Method of drug delivery to interstitial regions of the myocardium

Abstract

A method of treating the heart and other body tissues by injecting a compound comprised of microsphere encapsulated macromolecule therapeutic agents into the myocardium, such that the microsphere size inhibits capillary transport of the compound but may permit lymphatic transport of the compound, and the compound releases therapeutic agents upon degradation of the microsphere.

I claim:  
     
         1 . A substance for treatment of body tissue comprising: 
 a plurality of capsules comprising an encapsulating layer and a therapeutic agent within the encapsulating layer, wherein    said encapsulating layer is degradable when injected into the body tissue; the half life of said encapsulating layers being between five and sixty minutes;    said capsules having an outer diameter less than about  400  nanometers;    said therapeutic agent comprising a genetic material.    
     
     
         2 . The substance of claim  17  wherein the capsules further comprise a core of about  7 . 5  um diameter which is substantially devoid of therapeutic agent.  
     
     
         3 . A substance for treatment of body tissue comprising: 
 a plurality of capsules comprising an encapsulating layer and a therapeutic agent within the encapsulating layer, wherein said encapsulating layer is degradable when injected into the body tissue;    said capsules having an outer diameter between about 15 and 150 microns, the capsules also having a core of about 7.5 um diameter which is substantially devoid of therapeutic agent;    said therapeutic agent comprising a genetic material.    
     
     
         4 . A substance for treatment of body tissue comprising: 
 a plurality of microspheres comprising an outer layer and an inner core, the outer layer incorporating a therapeutic agent, the inner core comprising a substantially inert agent, the outer layer being degradable when injected into the body tissue thereby releasing the therapeutic agent to the body tissue;    said therapeutic agent comprising a genetic material.