U.S. patent application number 12/244333 was filed with the patent office on 2009-06-11 for method for treating ophthalmic lenses.
Invention is credited to Brendan Boland, John J. Cardiff, Richard Connolly, Ger M. Reynolds, Eoin Roche.
Application Number | 20090145086 12/244333 |
Document ID | / |
Family ID | 40373432 |
Filed Date | 2009-06-11 |
United States Patent
Application |
20090145086 |
Kind Code |
A1 |
Reynolds; Ger M. ; et
al. |
June 11, 2009 |
METHOD FOR TREATING OPHTHALMIC LENSES
Abstract
A method of treating an ophthalmic lens in a package involves:
placing the lens and an aqueous solution in a recess of package,
the solution including an organic surface treatment agent that
attaches to anterior and posterior surfaces of the lens; and
sealing the recess of the package with lidstock and sterilizing the
package contents. The bottom of the recess includes raised
projections.
Inventors: |
Reynolds; Ger M.;
(Waterford, IE) ; Roche; Eoin; (Waterford, IE)
; Connolly; Richard; (Kilkenny, IE) ; Cardiff;
John J.; (Waterford, IE) ; Boland; Brendan;
(Waterford, IE) |
Correspondence
Address: |
Bausch & Lomb Incorporated
One Bausch & Lomb Place
Rochester
NY
14604-2701
US
|
Family ID: |
40373432 |
Appl. No.: |
12/244333 |
Filed: |
October 2, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61012855 |
Dec 11, 2007 |
|
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Current U.S.
Class: |
53/440 |
Current CPC
Class: |
B29D 11/00067 20130101;
B65B 25/008 20130101 |
Class at
Publication: |
53/440 |
International
Class: |
B65B 63/08 20060101
B65B063/08 |
Claims
1. A method of treating an ophthalmic lens in a package,
comprising: placing the lens and an aqueous solution in a recess of
package, the solution comprising an organic surface treatment agent
that attaches to anterior and posterior surfaces of the lens; and
sealing the recess of the package with lidstock and sterilizing the
package contents; wherein a bottom of the recess includes raised
projections.
2. The method of claim 1, wherein the surface treatment agent
attaches to the lens surfaces by at least one of covalent bonding,
ionic attachment, and hydrogen bonding.
3. The method of claim 1, wherein the surface treatment agent
attaches to the lens surfaces by covalent bonding.
4. The method of claim 1, wherein the lens surfaces are ionically
charged, and the surface treatment agent has an opposite, ionic
charge.
5. The method of claim 1, wherein the package contents are
sterilized by autoclaving, and autoclaving effects attachment of
the surface treatment agent to the lens surfaces.
6. The method of claim 1, wherein attachment of the surface
treatment agent is effected by heating the solution while in
contact with the lens surfaces in the recess.
7. The method of claim 1, wherein the anterior surface of the lens
contacts a portion of the raised projections.
8. The method of claim 1, wherein the projections have a height of
at least 0.2 mm.
9. The method of claim 8, wherein the projections have a height of
at least 0.4 mm.
10. The method of claim 1, wherein the recess has a depth greater
than a height of the lens, and a sufficient volume of solution is
placed in the recess so that the lens is completely immersed in the
solution.
11. The method of claim 10, where the volume of the solution is at
least 0.5 ml.
12. The method of claim 11, where the volume of the solution is at
least 1 ml.
13. The method of claim 1, wherein the lens is a hydrogel contact
lens.
14. The method of claim 1, wherein the lens is a silicone hydrogel
contact lens.
15. The method of claim 1, wherein after placing the lens and the
solution in the recess of the package, the recess is sealed with
the lidstock without removing the solution.
16. The method of claim 1, wherein after placing the lens and the
solution in the recess of the package, the solution is removed with
a portion of the surface treatment agent remaining attached to the
lens surface, and an aqueous packaging solution is added to the
recess prior to sealing the recess with lidstock.
17. The method of claim 1, wherein the bottom includes several
parallel, longitudinal projections thereon.
18. The method of claim 1, wherein the bottom includes several
raised dot-like bumps.
Description
BACKGROUND OF THE INVENTION
[0001] This application claims benefit of provisional patent
application No. 61/012,855 filed on Dec. 11, 2007 which is
incorporated by reference herein.
[0002] This invention provides a method for treating ophthalmic
lenses in its package with an organic surface treatment agent.
[0003] It is often desired to improve the surface characteristics
of an ophthalmic lens. For example, in the case of intraocular
lenses, the surfaces of the lenses may be rendered more
biocompatible, for the purpose of reducing or eliminating
epithelial cell growth on the lens. Also, intraocular lenses are
often placed in the eye with an intraocular lens inserter which has
surfaces that contact the lens while it is extruded against these
surfaces; the lens surfaces may be modified to become more
lubricious so as to lower the coefficient of friction for
contacting the lens inserted. In the case of contact lenses, the
lens surfaces may be made more wettable by tear film or less
resistant to protein and/or lipid deposits from tear film, and more
comfortable during wear. With respect to silicon-containing lenses,
the lens surfaces have a higher tendency to be hydrophobic with
lower wettability, so often a surface treatment is desirable to
increase the surface wettability is desired. Various methods of
changing the surface characteristics of ophthalmic lenses are known
that involve attaching a treatment agent to the lens surfaces.
[0004] A conventional manner of packaging ophthalmic lenses,
especially contact lenses, is in a so-called blister package. Such
packages include a recess designed to hold an individual lens,
which is typically immersed in a saline packaging solution. The
packages are then enclosed and sealed with lidstock, the lidstock
conventionally being a metallic laminate that can withstand
post-packaging heat sterilization conditions. The packaging
solution may include various agents. As one example, because the
lens material may tend to stick to itself and to the lens package,
packaging solutions for blister packages have sometimes been
formulated to reduce or eliminate lens folding and sticking. For
this reason, polyvinyl alcohol (PVA) has been used in contact lens
packaging solutions. Additionally, U.S. Pat. No. 6,440,366
discloses contact lens packaging solutions comprising polyethylene
oxide (PEO)/polypropylene oxide (PPO) block copolymers, especially
poloxamers or poloxamines.
[0005] Various blister packages are known. Known blister packages
include recesses that are concave, recesses that are flat-bottomed,
and recesses that are partially concave with a flat bottom. One
specific example is a blister package with a flat bottom having
four parallel, longitudinal grooves therein, which is used to
package various contact lenses sold by Bausch & Lomb
Incorporated (Rochester, N.Y., USA). Other specific examples may be
found in U.S. Pat. Nos. 5,842,325; 5,722,536; 5,467,868;
2004/0031701; 2004/0004008; 2002/0046958; 6,072,172; 5,143,660; and
6,889,825.
SUMMARY OF THE INVENTION
[0006] This invention provides of a method of treating an
ophthalmic lens in a package, comprising: placing the lens and an
aqueous solution in a recess of package, the solution comprising an
organic surface treatment agent that attaches to anterior and
posterior surfaces of the lens; and sealing the recess of the
package with lidstock and sterilizing the package contents; wherein
a bottom of the recess includes raised projections.
[0007] This invention recognized that it may be desirable to effect
attachment of the treatment agent to the lens surfaces while the
lens is contained in a package, for example, to reduce material
handling steps and the accompanying costs associated therewith. And
if one employs a solution, containing the treatment agent, that is
ophthalmically compatible, this solution may serve as the final
packaging solution, and the heat sterilization of the package and
its contents can serve to effect chemical attachment of the
treatment agent to the lens surfaces.
[0008] However, problems were encountered in that the surfaces of
the lens were not uniformly coated with the treatment agent,
especially the lens surface in contact with the recess bottom.
These problems may be overcome by employing packages with recesses
including raised projections on the bottoms thereof, to ensure
better flow of the solution around the lens surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a top perspective view of a first embodiment of a
lens blister package suitable for the method of this invention.
[0010] FIG. 2 is a bottom perspective view of the lens blister
package of FIG. 1.
[0011] FIG. 3 is a top plan view of the lens blister package of
FIG. 1.
[0012] FIG. 4 is a cross-sectional view of the lens blister package
of FIG. 1, taken along line B-B of FIG. 3.
[0013] FIG. 5 is a top plan view of a second embodiment of a lens
blister package suitable for the method of this invention.
[0014] FIG. 6 is a top plan view of a third embodiment of a lens
blister package suitable for the method of this invention.
[0015] FIG. 7 is a cross-section view of the lens blister package
of FIG. 6, taken along line C-C.
[0016] FIG. 8 is a top plan view of a fourth embodiment of a lens
blister package suitable for the method of this invention.
[0017] FIG. 9 is a cross-section view of the lens blister package
of FIG. 8, taken along line D-D.
DETAILED DESCRIPTION OF VARIOUS PREFERRED EMBODIMENTS
[0018] This invention provides a method of treating an ophthalmic
lens in a package. The method comprises: placing the lens and an
aqueous solution in a recess of package, the solution comprising an
organic surface treatment agent that attaches to anterior and
posterior surfaces of the lens; and sealing the recess of the
package with lidstock and sterilizing the package contents; wherein
a bottom of the recess includes raised projections.
[0019] The term "ophthalmic lens" means a lens intended for direct
contact with ophthalmic tissue, including contact lenses and
intraocular lenses. In the following description, the process is
discussed with particular reference to silicone hydrogel contact
lenses, a preferred embodiment of this invention, but the invention
may be employed for surface treating other polymeric biomedical
devices.
[0020] Hydrogels comprise a hydrated, crosslinked polymeric system
containing water in an equilibrium state. Accordingly, hydrogels
are copolymers prepared from hydrophilic monomers. In the case of
silicone hydrogels, the hydrogel copolymers are generally prepared
by polymerizing a mixture containing at least one lens-forming
silicone-containing monomer and at least one lens-forming
hydrophilic monomer. Either the silicone-containing monomer or the
hydrophilic monomer may function as a crosslinking agent (a
crosslinking agent being defined as a monomer having multiple
polymerizable functionalities), or alternately, a separate
crosslinking agent may be employed in the initial monomer mixture
from which the hydrogel copolymer is formed. (As used herein, the
term "monomer" or "monomeric" and like terms denote relatively low
molecular weight compounds that are polymerizable by free radical
polymerization, as well as higher molecular weight compounds also
referred to as "prepolymers", "macromonomers", and related terms.)
Silicone hydrogels typically have a water content between about 10
to about 80 weight percent.
[0021] Examples of useful lens-forming hydrophilic monomers
include: amides such as N,N-dimethylacrylamide and
N,N-dimethylmethacrylamide; cyclic lactams such as
N-vinyl-2-pyrrolidone; (meth)acrylated alcohols, such as
2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate and glyceryl
methacrylate; (meth)acrylated poly(ethylene glycol)s; (meth)acrylic
acids such as methacrylic acid and acrylic acid; and
azlactone-containing monomers, such as
2-isopropenyl-4,4-dimethyl-2-oxazolin-5-one and
2-vinyl-4,4-dimethyl-2-oxazolin-5-one. (As used herein, the term
"(meth)" denotes an optional methyl substituent. Thus, terms such
as "(meth)acrylate" denotes either methacrylate or acrylate, and
"(meth)acrylic acid" denotes either methacrylic acid or acrylic
acid.) Still further examples are the hydrophilic vinyl carbonate
or vinyl carbamate monomers disclosed in U.S. Pat. No. 5,070,215,
and the hydrophilic oxazolone monomers disclosed in U.S. Pat. No.
4,910,277, the disclosures of which are incorporated herein by
reference. Other suitable hydrophilic monomers will be apparent to
one skilled in the art.
[0022] Applicable silicone-containing monomeric materials for use
in the formation of silicone hydrogels are well known in the art
and numerous examples are provided in U.S. Pat. Nos. 4,136,250;
4,153,641; 4,740,533; 5,034,461; 5,070,215; 5,260,000; 5,310,779;
and 5,358,995.
[0023] Examples of applicable silicone-containing monomers include
bulky polysiloxanylalkyl(meth)acrylic monomers. An example of such
monofunctional, bulky polysiloxanylalkyl(meth)acrylic monomers are
represented by the following Formula I:
##STR00001##
[0024] wherein:
[0025] X denotes --O-- or --NR--;
[0026] each R.sub.1 independently denotes hydrogen or methyl;
[0027] each R.sub.2 independently denotes a lower alkyl radical,
phenyl radical or a group represented by
##STR00002##
[0028] wherein each R.sub.2' independently denotes a lower alkyl or
phenyl radical; and h is 1 to 10. One preferred bulky monomer is
3-methacryloxypropyl tris(trimethyl-siloxy)silane or
tris(trimethylsiloxy)silylpropyl methacrylate, sometimes referred
to as TRIS.
[0029] Another class of representative silicone-containing monomers
includes silicone-containing vinyl carbonate or vinyl carbamate
monomers such as:
1,3-bis[4-vinyloxycarbonyloxy)but-1-yl]tetramethyldisiloxane;
1,3-bis[4-vinyloxycarbonyloxy)but-1-yl]polydimethylsiloxane;
3-(trimethylsilyl)propyl vinyl carbonate;
3-(vinyloxycarbonylthio)propyl[tris(trimethylsiloxy)silane];
3-[tris(trimethylsiloxy)silyl]propyl vinyl carbamate;
3-[tris(trimethylsiloxy)silyl]propyl allyl carbamate;
3-[tris(trimethylsiloxy)silyl]propyl vinyl carbonate;
t-butyldimethylsiloxyethyl vinyl carbonate; trimethylsilylethyl
vinyl carbonate; and trimethylsilylmethyl vinyl carbonate.
[0030] An example of silicone-containing vinyl carbonate or vinyl
carbamate monomers are represented by Formula II:
##STR00003##
wherein:
[0031] Y' denotes --O--, --S-- or --NH--;
[0032] R.sup.Si denotes a silicone-containing organic radical;
[0033] R.sub.3 denotes hydrogen or methyl;
[0034] d is 1, 2, 3 or 4; and q is 0 or 1.
[0035] Suitable silicone-containing organic radicals R.sup.Si
include the following:
##STR00004##
wherein:
[0036] R.sub.4 denotes
##STR00005##
wherein p' is 1 to 6;
[0037] R.sub.5 denotes an alkyl radical or a fluoroalkyl radical
having 1 to 6 carbon atoms;
[0038] e is 1 to 200; n' is 1, 2, 3 or 4; and m' is 0, 1, 2, 3, 4
or 5.
[0039] An example of a particular species within Formula II is
represented by Formula III:
##STR00006##
[0040] Another class of silicone-containing monomers includes
polyurethane-polysiloxane macromonomers (also sometimes referred to
as prepolymers), which may have hard-soft-hard blocks like
traditional urethane elastomers. Examples of silicone urethane
monomers are represented by Formulae IV and V:
E(*D*A*D*G)a*D*A*D*E'; or (IV)
E(*D*G*D*A)a*D*G*D*E'; (V)
wherein:
[0041] D denotes an alkyl diradical, an alkyl cycloalkyl diradical,
a cycloalkyl diradical, an aryl diradical or an alkylaryl diradical
having 6 to 30 carbon atoms;
[0042] G denotes an alkyl diradical, a cycloalkyl diradical, an
alkyl cycloalkyl diradical, an aryl diradical or an alkylaryl
diradical having 1 to 40 carbon atoms and which may contain ether,
thio or amine linkages in the main chain;
[0043] * denotes a urethane or ureido linkage;
[0044] a is at least 1;
[0045] A denotes a divalent polymeric radical of Formula VI:
##STR00007##
wherein:
[0046] each R.sub.s independently denotes an alkyl or
fluoro-substituted alkyl group having 1 to 10 carbon atoms which
may contain ether linkages between carbon atoms;
[0047] m' is at least 1; and
[0048] p is a number which provides a moiety weight of 400 to
10,000;
[0049] each of E and E' independently denotes a polymerizable
unsaturated organic radical represented by Formula VII:
##STR00008##
wherein:
[0050] R.sub.6 is hydrogen or methyl;
[0051] R.sub.7 is hydrogen, an alkyl radical having 1 to 6 carbon
atoms, or a --CO--Y--R.sub.9 radical wherein Y is --O--, --S-- or
--NH--;
[0052] R.sub.8 is a divalent alkylene radical having 1 to 10 carbon
atoms;
[0053] R.sub.9 is a alkyl radical having 1 to 12 carbon atoms;
[0054] X denotes --CO-- or --OCO--;
[0055] Z denotes --O-- or --NH--;
[0056] Ar denotes an aromatic radical having 6 to 30 carbon
atoms;
[0057] w is 0 to 6; x is 0 or 1; y is 0 or 1; and z is 0 or 1.
[0058] A more specific example of a silicone-containing urethane
monomer is represented by Formula (VIII):
##STR00009##
[0059] wherein m is at least 1 and is preferably 3 or 4, a is at
least 1 and preferably is 1, p is a number which provides a moiety
weight of 400 to 10,000 and is preferably at least 30, R.sub.10 is
a diradical of a diisocyanate after removal of the isocyanate
group, such as the diradical of isophorone diisocyanate, and each
E'' is a group represented by:
##STR00010##
[0060] A preferred silicone hydrogel material comprises (based on
the initial monomer mixture that is copolymerized to form the
hydrogel copolymeric material) 5 to 50 percent, preferably 10 to
25, by weight of one or more silicone macromonomers, 5 to 75
percent, preferably 30 to 60 percent, by weight of one or more
polysiloxanylalkyl (meth)acrylic monomers, and 10 to 50 percent,
preferably 20 to 40 percent, by weight of a hydrophilic monomer. In
general, the silicone macromonomer is a poly(organosiloxane) capped
with an unsaturated group at two or more ends of the molecule. In
addition to the end groups in the above structural formulas, U.S.
Pat. No. 4,153,641 to Deichert et al. discloses additional
unsaturated groups, including acryloxy or methacryloxy.
Fumarate-containing materials such as those taught in U.S. Pat.
Nos. 5,512,205; 5,449,729; and 5,310,779 to Lai are also useful
substrates in accordance with the invention. Preferably, the silane
macromonomer is a silicone-containing vinyl carbonate or vinyl
carbamate or a polyurethane-polysiloxane having one or more
hard-soft-hard blocks and end-capped with a hydrophilic
monomer.
[0061] Specific examples of contact lens materials for which the
present invention is useful are taught in U.S. Pat. No. 6,891,010
(Kunzler et al.); U.S. Pat. No. 5,908,906 (Kunzler et al.); U.S.
Pat. No. 5,714,557 (Kunzler et al.); U.S. Pat. No. 5,710,302
(Kunzler et al.); U.S. Pat. No. 5,708,094 (Lai et al.); U.S. Pat.
No. 5,616,757 (Bambury et al.); U.S. Pat. No. 5,610,252 (Bambury et
al.); U.S. Pat. No. 5,512,205 (Lai); U.S. Pat. No. 5,449,729 (Lai);
U.S. Pat. No. 5,387,662 (Kunzler et al.); U.S. Pat. No. 5,310,779
(Lai); and U.S. Pat. No. 5,260,000 (Nandu et al.), the disclosures
of which are incorporated herein by reference.
[0062] Generally, the monomer mixtures may be charged to a mold,
and then subjected to heat and/or light radiation, such as UV
radiation, to effect curing, or free radical polymerization, of the
monomer mixture in the mold. Various processes are known for curing
a monomeric mixture in the production of contact lenses or other
biomedical devices, including spincasting and static casting.
Additionally, the monomer mixtures may be cast in the shape of rods
or buttons, which are then lathe cut into a desired shape, for
example, into a lens-shaped article.
[0063] Following casting of the lens, the article may be extracted
to remove undesired extractables from the device. For example, in
the case of contact lenses made from a silicone hydrogel copolymer,
extractables include any remaining diluent, unreacted monomers, and
oligomers formed from side reactions of the monomers.
[0064] Then, the lens is hydrated, either as part of the extraction
process, or in a separate subsequent operation. For example, if an
organic solvent is used to extract the lens, then the lens is
hydrated to replace the organic solvent with water or aqueous
solution. Hydration may be performed while the lens is held in its
package, or prior to placing the lens in the package. In any event,
ultimately, the lens is contained in the package with an aqueous
packaging solution.
[0065] This invention recognized the desirability of effecting
attachment of the treatment agent to the lens surfaces while the
lens is contained in a package, in contrast to effecting attachment
prior to placing the lens in the package. This offers a reduction
in material handling steps and the accompanying costs associated
therewith. Also, if the solution containing the treatment agent is
ophthalmically compatible, this solution may serve as the final
packaging solution, and the heat sterilization of the package and
its contents can serve to effect chemical attachment of the
treatment agent to the lens surfaces.
[0066] As used herein, "attachment" of the treatment agent to the
lens surface, and like terms, denotes that the treatment agent is
substantially adhered to the lens surfaces. Thus, after a single
rinsing with water of the lens surfaces with the treatment agent
attached thereto, at least 50% of the treatment agent will remain
adhered to the lens surfaces.
[0067] It is preferred that the surface treatment agent is attached
to the lens surfaces by at least one of covalent bonding, ionic
attachment, and hydrogen bonding. Covalent bonding denotes that a
chemical reaction occurs between the treatment agent and the lens
surface, so that covalent bonds are formed therebetween. Ionic
attachment denotes that the lens surfaces are ionically charged,
and the organic surface treatment agent contains moieties with an
opposite, ionic charge. As an example the lens surfaces may be
anionic charged, and the treatment agent may be cationic or
zwitterionic, that interacts with the anionic lens surface.
[0068] A wide variety of organic surface treatment agents may be
employed, including treatment agents known in the art.
[0069] As a first example, this invention is applicable for the
organic surface treatment agents described in U.S. Pat. No.
7,083,646, the entire disclosure of which is incorporated herein by
reference. Generally, this method involves surface modification of
medical devices, particularly ophthalmic lenses, with one or more
reactive, hydrophilic polymers as the surface treatment agent. The
reactive, hydrophilic polymers are copolymers of at least one
hydrophilic monomer and at least one monomer that contains reactive
chemical functionality. The hydrophilic monomers can be aprotic
types such as N,N-dimethylacrylamide and N-vinylpyrrolidone, or
protic types such as methacrylic acid and 2-hydroxyethyl
methacrylate. The monomer containing reactive chemical
functionality can be an epoxide-containing monomer, such as
glycidyl methacrylate. The hydrophilic monomer and the monomer
containing reactive chemical functionality are copolymerized at a
desired molar ratio thereof. The hydrophilic monomer serves to
render the resultant copolymer hydrophilic. The monomer containing
reactive chemical functionality provides a reactive group that can
react with the lens surface. In other words, this resultant
copolymer contains the reactive chemical functionality that can
react with complementary functional groups at or near the lens
surface, and form covalent bonds therewith.
[0070] As a second example, this invention is applicable for the
organic surface treatment agents described in US 2007/0122540, the
entire disclosure of which is incorporated herein by reference.
Generally, this method involves surface modification of medical
devices, particularly ophthalmic lenses, where reactive surfactants
as the surface treatment agent are covalently bound to the lens
surfaces. Preferred reactive surfactants are functionalized
poloxamers or functionalized poloxamines having reactive
functionality that is complimentary to surface functionality of the
ophthalmic lens. Representative functionalized surfactants are
those containing epoxide, methacrylate, or isocyanate
functionalities, such as represented below.
##STR00011##
[0071] For the aforementioned methods where the surface treatment
agent is covalently bonded to the lens surface, the reactive groups
of the treatment agent are matched with the reactive groups on the
lens surface. For example, if the lens surfaces contain carboxylic
acid groups, a glycidyl group can be a reactive group of the
surface treatment agent. If the lens surfaces contain hydroxy or
amino functionality, an isocyanate group or carbonyl chloride group
can be a reactive group of the surface treatment agent. A wide
variety of suitable combinations of reactive groups will be
apparent to those of ordinary skill in the art.
[0072] Examples of suitable lens-forming monomers, providing
reactive groups on the lens surface, include those having hydroxy
functional groups, such as 2-hydroxyethyl methacrylate, glyceryl
methacrylate and 3-hydroxypropyl methacrylamide. Examples of
suitable lens-forming monomers providing the lens surfaces with
carboxylic acid reactive groups include methacrylic acid, acrylic
acid and N-carboxy-.beta.-alanine-N-vinyl ester. Examples of
suitable lens-forming monomers providing the lens surface with
oxazolinone reactive groups include
2-isopropenyl-4,4-dimethyl-2-oxazolin-5-one,
2-vinyl-4,4-dimethyl-2-oxazolin-5-one,
spiro-4'-(2'-isopropenyl-2'-oxazolin-5-one)cyclohexane,
spiro-4'-(2'-vinyl-2'-oxazolin-5'-one)cyclohexane and
2-(1-propenyl)-4,4-dimethyl-oxazolin-5-one. Examples of suitable
lens-forming monomers providing the lens surface with anhydride
functional groups include methacrylic anhydride, maleic anhydride
and acrylic anhydride. An example of a suitable lens-forming
monomer providing the lens surfaces with epoxide reactive groups
includes glycidyl methacrylate.
[0073] As another example, the surface treatment agent may be one
as employed in the method described in U.S. Pat. No. 6,428,839
(Kunzler et al.), the entire disclosure of which is incorporated
herein by reference. Generally, this method employs
poly(acrylic)acid (PAA) surface complexation. Hydrogel contact lens
copolymers containing polymerized hydrophilic lens-forming monomers
having relatively strong proton donating moieties, for example DMA
or NVP, are treated with water-based solutions containing PAA or
PAA co-polymers, acting as wetting agents, to render a lubricious,
stable, highly wettable PAA-based surface coating. Alternately,
other proton-donating wetting agents besides PAA-containing agents
may be employed, although generally, coating materials containing
carboxylic acid functionality are preferred. Surface treatment
agents include poly(vinylpyrrolidinone(VP)-co-acrylic acid(AA)),
poly(methylvinylether-alt-maleic acid), poly(acrylic
acid-graft-ethyleneoxide), poly(AA-co-methacrylic acid),
poly(acrylamide-co-AA), poly(AA-co-maleic), and
poly(butadiene-maleic acid). Particularly preferred polymers are
characterized by acid contents of at least about 30 mole percent,
preferably at least about 40 mole percent. The lens, with its
surface in contact with the PAA-containing solution, may be heated
by autoclaving, or subjected to microwave radiation, to facilitate
attachment of the PAA to the lens surface.
[0074] Other organic surface treatment agents will be apparent to
one skilled in the art.
[0075] There are various variations of the sequence of steps
employed in the methods of this invention.
[0076] As a first example, after placing the lens and the solution
containing the treatment agent in the recess of the package, the
recess is sealed with the lidstock without removing the solution.
In other words, according to this embodiment, this solution also
serves as the final packaging solution, and this solution is
ophthalmically compatible. Then, when the package contents are heat
sterilized, this heat treatment can serve to effect chemical
attachment of the treatment agent to the lens surfaces, if needed.
Any excess treatment agent, not attached to the lens surfaces,
remains in the final packaging solution.
[0077] As a second example, after placing the lens and the solution
containing the treatment agent in the recess of the package, this
solution is removed with a portion of the organic treatment agent
remaining attached to the lens surface. Any excess treatment agent
is removed with the solution. If heat treatment is needed to effect
chemical attachment of the treatment agent to the lens surfaces,
the heat treatment is performed prior to removing this solution
from the package recess. Subsequently, after removing this
solution, an aqueous packaging solution is added to the recess,
followed by sealing the recess with lidstock and sterilizing the
package contents.
[0078] The final packaging solution is an aqueous solution,
preferably a saline solution. having a pH value within the range of
about 6 to about 8, and preferably about 6.5 to about 7.8. Suitable
buffers may be included, such as: phosphate; borate; citrate;
carbonate; tris-(hydroxymethyl)aminomethane (TRIS);
bis(2-hydroxyethyl)-imino-tris-(hydroxymethyl)aminoalcohol
(bis-tris); zwitterionic buffers such as
N-[2-Hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine (Tricine)and
N-[2-Hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine, MOPS;
N-(Carbamoylmethyl)taurine (ACES); amino acids and amino acid
derivatives; and mixtures thereof. Generally, buffers will be used
in amounts ranging from about 0.05 to about 2.5 percent by weight,
and preferably from about 0.1 to about 1.5 percent by weight of the
solution. If needed, the solutions of the present invention may be
adjusted with tonicity agents, to approximate the osmotic pressure
of normal lacrimal fluids, which is equivalent to a 0.9 percent
solution of sodium chloride or 2.5 percent of glycerol solution.
The solutions are made substantially isotonic with physiological
saline used alone or in combination, otherwise if simply blended
with sterile water and made hypotonic or made hypertonic the lenses
will lose their desirable optical parameters. Correspondingly,
excess saline may result in the formation of a hypertonic solution,
which will cause stinging, and eye irritation. Examples of suitable
tonicity adjusting agents include, but are not limited to, sodium
and potassium chloride, dextrose, calcium and magnesium chloride
and the like and mixtures thereof. These agents are typically used
individually in amounts ranging from about 0.01 to about 2.5% w/v
and preferably from about 0.2 to about 1.5% w/v. Preferably, the
tonicity agent will be employed in an amount to provide a final
osmotic value of at least about 200 mOsm/kg, preferably from about
200 to about 450 mOsm/kg, more preferably from about 250 to about
400 mOsm/kg, and most preferably from about 280 to about 370
mOsm/kg.
[0079] Representative blister packages that may be employed in the
method of this invention are illustrated in FIGS. 1 to 9.
[0080] FIGS. 1 to 4 illustrate a first embodiment of a blister
package. Package 1 includes a substrate 3 including recess 2 formed
therein, recess 2 sized and configured to hold an individual
contact lens 5 therein. In the illustrated embodiment, recess 2 is
a concave recess with a flat bottom 6. Bottom 6 includes three
parallel, longitudinal ridges 7 thereon. Ridges 7 preferably have a
height of at least 0.2 mm, more preferably at least 0.4 mm. As seen
in FIG. 4, the anterior surface of contact lens 5 rests on at least
one of ridges 7 when the package is oriented as in FIG. 4. Without
these ridges, the anterior lens surface would rest on flat bottom
6, which could lead to non-uniform coating of the contact lens,
especially this anterior surface of the lens.
[0081] After contacting the contact lens with the treatment agent
solution, contact lens 5 is contained in recess 2 and immersed in
solution. Recess 2 is then sealed with lidstock, i.e., by sealing
the lidstock with heat to raised surface 9. The package and its
contents may now be sterilized, preferably by heat sterilization
such as autoclaving. Recess 2 has a depth greater than a height of
the lens, and a sufficiently large volume, that the lens is
completely immersed in the final packaging solution.
[0082] FIG. 5 illustrates a second embodiment of a blister package.
Package 11 includes a substrate 13 including recess 12 formed
therein. In this illustrated embodiment, recess 12 has a somewhat
oval-shaped flat bottom 16, and the bottom includes four
longitudinal ridges 17 thereon.
[0083] FIGS. 6 and 7 illustrates a third embodiment of a blister
package. Package 21 includes a substrate 23 including recess 22
formed therein. In this illustrated embodiment, recess 22 is a
concave recess, i.e., a rounded bowl shape. The bottom includes
five parallel, longitudinal ridges 27 thereon.
[0084] FIGS. 8 and 9 illustrates a fourth embodiment of a blister
package. Package 31 includes a substrate 33 including recess 32
formed therein. In this illustrated embodiment, recess 32 is a
concave recess, i.e., a rounded bowl shape, with multiple raised,
dot-like protrusions thereon.
[0085] Once the package recess contains the contact lens immersed
in the final packaging solution, the recess is then sealed with
lidstock, i.e., by sealing the lidstock with heat. As an example,
the lidstock is sealed to raised surface 9 in FIGS. 1 to 4. The
package and its contents may now be sterilized, preferably by heat
sterilization such as autoclaving. The recess has a depth greater
than a height of the lens, and a sufficiently large volume, that
the lens is completely immersed in the final packaging solution.
Preferably, the recess is filed with at least 0.5 ml of final
packaging solution, more preferably at least 1 ml, and most
preferably at least 1.2 ml.
[0086] While there is shown and described herein certain specific
structures and compositions and method steps of the present
invention, it will be apparent to those skilled in the art that
various modifications may be made without departing from the spirit
and scope of the underlying inventive concept and that the same is
not limited to particular structures herein shown and described
except insofar as indicated by the scope of the appended
claims.
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