Medical assembly with transducer for local delivery of a therapeutic substance and method of using same

Abstract

A medical Assembly is used to delivery a therapeutic substance to a treatment area. The medical assembly comprises a catheter having a distal end and a proximal end, a transducer supported by at least a portion of the distal end of the catheter assembly, and a delivery lumen mounted on the catheter for delivery of a therapeutic substance. Support for the transducer is provided at a preselected number of anchoring points, wherein an inner surface of the transducer is positioned at a preselected distance from an outer surface of the catheter. The preselected distance defines a gap that is occupied by a low density material such as a gas which reflects acoustic pressure waves directed toward the gap by a transducer when a voltage is applied to the transducer. The reflected pressure wave increases the energy in the system, enhancing transport of therapeutic substances from the delivery lumen to the surrounding tissues and/or cells to be treated. The medical assembly may optionally be used in conjunction with both macroporous and microporous balloons. The medical assembly may optionally be modified so that a plurality of transducers are used, wherein the distal end of a transducer is positioned at a preselected distance from the proximal end of an adjacent transducer.

1 . A medical assembly for local delivery of a therapeutic substance to an internal body tissue target area comprising: 
 (a) a catheter having a distal end and a proximal end;    (b) a delivery lumen on the catheter, the lumen extending from the distal end of the catheter to the proximal end of the catheter for the delivery of a therapeutic substance therethrough;    (c) a first transducer supported at the distal end of the catheter, the first transducer being supported by the catheter distal end at a preselected number of anchoring points, wherein an inner surface of the transducer is positioned at a controlled and preselected distance from an outer surface of the catheter, wherein the distance defines a gap between the outer surface of the catheter and the inner surface of the transducer; and    (d) a balloon incorporated at said distal end of the catheter, disposed distally from said transducer, said balloon being substantially impermeable to said therapeutic substance.    
   
   
       2 . The medical assembly of  claim 1 , wherein the gap is occupied by a low density material.  
   
   
       3 . The medical assembly of  claim 2 , wherein the low density material is selected from the group consisting of ambient air, oxygen, nitrogen, helium, open-cell polymer foam, closed-cell polymer foam and mixtures thereof.  
   
   
       4 . The medical assembly of  claim 1 , wherein the transducer comprises a hollow tubular shaped body, and wherein the catheter is extended through the hollow body.  
   
   
       5 . The medical assembly of  claim 1 , wherein said transducer is tubular.  
   
   
       6 . The medical assembly of  claim 1 , wherein the therapeutic substance is selected from a group consisting of antineoplastic, antiinflammatory, antiplatelet, anticoagulant, fibrinolytic, thrombin inhibitor, antimitotic, and antiproliferative substances and mixtures thereof.  
   
   
       7 . The medical assembly of  claim 1 , wherein the balloon comprises latex.  
   
   
       8 . The medical assembly of  claim 1 , wherein the balloon is secured to said distal end of the catheter by balloon seal members coupled to the distal end of the catheter.