Controlled drug delivery is useful because it allows to obtain better drug product effectiveness, reliability and safety. Interest in stimuli-responsive polymers is steadily gaining increasing momentum especially in the fields of controlled and self-regulated drug delivery. Stimuli-responsive or 'smart' polymers are macromolecules that display a significant physiochemical change in response to small changes in their environment such as temperature, pH, light, magnetic field, ionic factors, etc. The changes are reversible, and therefore, the smart polymers are capable of returning to its initial state as soon as the trigger is removed. They have become one important class of polymers and their applications have been increasing significantly in the last three decades. Smart polymers have very promising applications in the biomedical field as delivery systems of therapeutic agents, tissue engineering scaffolds, cell culture supports, bioseparation devices, etc. The versatility and untapped potential of smart polymeric materials makes them one of the most promising interfaces of chemistry and biology.