Silicone hydrogel lenses with relatively-long thermal stability
View Patent ↗The invention provides silicone hydrogel ophthalmic lenses (in particular contact lenses) having relatively-long thermal stability and methods for making such ophthalmic lenses.
1. A soft contact lens comprising a silicone hydrogel material comprising:
(1) first repeating units derived from N,N-dimethylacrylamide;
(2) second repeating units derived from a siloxane vinylic monomer of formula (Ia)
in which R″, R 11 and R 12 are methyl and m2 is 3; and
(3) third repeating units derived from α,ω-acrylamide terminated polydimethylsiloxane or α,ω-bis(methacryloxyethoxypropyl)-terminated polydimethylsiloxane, wherein the soft contact lens has a relatively-long thermal stability as characterized by having an autoclave-induced change in elastic modulus,
EM
19
A
C
_
-
EM
1
A
C
_
EM
1
A
C
_
,
of about 5% or less, wherein EM 1AC is the averaged after-one-autoclave elastic modulus of the soft contact lens and is obtained by averaging the elastic modulus of 15 soft contact lenses measured after being autoclaved one sole time for 30 minutes at 121° C. in a phosphate buffered saline at a pH of 7.20±0.05 and EM 19AC is the averaged after-19-autoclaves elastic modulus of the soft contact lens and is obtained by averaging the elastic modulus of 15 soft contact lenses measured after being stored and autoclaved 19 times each for 30 minutes at 121° C. in a phosphate buffered saline at a pH of 7.20±0.05.
2. The soft contact lens of claim 1 , having: an oxygen permeability (Dk) of at least about 40 barrers; a water content of from about 20% to about 75% by weight when fully hydrated; and an elastic modulus of from about 0.2 MPa to about 1.8 MPa.
3. The soft contact lens of claim 1 , wherein the silicone hydrogel material further comprises fifth repeating units derived from a UV-absorbing vinylic monomer.
4. The soft contact lens of claim 2 , wherein the silicone hydrogel material further comprises fifth repeating units derived from a UV-absorbing vinylic monomer.
5. A soft contact lens comprising a silicone hydrogel material, wherein the silicone hydrogel material is a polymerization product of a lens formulation comprising:
(1) from about 5% to about 60% by weight of N,N-dimethylacrylamide;
(2) from about 5% to about 50% by weight of a siloxane vinylic monomer of formula (Ia);
in which R″, R 11 and R 12 are methyl and m2 is 3;
(3) from about 5% to about 50% by weight of α,ω-acrylamide terminated polydimethylsiloxane or α,ω-bis(methacryloxyethoxypropyl)-terminated polydimethylsiloxane;
(4) from about 0.05% to about 1.5% by weight of a photoinitiator;
(5) from 0 to 4% by weight of a crosslinking agent selected from the group consisting of N,N′-methylene-bis-(meth)acrylamide, N,N′-ethylene-bis-(meth)acrylamide, N,N′-dihydroxyethylene-bis-(meth)acrylamide, 1,3-bis(acrylamidopropyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(methacrylamidopropyl)-1,1,3,3-tetramethyldisiloxane, and combinations thereof; and
(6) from 0 to 5% by weight of a polymerizable UV-absorbing or UV/High-Energy-Violet-Light-absorbing vinylic monomer,
provided that the above-listed components and any additional components add up to 100% by weight,
wherein the soft contact lens has a relatively-long thermal stability as characterized by having an autoclave-induced change in elastic modulus,
EM
19
A
C
_
-
EM
1
A
C
_
EM
1
A
C
_
,
of about 5% or less, wherein EM 1AC is the averaged after-one-autoclave elastic modulus of the soft contact lens and is obtained by averaging the elastic modulus of 15 soft contact lenses measured after being autoclaved one sole time for 30 minutes at 121° C. in a phosphate buffered saline at a pH of 7.20±0.05 and EM 19AC is the averaged after-19-autoclaves elastic modulus of the soft contact lens and is obtained by averaging the elastic modulus of 15 soft contact lenses measured after being stored and autoclaved 19 times each for 30 minutes at 121° C. in a phosphate buffered saline at a pH of 7.20±0.05.
6. The soft contact lens of claim 1 , having: an oxygen permeability (Dk) of at least about 40 barrers; a water content of from about 20% to about 75% by weight when fully hydrated; and an elastic modulus of from about 0.2 MPa to about 1.8 MPa.