Mono and Multi‐Stimuli Responsive Polymers: Application as Intelligent Nano‐Drug Delivery Systems

Stimuli-responsive polymers are one, which exerts a sharp and reversible transition in physical/chemical properties in response to tiny variations in environmental conditions. This type of polymer response is affected by different stimuli which were classified as internal stimulus (e.g. pH, redox potential, lysosomal enzymes and glucose) and external stimulus (e.g. light, magnetic field, temperature and ultrasound). The mono, dual or multi stimuli responsive polymers respond to a single, addition of two or more than two stimuli respectively. In this ambience, different "intelligent" polymeric nanoparticles which swell, dissolve and/or disintegrate as a response to external or internal stimulus have been actively developed to achieve enhanced release of drug at the target site. With the aim to further enhance release performances of intelligent nanoparticles, novel dual as well as multi-stimuli responsive nanoparticles which respond to a combination of two or more signals such as pH/redox, pH/temperature, pH/magnetic field, temperature/pH/redox, temperature/pH/magnetic, pH/redox/magnetic etc. have gathered much attention in the fields of drug delivery. In this chapter we highlight recent exciting developments in dual and multi-stimuli responsive polymers and their applications in nono-based delivery systems with a main focus on the release profile and therapeutic benefits in different disease conditions.