U.S. patent application number 12/248222 was filed with the patent office on 2009-07-09 for packaging solutions.
Invention is credited to Yu-Chin Lai, Weihong Lang.
Application Number | 20090173045 12/248222 |
Document ID | / |
Family ID | 40790667 |
Filed Date | 2009-07-09 |
United States Patent
Application |
20090173045 |
Kind Code |
A1 |
Lai; Yu-Chin ; et
al. |
July 9, 2009 |
Packaging Solutions
Abstract
Packaging systems for storing ophthalmic devices such as contact
lenses and to methods for packaging such ophthalmic devices with
solutions to improve the comfort of the lenses during wear are
disclosed. A packaging system includes an ophthalmic device stored
in an aqueous packaging solution comprising a hydrophilic polymer
having one or more non-ethylenically-unsaturated carboxylic acid
terminal groups.
Inventors: |
Lai; Yu-Chin; (Pittsford,
NY) ; Lang; Weihong; (Amston, CT) |
Correspondence
Address: |
Bausch & Lomb Incorporated
One Bausch & Lomb Place
Rochester
NY
14604-2701
US
|
Family ID: |
40790667 |
Appl. No.: |
12/248222 |
Filed: |
October 9, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61019864 |
Jan 9, 2008 |
|
|
|
Current U.S.
Class: |
53/431 ;
206/5.1 |
Current CPC
Class: |
B65B 25/008 20130101;
A61L 12/086 20130101; B65B 55/02 20130101 |
Class at
Publication: |
53/431 ;
206/5.1 |
International
Class: |
A45C 11/04 20060101
A45C011/04; B65B 55/22 20060101 B65B055/22 |
Claims
1. A method of preparing a package comprising a storable, sterile
ophthalmic device, the method comprising: (a) immersing an
ophthalmic device in an aqueous packaging solution comprising one
or more hydrophilic polymers having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups,
wherein the solution has an osmolality of at least about 200
mOsm/kg and a pH in the range of about 6 to about 9; (b) packaging
the solution and the device in a manner preventing contamination of
the device by microorganisms; and (c) sterilizing the packaged
solution and device.
2. The method of claim 1, wherein the ophthalmic device is a
contact lens.
3. The method of claim 1, wherein the ophthalmic device is a
silicone hydrogel contact lens.
4. The method of claim 1, wherein the hydrophilic polymer comprises
one or more units derived from N-vinylpyrrolidone.
5. The method of claim 1, wherein the hydrophilic polymer comprises
one or more units derived from N-vinylpyrrolidone, alkylene oxides,
glyceryl methacrylate, glyceryl acrylate, dimethyl methacrylamide,
dimethyl acrylamide, 2-hydroxyethyl methacrylate, 2-hydroxyethyl
acrylate, erythritol methacrylate, erythritol acrylate, xylitol
methacrylate, xylitol acrylate, sorbitol methacrylate, sorbitol
acrylate, derivatives thereof or mixtures thereof.
6. The method of claim 1, wherein the hydrophilic polymer is a
reaction product of a hydroxyl-terminated oligomer or polymer
having a plurality of hydrophilic groups with a saturated, cyclic
anhydride.
7. The method of claim 6, wherein the hydroxyl-terminated oligomer
or polymer comprises one or more units derived from
N-vinylpyrrolidone.
8. The method of claim 6, wherein the saturated, cyclic anhydride
is selected from the group consisting of succinic anhydride,
glutaric anhydride, adipic anhydride and mixtures thereof.
9. The method of claim 1, wherein the hydrophilic polymer has one
non-ethylenically-unsaturated carboxylic acid terminated group.
10. The method of claim 1, wherein the hydrophilic polymer is
terminated on each end with a non-ethylenically-unsaturated
carboxylic acid terminal group.
11. The method of claim 1, wherein the concentration of the
hydrophilic polymer in the aqueous packaging solution is about 0.01
to about 10% w/w.
12. The method of claim 1, wherein the solution does not contain an
effective disinfecting amount of a disinfecting agent.
13. The method of claim 1, wherein the solution does not contain a
germicide compound.
14. A packaging system for the storage of an ophthalmic device
comprising a sealed container containing one or more unused
ophthalmic device immersed in an aqueous packaging solution
comprising one or more hydrophilic polymers having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups,
wherein the solution has an osmolality of at least about 200
mOsm/kg, a pH of about 6 to about 9 and is heat sterilized.
15. The packaging system of claim 14, wherein the ophthalmic device
is a contact lens.
16. The packaging system of claim 14, wherein the hydrophilic
polymer comprises one or more units derived from
N-vinylpyrrolidone.
17. The packaging system of claim 14, wherein the hydrophilic
polymer comprises one or more units derived from
N-vinylpyrrolidone, alkylene oxides, glyceryl methacrylate,
glyceryl acrylate, dimethyl methacrylamide, dimethyl acrylamide,
2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, erythritol
methacrylate, erythritol acrylate, xylitol methacrylate, xylitol
acrylate, sorbitol methacrylate, sorbitol acrylate, derivatives
thereof or mixtures thereof.
18. The packaging system of claim 14, wherein the hydrophilic
polymer is a reaction product of a hydroxyl-terminated oligomer or
polymer having a plurality of hydrophilic groups with a saturated,
cyclic anhydride.
19. The packaging system of claim 18, wherein the
hydroxyl-terminated oligomer or polymer comprises one or more units
derived from N-vinylpyrrolidone.
20. The packaging system of claim 18, wherein the saturated, cyclic
anhydride is selected from the group consisting of succinic
anhydride, glutaric anhydride, adipic anhydride and mixtures
thereof.
21. The packaging system of claim 14, wherein the hydrophilic
polymer has one non-ethylenically-unsaturated carboxylic acid
terminated group.
22. The packaging system of claim 14, wherein the hydrophilic
polymer is terminated on each end with a
non-ethylenically-unsaturated carboxylic acid terminal group.
23. The packaging system of claim 14, wherein the solution does not
contain an effective disinfecting amount of a disinfecting
agent.
24. The packaging system of claim 14, wherein the solution does not
contain a germicide compound.
25. The packaging system of claim 14, wherein the package is heat
sterilized subsequent to sealing of the package.
Description
[0001] This application claims benefit of provisional patent
application No. 61/019,864 filed Jan. 9, 2008, which is
incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention generally relates to packaging
solutions for ophthalmic devices such as contact lenses.
[0004] 2. Description of Related Art
[0005] Blister-packs and glass vials are typically used to
individually package each soft contact lens for sale to a customer.
Saline or deionized water is commonly used to store the lens in the
blister-packs, as mentioned in various patents related to the
packaging or manufacturing of contact lenses. Because lens material
may tend to stick to itself and to the lens package, packaging
solutions for blister-packs 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.
[0006] It has been stated that if a lens is thoroughly cleaned
before insertion, lacrimal fluid can adequately wet the lens.
Furthermore, the difficulties of adding a surfactant to a packaging
solution, including the possibility of lowering shelf-life and/or
adverse reactions during heat sterilization, have further limited
the use of surfactants in a packaging solution for the purpose of
providing any possible or marginal effect on lens comfort. It is
only after a lens has been worn, when proteins or other deposits
have formed on the surface of the lens, that surfactants have been
used in standard lens-care solutions.
[0007] It is highly desirable that contact lens be as comfortable
as possible for wearers. Manufacturers of contact lenses are
continually working to improve the comfort of the lenses.
Nevertheless, many people who wear contact lenses still experience
dryness or eye irritation throughout the day and particularly
towards the end of the day. An insufficiently wetted lens at any
point in time will cause significant discomfort to the lens wearer.
Although wetting drops can be used as needed to alleviate such
discomfort, it would certainly be desirable if such discomfort did
not arise in the first place.
[0008] Poloxamine and poloxamers are examples of non-ionic
surfactants having one or more poly(oxyalkylene) chains.
Poloxamines and poloxamers are well-known wetting and lubricating
agents for contact lenses and have been used in lens wetting drops
and in lens-care solutions for treating lenses after use or while
in use in the eye. For example, U.S. Pat. No. 4,786,436 disclose
poloxamine as a wetting agent. Contact-lens rewetting drops
containing surfactants such as poloxamine and poloxamer have been
used to make contact lens wear more comfortable, to soothe the
eyes, and to moisten lenses to minimize dryness. Surfactants such
as poloxamine, poloxamer, and tyloxapol have been used in
multi-purpose solutions, for cleaning, wetting, and storing
lenses.
[0009] Certain combinations of poly(oxyalkylene) surfactants have
also been disclosed for use in the eye to preventively clean lenses
and inhibit deposits. For example, U.S. Pat. No. 5,209,865
discloses the combination of certain poloxamers and poloxamines to
maintain clean lenses in the eye.
[0010] U.S. Pat. No. 6,440,366 ("the '366 patent") discloses a
package containing a contact lens suitable for immediate use which
comprises (a) a solution comprising a non-ionic surfactant that is
a compound comprising at least 90 weight percent of
poly(oxyethylene) and poly(oxypropylene) segments, in one or more
block copolymer chains, and (b) an effective amount of a tonicity
adjusting agent such that the solution has an osmolality of 200 to
400 mOsm/kg; wherein the solution has a pH of about 6 to 8 and is
heat sterilized and lacks an effective disinfecting amount of a
disinfecting agent. The '366 patent further discloses that the
surfactant is a poly(oxypropylene)-poly(oxyethylene) adduct of
ethylene diamine.
[0011] It would be desirable to provide an improved packaging
system for ophthalmic devices such as a contact lens such that the
lens would be comfortable to wear in actual use and allow for
extended wear of the lens without irritation or other adverse
effects to the cornea.
SUMMARY OF THE INVENTION
[0012] In accordance with one embodiment of the present invention,
a method of preparing a package comprising a storable, sterile
ophthalmic device is provided comprising:
[0013] (a) immersing an ophthalmic device in an aqueous packaging
solution comprising a hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups,
wherein the solution has an osmolality of at least about 200
mOsm/kg and a pH in the range of about 6 to about 9;
[0014] (b) packaging the solution and the ophthalmic device in a
manner preventing contamination of the device by microorganisms;
and
[0015] (c) sterilizing the packaged solution and ophthalmic
device.
[0016] In accordance with a second embodiment of the present
invention, a packaging system for the storage of an ophthalmic
device is provided comprising a sealed container containing one or
more unused ophthalmic devices immersed in an aqueous packaging
solution comprising a hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups,
wherein the solution has an osmolality of at least about 200
mOsm/kg, a pH of about 6 to about 9 and is heat sterilized.
[0017] In accordance with a third embodiment of the present
invention, a packaging system for the storage of an ophthalmic
device is provided comprising:
[0018] (a) an aqueous packaging solution comprising a hydrophilic
polymer having one or more non-ethylenically-unsaturated carboxylic
acid terminated groups, wherein the solution has an osmolality of
at least about 200 mOsm/kg and a pH in the range of about 6 to
about 9;
[0019] (b) at least one ophthalmic device; and
[0020] (c) a container for holding the solution and ophthalmic
device sufficient to preserve the sterility of the solution and
ophthalmic device, wherein the solution does not contain an
effective disinfecting amount of a disinfecting agent.
[0021] The aqueous packaging solutions of the present invention
containing at least a hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups is
believed to provide a more uniform coating on the surface of an
ophthalmic device such as a contact lens thereby resulting in
improved lubricity of the lens. Thus, the lens will be more
comfortable to wear in actual use and would allow for the extended
wear of the lens without irritation or other adverse effects to the
cornea.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] The present invention provides a packaging system for the
storage of ophthalmic devices intended for direct contact with body
tissue or body fluid. As used herein, the term "ophthalmic device"
refers to devices that reside in or on the eye. These lenses can
provide optical correction, wound care, drug delivery, diagnostic
functionality or cosmetic enhancement or effect or a combination of
these properties. Representative examples of such devices include,
but are not limited to, soft contact lenses, e.g., a soft, hydrogel
lens; soft, non-hydrogel lens and the like, hard contact lenses,
e.g., a hard, gas permeable lens material and the like, intraocular
lenses, overlay lenses, ocular inserts, optical inserts and the
like. As is understood by one skilled in the art, a lens is
considered to be "soft" if it can be folded back upon itself
without breaking.
[0023] The ophthalmic devices can be any material known in the art
capable of forming an ophthalmic device as described above. In one
embodiment, an ophthalmic device includes devices which are formed
from material not hydrophilic per se. Such devices are formed from
materials known in the art and include, by way of example,
polysiloxanes, perfluoropolyethers, fluorinated poly(meth)acrylates
or equivalent fluorinated polymers derived, e.g., from other
polymerizable carboxylic acids, polyalkyl (meth)acrylates or
equivalent alkylester polymers derived from other polymerizable
carboxylic acids, or fluorinated polyolefins, such as fluorinated
ethylene propylene polymers, or tetrafluoroethylene, preferably in
combination with a dioxol, e.g., perfluoro-2,2-dimethyl-1,3-dioxol.
Representative examples of suitable bulk materials include, but are
not limited to, Lotrafilcon A, Neofocon, Pasifocon, Telefocon,
Silafocon, Fluorsilfocon, Paflufocon, Silafocon, Elastofilcon,
Fluorofocon or Teflon AF materials, such as Teflon AF 1600 or
Teflon AF 2400 which are copolymers of about 63 to about 73 mol %
of perfluoro-2,2-dimethyl-1,3-dioxol and about 37 to about 27 mol %
of tetrafluoroethylene, or of about 80 to about 90 mol % of
perfluoro-2,2-dimethyl-1,3-dioxol and about 20 to about 10 mol % of
tetrafluoroethylene.
[0024] In another embodiment, an ophthalmic device includes devices
which are formed from material hydrophilic per se, since reactive
groups, e.g., carboxy, carbamoyl, sulfate, sulfonate, phosphate,
amine, ammonium or hydroxy groups, are inherently present in the
material and therefore also at the surface of an ophthalmic device
manufactured therefrom. Such devices are formed from materials
known in the art and include, by way of example, polyhydroxyethyl
acrylate, polyhydroxyethyl methacrylate (HEMA), polyvinyl
pyrrolidone (PVP), polyacrylic acid, polymethacrylic acid,
polyacrylamide, polydimethylacrylamide (DMA), polyvinyl alcohol and
the like and copolymers thereof, e.g., from two or more monomers
selected from hydroxyethyl acrylate, hydroxyethyl methacrylate,
N-vinyl pyrrolidone, acrylic acid, methacrylic acid, acrylamide,
dimethyl acrylamide, vinyl alcohol and the like. Representative
examples of suitable bulk materials include, but are not limited
to, Polymacon, Tefilcon, Methafilcon, Deltafilcon, Bufilcon,
Phemfilcon, Ocufilcon, Focofilcon, Etafilcon, Hefilcon, Vifilcon,
Tetrafilcon, Perfilcon, Droxifilcon, Dimefilcon, Isofilcon,
Mafilcon, Nelfilcon, Atlafilcon and the like. Examples of other
suitable bulk materials include balafilcon A, hilafilcon A,
alphafilcon A, bilafilcon B and the like.
[0025] In another embodiment, ophthalmic devices include devices
which are formed from material which are amphiphilic segmented
copolymers containing at least one hydrophobic segment and at least
one hydrophilic segment which are linked through a bond or a bridge
member.
[0026] It is particularly useful to employ biocompatible materials
herein including both soft and rigid materials commonly used for
ophthalmic lenses, including contact lenses. In general,
non-hydrogel materials are hydrophobic polymeric materials that do
not contain water in their equilibrium state. Typical non-hydrogel
materials comprise silicone acrylics, such as those formed bulky
silicone monomer (e.g., tris(trimethylsiloxy)silylpropyl
methacrylate, commonly known as "TRIS" monomer), methacrylate
end-capped poly(dimethylsiloxane) prepolymer, or silicones having
fluoroalkyl side groups (polysiloxanes are also commonly known as
silicone polymers).
[0027] Hydrogels in general are a well-known class of materials
that comprise hydrated, crosslinked polymeric systems 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 device-forming
silicone-containing monomer and at least one device-forming
hydrophilic monomer. Either the silicone-containing monomer or the
hydrophilic monomer can function as a crosslinking agent (a
crosslinker being defined as a monomer having multiple
polymerizable functionalities) or a separate crosslinker may be
employed. Silicone hydrogels typically have a water content between
about 10 to about 80 weight percent.
[0028] Representative examples of useful hydrophilic monomers
include, but are not limited to, amides such as
N,N-dimethylacrylamide and N,N-dimethylmethacrylamide; cyclic
lactams such as N-vinyl-2-pyrrolidone; and (meth)acrylated
poly(alkene glycols), such as poly(diethylene glycols) of varying
chain length containing monomethacrylate or dimethacrylate end
caps. 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. For example, 2-hydroxyethylmethacrylate
(HEMA) is a well-known hydrophilic monomer that may be used in
admixture with the aforementioned hydrophilic monomers.
[0029] The monomer mixtures may also include a second
device-forming monomer including a copolymerizable group and a
reactive functional group. The copolymerizable group is preferably
an ethylenically unsaturated group, such that this device-forming
monomer copolymerizes with the hydrophilic device-forming monomer
and any other device-forming monomers in the initial device-forming
monomer mixture. Additionally, the second monomer can include a
reactive functional group that reacts with a complementary reactive
group of the hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups. In
other words, after the device is formed by copolymerizing the
device-forming monomer mixture, the reactive functional groups
provided by the second device-forming monomers remain to react with
a complementary reactive moiety of the hydrophilic polymer having
one or more non-ethylenically-unsaturated carboxylic acid
terminated groups.
[0030] Preferred reactive groups of the second device-forming
monomers include epoxide groups. Accordingly, preferred second
device-forming monomers are those that include both an
ethylenically unsaturated group (that permits the monomer to
copolymerize with the hydrophilic device-forming monomer) and the
epoxide group (that does not react with the hydrophilic
device-forming monomer but remains to react with the hydrophilic
polymer having one or more non-ethylenically-unsaturated carboxylic
acid terminated groups). Examples include glycidyl methacrylate,
glycidyl acrylate, glycidyl vinylcarbonate, glycidyl
vinylcarbamate, 4-vinyl-1-cyclohexene-1,2-epoxide and the like.
[0031] As mentioned, one preferred class of ophthalmic device
substrate materials are silicone hydrogels. In this case, the
initial device-forming monomer mixture further comprises a
silicone-containing monomer. 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. Specific examples
of suitable materials for use herein include those disclosed in
U.S. Pat. Nos. 5,310,779; 5,387,662; 5,449,729; 5,512,205;
5,610,252; 5,616,757; 5,708,094; 5,710,302; 5,714,557 and
5,908,906, the contents of which are incorporated by reference
herein.
[0032] Representative examples of applicable silicon-containing
monomers include bulky polysiloxanylalkyl(meth)acrylic monomers.
The term "monomer" and like terms as used herein denote relatively
low molecular weight compounds that are polymerizable by, for
example, free radical polymerization, as well as higher molecular
weight compounds also referred to as "prepolymers",
"macromonomers", and related terms. The term "(meth)" as used
herein denotes an optional methyl substituent. Accordingly, terms
such as "(meth)acrylate" denotes either methacrylate or acrylate,
and "(meth)acrylic acid" denotes either methacrylic acid or acrylic
acid.
[0033] An example of a bulky polysiloxanylalkyl(meth)acrylic
monomer is represented by the structure of Formula I:
##STR00001##
wherein X denotes --O-- or --NR--; each R.sup.1 independently
denotes hydrogen or methyl; each R.sup.2 independently denotes a
lower alkyl radical, phenyl radical or a group represented by
##STR00002##
wherein each R.sup.2' independently denotes a lower alkyl or phenyl
radical; and h is 1 to 10.
[0034] Examples of bulky monomers are methacryloxypropyl
tris(trimethyl-siloxy)silane or tris(trimethylsiloxy)silylpropyl
methacrylate, sometimes referred to as TRIS and
tris(trimethylsiloxy)silylpropyl vinyl carbamate, sometimes
referred to as TRIS-VC and the like.
[0035] Such bulky monomers may be copolymerized with a silicone
macromonomer, which is a poly(organosiloxane) capped with an
unsaturated group at two or more ends of the molecule. U.S. Pat.
No. 4,153,641 discloses, for example, various unsaturated groups
such as acryloxy or methacryloxy groups.
[0036] Another class of representative silicone-containing monomers
includes, but is not limited to, silicone-containing vinyl
carbonate or vinyl carbamate monomers such as, for example,
1,3-bis[4-vinyloxycarbonyloxy)but-1-yl]tetramethyl-disiloxane;
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; trimethylsilylmethyl vinyl carbonate and the like
and mixtures thereof.
[0037] Another class of silicon-containing monomers includes
polyurethane-polysiloxane macromonomers (also sometimes referred to
as prepolymers), which may have hard-soft-hard blocks like
traditional urethane elastomers. They may be end-capped with a
hydrophilic monomer such as 2-hydroxyethyl methacrylate (HEMA).
Examples of such silicone urethanes are disclosed in a variety or
publications, including Lai, Yu-Chin, "The Role of Bulky
Polysiloxanylalkyl Methacryates in Polyurethane-Polysiloxane
Hydrogels," Journal of Applied Polymer Science, Vol. 60, 1193-1199
(1996). PCT Published Application No. WO 96/31792 discloses
examples of such monomers, which disclosure is hereby incorporated
by reference in its entirety. Further examples of silicone urethane
monomers are represented by Formulae II and III:
E(*D*A*D*G).sub.a*D*A*D*E'; or (II)
E(*D*G*D*A).sub.a*D*A*D*E'; or (III)
wherein:
[0038] D independently denotes an alkyl diradical, an alkyl
cycloalkyl diradical, a cycloalkyl diradical, an aryl diradical or
an alkylaryl diradical having 6 to about 30 carbon atoms;
[0039] G independently denotes an alkyl diradical, a cycloalkyl
diradical, an alkyl cycloalkyl diradical, an aryl diradical or an
alkylaryl diradical having 1 to about 40 carbon atoms and which may
contain ether, thio or amine linkages in the main chain;
[0040] * denotes a urethane or ureido linkage;
[0041] a is at least 1;
[0042] A independently denotes a divalent polymeric radical of
Formula IV:
##STR00003##
wherein each R.sup.s independently denotes an alkyl or
fluoro-substituted alkyl group having 1 to about 10 carbon atoms
which may contain ether linkages between the carbon atoms; m' is at
least 1; and p is a number that provides a moiety weight of about
400 to about 10,000;
[0043] each of E and E' independently denotes a polymerizable
unsaturated organic radical represented by Formula V:
##STR00004##
wherein: R.sup.3 is hydrogen or methyl; [0044] R.sup.4 is hydrogen,
an alkyl radical having 1 to 6 carbon atoms, or a --CO--Y--R.sup.6
radical wherein Y is --O--, --S-- or --NH--; [0045] R.sup.5 is a
divalent alkylene radical having 1 to about 10 carbon atoms; [0046]
R.sup.6 is a alkyl radical having 1 to about 12 carbon atoms;
[0047] X denotes --CO-- or --OCO--; [0048] Z denotes --O-- or
--NH--; [0049] Ar denotes an aromatic radical having about 6 to
about 30 carbon atoms; [0050] w is 0 to 6; x is 0 or 1; y is 0 or
1; and z is 0 or 1.
[0051] A preferred silicone-containing urethane monomer is
represented by Formula VI:
##STR00005##
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 about 400 to about 10,000 and is preferably at least about 30,
R.sup.7 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:
##STR00006##
[0052] In another embodiment of the present invention, a silicone
hydrogel material comprises (in bulk, that is, in the monomer
mixture that is copolymerized) about 5 to about 50 percent, and
preferably about 10 to about 25, by weight of one or more silicone
macromonomers, about 5 to about 75 percent, and preferably about 30
to about 60 percent, by weight of one or more polysiloxanylalkyl
(meth)acrylic monomers, and about 10 to about 50 percent, and
preferably about 20 to about 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 discloses
additional unsaturated groups, including acryloxy or methacryloxy.
Fumarate-containing materials such as those disclosed in U.S. Pat.
Nos. 5,310,779; 5,449,729 and 5,512,205 are also useful substrates
in accordance with the invention. Preferably, the silane
macromonomer is a silicon-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.
[0053] The above silicone materials are merely exemplary, and other
materials for use as substrates that can benefit by being packaged
in the packaging solution according to the present invention and
have been disclosed in various publications and are being
continuously developed for use in contact lenses and other medical
devices can also be used. For example, an ophthalmic lens for use
herein can be a cationic lens such as a cationic contact lens or
fluorinated silicone-containing monomers. Such monomers have been
used in the formation of fluorosilicone as disclosed in, for
example, U.S. Pat. Nos. 4,954,587; 5,010,141 and 5,079,319. The use
of silicone-containing monomers having certain fluorinated side
groups, i.e., --(CF.sub.2)--H, have been found to improve
compatibility between the hydrophilic and silicone-containing
monomeric units. See, e.g., U.S. Pat. Nos. 5,321,108 and
5,387,662.
[0054] Ophthalmic devices such as contact lenses for application of
the present invention can be manufactured employing various
conventional techniques, to yield a shaped article having the
desired posterior and anterior lens surfaces. In one embodiment, an
ophthalmic device can be prepared by polymerizing the monomeric
mixtures to form a product that can be subsequently formed into the
appropriate shape by, for example, lathing, injection molding,
compression molding, cutting and the like. For example, in
producing contact lenses, the initial monomeric mixture may be
polymerized in tubes to provide rod-shaped articles, which are then
cut into buttons. The buttons may then be lathed into contact
lenses.
[0055] Alternately, the ophthalmic devices may be cast directly in
molds, e.g., polypropylene molds, from the monomeric mixtures,
e.g., by spincasting and static casting methods. Spincasting
methods are disclosed in U.S. Pat. Nos. 3,408,429 and 3,660,545,
and static casting methods are disclosed in U.S. Pat. Nos.
4,113,224, 4,197,266, and 5,271,875. Spincasting methods involve
charging the monomer mixture to a mold, and spinning the mold in a
controlled manner while exposing the monomer mixture to a radiation
source such as UV light. Static casting methods involve charging
the monomeric mixture between two mold sections, one mold section
shaped to form the anterior lens surface and the other mold section
shaped to form the posterior lens surface, and curing the monomeric
mixture while retained in the mold assembly to form a lens, for
example, by free radical polymerization of the monomeric mixture.
Examples of free radical reaction techniques to cure the lens
material include thermal radiation, infrared radiation, electron
beam radiation, gamma radiation, ultraviolet (UV) radiation, and
the like; or combinations of such techniques may be used. U.S. Pat.
No. 5,271,875 describes a static cast molding method that permits
molding of a finished lens in a mold cavity defined by a posterior
mold and an anterior mold. As an additional method, U.S. Pat. No.
4,555,732 discloses a process where an excess of a monomeric
mixture is cured by spincasting in a mold to form a shaped article
having an anterior lens surface and a relatively large thickness,
and the posterior surface of the cured spincast article is
subsequently lathed to provide a contact lens having the desired
thickness and posterior lens surface.
[0056] Polymerization may be facilitated by exposing the mixture to
heat and/or radiation, such as ultraviolet light, visible light, or
high energy radiation. A polymerization initiator may be included
in the mixture to facilitate the polymerization step.
Representative examples of free radical thermal polymerization
initiators include organic peroxides such as acetal peroxide,
lauroyl peroxide, decanoyl peroxide, stearoyl peroxide, benzoyl
peroxide, tertiarylbutyl peroxypivalate, peroxydicarbonate, and the
like. Representative UV initiators are those known in the art and
include benzoin methyl ether, benzoin ethyl ether, Darocure 1173,
1164, 2273, 1116, 2959, 3331 (EM Industries) and Igracure 651 and
184 (Ciba-Geigy), and the like. Generally, the initiator will be
employed in the monomeric mixture at a concentration of about 0.01
to 1 percent by weight of the total mixture.
[0057] After producing a lens having the desired final shape, it is
desirable to remove residual solvent from the lens before
edge-finishing operations. This is because, typically, an organic
diluent is included in the initial monomeric mixture in order to
minimize phase separation of polymerized products produced by
polymerization of the monomeric mixture and to lower the glass
transition temperature of the reacting polymeric mixture, which
allows for a more efficient curing process and ultimately results
in a more uniformly polymerized product. Sufficient uniformity of
the initial monomeric mixture and the polymerized product are of
particular concern for silicone hydrogels, primarily due to the
inclusion of silicone-containing monomers which may tend to
separate from the hydrophilic comonomer. Suitable organic diluents
include, for example, monohydric alcohols such as C.sub.6-C.sub.10
straight-chained aliphatic monohydric alcohols, e.g., n-hexanol and
n-nonanol; diols such as ethylene glycol; polyols such as glycerin;
ethers such as diethylene glycol monoethyl ether; ketones such as
methyl ethyl ketone; esters such as methyl enanthate; and
hydrocarbons such as toluene. Preferably, the organic diluent is
sufficiently volatile to facilitate its removal from a cured
article by evaporation at or near ambient pressure. Generally, the
diluent is included at about 5 to about 60 percent by weight of the
monomeric mixture, with about 10 to about 50 percent by weight
being especially preferred.
[0058] The cured lens can then be subjected to solvent removal,
which can be accomplished by evaporation at or near ambient
pressure or under vacuum. An elevated temperature can be employed
to shorten the time necessary to evaporate the diluent. The time,
temperature and pressure conditions for the solvent removal step
will vary depending on such factors as the volatility of the
diluent and the specific monomeric components, as can be readily
determined by one skilled in the art. According to a preferred
embodiment, the temperature employed in the removal step is
preferably at least about 50.degree. C., for example, about
60.degree. C. to about 80.degree. C. A series of heating cycles in
a linear oven under inert gas or vacuum may be used to optimize the
efficiency of the solvent removal. The cured article after the
diluent removal step should contain no more than twenty percent by
weight of diluent, preferably no more than about 5 percent by
weight or less.
[0059] Following removal of the organic diluent, the lens can then
be subjected to mold release and optional machining operations. The
machining step includes, for example, buffing or polishing a lens
edge and/or surface. Generally, such machining processes may be
performed before or after the article is released from a mold part.
Preferably, the lens is dry released from the mold by employing
vacuum tweezers to lift the lens from the mold, after which the
lens is transferred by means of mechanical tweezers to a second set
of vacuum tweezers and placed against a rotating surface to smooth
the surface or edges. The lens may then be turned over in order to
machine the other side of the lens
[0060] Next, the ophthalmic device such as a lens will be immersed
in an aqueous packaging solution and stored in a packaging system
according to the present invention. Generally, a packaging system
for the storage of an ophthalmic device according to the present
invention includes at least a sealed container containing one or
more unused ophthalmic devices immersed in an aqueous packaging
solution. Preferably, the sealed container is a hermetically sealed
blister-pack, in which a concave well containing an ophthalmic
device such as a contact lens is covered by a metal or plastic
sheet adapted for peeling in order to open the blister-pack. The
sealed container may be any suitable generally inert packaging
material providing a reasonable degree of protection to the lens,
preferably a plastic material such as polyalkylene, PVC, polyamide,
and the like.
[0061] The aqueous packaging solution will contain at least a
hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups.
The devices may either be unhydrated or prehydrated in water or an
aqueous solution. The hydrophilic polymers can have a weight
average molecular weight ranging from about 1,000 to about
1,000,000 and preferably from about 5,000 to about 100,000.
[0062] One class of a hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups can
be of the general formula:
##STR00007##
wherein R is a residue of a non-ethylenically-unsaturated
carboxylic acid group-forming monomer, e.g., a saturated anhydride
as discussed below, L is a linking group such as a direct bond or a
divalent linkage group that includes a hydrocarbon group or a
heterohydrocarbon group containing one or more atoms selected from
the group consisting of O, N, S, and combinations thereof; M is an
oligomer or polymer having a plurality of hydrophilic groups and n
is an integer from 5 to about 10,000 and preferably about 50 to
about 1,000. Representative examples of suitable L groups include
an unsaturated or saturated, unsubstituted or substituted
C.sub.1-C.sub.10 branched hydrocarbon group optionally containing
one or more heteroatoms, an unsaturated or saturated, unsubstituted
or substituted C.sub.3-C.sub.10 linear hydrocarbon group optionally
containing one or more heteroatoms, an unsaturated or saturated,
unsubstituted or substituted C.sub.3-C.sub.25 cyclic hydrocarbon
group optionally containing one or more heteroatoms and the
like.
[0063] Another class of a hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups can
be of the general formula:
##STR00008##
wherein R, L, M and n independently have the aforestated
meanings.
[0064] The hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups can
be obtained by reacting a hydroxyl-terminated oligomer or polymer
having a plurality of hydrophilic groups with a
non-ethylenically-unsaturated carboxylic acid group-forming monomer
such as a saturated cyclic anhydride under conditions effective to
produce the hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups. In
one embodiment, the hydroxyl-terminated oligomer or polymer is a
monohydroxyl-terminated oligomer or polymer. In another embodiment,
the hydroxyl-terminated oligomer or polymer is a diterminal
hydroxyl-terminated oligomer or polymer, i.e., the oligomer or
polymer is terminated on each end with a hydroxyl-containing
terminal group.
[0065] The oligomeric or polymeric chain comprises units derived
from N-vinylpyrrolidone. In another embodiment, the oligomeric or
polymeric chain comprises units are derived from mono- or
polyhydric alcohols, e.g., glyceryl methacrylate, glyceryl
acrylate, HEMA, erythritol (meth)acrylate, xylitol (meth)acrylate,
sorbitol (meth)acrylate, and the like, acrylamides, e.g., dimethyl
methacrylamide, DMA and the like, copolymers thereof and
derivatives thereof. The oligomeric or polymeric chain can also
comprises units derived from one of the foregoing monomers of an
alkylene oxide (such as ethylene oxide).
[0066] The hydroxyl-terminated hydrophilic polymer can be
synthesized by, for example, (a) mixing one or more oligomeric or
polymeric chain-forming monomers or polymers with a
hydroxyl-containing monomer; (b) adding a polymerization initiator;
and (c) subjecting the monomer/initiator mixture to thermal energy
or a source of ultraviolet or other light and curing the mixture.
The mixture preferably contains at least one hydroxyl-containing
monomer so that the polymer formed is hydroxyl-terminated. Useful
hydroxyl-containing monomers include, by way of example,
2-isopropoxyethanol, allyl alcohol and the like.
[0067] Polymerization initiators include free-radical-generating
polymerization initiators and ultraviolet (UV) free-radical
initiators. Representative free radical thermal polymerization
initiators are usually peroxides or azo initiators such as, for
example, acetal peroxide, lauroyl peroxide, decanoyl peroxide,
stearoyl peroxide, benzoyl peroxide, tertiarylbutyl peroxypivalate,
peroxydicarbonate, 2,2'-azo-bis(2-methylpropionitrile), benzoin
methyl ether and the like and mixtures thereof. Representative UV
initiators are those known in the field such as, for example,
benzoin methyl ether, benzoin ethyl ether, Darocure 1173, 1164,
2273, 1116, 2959, 3331 (EM Industries) and Igracure 651 and 184
(Ciba-Geigy), and the like and mixtures thereof. Other
polymerization initiators which may be used are disclosed in, for
example, "Polymer Handbook", 4th edition, Ed. J. Brandrup, E. H.
Immergut, E. A. Grulke, A. Abe and D. R. Bloch, Pub.
Wiley-Interscience, New York, 1998. The curing process will of
course depend upon the initiator used and the physical
characteristics of the comonomer mixture such as viscosity. In any
event, the level of initiator employed may vary within the range of
about 0.01 to about 2 weight percent of the mixture of
monomers.
[0068] Polymerization of the mixture to form the
hydroxyl-terminated hydrophilic polymer can be carried out in the
presence of a solvent. Suitable solvents are in principle all
solvents which dissolve the reactants such as, for example, water,
alcohols such as lower alkanols, e.g., methanol, methanol and the
like; carboxamides such as dimethylformamide and the like; dipolar
aprotic solvents such as dimethyl sulfoxide and the like; ketones
such as acetone, methyl ethyl ketone, cyclohexanone, and the like;
aliphatic or aromatic hydrocarbons such as toluene, xylene,
n-hexane and the like; ethers such as tetrahydrofuran,
dimethoxyethane, dioxane and the like; halogenated hydrocarbons
such as trichloroethane and the like, and also mixtures of suitable
solvents, for example mixtures of water and an alcohol, e.g., a
water/methanol or water/ethanol mixture, and the like.
[0069] Suitable saturated anhydrides are saturated, cyclic
anhydrides. Preferably, the anhydride ring incorporates from two to
four methylene or substituted methylene groups. Representative
examples of such saturated, cyclic anhydrides include succinic
anhydride, glutaric anhydride, adipic anhydride, methylsuccinic
anhydride, 2-phenylglutaric anhydride, 3-methylglutaric anhydride,
3-methyladipic anhydride, and the like, and mixtures thereof.
[0070] The hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups can
be obtained by, for example, (a) reacting a hydroxyl-terminated
oligomer or polymer having a plurality of hydrophilic groups with a
non-ethylenically-unsaturated carboxylic acid group-forming monomer
optionally in the presence of a polymerization initiator and (b)
subjecting the monomer/initiator mixture to thermal energy or a
source of ultraviolet or other light and curing the mixture.
Polymerization initiators which may be used include the
free-radical-generating polymerization initiators and UV
free-radical initiators discussed above. The curing process will of
course depend upon the initiator used and the physical
characteristics of the comonomer mixture such as viscosity. In any
event, the level of initiator employed may vary within the range of
about 0.01 to about 2 weight percent of the mixture of
monomers.
[0071] The relative amounts of hydroxyl-terminated hydrophilic
polymer and the saturated, cyclic anhydride can vary over a fairly
broad range. The amounts can be chosen to provide a polymer having
the molecular weights discussed above. Generally, the
anhydride:hydroxyl-terminated hydrophilic polymer ratio is about
2:1.
[0072] Polymerization of the mixture to form the hydrophilic
polymer can be carried out in the presence of a solvent. Suitable
solvents are in principle all solvents which can dissolve the
reactants such as, for example, water, alcohols such as lower
alkanols, e.g., methanol, methanol and the like; carboxamides such
as dimethylformamide and the like; dipolar aprotic solvents such as
dimethyl sulfoxide and the like; ketones such as acetone, methyl
ethyl ketone, cyclohexanone and the like; aliphatic or aromatic
hydrocarbons such as toluene, xylene, n-hexane and the like; ethers
such as tetrahydrofuran, dimethoxyethane, dioxane and the like;
halogenated hydrocarbons such as trichloroethane and the like, and
mixtures thereof, e.g., mixtures of water and an alcohol, e.g., a
water/methanol or water/ethanol mixture, and the like.
[0073] The amount of the hydrophilic polymer employed in a
packaging solution for storing an ophthalmic device in a packaging
system of the present invention is an amount effective to improve
the surface properties of the ophthalmic device. Generally, the
concentration of a hydrophilic polymer present in the packaging
solution of the invention will range from about 0.01 to about 10%
w/w.
[0074] The packaging solutions according to the present invention
are physiologically compatible. Specifically, the solution must be
"ophthalmically safe" for use with a lens such as a contact lens,
meaning that a contact lens treated with the solution is generally
suitable and safe for direct placement on the eye without rinsing,
that is, the solution is safe and comfortable for daily contact
with the eye via a contact lens that has been wetted with the
solution. An ophthalmically safe solution has a tonicity and pH
that is compatible with the eye and includes materials, and amounts
thereof, that are non-cytotoxic according to ISO standards and U.S.
Food & Drug Administration (FDA) regulations.
[0075] The packaging solution should also be sterile in that the
absence of microbial contaminants in the product prior to release
must be statistically demonstrated to the degree necessary for such
products. The liquid media useful in the present invention are
selected to have no substantial detrimental effect on the lens
being treated or cared for and to allow or even facilitate the
present lens treatment or treatments. The liquid media are
preferably aqueous-based. A particularly useful aqueous liquid
medium is that derived from saline, for example, a conventional
saline solution or a conventional buffered saline solution.
[0076] The pH of the present solutions should be maintained within
the range of about 6 to about 9, and preferably about 6.5 to about
7.8. Suitable buffers may be added, such as boric acid, sodium
borate, potassium citrate, citric acid, sodium bicarbonate, TRIS
and various mixed phosphate buffers (including combinations of
Na.sub.2 HPO.sub.4, NaH.sub.2 PO.sub.4 and KH.sub.2 PO4) 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. The packaging solutions of this invention preferably
contain a borate buffer, containing one or more of boric acid,
sodium borate, potassium tetraborate, potassium metaborate or
mixtures of the same.
[0077] Typically, the solutions of the present invention are also
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.
[0078] Examples of suitable tonicity adjusting agents include, but
are not limited to, sodium and potassium chloride, dextrose,
glycerin, 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 400 mOsm/kg,
more preferably from about 250 to about 350 mOsm/kg, and most
preferably from about 280 to about 320 mOsm/kg.
[0079] If desired, one or more additional components can be
included in the packaging solution. Such additional component or
components are chosen to impart or provide at least one beneficial
or desired property to the packaging solution. Such additional
components may be selected from components which are conventionally
used in one or more ophthalmic device care compositions. Examples
of such additional components include cleaning agents, wetting
agents, nutrient agents, sequestering agents, viscosity builders,
contact lens conditioning agents, antioxidants, and the like and
mixtures thereof. These additional components may each be included
in the packaging solutions in an amount effective to impart or
provide the beneficial or desired property to the packaging
solutions. For example, such additional components may be included
in the packaging solutions in amounts similar to the amounts of
such components used in other, e.g., conventional, contact lens
care products.
[0080] Useful sequestering agents include, but are not limited to,
disodium ethylene diamine tetraacetate, alkali metal
hexametaphosphate, citric acid, sodium citrate and the like and
mixtures thereof.
[0081] Useful viscosity builders include, but are not limited to,
hydroxyethyl cellulose, hydroxymethyl cellulose, polyvinyl
pyrrolidone, polyvinyl alcohol and the like and mixtures
thereof.
[0082] Useful antioxidants include, but are not limited to, sodium
metabisulfite, sodium thiosulfate, N-acetylcysteine, butylated
hydroxyanisole, butylated hydroxytoluene and the like and mixtures
thereof.
[0083] The method of packaging and storing an ophthalmic device
such as a contact lens according to the present invention includes
at least packaging an ophthalmic device immersed in the aqueous
packaging solution described above. The method may include
immersing the ophthalmic device in an aqueous packaging solution
prior to delivery to the customer/wearer, directly following
manufacture of the contact lens. Alternately, the packaging and
storing in the solution of the present invention may occur at an
intermediate point before delivery to the ultimate customer
(wearer) but following manufacture and transportation of the lens
in a dry state, wherein the dry lens is hydrated by immersing the
lens in the contact-lens packaging solution. Consequently, a
package for delivery to a customer may include a sealed container
containing one or more unused contact lenses immersed in an aqueous
packaging solution according to the present invention.
[0084] In one embodiment, the steps leading to the present
ophthalmic device packaging system includes (1) molding an
ophthalmic device in a mold comprising at least a first and second
mold portion, (2) hydrating and cleaning the device in a container
comprising at least one of the mold portions, (3) introducing the
packaging solution with the hydrophilic polymer having one or more
non-ethylenically-unsaturated carboxylic acid terminated groups
into the container with the device supported therein, and (4)
sealing the container. Preferably, the method also includes the
step of sterilizing the contents of the container. Sterilization
may take place prior to, or most conveniently after, sealing of the
container and may be effected by any suitable method known in the
art, e.g., by autoclaving of the sealed container at temperatures
of about 120.degree. C. or higher.
[0085] The following examples are provided to enable one skilled in
the art to practice the invention and are merely illustrative of
the invention. The examples should not be read as limiting the
scope of the invention as defined in the claims.
[0086] In the examples, the following abbreviations are used.
[0087] I4D5S4H: A prepolymer derived from 10 moles of isophorone
diisocyanate, 4 moles of diethyleneglycol, 5 moles of
hydroxybutyl-terminated polydimethylsiloxane of Mn 4000 and
end-capped with 2-hydroxyethyl methacrylate
[0088] TRIS: tris(trimethylsiloxy)silylpropyl methacrylate
[0089] NVP: N-vinyl-2-pyrrolidone
[0090] PVP: poly(vinylpyrrolidone)
[0091] DMA: N,N-dimethyl acrylamide
[0092] HEMA: 2-hydroxyethyl methacrylate
[0093] HEMAVC: methacryloxyethyl vinyl carbonate
[0094] D 1173: 2-hydroxy-2-methyl-1-phenylpropan-1-one (available
as Darocur 1173 initiator)
[0095] IMVT:
1,4-bis(4-(2-methacryloxyethyl)phenylamino)anthraquinone
[0096] PP: polypropylene
[0097] DI: de-ionized water
[0098] IPA: isopropyl alcohol
[0099] AIBN: azo bis-isobutylnitrile (commercially available as
Vazo.TM. 64)
[0100] THF: tetrahydrofuran
EXAMPLE 1
[0101] Preparation of Hydroxyl Functionalized Poly(Vinyl
Pyrrolidone).
[0102] To a 2-liter three-neck flask equipped with a condenser and
nitrogen inlet tube was added 900 ml of 2-isopropoxyethanol (about
813.6 g, 7.812 mol, Aldrich Chemical Company), 30 mol of freshly
distilled NVP (about 31.35 g, 0.282 mol) and AIBN (0.317 g; 1.930
mmol). The contents were bubbled vigorously with nitrogen for 1
hour. Then, while under nitrogen blanket, the contents were heated
at 80.degree. C. for two days. The solution was ultra filtrated
using a 1000 NMWL RC film. Next, the solvent was removed using a
rotavapor at 50 to 60 rpms. THF (100 ml) was added to dissolve the
product and then tin 2000 mL ether was poured to precipitate the
product. The product was dried in a vacuum oven to give 30.85 g of
product. The hydroxyl functionalized PVP had a number average
molecular weight (M.sub.n) of 1357 as determined by titration.
EXAMPLE 2
[0103] Preparation of Acid-Terminated PVP.
[0104] To a thoroughly dried 500-mL round bottom flask equipped
with nitrogen inlet tube and drying tube, is charged 200 mL of
anhydrous THF. Next, succinic anhydride (2.00 g, 0.02 mole) and the
hydroxyl functionalized poly(vinyl pyrrolidone) (13.57 g, 0.010
mole) of Example 1 are added to the flask. The contents are heated
under reflux for 48 hours with stirring. The solution is
concentrated to 100 mL and is poured into 2000 mL of ether to
precipitate the product.
EXAMPLE 3
[0105] Preparation of Poly (Vinyl Pyrrolidone-co-allyl
Alcohol).
[0106] To a 1000 ml three-neck flask equipped with a condenser and
nitrogen inlet tube was added 250 mL of distilled water, 45.51 g
(409.5 mmole) of freshly distilled NVP, 1,1725 g (20.19 mmole) of
allyl alcohol and AIBN (0.47 g; 2.862 mmol). The contents were
bubbled vigorously with nitrogen for 1 hour. While under nitrogen
blanket and with stirring, the contents were heated up to
70.degree. C. for two days. The solution became viscous even after
one hour of heating. After two days, the product was recovered by
freeze drying. The product had a Mn of 1,020,00, a Mw of 1,355,000
and a polydispersity of 1.327, as determined by Size Exclusion
Chromatography. It was found that there was 1 allyl alcohol per 100
vinylpyrrolidone units.
EXAMPLE 4
[0107] Preparation of Acid-Terminated PVP.
[0108] To a thoroughly dried 2-L round bottom flask equipped with
nitrogen inlet tube and drying tube is charged with 30 g of product
from Example 3 and 300 ml of anhydrous THF 200. The solution is
refluxed until full solution. Next, succinic anhydride (0.9 g,
0.009 mole) is added to the flask. The contents are heated under
reflux for 48 hours with stirring. The solution is then
concentrated to 100 mL and is poured into 2 liter ether to
precipitate the product.
EXAMPLE 5
[0109] Preparation of a Polyurethane-Siloxane Hydrogel Lens.
[0110] A monomer mixture was made by mixing the following
components listed in Table 1, at amounts per weight.
TABLE-US-00001 TABLE 1 Ingredient Amount I4D5S4H 53 TRIS 15 DMA 9
NVP 24 HEMA 5 HEMAVC 1 Hexanol 10 Darocur-1173 0.5 IMVT 150 ppm
[0111] Lenses were cast using polypropylene molds, both in an open
air bench top and in a dry box filled with nitrogen, and then cured
in an oven at under the following thermal conditions: held at room
temperature for 12 minutes, then ramped up to 100.degree. C. in 54
minutes, and further held at 100.degree. C. for 2 hours. After
casting, the lenses were released from the molds and extracted in
IPA for 2 hours. The lenses were rinsed with distilled water and
then placed in borate buffered saline. Some of these lenses were
autoclaved for one cycle.
EXAMPLE 6
[0112] An aqueous packaging solution containing 3% by weight of the
acid-terminated PVP of Example 2 dissolved in a borate buffered
saline at a pH of 7.2 is placed in a polypropylene blister package.
Next, the lenses of Example 5 are immersed in the aqueous packaging
solution in the polypropylene blister package. The package is
sealed with foil lidstock and then autoclaved for 1 cycle.
EXAMPLE 7
[0113] An aqueous packaging solution containing 3% by weight of the
acid-terminated PVP of Example 4 dissolved in a borate buffered
saline at a pH of 7.2 is placed in a polypropylene blister package.
Next, the lenses of Example 5 are immersed in the aqueous packaging
solution in the polypropylene blister package. The package is
sealed with foil lidstock and then autoclaved for 1 cycle.
EXAMPLE 8
[0114] An aqueous packaging solution containing 1% by weight of the
acid-terminated PVP of Example 1 dissolved in a borate buffered
saline at a pH of 7.2 is placed in a polypropylene blister package.
Next, a balafilcon A contact lens (a commercially available group
III extended wear contact lenses from Bausch & Lomb
Incorporated of Rochester, N.Y., sold under the trade name
Purevision.RTM., made of a silicone hydrogel material and having an
anionic charge and approximately 38% water) is immersed in the
aqueous packaging solution in the polypropylene blister package.
The package is sealed with foil lidstock and then autoclaved for 1
cycle.
EXAMPLE 9
[0115] An aqueous packaging solution containing 1% by weight of the
acid-terminated PVP of Example 4 dissolved in a borate buffered
saline at a pH of 7.2 is placed in a polypropylene blister package.
Next, a balafilcon A contact lens (a commercially available group
III extended wear contact lenses from Bausch & Lomb
Incorporated of Rochester, N.Y., sold under the trade name
Purevision.RTM., made of a silicone hydrogel material and having an
anionic charge and approximately 38% water) is immersed in the
aqueous packaging solution in the polypropylene blister package.
The package is sealed with foil lidstock and then autoclaved for 1
cycle.
EXAMPLE 10
[0116] An aqueous packaging solution containing 2% by weight of the
acid-terminated PVP of Example 1 dissolved in a borate buffered
saline at a pH of 7.2 is placed in a polypropylene blister package.
Next, a balafilcon A contact lens (a commercially available group
III extended wear contact lenses from Bausch & Lomb
Incorporated of Rochester, N.Y., sold under the trade name
Purevision.RTM., made of a silicone hydrogel material and having an
anionic charge and approximately 38% water) is immersed in the
aqueous packaging solution in the polypropylene blister package.
The package is sealed with foil lidstock and then autoclaved for 1
cycle.
EXAMPLE 11
[0117] An aqueous packaging solution containing 2% by weight of the
acid-terminated PVP of Example 4 dissolved in a borate buffered
saline at a pH of 7.2 is placed in a polypropylene blister package.
Next, a balafilcon A contact lens (a commercially available group
III extended wear contact lenses from Bausch & Lomb
Incorporated of Rochester, N.Y., sold under the trade name
Purevision.RTM., made of a silicone hydrogel material and having an
anionic charge and approximately 38% water) is immersed in the
aqueous packaging solution in the polypropylene blister package.
The package is sealed with foil lidstock and then autoclaved for 1
cycle.
[0118] It will be understood that various modifications may be made
to the embodiments disclosed herein. Therefore the above
description should not be construed as limiting, but merely as
exemplifications of preferred embodiments. For example, the
functions described above and implemented as the best mode for
operating the present invention are for illustration purposes only.
Other arrangements and methods may be implemented by those skilled
in the art without departing from the scope and spirit of this
invention. Moreover, those skilled in the art will envision other
modifications within the scope and spirit of the features and
advantages appended hereto.
* * * * *