A Swallowable Smart Pill for Local Drug Delivery

In this paper, a smart pill for local drug delivery is presented. The pill is designed to achieve local therapy on gastrointestinal tissue thanks to a novel drug delivery system (DDS). The DDS consists of a miniature electrolytic pump. This microfabricated pump is ideal for medical applications because of its low power consumption, compatibility with small size batteries, integrability on miniaturized systems, and biocompatibility. The actuation principle of the micropump relies on the electrolysis of a water-based solution, which is separated from a drug reservoir by an elastic membrane. The electrolytically produced gases pressurize the electrolytic solution reservoir, causing the deflection of the elastic membrane. Such deflection, in turn, forces the drug out of its reservoir through a nozzle. In order to measure and monitor the membrane displacement, and therefore the volume of drug ejected, a strain gauge sensor has been prepared using a conductive thermoplastic nanocomposite elastomer (CTPE). The sensor is fixed on the deformable membrane. The CTPE shows high sensitivity and allows to customize the resistance of the device to obtain low power consumption. Thus, by measuring the current though the electrolytic cell and monitoring membrane deformation, the volume of the ejected drug can be controlled.