Cannula for Pressure Mediated Drug Delivery

Available for licensing are methods and devices for selectively delivering therapeutic substances to specific histological or microanatomical areas of organs (e.g., introduction of the therapeutic substance into a hollow organ space such as the hepatobiliary duct or the gallbladder lumen) at a controlled pressure, volume and/or rate which allows the substance to reach a predetermined cellular layer. The volume or flow rate of the substance can be controlled so that the intralumenal pressure reaches a predetermined threshold beyond which subsequent subepithehal delivery of the substance occurs. Alternatively, a lower pressure is selected that does not exceed the threshold level, so that delivery occurs substantially to the epithelial layer. Such site-specific delivery of therapeutic agents permits localized delivery in concentrations that may otherwise produce systemic toxicity. Occlusion of venous or lymphatic drainage from the organ can also help prevent systemic administration of therapeutic substances, and increases selective delivery to superficial epithelial cellular layers. Delivery of genetic vectors can also be delivered to target cells. The access device comprises a cannula with a wall piercing tracar within the lumen. Two axially spaced inflatable balloons engage the wall securing the cannula and sealing the puncture site. A catheter equipped with an occlusion balloon is guided through the cannula to the location where the therapeutic substance is to be delivered.