History and continued development of drug delivery systems based on smart negative temperature sensitive hydrogels

Increased therapeutic efficiency, as well as increased patient compliance, is the common theme underlying new drug delivery systems. The development of systems that can release active agents in response to physiological variation has been to the forefront of drug delivery research recently, and achievement of such is considered a compelling goal for the next generation of drug therapy research. Arguably with regards such pulsatile drug delivery devices, the development of negative temperature sensitive hydrogels has gained most attention in recent times, and there is a large body of published studies relating to their characterisation and smart applications. As such, this review article focuses mainly on negative thermosensitive hydrogels, investigating past and recent developments.