U.S. patent application number 16/164256 was filed with the patent office on 2019-05-23 for disinfection system of contact lens.
This patent application is currently assigned to MENICON CO., LTD.. The applicant listed for this patent is MENICON CO., LTD.. Invention is credited to Yukihiro KOJIMA, Osamu MORI.
Application Number | 20190151493 16/164256 |
Document ID | / |
Family ID | 42575668 |
Filed Date | 2019-05-23 |
United States Patent
Application |
20190151493 |
Kind Code |
A1 |
MORI; Osamu ; et
al. |
May 23, 2019 |
DISINFECTION SYSTEM OF CONTACT LENS
Abstract
A disinfection system of a contact lens comprising immersing the
contact lens in a disinfecting solution containing hydrogen
peroxide in a concentration of 1 to 10% and neutralizing the
hydrogen peroxide in the disinfecting solution through contact with
a metal catalyst, where the disinfecting solution contains an
organic carboxylic acid or a salt of the organic carboxylic acid,
the organic carboxylic acid having a structure in which a hydroxyl
group and a carboxyl group are bonded to one carbon atom; the
disinfecting solution is adjusted to have a pH of 6 to 8; and the
disinfecting solution after the neutralization is adjusted to have
an osmotic pressure of 250 to 350 mOsm.
Inventors: |
MORI; Osamu; (Kasugai-shi,
JP) ; KOJIMA; Yukihiro; (Kasugai-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MENICON CO., LTD. |
Nagoya-shi |
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JP |
|
|
Assignee: |
MENICON CO., LTD.
Nagoya-shi
JP
|
Family ID: |
42575668 |
Appl. No.: |
16/164256 |
Filed: |
October 18, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15250413 |
Aug 29, 2016 |
10137218 |
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16164256 |
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13311712 |
Dec 6, 2011 |
9427488 |
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15250413 |
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PCT/JP2009/002993 |
Jun 29, 2009 |
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13311712 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61L 12/128 20130101;
A61L 12/086 20130101 |
International
Class: |
A61L 12/12 20060101
A61L012/12; A61L 12/08 20060101 A61L012/08 |
Claims
1. A disinfection system of a contact lens including immersing the
contact lens in a disinfecting solution containing hydrogen
peroxide in a concentration of 1 to 10% and neutralizing the
hydrogen peroxide in the disinfecting solution through contact with
a metal catalyst, the disinfection system comprising the steps of:
adding one of an organic carboxylic acid and a salt thereof into
the disinfecting solution, the organic carboxylic acid having a
structure in which a hydroxyl group and a carboxyl group are bonded
to one carbon atom; adjusting a pH of the disinfecting solution to
6 to 8; and adjusting an osmotic pressure of the disinfecting
solution after the neutralization to 250 to 350 mOsm.
2. The disinfection system of a contact lens according to claim 1,
wherein the pH of the disinfecting solution is adjusted by adding
one of an acid and an alkaline agent into an aqueous hydrogen
peroxide solution, together with the organic carboxylic acid or the
salt thereof.
3. The disinfection system of a contact lens according to claim 1,
wherein the organic carboxylic acid is glycolic acid.
4. The disinfection system of a contact lens according to claim 1,
wherein the organic carboxylic acid is tartaric acid.
5. The disinfection system of a contact lens according to claim 1,
wherein the organic carboxylic acid is citric acid.
6. The disinfection system of a contact lens according to claim 1,
wherein the organic carboxylic acid or the salt thereof is
contained at a concentration of at least 0.1% or more.
7. The disinfection system of a contact lens according to claim 1,
wherein the disinfecting solution further contains a chelating
agent.
8. The disinfection system of a contact lens according to claim 7,
wherein the chelating agent is at least one selected from the group
consisting of EDTA, a salt thereof, etidronic acid, and a salt
thereof.
9. The disinfection system of a contact lens according to claim 1,
wherein the metal catalyst is a metal film catalyst.
10. The disinfection system of a contact lens according to claim 1,
wherein the disinfecting solution further contains at least one of
surfactant and a nonionic tonicity agent.
11. The disinfection system of a contact lens according to claim 1,
wherein the metal catalyst is contained in a predetermined
treatment container for contact lens disinfection, and the
disinfecting solution is contained in the treatment container to
allow the metal catalyst be in contact with the disinfecting
solution.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/250,413, filed on Aug. 29, 2016, which is a
continuation of U.S. patent application Ser. No. 13/311,712, filed
on Dec. 6, 2011, which is a continuation of the International
Application No. PCT/JP2009/002993 filed on Jun. 29, 2009, the
entireties of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a disinfection system of
contact lenses, and particularly to a disinfection system in which
a hydrogen peroxide-containing disinfecting solution for an
immersion treatment of contact lenses is effectively neutralized
with a metal catalyst.
BACKGROUND ART
[0003] As one of methods for chemically cleaning and disinfecting
contact lenses, particularly soft contact lenses, there has
hitherto been widely known a disinfection system using hydrogen
peroxide. The hydrogen peroxide used therein is an effective
disinfectant, and particularly attractive for disinfection of the
contact lenses, because a decomposed product thereof is only water.
However, such hydrogen peroxide is an active oxidant, so that the
hydrogen peroxide should be completely removed from the contact
lenses that were subjected to a disinfection treatment, before the
contact lenses are worn again on the eye.
[0004] In a chemical disinfection method using such hydrogen
peroxide, in order to obtain a desired disinfection effect, the
hydrogen peroxide is generally required to have a concentration as
high as about 3%, and a neutralization treatment for decomposing
and detoxifying the hydrogen peroxide remaining on surfaces or in
the insides of the contact lenses should be performed after the
disinfection. The reason for this is that the hydrogen peroxide
inevitbaly remains on the surfaces or in the insides of the contact
lenses after disinfection, because the hydrogen peroxide is used at
a relatively high concentration. The hydrogen peroxide remaining on
or in the lenses may seriously damage the eyes, even if the amount
is small.
[0005] Thus, to the contact lenses subjected to the disinfection
treatment by using the hydrogen peroxide, the neutralization
treatment is conventionally applied. Specifically, the remaining
hydrogen peroxide is removed by rinsing with a physiological
saline, or completely decomposed and removed by using a metal
catalyst such as platinum, a reducing agent such as sodium sulfite,
sodium thiosulfate or pyruvic acid, an enzyme catalyst such as
catalase or peroxidase, or the like. However, such a neutralization
treatment generally makes a disinfection treatment operation of the
contact lenses very cumbersome and complicated.
[0006] Accordingly, in order to easily perform the disinfection
operation of the contact lenses using such hydrogen peroxide,
JP-T-4-507052 discloses a vertical type contact lens case as an
apparatus for sterilizing the contact lenses. In such a contact
lens case, a hydrogen peroxide-containing sterilizing solution is
contained, and the contact lenses to be treated and a catalyst
agent are disposed therein so as be in contact with the sterilizing
solution. As a result, the contact lenses are disinfected or
sterilized, while a neutralization treatment is performed in which
the hydrogen peroxide in the sterilizing solution is decomposed
with the catalyst agent. The neutralization rate of the hydrogen
peroxide in such a sterilizing solution depends on the amount of
catalyst (metal) in the catalyst agent. In order to completely
remove the hydrogen peroxide effectively from the contact lenses,
the neutralization efficiency needs to be increased by improving
the neutralization rate without influencing a disinfecting effect
on the lenses. For this purpose, the amount of the catalyst metal
needs to be increased. Further, the catalyst agent (catalyst metal)
used herein needs to be replaced with a new one at a predetermined
time intervals in order to assure the safety, for example.
Accordingly, in the disinfection system using the hydrogen
peroxide, it is a major object to reduce the amount of the catalyst
metal in terms of cost reduction.
[0007] Further, JP-A-63-274602 discloses a stabilized hydrogen
peroxide solution including a hydrogen peroxide solution, and a
peroxide stabilizer composed of a predetermined sulfonic acid
compound and a secondary peroxide stabilizer such as glycerin or
polyvinyl alcohol, which are added to the hydrogen peroxide
solution. It also discloses that the sterilization by heat can be
performed in combination by the use of this stabilized hydrogen
peroxide solution as a disinfecting solution of contact lenses,
resulting in the reduction of time for immersing lens materials in
the disinfecting solution. However, it discloses that the hydrogen
peroxide must be removed after the disinfection treatment, and in
order to remove it, the contact lenses are rinsed or a known
hydrogen peroxide-decomposing material is allowed to be in contact
with the solution, after the disinfection treatment.
[0008] Furthermore, WO2002/26922 proposes a technique of inhibiting
foaming at the time of a disinfection operation of contact lenses
by allowing a surfactant composed of a block copolymer having a
hydrophobic block and a hydrophilic block to be contained in a
contact lens disinfecting solution containing an effective
disinfecting amount of hydrogen peroxide. In addition,
JP-A-3-278837 discloses a method of disinfecting contact lenses by
using a hydrogen peroxide-decomposing catalyst in which manganese
oxide, cobalt oxide or copper oxide is carried on an inorganic
carrier. However, these Patent Documents do not disclose in any way
that the disinfection of the contact lenses is effectively
performed by increasing the neutralization rate of the hydrogen
peroxide in the disinfecting solution to improve its neutralization
efficiency by using a specific composition of the disinfecting
solution, in other words, by adding specific components to the
disinfecting solution.
[0009] As described above, various disinfection systems of contact
lenses using hydrogen peroxide solutions have conventionally been
proposed. However, none of them has proposed or reported any
composition of solution for increasing the neutralization rate of
hydrogen peroxide to improve its neutralization efficiency, while
securing the effective disinfection effect by a hydrogen
peroxide-containing solution (disinfecting solution).
SUMMARY OF INVENTION
[0010] The present invention has been made in the light of the
situations described above. It is therefore an object of the
present invention to provide a disinfection system of a contact
lens using hydrogen peroxide, in which neutralization efficiency of
such hydrogen peroxide is increased to reduce the amount of metal
used in a metal catalyst, thereby advantageously saving
resource.
[0011] To achieve the object described above and other objects
which will be understood from the description of the entire
specification, the present invention can be suitably carried out in
various aspects described below, and the respective aspects
described below can also be employed in any combination. It is to
be understood that the aspects and technical features of the
present invention are not limited to those described below and
should be recognized on the basis of the concept of the invention
as disclosed in the entire specification.
[0012] (1) A disinfection system of a contact lens including
immersing the contact lens in a disinfecting solution containing
hydrogen peroxide in a concentration of 1 to 10% and neutralizing
the hydrogen peroxide in the disinfecting solution through contact
with a metal catalyst, the disinfection system comprising the steps
of: adding one of an organic carboxylic acid and a salt thereof
into the disinfecting solution, the organic carboxylic acid having
a structure in which a hydroxyl group and a carboxyl group are
bonded to one carbon atom; adjusting a pH of the disinfecting
solution to 6 to 8; and adjusting an osmotic pressure of the
disinfecting solution after the neutralization to 250 to 350
mOsm.
[0013] (2) The disinfection system of a contact lens according to
the above aspect (1), where the pH of the disinfecting solution is
adjusted by adding one of an acid and an alkaline agent into an
aqueous hydrogen peroxide solution, together with the organic
carboxylic acid or the salt thereof.
[0014] (3) The disinfection system of a contact lens according to
the above aspect (1) or (2), where the organic carboxylic acid is
glycolic acid.
[0015] (4) The disinfection system of a contact lens according to
the above aspect (1) or (2), where the organic carboxylic acid is
tartaric acid.
[0016] (5) The disinfection system of a contact lens according to
the above aspect (1) or (2), where the organic carboxylic acid is
citric acid.
[0017] (6) The disinfection system of a contact lens according to
any one of the above aspects (1) to (5), where the organic
carboxylic acid or the salt thereof is contained at a concentration
of at least 0.1% or more.
[0018] (7) The disinfection system of a contact lens according to
any one of the above aspects (1) to (6), where the disinfecting
solution further contains a chelating agent.
[0019] (8) The disinfection system of a contact lens according to
the above aspect (7), where the chelating agent is at least one
selected from the group consisting of EDTA, a salt thereof,
etidronic acid, and a salt thereof.
[0020] (9) The disinfection system of a contact lens according to
any one of the above aspects (1) to (8), where the metal catalyst
is a metal film catalyst.
[0021] (10) The disinfection system of a contact lens according to
any one of the above aspects (1) to (9), where the disinfecting
solution further contains at least one of surfactant and a nonionic
tonicity agent.
[0022] (11) The disinfection system of a contact lens according to
any one of the above aspects (1) to (10), where the metal catalyst
is contained in a predetermined treatment container for contact
lens disinfection, and the disinfecting solution is contained in
the treatment container to allow the metal catalyst be in contact
with the disinfecting solution.
[0023] As described above, in the disinfection system of a contact
lens in accordance with the present invention, the organic
carboxylic acid or salt thereof, which has the specific structure
in which the hydroxyl group and the carboxyl group are bonded, is
added into the disinfecting solution containing the hydrogen
peroxide, and the pH of the disinfecting solution is adjusted to 6
to 8, so that the contact lens is effectively disinfected by being
immersed into the disinfecting solution, and the neutralization
rate of the hydrogen peroxide in the disinfecting solution is
effectively improved, which results in the improvement of the
neutralization efficiency of the hydrogen peroxide. As a result,
the amount of metal used in the metal catalyst, which is necessary
for completing the neutralization within a desired period of time,
can be reduced, thereby advantageously saving the resource of the
catalyst metal, which is valuable. Further, the disinfection system
can be provided at a lower cost by saving the catalyst metal.
[0024] Moreover, in the disinfection system of the present
invention, the disinfecting solution after the neutralization
treatment is constituted so as to have an osmotic pressure of 250
to 350 mOsm. Therefore, the contact lens after the neutralization
treatment can be worn on the eye as it is, without performing a
cleaning treatment such as rinsing. In particular, when the
disinfecting solution is prepared by containing the surfactant
and/or the nonionic tonicity agent, the characteristics of direct
wearing of the contact lens after the disinfection are more
advantageously exhibited.
DETAILED DESCRIPTION OF THE INVENTION
[0025] In the disinfection system of a contact lens in accordance
with the present invention, the hydrogen peroxide-containing
disinfecting solution into which the contact lens to be disinfected
is immersed is prepared so as to have a hydrogen peroxide
concentration of 1 to 10% (on weight basis). The amount of the
hydrogen peroxide smaller than the above-described range may cause
a problem that the disinfection effect due to the hydrogen peroxide
cannot be sufficiently exhibited. Conversely, the amount of the
hydrogen peroxide exceeding the above-described range, although the
excellent disinfection effect is obtained, may cause problems that
the neutralization treatment requires much more time, the amount of
metal catalyst used for decomposition and neutralization of the
hydrogen peroxide is increased, and the hydrogen peroxide becomes
liable to remain on a surface or in the inside of the contact lens
due to the insufficient neutralization treatment, resulting in an
adverse effect on the eye. In order to advantageously avoid these
problems, a hydrogen peroxide concentration of 2 to 6% by weight is
particularly suitably employed.
[0026] Further, the metal catalyst which carries out the
neutralization treatment, in which the hydrogen oxide is detoxified
to eliminate adverse effect on the eye, by contacting and
decomposing the hydrogen peroxide contained in the disinfecting
solution, is appropriately selected from various known metal
catalysts which have hitherto been used for the decomposition and
neutralization treatment of the hydrogen peroxide. For example,
platinum is preferably used as a metal catalyst. In addition,
metals such as palladium, silver, copper, manganese, cobalt and
aluminum or oxides of such metals can also be used, for
example.
[0027] These metals or the oxides thereof can be formed as the
metal catalysts in the same catalyst form as the conventional one.
In the present invention, a metal film catalyst, in other words,
the catalyst formed by adhering the above-mentioned metal or the
oxide thereof in film form to a predetermined substrate is
particularly advantageously used. Specifically, such a metal film
catalyst is obtained by a known film forming technique, i.e., by
plating or sputtering the above-mentioned catalyst metal on a
surface of the substrate having various shapes such as a disk and a
flat plate having a predetermined size. The metal film catalyst is
disposed in the disinfecting solution and is allowed to be in
contact with the hydrogen peroxide present in the disinfecting
solution. Further, as a material of such a substrate, at least one
selected from the group consisting of a plastic, a metal, a glass,
a ceramic and an ion-exchange resin is suitably used. Furthermore,
examples of plastic materials include an
acrylonitrile-butadiene-styrene (ABS) resin, polyurethane, modified
polyphenylene ether, polystyrene, polycarbonate, polyethylene
terephthalate (PET), polybutylene terephthalate (PBT), polyvinyl
chloride, polyetherimide, polysulfone, polymethyl methacrylate and
copolymer resins thereof.
[0028] Then, in the present invention, the specific organic
carboxylic acid or salt thereof, having a structure in which a
hydroxyl group and a carboxyl group are bonded to one carbon atom,
is allowed to be contained in such a disinfecting solution, and the
pH of such a disinfecting solution is adjusted to 6 to 8, thereby
effectively performing the above-mentioned contact lens
disinfection and the neutralization treatment with the metal
catalyst. That is to say, while the disinfection treatment is
effectively performed with the hydrogen peroxide, the
neutralization rate of the hydrogen peroxide with the metal
catalyst can be effectively increased, which results in
advantageous improvement of its neutralization efficiency.
[0029] The specific organic carboxylic acid or salt thereof used
herein has a structure in which a hydroxyl group and a carboxyl
group are bonded to one carbon atom, thereby effectively
contributing to the acceleration of the decomposition and
neutralization of the hydrogen peroxide. Example of the organic
carboxylic acid include glycolic acid, malic acid, tartaric acid
and citric acid. In order to achieve the object of the present
invention, glycolic acid is advantagously used.
[0030] Then, such a specific organic carboxylic acid is generally
contained in the disinfecting solution at a rate of at least 0.1%
weight basis in order to advantageously improve the neutralization
efficiency of the hydrogen peroxide, which is desired in the
present invention. On the other hand, the upper limit of the
content of such a specific organic carboxylic acid is generally
about 5%. However, depending on the kind of the carboxylic acid,
the concentration thereof is appropriately determined so that the
disinfecting solution after the neutralization treatment has a
desired osmotic pressure.
[0031] Further, in the present invention, the pH of the
disinfecting solution containing the above-mentioned specific
organic carboxylic acid or salt thereof is adjusted to 6 to 8. To
adjust pH, an acid or an alkaline agent is used. In particular, in
the preparation of the hydrogen peroxide-containing disinfecting
solution, a proper commercially available aqueous hydrogen peroxide
solution is generally used, and such an aqueous hydrogen peroxide
solution is maintained under an acidic condition for stability of
the solution. Accordingly, in the present invention, a known proper
alkaline agent such as sodium hydroxide or potassium hydroxide is
advantageously added together with the above-mentioned organic
carboxylic acid or salt thereof to perform the pH adjustment of
such an aqueous hydrogen peroxide solution, thereby adjusting the
pH of the resulting disinfecting solution to 6 to 8.
[0032] As described above, the disinfection of the contact lens is
performed by using the disinfecting solution of the present
invention with the pH adjusted to 6 to 8, while the hydrogen
peroxide in the disinfecting solution is neutralized with the metal
catalyst, whereby the neutralization rate thereof can be
effectively increased, resulting in the improvement of the
neutralization efficiency. Further, the pH of the hydrogen peroxide
after the neutralization becomes nearly neutral, so that there is
also an advantage of less irritation even when the lens after the
treatment is directly placed on the eye. The pH of the disinfecting
solution lower than 6 will not sufficiently increase the
neutralization rate of the hydrogen peroxide with the metal
catalyst, for example. The pH of the disinfecting solution
exceeding 8 will decrease the stability of the disinfecting
solution, which fails to provide a sufficient time for application
of the disinfecting solution to the disinfection system.
[0033] In the present invention, even when the pH of the
disinfecting solution is adjusted to 6 to 8, since the
above-mentioned specific organic carboxylic acid or salt thereof is
present, the stability of the hydrogen peroxide is effectively
enhanced by a chelate action thereof. Accordingly, in the
disinfecting solution of the present invention, most of the
hydrogen peroxide is not decomposed and present, particularly at a
residual rate of 90% or more, even after the elapse of a long
period of time after the preparation thereof. Therefore, the
disinfecting solution can be advantageously used for the
disinfection of the contact lens over a long period of time.
[0034] Further, in the disinfection system of a contact lens in
accordance with the present invention, the contents of the
essential components in the disinfecting solution (unused) used for
the disinfection and neutralization of the contact lens and the
amounts of addition components to be added as necessary are
adjusted, and a known tonicity agent is further added and contained
as necessary, so that the disinfecting solution after the
neutralization treatment has an osmotic pressure of 250 to 350
mOsm. The adjustment of the osmotic pressure of the disinfecting
solution after the neutralization treatment allows the osmotic
pressure of the disinfecting solution to be almost equivalent to
the osmotic pressure of the tear fluid, so that it is possible to
wear the contact lens after the disinfection and neutralization
treatments on the eye as it is. Even in the case where the
disinfecting solution enter in the eye by wearing the contact lens
with the disinfecting solution remaining on and adhering to a lens
surface thereof, irritation to the eye of a wearer can be
advantageously reduced, and the adverse effect on the eye can be
advantageously avoided.
[0035] In the disinfecting solution used in the present invention,
known various addition components used in the general preparation
of disinfecting solutions, for example, a chelating agent, a
surfactant, a tonicity agent, a buffer, a thickener, a preservative
and the like, may be contained as needed, either alone or as a
combination of two or more thereof, in addition to the hydrogen
peroxide and the specific organic carboxylic acid or salt thereof
as the essential components. However, it is necessary that all of
those respective components are safe to the living body and
ophthalmic physiologically acceptable, and do not impede the
functions and effects of the present invention as described above.
Further, each of the components is used within the quantitative
range that does not impair the effects.
[0036] In particular, the chelating agent improves the stability of
the disinfecting agent of the present invention to advantageously
achieve long-term reservation thereof. At least one of EDTA
(ethylenediaminetetraacetic acid), a salt thereof, etidronic acid,
and a salt thereof is advantageously used. The chelating agent is
generally contained in the disinfecting solution at a concentration
of about 0.01 to 0.5% by weight.
[0037] The surfactant is further contained for the cleaning of the
contact lens, separately from the disinfection of the contact lens.
As such surfactants, there can be advantageously employed all of
known anionic, nonionic, amphoteric and cationic surfactants which
have hitherto been used in contact lens solutions and the like. By
the addition of the surfactant, an effective cleaning effect such
as a lipid-removing action is imparted to the disinfecting
solution. Among others, in the present invention, nonionic
surfactants are preferably used. Examples of the nonionic
surfactant include polyethylene glycol ethers of higher alcohols,
polyethylene glycol esters of higher fatty acids, polyglycerol
esters of fatty acids, polyethylene glycol ethers of alkyl phenols,
polyethylene glycol sorbitan alkyl esters,
polyoxyethylene-polyoxypropylene glycols (poloxamers), and
ethylenediamine tetrapolyoxyethylene polyoxypropylenes
(poloxamines). Of these, block copolymers of polyoxyethylene and
polyoxypropylene or derivatives thereof (poloxamers or poloxamines)
are particularly advantageously used.
[0038] Further, the tonicity agent is added in order to easily
perform the adjustment of the osmotic pressure of the disinfecting
solution before the disinfection treatment of the contact lens, and
eventually after the disinfection thereof. Known various tonicity
agents which have been generally used in contact lens solutions are
appropriately used. Of these, known nonionic tonicity agents such
as propylene glycol, glycerol and saccharides are particularly
advantageously used in the present invention. By the addition of
such a nonionic tonicity agent into the disinfecting solution,
lipophilicity of the solution is increased, and the occurrence of
ocular irritation can be more advantageously inhibited, thereby
obtaining more excellent sense of use. Of these, propylene glycol
is more suitably employed, because it increases the viscosity of
the solution, advantageously resulting in the reduction in the
occurrence of ocular irritation.
[0039] In the preparation of the disinfecting solution of the
present invention, no special method is required in any way. As in
the preparation of the conventional disinfecting solution for
contact lenses, the desired disinfecting solution can be easily
obtained by adding or dissolving the respective components in an
aqueous medium, without regard to the addition order, or
sequentially or concurrently, or in appropriate combination
thereof. It is to be understood that, in the preparation of the
disinfecting solution, other than water itself such as purified
water or distilled water, any known aqueous solution such as a
physiological saline, a contact lens storing solution or a cleaning
solution may be used as the aqueous medium, as long as it is a
solution mainly composed of water.
[0040] Then, in the present invention, the contact lens to be
subjected to the disinfection treatment is immersed in the
disinfecting solution prepared in this way, thereby disinfecting
the contact lens with the hydrogen peroxide. Then, after such a
disinfection treatment has been performed for a period of time that
is enough to disinfect the contact lens, the metal catalyst is
allowed to be in contact with the disinfecting solution in which
the contact lens is immersed, in order to neutralize the hydrogen
peroxide so that the hydrogen peroxide does not remain in the
disinfecting solution. Accordingly, the neutralization treatment is
performed through contact with the hydrogen peroxide. As procedures
for the disinfection treatment and the neutralization treatment,
any known procedures are appropriately employed.
[0041] For example, in addition to the procedure in which the
disinfection treatment and the neutralization treatment are
performed by immersing the contact lens and the metal catalyst
concurrently or sequentially in the disinfecting solution in a
state where a predetermined amount of the disinfecting solution is
contained in a predetermined treatment container, any known
procedures may be suitably employed, such as a procedure in which
the disinfection treatment and the neutralization treatment are
performed in parallel with each other by pouring the disinfecting
solution in a treatment container in a state where the contact lens
and the metal catalyst are arranged in the treatment container, a
procedure in which the treatments are performed by allowing the
disinfecting solution to be contained in a treatment container in a
state where one of the contact lens and the metal catalyst is
arranged in the treatment container and thereafter the other one of
the contact lens and the metal catalyst is immersed in the
disinfecting solution to be in contact therewith.
[0042] Further, as a structure of the treatment container, a known
container for a contact lens treatment using a solution can be
appropriately selected and used. Specifically, a sterilizing device
having the structure as disclosed in the foregoing JP-T-4-507052
can be used as it is. In any case, the treatment container having
any structure may be employed as long as the contact lens and the
metal catalyst can be immersed into and contacted with the
disinfecting solution in a state where the container contains the
contact lens and the metal catalyst.
[0043] Further, the kind of the contact lens to be disinfected in
such a disinfection system in accordance with the present invention
is not limited. For example, all kinds of contact lenses may be
disinfected irrespective of water-containing or
non-water-containing and soft or hard materials. The present
invention is applicable to all contact lenses made from any
material. However, conventional disinfection systems using the
hydrogen peroxide are used to disinfect soft contact lenses, so
that in the present invention, the disinfection system is also
mainly applied to the disinfection of the soft contact lenses.
Here, the soft contact lenses composed of water-containing
hydrogels are known. As a typical example of such contact lenses,
there is one formed of a polymer or copolymer of a hydrophilic
monomer such as 2-hydroxyethyl methacrylate,
N,N-dimethylacrylamide, N-vinyl-2-pyrrolidone or methacrylic acid.
In recent years, the soft contact lenses also include contact
lenses composed of silicone hydrogels, which are copolymers
produced by copolymerizing silicone-containing hydrophobic monomers
in combination with these hydrophilic monomers. The present
invention is also applicable to such soft contact lenses.
[0044] After the application of the disinfection system in
accordance with the present invention, the contact lens that was
subjected to the disinfection treatment is generally taken out of
the disinfecting solution and worn on the eye. Since the
neutralization treatment using the metal catalyst is performed to
the hydrogen peroxide in the disinfecting solution, the amount of
the hydrogen peroxide remaining in the disinfecting solution is
extremely reduced, and the hydrogen peroxide adhering to the
contact lens or remaining in the lens is also negligible.
Accordingly, even when the contact lens taken out of the
disinfecting solution is worn on the eye as it is, it can be safely
worn without causing problem.
EXAMPLES
[0045] To further clarify the present invention, some examples of
the invention will be described. It is to be understood that the
invention is not limited to the details of illustrated examples and
the forgoing description, but may be embodied with various changes,
modifications, and improvements, which may occur to those skilled
in the art without departing from the scope of the invention.
Preparation of Disinfecting Solution Specimens
[0046] A commercially available aqueous hydrogen peroxide solution
was diluted with distilled water to various concentrations
indicated in the following Tables 1 to 4, and various addition
components indicated in these Tables were added to be contained,
thereby preparing various disinfecting solution specimens of
Examples 1 to 18 and Comparative Examples 1 to 14. Further, in the
preparation of such disinfecting solution specimens, hydrochloric
acid was used as an acid and caustic soda was used as an alkaline
agent to obtain the disinfecting solution specimens having desired
pH values.
[0047] The addition components in the following Tables were added
and contained as follows: a poloxamer
(polyoxyethylene-polyoxypropylene glycol) as a nonionic surfactant;
EDTA.2Na (ethylenediamine tetraacetic acid disodium salt) and
etidronic acid as chelating agents; PG (propylene glycol) as a
nonionic tonicity agent; glycolic acid, tartaric acid and citric
acid as specific organic carboxylic acid components of the present
invention; and NaCl, boric acid, phosphoric acid, tris, taurine and
aspartic acid as other auxiliary components such as a buffer.
[0048] Further, in order to evaluate stability of the respective
solutions, the respective disinfecting solution specimens thus
prepared were stored under accelerating conditions (40.degree.
C..times.3 months), and thereafter, the residual rate of hydrogen
peroxide in the respective disinfecting solution specimens was
measured and determined by "the titration method of oxydol"
described in The Japanese Pharmacopoeia. The results thereof are
shown together in the following Tables 1 to 4. "Excellent" denotes
that the residual rate thereof was 95% or more, "Good" denotes that
the residual rate was from 90% to less than 95%, "Fair" denotes
that the residual rate was from 80% to less than 90%, and "Poor"
denotes that the residual rate was less than 80%.
TABLE-US-00001 TABLE 1 Addition Examples Components 1 2 3 4 5 6 7 8
9 Disinfecting Hydrogen 3.4 3.4 3.4 3.4 5.3 8.5 3.4 3.4 3.4
Solution Peroxide Composition EDTA.cndot.2Na -- 0.1 0.1 0.1 0.1 0.1
0.1 0.1 0.1 [% by weight] Glycolic Acid 1 1 1 1 1 1 1 -- --
Tartaric Acid -- -- -- -- -- -- -- 1 -- Citric Acid -- -- -- -- --
-- -- 1 NaCl -- -- -- -- -- -- -- 0.35 0.45 Disinfecting Solution
pH 7.4 6 7.4 7.4 7.4 7.4 8 7.4 7.4 (before Neutralization)
Disinfecting H.sub.2O.sub.2 Residual 90 100 98 99 96 -- 97 94 92
Solution Stability Rate [%] (Acceleration) Evaluation Good
Excellent Excellent Excellent Excellent -- Excellent Good Good
TABLE-US-00002 TABLE 2 Addition Examples Components 10 11 12 13 14
15 16 17 18 Disinfecting Hydrogen 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4
3.4 Solution Peroxide Composition Poloxamer 0.08 -- 0.08 0.08 0.08
0.08 0.08 0.08 0.08 [% by weight] EDTA.cndot.2Na -- -- 0.1 0.1 0.1
0.1 -- 0.1 0.1 Etidronic Acid -- 0.02 0.02 0.02 0.02 -- 0.02 0.02
0.02 PG 0.50 -- 0.50 -- -- 0.50 0.50 0.50 0.50 Glycolic Acid 0.70
1.00 0.70 0.70 0.70 0.60 1.00 -- 0.70 Tartaric Acid -- -- -- -- --
-- -- 1 -- NaCl -- -- -- 0.20 0.20 -- -- 0.10 -- Disinfecting
Solution pH 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.4 (before
Neutralization) Disinfecting H.sub.2O.sub.2 Residual 92 97 100 99
99 97 96 95 100 Solution Rate [%] Stability Evaluation Good
Excellent Excellent Excellent Excellent Excellent Excellent Good
Excellent (Acceleration)
TABLE-US-00003 TABLE 3 Comparative Examples Addition Components 1 2
3 4 5 6 Disinfecting Solution Hydrogen Peroxide 3.4 3.4 3.4 12 3.4
3.4 Composition EDTA.cndot.2Na -- 0.1 0.1 0.1 0.1 -- [% by weight]
Etidronic Acid 0.02 -- -- -- 0.02 0.02 PG -- -- -- -- 0.50 0.50
Glycolic Acid 1.00 1.00 1.00 1.00 0.45 1.20 Disinfecting Solution
pH 2 4 9 7.4 7.4 7.4 (before Neutralization) Disinfecting
H.sub.2O.sub.2 Residual Rate [%] 98 97 68 -- 98 96 Solution
Stability Evaluation Excellent Excellent Poor -- Excellent
Excellent (Acceleration)
TABLE-US-00004 TABLE 4 Addition Comparative Examples Components 7 8
9 10 11 12 13 14 Disinfecting Hydrogen 3.4 3.4 3.4 3.4 3.4 3.4 3.4
3.4 Solution Peroxide Composition Poloxamer -- -- -- -- -- 0.08
0.08 -- [% by weight] EDTA.cndot.2Na 0.1 0.1 0.1 0.1 -- 0.1 0.1 0.1
Etidronic Acid -- -- -- -- -- 0.02 0.02 -- PG -- -- -- -- -- 0.50
0.50 -- NaCl 0.30 0.55 0.35 0.55 0.35 0.15 0.15 -- Boric Acid 1 --
-- -- -- -- -- -- Phosphoric Acid -- 1 -- -- -- -- -- -- Tris -- --
1 -- -- -- -- -- Taurine -- -- -- 1 -- -- -- -- Aspartic Acid -- --
-- -- 1 1 1 -- Disinfecting Solution pH 7.4 7.4 7.4 7.4 7.4 7.4 7.4
7.4 (before Neutralization) Disinfecting H.sub.2O.sub.2 Residual 90
86 99 100 75 93 93 100 Solution stability Rate [%] (Acceleration)
Evaluation Good Fair Excellent Excellent Poor Good Good
Excellent
[0049] In the disinfecting solution specimens prepared as described
above, as indicated in Tables 1 to 4 above, it is confirmed that
all of the disinfecting solution specimens of Examples 1 to 18 that
are in accordance with the present invention are high in the
residual rate of hydrogen peroxide and excellent in their solution
stability, even when stored under the accelerating conditions
(40.degree. C..times.3 months). In contrast, in the disinfecting
solution specimen of Comparative Example 3 having the solution pH
exceeding 8 and the disinfecting solution specimen of Comparative
Example 8 or 11 further containing phosphoric acid or aspartic
acid, it is confirmed that the residual rate of hydrogen peroxide
is decreased to cause a problem in solution stability.
Disinfection and Neutralization Treatments
[0050] Using the respective disinfecting solution specimens
obtained above, disinfection and neutralization treatments of
contact lenses were performed. Specifically, a plastic disck that
is plated with Pt or Pd (a plactic disck A having a catalyst
surface area of about 10.4 cm.sup.2 or a plastic disk B having a
catalyst surface area of about 7.0 cm.sup.2) was first placed as a
metal catalyst at a bottom portion of a plastic container having a
volume of 20 mL, and 10 mL of each of disinfecting solution
specimens prepared above was poured therein. Then, a commercially
available soft contact lens: Month Wear (group II: manufactured by
Menicon Co., Ltd.) or Menicon Focus (group IV: manufactured by
Menicon Co., Ltd.) as a test lens was accommodated in a
commercially available basket-shaped case (having a basket-like
housing portion) for a lens treatment, and immersed together with
that case into the disinfecting solution specimen contained in the
plastic container, followed by keeping under room temperature for 2
hours, thereby performing the disinfection of the test lens and the
neutralization treatment of the disinfecting solution specimen.
[0051] For each disinfecting solution specimen present in the
plastic container after such disinfection and neutralization
treatments, the amount of hydrogen peroxide remaining therein was
determined by "the titration method of oxydol" described in The
Japanese Pharmacopoeia, and evaluation of the neutralization rate
was performed. The evaluation results thereof are shown in the
following Tables 5 to 8. "Excellent" denotes that the residual
amount thereof was less than 100 ppm, "Good" denotes that the
residual amount thereof was 100 ppm to less than 200 ppm, "Fair"
denotes that the residual amount thereof was 200 ppm to less than
500 ppm, and "Poor" denotes that the residual amount thereof was
500 ppm or more.
[0052] Further, the above-mentioned disinfection and neutralization
treatments were performed to the two commercially available soft
contact lenses, namely "Month Wear" (manufactured by Menicon Co.,
Ltd.) belonging to group II and "Menicon Focus" (manufactured by
Menicon Co., Ltd.) belonging to group IV, and thereafter, the
amount of change in DIA (diameter) of each lens was measured. Then,
lens compatibility was evaluated, and the results thereof are shown
together in the following Tables 5 to 8. "Good" denotes that the
amount of change in DIA of the both of the lenses was within a
standard, "Fair" denotes that only one lens was within the
standard, and "Poor" denotes that both of the lenses were out of
the standard.
TABLE-US-00005 TABLE 5 Examples 1 2 3 4 5 6 7 8 9 Metal Catalyst Pt
Pt Pt Pt Pt Pt Pt Pt Pt Catalyst Surface A A A B A A A A A Area
Neutralization Rate Excellent Good Excellent Good Excellent Good
Excellent Good Good Osmotic Pressure 274 290 294 294 294 294 296
283 274 after Neutralization [mOsm] Lens Compatibility Good Good
Good Good Good Good Good Good Good
TABLE-US-00006 TABLE 6 Examples 10 11 12 13 14 15 16 17 18 Metal
Catalyst Pt Pt Pt Pt Pt Pt Pt Pt Pd Catalyst Surface A A A A B A A
A A Area Neutralization Rate Good Excellent Good Good Good Good
Excellent Good Good Osmotic Pressure 260 279 286 282 282 253 348
276 286 after Neutralization [mOsm] Lens Compatibility Good Good
Good Good Good Good Good Good Good
TABLE-US-00007 TABLE 7 Comparative Examples 1 2 3 4 5 6 Metal
Catalyst Pt Pt Pt Pt Pt Pt Catalyst Surface Area A A A A A A
Neutralization Rate Poor Fair Excellent Poor Good Excellent Osmotic
Pressure after 150 215 300 294 217 403 Neutralization [mOsm] Lens
Compatibility Good Good Good -- Fair Fair
TABLE-US-00008 TABLE 8 Comparative Examples 7 8 9 10 11 12 13 14
Metal Catalyst Pt Pt Pt Pt Pt Pt Pd -- Catalyst A A A A A A A --
Surface Area Neutralization Good Fair Poor Poor Poor Poor Poor Fair
Rate Osmotic 277 275 283 277 255 284 284 18 Pressure after
Neutralization [mOsm] Lens Poor Good Good Fair Good Good Good Poor
Compatibility
[0053] As is apparent from the results shown in Tables 5 to 8, in
all of Examples 1 to 18 in which the disinfection and
neutralization treatments were performed using the disinfecting
solution specimens in accordance with the present invention, the
sufficient neutralization rates and the sufficient lens
compatibility were secured. Further, in Examples 4 and 14 in which
the catalyst surface area was about 7.0 cm.sup.2, the sufficient
neutralization rates were secured, which means that the intended
disinfection and neutralization treatments using the hydrogen
peroxide were realized by using small amount of catalyst metal.
Thus, the valuable catalyst metal can be saved and the more
inexpensive disinfection system can be advantageously provided.
[0054] In contrast, the disinfecting solution specimens of
Comparative Examples 1 and 2 having the pH of lower than 6 have
insufficient neutralization rates. Thus, in order to reduce the
amount of the remaining hydrogen peroxide to such a degree as to
become harmless to the eye, a larger amount of catalyst metal is
required, or that the treating time should be made longer. Further,
if the osmotic pressure of the disinfecting solution specimens
after the neutralization treatment is too low (Comparative Examples
5 and 14) or too high (Comparative Example 6), it is impossible to
wear the lens on the eye as it is, and a problem in lens
compatibility is caused due to changes in size of lenses, after the
neutralization treatment. Furthermore, the addition components such
as boric acid, phosphoric acid, tris, taurine and aspartic acid
which are used as a buffer, for example, in conventional contact
lens solution cause a problem in the neutralization rate or lens
compatibility, as indicated in the results of Comparative Examples
7 to 13. In the disinfection system in accordance with the present
invention, those addition components act as interfering components,
so that the addition of such interfering components should be
avoided in the present invention.
* * * * *