U.S. patent application number 10/811690 was filed with the patent office on 2004-10-28 for hydrogel contact lenses and package systems and production methods for same.
This patent application is currently assigned to Ocular Sciences, Inc.. Invention is credited to Marmo, J. Christopher.
Application Number | 20040214914 10/811690 |
Document ID | / |
Family ID | 33418180 |
Filed Date | 2004-10-28 |
United States Patent
Application |
20040214914 |
Kind Code |
A1 |
Marmo, J. Christopher |
October 28, 2004 |
Hydrogel contact lenses and package systems and production methods
for same
Abstract
Contact lenses ready for use in an eye are provided including a
contact lens body containing a hydrophilic polymeric component and
a water soluble polymer component. Such contact lenses, which
preferably are wet cast molded, are particularly useful as
disposable or single use lenses. New contact lens packaging systems
and production methods are also provided.
Inventors: |
Marmo, J. Christopher;
(Danville, CA) |
Correspondence
Address: |
STOUT, UXA, BUYAN & MULLINS LLP
4 VENTURE, SUITE 300
IRVINE
CA
92618
US
|
Assignee: |
Ocular Sciences, Inc.
Concord
CA
|
Family ID: |
33418180 |
Appl. No.: |
10/811690 |
Filed: |
March 29, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60465090 |
Apr 24, 2003 |
|
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Current U.S.
Class: |
523/106 |
Current CPC
Class: |
G02B 1/043 20130101;
G02B 1/043 20130101; C08L 33/14 20130101 |
Class at
Publication: |
523/106 |
International
Class: |
C08K 003/00 |
Claims
1. A contact lens comprising: a contact lens body comprising a
hydrophilic polymeric material and a water soluble polymer
component, the contact lens body being ready for use in an eye.
2. The contact lens of claim 1 wherein the water soluble polymer
component is in intimate admixture with the hydrophilic polymeric
material.
3. The contact lens of claim 1 wherein the water soluble polymer
component is ophthalmically acceptable.
4. The contact lens of claim 1 wherein the water soluble polymer
component is derived from a diluent material used during
polymerization of the hydrophilic polymeric material.
5. (canceled)
6. The contact lens of claim 4 wherein the contact lens body is
produced using wet cast molding.
7. The contact lens of claim 1 which is structured to be disposed
of after a single use in an eye, and the contact lens body has an
increased modulus relative to an identical lens body in which the
water soluble polymer component is replaced with water.
8. (canceled)
9. (canceled)
10. The contact lens of claim 1 wherein the contact lens body is
configured so that at least a portion of the water soluble polymer
component leaves the contact lens body during use of the contact
lens body in an eye.
11. The contact lens of claim 1 wherein the water soluble polymer
component and the hydrophilic polymeric material form an
interpenetrating network or a psuedo interpenetrating network.
12. (canceled)
13. (canceled)
14. The contact lens of claim 1 wherein the hydrophilic polymeric
material is obtained by polymerization of at least one hydrophilic
monomeric component and at least one cross-linking monomeric
component.
15. (canceled)
16. The contact lens of claim 1 wherein the water soluble polymer
component is selected from the group consisting of hydrophillic
vinylic monomers, such as vinyl (C.sub.4--C.sub.45)alkyl ethers,
vinyl (C.sub.7--C.sub.49)alkenoic acids and the like and mixtures
thereof; hydroxy substituted (C.sub.5--C.sub.45)alkyl, alkoxy-alkyl
and polyalkoxy-alkyl and mono- or bi-cycloaliphatic fumarates,
maleates, acrylates, methacrylates, acrylamides and
methacrylamides, and the like and mixtures thereof; acrylic acid,
methacrylic acid, the corresponding amino or mono- and di-(lower
alkyl) amino substituted acrylic monomers and the like and mixtures
thereof; and vinyl-lactams and the like and mixtures thereof.
17. The contact lens of claim 1 wherein the water soluble polymer
component is selected from the group consisting of polyalkylene
glycols, polyvinyl pyrrolidone, polymethacrylic acid, polyvinyl
alcohol and mixtures thereof.
18. A package system comprising: a contact lens ready for use in an
eye and comprising a contact lens body comprising a hydrophilic
polymeric material and a water soluble polymer component; a liquid
medium comprising an amount of the water soluble polymer component
in addition to that present in the contact lens body; and a
container holding the contact lens and the liquid medium.
19. The package system of claim 18 wherein the container is
structured to hold the contact lens in contact with the liquid
medium and the liquid medium includes the water soluble polymer
component prior to the liquid medium being placed in contact with
the contact lens.
20. (canceled)
21. (canceled)
22. The package system of claim 12 wherein the water soluble
polymer component in the contact lens body is derived from a
diluent material used during polymerization of the hydrophilic
polymeric material, and the contact lens body is produced using wet
cast molding.
23. (canceled)
24. The package system of claim 18 wherein the contact lens is
structured to be disposed of after a single use in an eye, and the
contact lens body has an increased modulus relative to an identical
lens body in which the water soluble polymer component is replaced
with water.
25. (canceled)
26. The package system of claim 18 wherein the water soluble
polymer component in the contact lens body is physically
immobilized by the hydrophilic polymeric material.
27. The package system of claim 18 wherein the contact lens body is
configured so that at least a portion of the water soluble polymer
component leaves the contact lens body during use of the contact
lens body in an eye.
28. The package system of claim 18 wherein the water soluble
polymer component and the hydrophilic polymeric material form an
interpenetrating network or a psuedo interpenetrating network.
29. (canceled)
30. The package system of claim 12 wherein the hydrophilic
polymeric material is obtained by polymerization of at least one
hydrophilic monomeric component and at least one cross-linking
monomeric component.
31. (canceled)
32. The package system of claim 18 wherein the water soluble
polymer component is selected from the group consisting of
hydrophillic vinylic monomers, such as vinyl
(C.sub.4--C.sub.45)alkyl ethers, vinyl (C.sub.7--C.sub.49)alkenoic
acids and the like and mixtures thereof; hydroxy substituted
(C.sub.5--C.sub.45)alkyl, alkoxy-alkyl and polyalkoxy-alkyl and
mono- or bi-cycloaliphatic fumarates, maleates, acrylates,
methacrylates, acrylamides and methacrylamides, and the like and
mixtures thereof; acrylic acid, methacrylic acid, the corresponding
amino or mono- and di-(lower alkyl) amino substituted acrylic
monomers and the like and mixtures thereof; and vinyl-lactams and
the like and mixtures thereof.
33. The package system of claim 18 wherein the water soluble
polymer component is selected from the group consisting of
polyalkylene glycols, polyvinyl pyrrolidone, polymethacrylic acid,
polyvinyl alcohol and mixtures thereof.
34. A method of producing a contact lens, the method comprising
polymerizing at least one hydrophilic monomeric component in the
presence of a water soluble polymer component to form a contact
lens body comprising a hydrophilic polymeric material and the water
soluble polymer component; and placing the contact lens body in a
packaging container.
35. The method of claim 34 wherein the polymerizing step is a
solution polymerization step.
36. The method of claim 34 wherein the water soluble polymer
component is included in a diluent used during the polymerizing
step, and the polymerizing step occurs in a contact lens mold.
37. (canceled)
38. The method of claim 34 wherein an effective amount of at least
one cross-linking monomeric component is present during the
polymerizing step.
39. (canceled)
40. The method of claim 34 wherein the water soluble polymer
component and the hydrophilic polymeric material form an
interpenetrating network or a psuedo interpenetrating network in
the contact lens body.
41. (canceled)
42. The method of claim 34 wherein the water soluble polymer
component is selected from the group consisting of hydrophillic
vinylic monomers, such as vinyl(C.sub.4--C.sub.45)alkyl ethers,
vinyl (C.sub.7--C.sub.49)alkenoi- c acids and the like and mixtures
thereof; hydroxy substituted (C.sub.5--C.sub.45)alkyl, alkoxy-alkyl
and polyalkoxy-alkyl and mono- or bi-cycloaliphatic fumarates,
maleates, acrylates, methacrylates, acrylamides and
methacrylamides, and the like and mixtures thereof; acrylic acid,
methacrylic acid, the corresponding amino or mono- and di- (lower
alkyl) amino substituted acrylic monomers and the like and mixtures
thereof; and vinyl-lactams and the like and mixtures thereof.
43. The method of claim 34 wherein the water soluble polymer
component is selected from the group consisting of polyalkylene
glycols, polyvinyl pyrrolidone, polymethacrylic acid, polyvinyl
alcohol and mixtures thereof.
44. The method of claim 34 which further comprises placing a liquid
medium in the container.
45. The method of claim 44 wherein the liquid medium includes an
amount of the water soluble polymer component in addition to that
present in the contact lens body.
46. (canceled)
47. (canceled)
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of Provisional U.S.
Patent Application Ser. No. 60/465,090 filed Apr. 24, 2003, the
disclosure of which is incorporated in its entirety herein by
reference.
[0002] The present invention relates to hydrogel-containing contact
lenses, packaging systems including same and methods of producing
same. More particularly the invention relates to
hydrogel-containing contact lenses, for example, disposable contact
lenses, including water soluble polymer components, and packaging
systems for use with same and methods of producing same.
BACKGROUND OF THE INVENTION
[0003] In the recent past, a method for producing
hydrogel-containing contact lenses has been developed which is more
economical than either lathe cutting or spin casting, and provides
better control over the final shape of the hydrated lens. This
method involves direct molding of a monomer mixture wherein said
mixture is dissolved in a non-aqueous, displaceable solvent. The
mixture is placed in a mold having the precise shape of the final
desired hydrogel (i.e., water-swollen) lens, and the
monomer/solvent mixture is subjected to conditions whereby the
monomer(s) polymerize, to thereby produce a polymer/solvent mixture
in the shape of the final desired hydrogel lens.
[0004] After the polymerization is complete, the solvent is
displaced with water to produce a hydrated lens whose final size
and shape are quite similar to the size and shape of the original
molded polymer/solvent article.
[0005] Such direct molding of hydrogel contact lenses is disclosed
in Larsen, U.S. Pat. No. 4,495,313 and in Larsen et al., U.S. Pat.
Nos. 4,680,336, 4,889,664 and 5,039,459. In addition, other patents
to be considered include Larson U.S. Pat. No. 4,565,348; Okkada et
al U.S. Pat. No. 4,347,198; Shepherd U.S. Pat. No. 4,208,364;
Mueller et al EP-A-0493,320A2; and Wichterle et al U.S. Pat. No. RE
27,401 (U.S. Pat. No. 3,220,960). The disclosure of each of these
patents is incorporated in its entirety herein by reference.
[0006] It would be advantageous to provide new and beneficial
hydrogel-containing contact lenses, packaging systems for such
lenses and methods of producing such contact lenses.
SUMMARY OF THE INVENTION
[0007] New hydrogel-containing contact lenses, packaging systems
for use with such lenses and methods of producing such lenses have
been discovered. The present hydrogel-containing lenses take
advantage of the economies and shape control benefits of direct
molding of hydrogel-containing contact lenses. In addition, by
properly selecting the diluent or material included in the mold
during lens formation, in particular by employing one or more water
soluble polymer components, such diluent or material may remain
with/in the lens ready for use in an eye. Thus, the present methods
of making hydrogel-containing contact lenses are even less complex
and more economical, for example, by eliminating the solvent
displacing step, relative to prior art direct molding processes
discussed elsewhere herein. The present packaging systems
advantageously maintain the diluent or material in the contact
lenses prior to use in an eye. In addition, the hydrogel-containing
lenses advantageously have increased modulus or strength when first
placed in an eye. Over time, for example, over a one day use
period, the diluent or material is removed from the lens and
replaced by water or tear fluid in the eye. When the lens is
removed from the eye, it has less strength and provides an
indication to the wearer that the lens should be disposed of and
replaced. In addition, should the wearer use the lens again, the
lens would be less comfortable to wear, for example, due to the
loss of the diluent or material. This reduced comfort feature
provides an indication to the wearer that the lens should be
disposed of and replaced. The present lenses are particularly
advantageous when provided as disposable lenses, for example,
lenses suitable or structured for one time usage.
[0008] In one broad aspect, the present invention is directed to
contact lenses which comprise contact lens bodies. The contact lens
bodies comprise a hydrophilic polymeric material and a water
soluble polymer component (WSPC). Such contact lens bodies are
ready for use in an eye. In one embodiment, the WSPC is in intimate
admixture with the hydrophilic polymeric material.
[0009] In a very useful embodiment, the WSPC is derived from a
diluent material used during polymerization of the hydrophilic
polymeric material. The WSPC advantageously is derived from a
diluent material, for example, is at least a portion of the diluent
material, used during solution polymerization of a hydrophilic
polymeric material.
[0010] In one embodiment, the contact lens body is produced using
wet cast molding.
[0011] As noted above, the present contact lenses advantageously
are structured to be disposed of after a single use in the eye.
[0012] The present contact lens bodies including the WSPCs
preferably have increased modulus relative to identical lens bodies
in which the WSPC is replaced with water.
[0013] The WSPC advantageously is physically immobilized by the
hydrophilic polymeric material in the present contact lens bodies.
For example, the WSPC and the hydrophilic polymeric material may
form an interpenetrating network or a psuedo interpenetrating
network, preferably a psuedo interpenetrating network, in the lens
body.
[0014] The present contact lens bodies preferably are configured or
structured so that at least a portion of the WSPC leaves or is
removed from the contact lens body during use of the contact lens
body in an eye.
[0015] The hydrophilic polymeric material preferably is obtained by
polymerization of at least one monomeric component, for example, by
the polymerization of at least one hydrophilic monomeric component
and at least one cross-linking monomeric component.
[0016] The hydrophilic monomeric component may be selected from any
suitable such component. In a very useful embodiment, the
hydrophilic monomeric component is selected from hydroxyalkyl
acrylates, hydroxyalkyl methacrylates, N-vinyl pyrrolidone,
acrylamides, vinyl alcohol, hydrophilic polyurethane precursors,
glycerol acrylates, glycerol methacrylates, acrylates,
methacrylates, substituted counterparts thereof and the like and
mixtures thereof.
[0017] As used herein, the term "substituted counterparts thereof"
refers to entities, e.g., compounds, which include one or more
substituents and are effective to function in the present invention
substantially like the unsubstituted entities, for example, the
compounds listed herein.
[0018] Any suitable WSPC may be employed provided that it is
effective in the present contact lenses, as described herein.
[0019] In one embodiment, the monomeric components from which the
WSPCs are derived, for example, at least one ethylenically
unsaturated hydrophilic monomeric component, are polymerizable to
form linear or branched chain water soluble polymers or
copolymers.
[0020] Hydrophilic monomeric components suitable for production of
the WSPCs include, but are not limited to, hydrophilic vinylic
monomers, such as vinyl (C.sub.4--C.sub.45)alkyl ethers, vinyl
(C.sub.7--C.sub.49)alkeno- ic acids and the like and mixtures
thereof; hydroxy substituted (C.sub.5--C.sub.45)alkyl, alkoxy-alkyl
and polyalkoxy-alkyl and mono- or bi-cycloaliphatic fumarates,
maleates, acrylates, methacrylates, acrylamides and
methacrylamides, and the like and mixtures thereof; acrylic acid,
methacrylic acid, the corresponding amino or mono- and di-(lower
alkyl) amino substituted acrylic monomers and the like and mixtures
thereof; and vinyl-lactams and the like and mixtures thereof.
Typical monomers include, but are not limited to, 2-hydroxyethyl,
2-hydroxypropyl, and 3-hydroxypropyl acrylates and methacrylates;
N-vinylpyrrolidone; N,N-dimethylaminoethyl methacrylate;
methoxyethyl-, ethoxyethyl, methoxy-ethoxyethyl and
ethoxy-ethoxyethyl acrylates and methacrylates; (meth)acrylamides
like N,N-dimethyl, N,N-diethyl, 2-hydroxyethyl-, 2-hydroxypropyl-,
and 3-hydroxypropyl acrylamides and methacrylamides; vinyl sulfonic
acid; styrene sulfonic acid; 2-methacrylamide-2-methyl
propane-sulfonic acid and the like and mixtures thereof.
[0021] In one embodiment, the WSPC preferably includes units
derived from one or more of acrylic acid, hydrophilic derivatives
of acrylic acid, methacrylic acid, hydrophilic derivatives of
methacrylic acid, cationic/anionic pairs of monomeric components,
cationic monomeric components, anionic monomeric components,
nonionic monomeric components, hydrophilic vinylic monomeric
components, salts thereof and mixtures thereof.
[0022] In one very useful embodiment, the WSPC is selected from
polyalkylene glycols, for example, polyethylene glycols,
polypropylene glycols and the like, polyvinyl pyrrolidone,
polymethacrylic acid, polyvinyl alcohol, and the like and mixtures
thereof.
[0023] In another broad aspect of the present invention, packaging
systems are provided which comprise a contact lens ready for use in
an eye, a liquid medium, and a container holding the contact lens
and the liquid medium. The contact lens comprises a contact lens
body including a hydrophilic polymeric material and a WSPC, as
described elsewhere herein. The liquid medium, preferably an
aqueous liquid medium, comprises an amount of the WSPC in addition
to that present in the contact lens body.
[0024] The liquid medium preferably includes the WSPC prior to the
liquid medium being placed in the container, for example, in
contact, with the contact lens.
[0025] Advantageously, the container is sealed, for example, using
any suitable conventional container seal assembly, such as a
conventional container seal assembly, and preferably sterilized to
protect, preserve and maintain sterilized the contact lens and the
liquid medium during shipment and storage.
[0026] In a further broad aspect of the present invention, methods
for producing contact lenses are provided. Such methods comprise
polymerizing at least one hydrophilic monomeric component in the
presence of a WSPC to form a contact lens body comprising a
hydrophilic polymeric material and the WSPC. Advantageously, an
effective amount of at least one cross-linking monomeric component
is present during the polymerizing step. The contact lens body is
placed in a packaging container, preferably in a packaging system
as described elsewhere herein.
[0027] Advantageously the polymerizing step is a solution
polymerizing step. The WSPC preferably is included in a diluent
used during the polymerizing step. The polymerizing step preferably
occurs in a contact lens mold, for example, a conventional contact
lens mold, such as a conventional thermoplastic contact lens
mold.
[0028] In one very useful embodiment, a liquid medium, preferably
an aqueous liquid medium, is also placed in the packaging
container. This liquid medium preferably includes an amount of the
WSPC in addition to that present in the contact lens body. The WSPC
and the liquid medium preferably are ophthalmically acceptable.
[0029] In addition, the present methods preferably further comprise
sealing the container with a contact lens body, and preferably the
liquid medium, included therein.
[0030] Each and every feature described herein, and each and every
combination of two or more of such features, is included within the
scope of the present invention provided that the features included
in such a combination are not mutually inconsistent.
[0031] These and other aspects of the present invention are set
forth in the following detailed description, examples and claims,
particularly when considered in conjunction with the accompanying
drawings in which like parts bear like reference numerals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a schematic illustration of a packaging system in
accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0033] The present contact lenses comprise a contact lens body
comprising a hydrophilic polymeric material and a WSPC, preferably
an effective amount of the WSPC, for example, to increase the
modulus or strength of the contact lens and/or to provide enhanced
lubrication to the eye wearing the contact lens and/or to increase
the comfort to the lens wearer of wearing the contact lens. Such
benefits, e.g., increases and/or enhancements, are relative to an
identical contact lens without the WSPC.
[0034] The hydrophilic polymeric materials useful in the present
contact lenses may be selected from any suitable such materials.
Preferably, such hydrophilic polymeric materials are such as to
take on or absorb sufficient water so as to expand or swell. Such
water-swellable materials are often referred to as hydrogels. A
number of hydrophilic polymeric materials are conventionally used
in contact lenses, and such conventionally used materials may be
employed in the present contact lenses. Specific examples, without
limitation, of useful hydrophilic polymeric materials are
identified elsewhere herein.
[0035] An important feature of the present invention is the
inclusion of WSPCs in the present contact lenses.
[0036] The WSPCs useful in the present invention may be chosen from
any suitable such components. The presently useful WSPCs
advantageously are ophthalmically acceptable and substantially not
cytotoxic.
[0037] In a very useful embodiment, the WSPC is effective to
provide at least one benefit to the contact lens and/or to the
wearing of the contact lens and/or to the wearer of the contact
lens. For example, the WSPC advantageously is present in an amount
effective to increase the modulus or strength of the contact lens
relative to an identical contact lens in which the WSPC is replaced
by water. The WSPC may be selected, and present in the contact lens
in an amount, so as to be effective as a lubricant or lubricity
agent as the WSPC dissolves into the tear fluid while the contact
lens is in use in an eye. Thus, the lens wearer's eye, for example,
cornea and/or eyelids, is more effectively lubricated when wearing
the present contact lenses, which enhances the comfort of wearing
the lenses, relative to an identical contact lens in which the WSPC
is replaced by water.
[0038] The WSPC may be selected to have substantially no
detrimental effect on the optical clarity and/or optical power of
the contact lens while in use.
[0039] Specific examples, without limitation, of useful WSCPs are
identified elsewhere herein. The WSPC may be included in the
present contact lenses in any suitable amount effective to provide
the desired result. Such amounts may be in a range of about 1% or
about 5% or about 10% or about 15% to about 20% or about 30% or
about 40% or about 50% or more of the hydrophilic polymeric
material present in the contact lens.
[0040] One very useful class of WSPCs include polyethylene glycols.
Polyethylene glycols are compounds that can be represented by the
following formula:
HO--(CH.sub.2--CH.sub.2O).sub.n--H
[0041] wherein n represents a number such that the molecular weight
of the polyethylene glycol is within the range of from about 300 to
about 10,000 and preferably from about 400 to about 2000 or about
5000. Such polyethylene glycols are commercially available
products.
[0042] The WSPCs employed are ultimately water-displaceable. That
is, after placing the contact lens including the hydrophilic
polymeric material and the WSPC in the eye, the WSPC is ultimately
at least partially, and even substantially completely, replaced
with water in the eye.
[0043] However, it is advantageous to provide the WSPCs in the
present contact lenses so that the hydrophilic polymeric material
physically immobilizes the WSPC, at least to a limited extent. For
example, the hydrophilic polymeric material may immobilize the WSPC
in the contact lens sufficiently so that the WSPC is replaced by
water substantially only after the lens is placed in an eye. In one
useful embodiment, the WSPC is present in the present contact
lenses in an interpenetrating network or pseudo penetrating network
with the hydrophilic polymeric material, for example, to provide
the desired degree of physical immobilization of the WSPC.
[0044] The replacement, for example, controlled replacement, of the
WSPC by water in the eye, can allow the WSPC, in the eye, to
provide added lubrication and comfort to the lens wearer. In
addition, the removal of the WSPC from the contact lens in the eye
may reduce the modulus or strength of the lens. Thus, after the
lens wearer removes the WSPC-depleted lens from his/her eye, the
lens will have different strength properties than before it was
placed in the eye. These different properties provide an indication
to the wearer that the lens is to be disposed of, rather than to be
reused. In other words, the replacement of the WSPC in the contact
lens with water in the eye, advantageously facilitates lens wearer
compliance with proper usage of disposable contact lenses. The
present lenses preferably are structured to be disposed of after a
single use in the eye.
[0045] Mixtures of two or more WSPCs may be included in a single
contact lens in accordance with the present invention.
[0046] The hydrophilic polymeric material employed in the present
contact lenses may be derived from any suitable monomer or mixture
of monomers. In one embodiment, a monomer mixture used which
contains a major proportion of at least one hydrophilic monomer
such as 2-hydroxyethyl methacrylate ("HEMA") as the major
component, one or more cross-linking monomers, and optionally small
amounts of other monomers such as methacrylic acid. HEMA is one
preferred hydrophilic monomer. Other hydrophilic monomers that can
be employed include, without limitation, 2-hydroxyethyl acrylate,
2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate,
3-hydroxypropyl methacrylate, N-vinyl pyrrolidone, glycerol
mono-methacrylate, glycerol mono-acrylate, and the like and
mixtures thereof.
[0047] The cross-linking monomers that can be employed, either
singly or in combination, include, without limitation, ethylene
glycol dimethacrylate ("EGDMA"), trimethylolpropane trimethacrylate
("TMPTMA"), glycerol trimethacrylate, polyethylene glycol
dimethacrylate (wherein the polyethylene glycol has a molecular
weight up to, for example, about 5000), other polyacrylate and
polymethacrylate esters, end-capped polyoxyethylene polyols
containing two or more terminal methacrylate moieties and the like
and mixtures thereof. The cross-linking monomer is used in the
usual amounts, e.g., from about 0.01% or less to about 0.5% or
more, by weight of the reactive monomer mixture. The cross-linking
monomer can be a hydrophilic monomer.
[0048] Other monomers that can be used include methacrylic acid,
which is used to influence the amount of water that the hydrophilic
polymeric material absorbs at equilibrium. Methacrylic acid is
usually employed in amounts of from about 0.2 to about 8 parts, by
weight, per 100 parts of hydrophilic monomer. Other monomers that
can be present in the polymerization mixture include methoxyethyl
methacrylate, acrylic acid, ultra-violet absorbing monomers, and
the like and mixtures thereof.
[0049] A polymerization catalyst is included in the monomer
mixture. The polymerization catalyst can be a compound such as
lauroyl peroxide, benzoyl peroxide, isopropyl percarbonate,
azobisiso-butyronitrile, and the like and mixtures thereof, that
generates free radicals at moderately elevated temperatures, or the
polymerization catalyst can be a photoinitiator system such as an
aromatic .alpha.-hydroxy ketone or a tertiary amine plus a
diketone. Illustrative examples of photoinitiator systems are
2-hydroxy-2-methyl-1-phenyl-propan-1-one and a combination of
camphorquinone and ethyl 4-(N,N-dimethyl-amino)benzoate. The
catalyst is used in the polymerization reaction mixture in
catalytically effective amounts, e.g., from about 0.1 to about 2
parts by weight per 100 parts of hydrophilic monomer.
[0050] The presently useful WSPCs preferably are included in the
contact lenses during polymerization, for example, solution
polymerization, to produce the hydrophilic polymeric material. In a
particularly useful embodiment, the WSPC in the contact lens is
derived from a diluent material used during such polymerization of
the hydrophilic polymeric material.
[0051] In another broad aspect, the present invention is directed
to methods of producing contact lenses. Such methods comprise
polymerizing, preferably solution polymerizing at least one
hydrophilic monomeric component in the presence of a WSPC to form a
contact lens body comprising a hydrophilic polymeric material and
the WSPC. The WSPC preferably is included in a diluent used during
the polymerizing step. The contact lens body is ready for use in
the eye and is advantageously placed in a packaging container, for
example, for shipment and/or storage.
[0052] The polymerizing step advantageously occurs in a contact
lens mold, for example, a conventional contact lens mold. The
polymerizing step may take place in a manner substantially similar
or analogous to the corresponding step in the conventional wet cast
molding process for making hydrophilic contact lenses. The
polymerization reaction conditions useful in the present methods
are substantially the same as those used in conventional wet cast
molding processes for producing hydrophilic contact lenses and,
therefor, are not detailed herein.
[0053] The resulting contact lens body preferably includes an
interpenetrating network or a pseudo interpenetrating network of
the hydrophilic polymeric material and the WSPC. One important
feature of the present methods is that the WSPC is not replaced,
for example, with water, prior to the contact lens being placed
into a packaging container or into an eye. As described elsewhere
herein, the WSPC in the contact lens in the eye produces one or
more benefits.
[0054] In a further broad aspect, the present invention is directed
to package systems for contact lenses, for example, the present
contact lenses. Such package systems comprise a contact lens ready
for use in an eye, a liquid medium, preferably an aqueous liquid
medium, and a container holding the contact lens and the liquid
medium. The contact lens comprises a contact lens body comprising a
hydrophilic polymeric material and a WSPC, as described elsewhere
herein.
[0055] The liquid medium comprises an amount of the WSPC in
addition to the WSPC present in the contact lens body. Although the
WSPC in the liquid medium need not be the same as the WSPC in the
lens body, preferably it is substantially the same WSPC as that
present in the lens body. Advantageously, the liquid medium
includes the WSPC prior to the liquid medium being placed in
contact with the lens body. The presence of the WSPC in the liquid
medium preferably is effective to inhibit migration of the WSPC in
the lens body from the lens body. Thus, the amount or concentration
of the WSPC in the lens body is substantially maintained in the
packaging system, and is available for providing one or more
benefits, as described elsewhere herein, after the contact lens is
placed in an eye. The concentration of the WSPC in the liquid
medium may be about equal to, or somewhat more or less than, that
present in the lens body prior to the lens body being placed in
contact with the liquid medium. The liquid medium, other than the
WSPC, may have a composition substantially similar or analogous to
liquid medium used in package systems for conventional hydrophilic
contact lenses. Saline solutions, buffered saline solutions, other
aqueous solutions and the like, together with the WSPC, may be
employed.
[0056] The container advantageously is sealed, after placing the
contact lens and liquid medium in the container, to preserve these
components during shipment and storage. The container and seal may
be substantially similar or analogous to a conventional blister
pack which is used for packaging conventional hydrophilic contact
lenses.
[0057] Referring now to FIG. 1, a package system in accordance with
the present invention is shown at 10. Package system 10 includes a
container 12, a contact lens 14, including a contact lens body
including a hydrophilic polymeric material and a WSPC, a liquid
medium 16, comprising an aqueous saline solution containing a
separate amount of the WSPC present in the contact lens, and a
removable seal 18.
[0058] The container 12 and seal 18 are similar to the container
and seal used in a conventional blister pack used with conventional
hydrophilic contact lenses.
[0059] With the container 12 unsealed, the liquid medium 16 and the
contact lens 14, directly from the contact lens mold, are placed
therein. The seal 18 is placed over, and secured to the top of
container 12, thereby sealing the compartment 20 containing the
contact lens 14 in contact with the liquid medium 16.
[0060] The contact lens 14 can be used by opening seal 18 (as shown
by the shadow lines in FIG. 1), removing lens 14 from compartment
20 and placing the lens into one's eye. The container 12, liquid
medium 16 and seal 18 can then be properly disposed of.
[0061] The following non-limiting examples illustrate certain
aspects of the present invention:
EXAMPLE 1
[0062] A one day disposable, hydrogel-containing contact lens is
wet cast molded in a polypropylene mold as follows. A monomer
mixture of 98% by weight of 2-hydroxyethyl methacrylate, 1.6% by
weight methacrylic acid and 0.4% by weight of ethylene glycol
dimethacrylate is formed together with an effective amount of a
conventional thermal initiator. This monomer is diluted by 20% by
weight with water soluble polyethylene glycol having a molecular
weight of about 1000. The diluted solution is added to a
polypropylene contact lens mold and is cured using thermal curing.
If desired, an ultraviolet light initiator can be included in place
of the thermal initiator, and the solution can be cured using
ultraviolet light curing. After curing, the lens is removed from
the mold and placed in a packaging system similar to a conventional
blister pack and hydrated with saline solution. The hydrated lens
is formed to have mechanical properties similar to a dry cast
molded lens.
EXAMPLE 1A
[0063] Alternately, and advantageously, the saline solution used in
the package is altered to include about 20% of the polyethylene
glycol, which is at substantial equilibrium with both the contact
lens and the saline solution in the package. The use of this
polyethylene glycol in the saline solution is effective to reduce,
or even substantially eliminate, the polyethylene glycol from
diffusing out of the contact lens during storage in the
package.
EXAMPLE 2
[0064] A one day disposable, hydrogel-containing contact lens is
wet cast molded in a polypropylene mold as follows. A monomer
mixture of 98% by weight of 2-hydroxyethyl methacrylate, 1.6% by
weight methacrylic acid and 0.4% by weight of ethylene glycol
dimethacrylate is formed together with an effective amount of a
conventional thermal initiator. This monomer is diluted by 30% by
weight with water soluble polyethylene glycol having a molecular
weight of about 1000. The diluted solution is added to a
polypropylene contact lens mold and is cured using thermal curing.
If desired, an ultraviolet light initiator can be included in place
of the thermal initiator, and the solution can be cured using
ultraviolet light curing. After curing, the lens is removed from
the mold and placed in a packaging system similar to a conventional
blister pack and hydrated with saline solution. The hydrated lens
is formed to have mechanical properties similar to a dry cast
molded lens.
EXAMPLE 2A
[0065] Alternately, and advantageously, the saline solution used in
the package is altered to include about 30% of the polyethylene
glycol, which is at substantial equilibrium with both the contact
lens and the saline solution in the package. The use of this
polyethylene glycol in the saline solution is effective to reduce,
or even substantially eliminate, the polyethylene glycol from
diffusing out of the contact lens during storage in the
package.
EXAMPLE 3
[0066] A one day disposable hydrogel-containing contact lens is wet
cast molded in a polypropylene mold as follows. A monomer mixture
of 98% by weight of 2-hydroxyethyl methacrylate, 1.6% by weight
methacrylic acid and 0.4% by weight of ethylene glycol
dimethacrylate is formed together with an effective amount of a
conventional thermal initiator. This monomer is diluted by 40% by
weight with water soluble polyethylene glycol having a molecular
weight of about 1000. The diluted solution is added to a
polypropylene contact lens mold and is cured using thermal curing.
If desired, an ultraviolet light initiator can be included in place
of the thermal initiator, and the solution can be cured using
ultraviolet light curing. After curing, the lens is removed from
the mold and placed in a packaging system similar to a conventional
blister pack and hydrated with saline solution. The hydrated lens
is formed to have mechanical properties similar to a dry cast
molded lens.
EXAMPLE 3A
[0067] Alternately, and advantageously, the saline solution used in
the package is altered to include about 40% of the polyethylene
glycol, which is at substantial equilibrium with both the contact
lens and the saline solution in the package. The use of this
polyethylene glycol in the saline solution is effective to reduce,
or even substantially eliminate, the polyethylene glycol from
diffusing out of the contact lens during storage in the
package.
EXAMPLE 4
[0068] A one day disposable hydrogel-containing contact lens is wet
cast molded in a polypropylene mold as follows. A monomer mixture
of 98% by weight of 2-hydroxyethyl methacrylate, 1.6% by weight
methacrylic acid and 0.4% by weight of ethylene glycol
dimethacrylate is formed together with an effective amount of a
conventional thermal initiator. This monomer is diluted by 50% by
weight with water soluble polyethylene glycol having a molecular
weight of about 1000. The diluted solution is added to a
polypropylene contact lens mold and is cured using thermal curing.
If desired, an ultraviolet light initiator can be included in place
of the thermal initiator, and the solution can be cured using
ultraviolet light curing. After curing, the lens is removed from
the mold and placed in a packaging system similar to a conventional
blister pack and hydrated with saline solution. The hydrated lens
is formed to have mechanical properties similar to a dry cast
molded lens.
EXAMPLE 4A
[0069] Alternately, and advantageously, the saline solution used in
the package is altered to include about 50% of the polyethylene
glycol, which is at substantial equilibrium with both the contact
lens and the saline solution in the package. The use of this
polyethylene glycol in the saline solution is effective to reduce,
or even substantially eliminate, the polyethylene glycol from
diffusing out of the contact lens during storage in the
package.
EXAMPLE 5
[0070] A one day disposable hydrogel-containing contact lens is wet
cast molded in a polypropylene mold as follows. A mixture of 48.8%
by weight of 2-hydroxyethyl methacrylate, 0.5% by weight
methacrylic acid, 0.7% by weight of a cross-linking component sold
under the tradename Craynor 435 and 50% by weight of methyl
terminated polyethylene glycol having a molecular weight of about
350 (PEGME-350) is formed together with an effective amount of a
conventional thermal initiator. This mixture is added to a
polypropylene contact lens mold and is cured using thermal curing.
If desired, an ultraviolet light initiator can be included in place
of the thermal initiator, and the mixture can be cured using
ultraviolet light curing. After curing, the lens is removed from
the mold and placed in a packaging system similar to a conventional
blister pack and hydrated with saline solution. The hydrated lens
is formed to have mechanical properties similar to a dry cast
molded lens.
EXAMPLE 5A
[0071] Alternately, and advantageously, the saline solution used in
the package is altered to include about 50% of the PEGME-350, which
is at substantial equilibrium with both the contact lens and the
saline solution in the package. The use of this methyl terminated
polyethylene glycol in the saline solution is effective to reduce,
or even substantially eliminate, the methyl terminated polyethylene
glycol from diffusing out of the contact lens during storage in the
package.
EXAMPLE 6
[0072] A one day disposable hydrogel-containing contact lens is wet
cast molded in a polypropylene mold as follows. A mixture of 37.3%
by weight of 2-hydroxyethyl methacrylate, 0.6% by weight
methacrylic acid, 0.2% by weight of ethylene glycol dimethacrylate,
30.8% by weight of polyethylene glycol having a molecular weight of
about 300 and 31.1% by weight of deionized water is formed together
with an effective amount of a conventional thermal initiator. The
mixture is added to a polypropylene contact lens mold and is cured
using thermal curing. If desired, an ultraviolet light initiator
can be included in place of the thermal initiator, and the mixture
can be cured using ultraviolet light curing. After curing, the lens
is removed from the mold and placed in a packaging system similar
to a conventional blister pack and hydrated with saline solution.
The hydrated lens is formed to have mechanical properties similar
to a dry cast molded lens.
EXAMPLE 6A
[0073] Alternately, and advantageously, the saline solution used in
the package is altered to include about 30.8% of the polyethylene
glycol, which is at substantial equilibrium with both the contact
lens and the saline solution in the package. The use of this
polyethylene glycol in the saline solution is effective to reduce,
or even substantially eliminate, the polyethylene glycol from
diffusing out of the contact lens during storage in the
package.
EXAMPLE 7 TO 18
[0074] Each of twelve (12) patients removes a different one of the
lenses produced in accordance with Examples 1 to 6 and 1A to 6A
from the solution and places it on his/her eye. In each case, while
the lens is on the patient's eye, the polyethylene glycol or methyl
terminated polyethylene glycol diffuses out of the lens and into
the eye, thereby advantageously increasing the lubrication of the
cornea and the eyelid of the eye.
[0075] If the patient was to remove the lens, place it into a
saline solution and wear it again the next day, the lens would be
significantly less comfortable to wear due to the loss of the
polyethylene glycol, or methyl terminated polyethylene glycol and
the loss of lubrication. In addition, because of the loss of the
polyethylene glycol, or methyl terminated polyethylene glycol, the
lens has less modulus or strength and appears more "floppy" after
the lens is worn in the eye. In effect, the loss of the
polyethylene glycol, or methyl terminated polyethylene glycol from
the contact lens creates a trigger mechanism and/or provides an
indication to the patient to be compliant with the one day
disposable modality.
[0076] While this invention has been described with respect to
various specific examples and embodiments, it is to be understood
that the invention is not limited thereto and that it can be
variously practiced within the scope of the following claims.
* * * * *