The evident rapid expansion of scientific work and intense interest in both experimental and clinical aspects of new drug delivery systems provided strong motivation for planning this symposium. In designing the program, speakers were identified for their particular expertise in a wide range of topics such as dermal delivery systems, pro-drugs, oral prolonged release, rate-controlled drug delivery, the pharmacokinetics of drug release systems, the synthesis of polymeric drug carriers and the refinement of drug delivery pumps. Because of the considerable involvement of diverse scientists from laboratories around the world where investigations relevant to the topic are now being pursued, a deliberate effort was made to invite international leaders in the field to share their knowledge and experimental outcomes. Thus, plenary papers and panel discussions were offered by organic chemists, bioengineers, patholo- gists, material scientists, physical chemists, and pharmacokineti- cists from academic and industrial laboratories in some dozen countries. This book which records the presentations offered at the sym- posium covers a broad array of topics ranging from general overviews of the physicochemical concepts and analytical methodology which underpin the refinement of drug delivery systems and the tissue responses associated with the use of such systems through detailed discussions of a variety of current approaches employed in the development of new systems.