Development of DDS Capsules Including Gas Bubbles by Shock Waves and Their Applications

摘要

This paper describes development of shock wave drug delivery systems, especially deformation process of a bubble in a microcapsule composed of membrane, liquid and gas bubble. We have proposed drug delivery systems (DDS) using shock waves. This method is efficient way to transfer drugs near the affected part in human body, because there are no thermal effects on the living tissue by using shock wave comparing with that by the ultrasonic. The mechanical properties of membrane and geometry of the membrane is important parameter for changing the penetration strength of micro jet in the microcapsule. In our previous investigations, the relations between the elasticity of capsule membrane and the probability of disintegration of membrane by shock-induced micro jet from a bubble were clarified. But the effects of structures of the capsule composed of membrane, liquid and gas on disintegration rate of capsule have not been elucidated yet. So it is necessary to find the optical structure of microcapsule using gas ratio and membrane thickness. Then it is also necessary to observe the deformation process of a bubble inside a capsule. In addition to these, for actual applications, it is also necessary to make microcapsules made of liposome composed of membrane, liquid and gas. In this paper, (1) making polymer microcapsules including a bubble and analysis of a bubble deformation process in a polymer capsule by pressure wave, (2) making liposome microcapsules with different elastic membrane and disintegration tests by ultrasonic waves were investigated.