Bioabsorbable drug delivery devices

Abstract

A bioabsorbable drug delivery device and various methods of making the same. The devices are preferably formed from bioabsorbable materials using low temperature fabrication processes, whereby drugs or other bio-active agents are incorporated into or onto the device and degradation of the drugs or other agents during processing is minimized. Radiopaque markers may also be incorporated into, or onto, the devices. The devices may be generally tubular helical stents comprised of a solid ladder or an open lattice configuration, or a hybrid combination thereof. The tubular helical stents are generally formed from precursor fibers, films or tubes. The solid ladder configuration provides increased radiopacity and increased radial strength, whereas the open lattice configuration provides better endothelialization and fluid flow through the stent. The drug or other agent delivery capacity of the devices may provide local or regionalized drug or other agent delivery, or a combination thereof, with more consistent concentrations of drugs or other agents delivered from the device to the treatment site along the entire length of the device.

1 . An implantable drug delivery device comprising:
 at least one bioabsorbable polymer and at least one drug or bio-active agent incorporated into a solvent cast film formed at low temperatures;   a strip cut from the film, the strip having a pair of opposed sides and a pair of opposed ends; and   a tubular structure formed from the strip by manipulation thereof.   
   
   
       2 . The implantable drug delivery device of  claim 1 , further comprising a radiopaque material incorporated into, or onto, the device. 
   
   
       3 . The implantable drug delivery device of  claim 1 , wherein the tubular structure further comprises a helical structure comprising a stent having a solid ladder configuration between ends thereof. 
   
   
       4 . The implantable drug delivery device of  claim 3 , wherein each of the opposed ends are angled 10-30°, and preferably 20°, relative to a respective one of the opposed sides of the stent. 
   
   
       5 . The implantable drug delivery device of  claim 1 , wherein the tubular structure further comprises a helical structure comprising a stent having an open lattice structure between ends thereof. 
   
   
       6 . The implantable drug delivery device of  claim 4 , wherein each of the opposed ends are angled 10-30°, and preferably 20°, relative to a respective one of the opposed sides of the stent. 
   
   
       7 . The implantable drug delivery device of  claim 6 , wherein the open lattice structure comprises struts laser cut into the film. 
   
   
       8 . The implantable drug delivery device of  claim 1 , wherein the tubular structure further comprises a helical structure comprising a stent having a hybrid structure including solid ladder and open lattice portions between ends thereof. 
   
   
       9 . The implantable drug delivery device of  claim 8 , wherein each of the opposed ends are angled 10-30°, and preferably 20°, relative to a respective one of the opposed sides of the stent. 
   
   
       10 . The implantable drug delivery device of  claim 1 , wherein the at least one bioabsorbable polymer further comprises at least one of a bulk erosion polymer and a surface erosion polymer. 
   
   
       11 . The implantable drug delivery device of  claim 10 , wherein the tubular structure further comprises a ring or wrap. 
   
   
       12 . The implantable drug delivery device of  claim 1 , wherein the incorporation of the at least one drug or bio-active agent into the solvent cast film formed at low temperature provides improved drug diffusion and tissue uptake. 
   
   
       13 . The implantable drug delivery device of  claim 12 , wherein the drug diffusion and tissue uptake varies over time based on the at least one bioabsorbable polymer and the at least one drug or bio-active agent incorporated into the film. 
   
   
       14 . A method of forming a drug delivery device, the method comprising:
 co-extruding different bioabsorbable polymer tubes at one time to form a sheath and a core of a stent, wherein the materials having lower melting points comprise the sheath and incorporate at least one drug or other bioactive agent, and the materials having higher melting points comprise the core of the stent.   
   
   
       15 . The method of  claim 14 , wherein the materials comprising the sheath comprises at least one of polycaprolactone and polydioxanone. 
   
   
       16 . The method of  claim 14 , further comprising coating the drugs or bioactive agents onto the device after extrusion thereof. 
   
   
       17 . The method of  claim 14 , further comprising incorporating radiopaque materials into, or onto, the device. 
   
   
       18 . A method of forming a drug delivery device comprising:
 co-mingling different bioabsorbable polymeric fibers that are separately extruded and later combined to form the device.   
   
   
       19 . The method of  claim 18 , further comprising at least a first bioabsorbable polymeric fiber and a second bioabsorbable polymeric fiber, the first fiber having a lower melting point than the second fiber, wherein at least one drug or other bioactive agent is incorporated into the first fiber. 
   
   
       20 . The method of  claim 19 , further comprising incorporating radiopaque material into, or onto, the device.