Design of a self-regulated drug delivery device

Most conventional drug delivery systems are based on polymers or lipid vesicles. These chemically synthesized materials can be designed to be biocompatible and have good functionality, but they often lack well-defined properties, due to an inherent size and structure distribution resulting from chemical synthesis. On the other hand, micro-fabrication technology developed for microelectronic applications is capable of mechanically creating devices with more precisely defined features, in a size range similar to polymeric and lipid materials. In this paper, we describe the design of a self-regulated drug delivery device based on the integration of both mechanical and chemical methods. In this device, a constant release rate can be achieved by carefully designing the shape of the drug reservoir, while a pH-sensitive hydrogel switch is used to regulate the drug release.