Innovative ambulatory drug delivery system using an electrolytic hydrogel infusion pump

This report describes an ambulatory infusion device developed to provide parenteral drug delivery at a precisely controlled rate. The device is based on the innovative and unique concept of utilizing electrohydrolysis of a negatively charged hydrogel. The system consists of two modules: a pump unit and an electronic control unit. The pump module, which can be a disposable unit, contains medication separated by a flexible membrane from a gas generating chamber; this latter is an electrolytic cell comprising a hydrogel block and two platinum electrodes. The microcontroller-based control module is constructed with a user interface which includes input keys and a liquid crystal display, as well as a control to alter driving current level, depending on the infusion rate required. A microprocessor instantaneously calculates the current level required; this is based on operator-selected infusion rate, ambient pressure, and temperature sensor output. The accuracy and precision of the device were verified for all flow rates and for different environmental conditions; in vitro test results showed acceptable accuracy with less than +/- 5% error over the whole operating range of 0.1-100 [ml/h]. The device is small, lightweight, simple and easy to manufacture, and is also designed to be comfortably and conveniently worn by patients. It can be used for a variety of regimens including, for example, chemotherapy, insulin delivery, and pain management, antibiotic and AIDS therapy.