THE USE OF THERMORESPONSIVE HYDROGELS FOR ON-OFF RELEASE OF MOLECULES

Two responsive delivery devices are described from which the release of molecules is dependent on the temperature of the milieu. The devices utilise thermoresponsive hydrogels which possess a lower critical solution temperature (LCST). A novel thermoresponsive device based on the use of a thermoresponsive valve is described from which significant release of molecules only occurs at temperatures above the LCST of the hydrogel. Thermoresponsive hydrogel discs were also prepared from which significant release of molecules only occurs at temperatures below the LCST of the hydrogel. It was found that the release of molecules from both devices, the thermoresponsive valve-based device and the discs, could be controlled by changing the environmental temperature.