanding of physicochemical changes and how such changes affect the performance of the drug or active ingredient will allow researchers to develop formulations with optimized performance.

This volume was developed from a symposium presented at the 2005 International Chemical Congress of Pacific Basin Societies sponsored by the American Chemical Society Division of Macromolecular Chemistry in Honolulu, Hawaii, December 15-20, 2005.