Polyurethanes for Controlled Drug Delivery

Polyurethanes (PUs) are synthesized by reaction of diisocyanates with polyols, resulting in the formation of repeatable units of carbamate (urethane) linkages. They are often coupled with other diols or diamines (chain extenders) to fine-tune their mechanical properties. PUs are used in day-to-day household items, for heavy engineering, in sophisticated instruments, and also in biomedical research. This chapter reviews the applications of PUs in the context of drug delivery. The chapter is classified on the basis of different delivery systems that may be fabricated from PUs such as nanoparticle systems, shape-memory system, stimulus-responsive system, and covalently conjugated systems. PUs have been around for more than 75. years, and still have a lot to offer to meet the demands of newer systems.