Implantable Drug Delivery Vehicle Using Bipolar Membrane

Implantable drug delivery can localize drug effect only on diseases region, resulting in the minimization of the amount of mis-delivered drug and its side effect as well as the maximization of drug efficacy. The previous implantable drug delivery systems use convection of drug solution or, diffusion of drug solute for drug effect localization onto legion. However, each method has clear limitation; convection method causes mis-delivery to normal tissue due to drug solution flow and diffusion method is impossible to control drug release rate. In addition, these methods focus on exposing drug only to the surface of disease region, and therefore it is hard to target drug to lesion located in deep tissue. The bipolar membrane under electric field according to bias direction and amplitude can control drug release rate. Under forward bias, bipolar membrane has ionic conduction and release ionized drug while under reverse bias, it inhibitions drug from leakage due to ionic depletion zone. The strength of applied voltage can decide drug release rate. This drug release type by electrophoresis can focus drug on legion. Furthermore, electric field passing through the legion, called iontophoresis, can guide drug to reach for the deep legion, resulting in increase in the biodistribution of drug.