Vitreoretinal silicone tamponades made by supercritical fluid extraction
View Patent ↗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.
1. A method of using a tamponade 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 tamponade consisting essentially of a silicone oil that was purified by supereritical carbon dioxide extraction to remove cyclic and oligomeric impurities.
2. The process of claim 1 wherein said extraction is conducted at a pressure of approximately 3000 psi, and a temperature of approximately 55 degrees Celsius.
3. 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.
4. A method of using a tamponade 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 tamponade consisting essentially of a silicone oil that was purified with a mixture comprising carbon dioxide under supercritical extraction conditions to remove cyclic and oligomeric impurities.
5. The process of claim 4 wherein said extraction is conducted at a pressure of approximately 3000 psi, and a temperature of approximately 55 degrees Celsius.
6. The process of claim 4 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 4 wherein said carbon dioxide mixture comprises approximately 90 percent carbon dioxide and approximately 10 percent acetone.
8. The process of claim 4 wherein said carbon dioxide mixture comprises carbon dioxide and a modifier.
9. The process of claim 4 wherein said carbon dioxide mixture comprises carbon dioxide and acetone or acetonitrile.
10. The process of claim 4 wherein said carbon dioxide mixture comprises carbon dioxide and methanol.
11. The process of claim 4 wherein said carbon dioxide mixture comprises carbon dioxide and isopropanol.
12. The process of claim 4 wherein said carbon dioxide mixture comprises approximately 90 percent carbon dioxide and approximately 10 percent methanol.
13. The process of claim 4 wherein said carbon dioxide mixture comprises approximately 90 percent carbon dioxide and approximately 10 percent isopropanol.