Micro-capsule destruction using ultrasound for drug delivery system

In this paper, micro-capsule destruction by pulse waves for drug delivery systems (DDS) is discussed. In a DDS using ultrasound, micro-capsules with an elastic thin shell release the enclosed drugs at the moment of their destruction. An optical observation of the micro-capsule destruction by the pulse wave, using a highspeed video camera, is carried out. As the pulse duration is increased, the violent capsule destructions appear. Under the driving conditions of the pulse wave, the internal gas of the microcapsule cannot be emitted completely towards the surrounding media and a part of the internal gas remains inside the broken shell. For the complete emission of the internal gas, a sufficient pulse duration is necessary after the capsule destruction. It is found that the capsule destruction by the pulse wave mostly depend on the amplitude of the driving sound pressure rather than the pulse duration.