抄録
Electro-responsive on-off switching controlled release devices using shape memory alloy (SMA) for the actuator were prepared and the functions were tested. The devices are constructed from SMA coil, bias spring and drug reservoir, and they are connected with each other. The reservoir and the outer wall of the device have small holes. The two holes overlap by SMA shrinkage and shifting of reservoir with switching on of electric current so as to cause the drug release, Then, the temperature change in SMA coil and the moving distance of reservoir was investigated under on-off states of electric current. It was observed that the reservoir movement occurred quickly with the shrinkage of SMA coil after on state of electric current and reached to about 12 mm at 35°C in SMA coil temperature. The reservoir returned to the original position correctly after off state of electric current. Then, a model drug is charged into the reservoir and the release function was tested. Very sensitive on-off switching release under on-off states of electric current was observed using the device with SMA actuator. Therefore, the possible mechanism can be explained by the opening and shutting of the reservoir gate with its movements owing to the repetition of shrinkage and expansion of SMA according to on-off switching of electric current. It was proved that electro-responsive on-off switching controlled release system is possible for the actuator using SMA.
