Drug delivery systems

Abstract

Drug delivery systems have an important role to play in the administration of drugs, vaccines, and diagnostic agents. Systems based on biodegradable polymers can be especially advantageous for use as implants that provide a slow, steady release of a pharmacological agent. Materials include poly--hydroxy acids, polyanhydrides, and polyphosphazenes. The products of biotechnology in the form of peptides and proteins are challenging compounds that are difficult to deliver. Novel methods of delivery include polymeric microspheres and microcapsules. Polymers can be used to deliver antigens in order to obtain improved responses after injection. Nanoparticles based on polymeric materials can be employed to deliver drugs to specific target sites, especially via the bloodstream or lymphatic system. Natural polymers also have an important role in drug delivery, for example chitosan is of special interest for its ability to interact with mucosal surfaces and to provide a bioadhesive effect that will retain drugs at target sites.