Drug delivery system and method

Abstract

A method for delivering a therapeutic agent to a predetermined location in a host is disclosed, wherein a liposome-encapsulated therapeutic agent is administered to the host, and an electrical field which encompasses a predetermined region within the host is established, such that as the liposome-encapsulated agent is exposed to the electrical field the release of the agent from the liposome to the predetermined region is enhanced.

1 - 6 . (canceled)  
   
   
       7 . A system for the delivery of electroporation-inducing electrical fields to the tissue of a patient comprising: 
 a plurality of tissue penetrating electrodes suitable for insertion into the tissue of a patient;    an electrically insulative material suitable to be implanted into the tissue of said patient, wherein said insulative material is disposed proximate to at least a portion of at least one of said electrodes, and of sufficient dielectric strength, to impede current flow from said portion of the electrode into the adjacent tissue;    electrical pulse generating means for generating electroporation-inducing electrical fields connected to said plurality of electrodes, said electrical pulse generating means capable of propagating electrical signals of sufficient magnitude and duration to cause the permeabilization of at least a portion of the cells within the tissue between the conductive regions of said electrodes.    
   
   
       8 . A system as recited in  claim 7 , wherein said electrically insulative material provides a physical barrier impeding current flow outside of the tissue between the conductive regions of said electrodes.  
   
   
       9 . A system as recited in  claim 8 , wherein said insulative material surrounds at least a portion of at least one of said plurality of electrodes.  
   
   
       10 . A system as recited in  claim 7 , wherein said insulative material is a non-conductive coating.  
   
   
       11 . A system as recited in  claim 10 , wherein said non-conductive coating is Teflon.  
   
   
       12 . A system as recited in  claim 7  wherein said electrodes comprise stainless steel.  
   
   
       13 . A system as recited in  claim 7 , wherein said electrodes comprise an electrochemically stable metal  
   
   
       14 . A system as recited in  claim 13 , wherein said electrochemically stable metal is platinum.  
   
   
       15 . A system as recited in  claim 13 , wherein said electrochemically stable metal is platinum iridium.  
   
   
       16 . A method for the delivery of electroporation-inducing electrical fields to a pre-determined three-dimensional space in the tissue of a patient comprising: 
 inserting a plurality of tissue penetrating electrodes into the tissue of a patient, wherein an electrically insulative material is disposed proximate to at least a portion of at least one of said electrodes, and is of sufficient dielectric strength, to impede current flow from said portion of said electrode into the adjacent tissue;    providing an electrical connection between said electrodes and an electrical pulse generating means for generating electroporation-inducing electrical fields;    activating said electrical pulse generating means to transmit electrical signals to at least two of said electrodes of sufficient magnitude and duration to generate an electrical field to cause the permeabilization of cells within the pre-determined three-dimensional space, while current flow is impeded by said insulative material in tissue regions adjacent said insulative material such that the electric field in said adjacent regions is of insufficient magnitude and duration to cause the permeabilization of cells.    
   
   
       17 . A method according to  claim 16  wherein the plurality of electrodes comprise a bipolar electrode array wherein the electrodes are placed anterior and posterior to the target tissue.  
   
   
       18 . A method according to  claim 17  wherein the insulative material is disposed on said at least one electrode such that it impedes current flow in the tissue superior to the target tissue.  
   
   
       19 . A method according to  claim 16  wherein the plurality of electrodes comprise at least three electrodes wherein a reference electrode is located in the center of the target tissue with satellite electrodes placed anterior and posterior to the target tissue.  
   
   
       20 . A method according to  claim 19  wherein the insulative material is disposed on said at least one electrode such that it impedes current flow in the tissue superior to the target tissue.  
   
   
       21 . A method according to  claim 16  wherein the plurality of electrodes comprise at least four electrodes surrounding the target tissue.  
   
   
       22 . A method according to  claim 21  wherein the insulative material is disposed on said at least one electrode such that it impedes current flow in the tissue superior to the target tissue.  
   
   
       23 . A method for the delivery of a therapeutic agent to a pre-determined three-dimensional space in the tissue of a patient comprising: 
 administering a pre-determined quantity of a therapeutic agent to the tissue of a patient;    inserting a plurality of tissue penetrating electrodes into the tissue proximate the site of the administration, wherein an electrically insulative material is disposed proximate to at least a portion of at least one of said electrodes, and is of sufficient dielectric strength, to impede current flow from said portion of said electrode into the adjacent tissue;    providing an electrical connection between said electrodes and an electrical pulse generating means for generating electroporation-inducing electrical fields; and    activating said electrical pulse generating means to transmit electrical signals to at least two of said electrodes of sufficient magnitude and duration to generate an electrical field to cause the permeabilization of cells within the pre-determined three-dimensional space, while current flow is impeded by said insulative material in tissue regions adjacent said insulative material such that the electric field in said adjacent regions is of insufficient magnitude and duration to cause the permeabilization of cells.    
   
   
       24 . A method according to  claim 23  wherein the plurality of electrodes comprise a bipolar electrode array wherein the electrodes are placed anterior and posterior to the target tissue.  
   
   
       25 . A method according to  claim 24  wherein the insulative material is disposed on said at least one electrode such that it impedes current flow in the tissue superior to the target tissue.  
   
   
       26 . A method according to  claim 23  wherein the plurality of electrodes comprise at least three electrodes wherein a reference electrode is located in the center of the target tissue with satellite electrodes placed anterior and posterior to the target tissue.  
   
   
       27 . A method according to  claim 26  wherein the insulative material is disposed on said at least one electrode such that it impedes current flow in the tissue superior to the target tissue.  
   
   
       28 . A method according to  claim 23  wherein the plurality of electrodes comprise at least four electrodes surrounding the target tissue.  
   
   
       29 . A method according to  claim 28  wherein the insulative material is disposed on said at least one electrode such that it impedes current flow in the tissue superior to the target tissue.