Supercritical fluid extraction of vitreoretinal silicone tamponades

Abstract

A process for the purification of a silicone oil or fluid using neat supercritical carbon dioxide or a supercritical carbon dioxide mixture extraction to produce vitreoretinal silicone tamponades. The subject process is an economical, highly effective, reproducible, contaminant-free method by which unreacted relatively low molecular weight cyclic siloxanes and oligomers are removed from relatively high molecular weight silicone oil or fluid.

We claim:  
     
         1 . A process for the purification of silicone oil or fluid for use as an ocular tamponade comprising: 
 performing a supercritical carbon dioxide extraction of said silicone oil or fluid to remove cyclic and oligomeric impurities.    
     
     
         2 . A process for the purification of silicone oil or fluid for use as an ocular tamponade comprising: 
 performing a supercritical carbon dioxide mixture extraction of said silicone oil or fluid to remove cyclic and oligomeric impurities.    
     
     
         3 . The process of  claim 1  wherein said extraction is conducted at a pressure of approximately 3000 psi, a temperature of approximately 55 degrees Celsius and a carbon dioxide flow rate of approximately 52 gm/minute.  
     
     
         4 . The process of  claim 2  wherein said extraction is conducted at a pressure of approximately 3000 psi, a temperature of approximately 55 degrees Celsius and a carbon dioxide mixture flow rate of approximately 52 gm/minute.  
     
     
         5 . The process of  claim 1  wherein said extraction is conducted at a carbon dioxide flow rate of approximately 20 to 26 gm/minute and a flow time of approximately 90 minutes.  
     
     
         6 . The process of  claim 2  wherein said extraction is conducted at a carbon dioxide mixture flow rate of approximately 20 to 26 gm/minute and a flow time of approximately 90 minutes.  
     
     
         7 . The process of  claim 2  wherein said carbon dioxide mixture comprises approximately 90 percent carbon dioxide and approximately 10 percent acetone.  
     
     
         8 . The process of  claim 2  wherein said carbon dioxide mixture comprises carbon dioxide and a modifier.  
     
     
         9 . The process of  claim 2  wherein said carbon dioxide mixture comprises carbon dioxide and acetone or acetonitrile.  
     
     
         10 . The process of  claim 2  wherein said carbon dioxide mixture comprises carbon dioxide and methanol.  
     
     
         11 . The process of  claim 2  wherein said carbon dioxide mixture comprises carbon dioxide and isopropanol.  
     
     
         12 . The process of  claim 2  wherein said carbon dioxide mixture comprises approximately 90 percent carbon dioxide and approximately 10 percent methanol.  
     
     
         13 . The process of  claim 2  wherein said carbon dioxide mixture comprises approximately 90 percent carbon dioxide and approximately 10 percent isopropanol.  
     
     
         14 . A silixone oil or fluid ophthalmic tamponade produced using the process of  claim 1  or  2 .  
     
     
         15 . A method of using the silicone oil or fluid ophthalmic tamponade of  claim 14  in an ophthalmic surgical procedure comprising: 
 creating an incision into a posterior chamber of an eye;  
 positioning damaged retinal tissue within the eye; and  
 filling said posterior chamber of the eye with said silicone oil.  
 
     
     
         16 . A method of using the silicone oil ophthalmic tamponade of  claim 14  in an ophthalmic surgical procedure comprising: 
 creating an incision into a posterior chamber of an eye; and  
 filling said posterior chamber of the eye with said silicone oil or fluid.