Silicone hydrogel contact lenses for sustained release of beneficial polymers

1. An unworn silicone hydrogel contact lens immersed in a packaging solution and sealed in a package, said contact lens comprising:

a) a hydrated polymerization product of a monomer mixture comprising at least one silicone monomer and at least one anionic monomer in an amount to provide the polymerization product with an ionic content of about 0.6% to about 2.2%; and

b) a cationic polymer having a molecular weight of about 1,500 to 30,000 electrostatically attached to the hydrated polymerization product, wherein the contact lens sustains release of the cationic polymer for at least 6 hours.

2. The contact lens of claim 1 , wherein the at least one anionic monomer is selected from (meth)acrylic acid, acrylic acid, crotonic acid, and trimethylsilyl methacrylate.

3. The contact lens of claim 1 , wherein the ionic content is about 1.0% to about 2.0%.

4. The contact lens of claim 1 , wherein the ionic content is about 1.6% to about 1.8%.

5. The contact lens of claim 1 , wherein the cationic polymer has a molecular weight of about 3,000 to 15,000.

6. The contact lens of claim 1 , wherein the cationic polymer has a molecular weight of about 15,000 to 30,000.

7. The contact lens of claim 1 , wherein the cationic polymer is an antimicrobial peptide.

8. The contact lens of claim 1 , wherein the contact lens sustains release of the cationic polymer for at least 8 hours.

9. The contact lens of claim 1 , wherein the packaging solution comprises from about 50 ppm to about 10,000 ppm of the cationic polymer prior to contact with the hydrogel.

10. The contact lens of claim 1 , wherein the packaging solution has an ionic strength of less than about 0.15.

11. The contact lens of claim 1 , wherein the monomer mixture further comprises at least one hydrophilic monomer selected from N-vinyl-N-methylacetamide (VMA), N-vinyl pyrrolidone (NVP), or a combination thereof.

12. An unworn silicone hydrogel contact lens immersed in a packaging solution and sealed in a package, said contact lens comprising a hydrated polymerization product of a monomer mixture comprising: at least one silicone monomer; at least one hydrophilic monomer selected from N-vinyl-N-methylacetamide (VMA), N-vinyl pyrrolidone (NVP), or a combination of both VMA and NVP; and at least one carboxylic-acid-containing monomer in an amount to provide the hydrated polymerization product with an ionic content of about 1.0% to about 2.2%.

13. The contact lens of claim 12 , wherein the carboxylic-acid containing monomer is selected from (meth)acrylic acid, acrylic acid, crotonic acid, and trimethylsilyl methacrylate.

14. The contact lens of claim 12 , wherein the ionic content is about 1.0% to about 2.0%.

15. The contact lens of claim 12 , wherein the ionic content is about 1.6% to about 1.8%.

16. The contact lens of claim 12 , wherein the monomer mixture comprises about 25 wt. % to about 75 wt. % of the hydrophilic monomer.

17. The contact lens of claim 12 , wherein the monomer mixture comprises about 35 wt. % to about 55 wt. % of VMA.

18. The contact lens of claim 12 , further comprising a cationic polymer having a molecular weight of about 2,000 to 30,000 electrostatically attached to the hydrated polymerization product, wherein the contact lens sustains release of the cationic polymer for at least 6 hours.

19. A method of replenishing the contact lens of claim 1 with cationic polymer after it has been worn, comprising storing the worn contact lens in a multi-purpose contact lens care solution (MPS) that comprises additional cationic polymer, wherein the additional cationic polymer incorporates into the contact lens during the storage.

20. A method of manufacturing the silicone hydrogel contact lens of claim 1 , said method comprising: polymerizing the monomer mixture to provide a lens-shaped polymerization product; optionally hydrating the polymerization product to form a hydrogel; immersing the polymerization product or hydrogel in the packaging solution; sealing the package; and optionally sterilizing the sealed package by autoclave.

21. The method of claim 19 , wherein the monomer mixture comprises trimethylsilyl methacrylate (TMSMA) and wherein the monomer mixture is polymerized in a polypropylene mold.