AU605464B2

AU605464B2 - Contact-lens care set

Info

Publication number: AU605464B2
Application number: AU60652/86A
Authority: AU
Inventors: Gerhard Dr. Ludwig; Horst Dr. Schafer; Rainer Dr. Sunderdiek
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1985-09-11
Filing date: 1986-07-29
Publication date: 1991-01-17
Anticipated expiration: 2006-07-29
Also published as: FI84521B; FI863207A; DE3532433A1; DK431286D0; DK166654B1; NO170308C; NO170308B; FI863207A0; NO863126L; NO863126D0; ES2002483A6; FI84521C; AU6065286A; DK431286A

Description

AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION 464

(ORIGINAL)

FOR OFFICE USE Application Number: Lodged: .4 4 4w k4 4 4W 4 41 ~s 4*4, 4 4*4' 4 4 9 4~4~ Complete Specification Lodged: Accepted: Published: Priority: Related Art: t~ -U TO BE COMPLETED BY APPLICANT 4,4,4 4 #4* 4 I 44 4 4494 4, 4,44 p 4 1 4 44 44 4 *4*4

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4114*1 4 4 Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: CIBA GEIGY AG Klybeckstrasse 141, 4002 Basle, SWITZERLAND Dr. Horst Schafer, Dr. Gerhard Ludwig, Dr. Rainer Sunderdiek ARTHUR S. CAVE CO.

Patent Trade Mark Attorneys Level 10 Barrack Street SYDNEY N.S.W. 2000

AUSTRALIA

Complete Specification for the invention entitled CONTACT-LENS CARE SET.

The following statement is a full description of this invention including the best method of performing it known to me:- 1 ASC 49 j\ 319MRAP t Contact-Lens Care Set The Invention relates to a contact lens care set.

Care sets for soft and hard contact lenses serve to clean, to disinfect and to stabilize the optical properties and to improve the wear comfort of the contact lenses. Hydrogen peroxide, as antimicrobial substance, has become more important recently for disinfecting and cleaning contact lenses. Compared to chlorhexidine salts or organomercury compounds, such as thiomersal, which are also used to disinfect contact lenses, hydrogen peroxide has a better antimicrobiological effect, especially with respect to the relatively resistant Aspergillus species. The known hydrogen peroxide solutions, used to clean contact lenses, are 3% peroxide solutions (German Patent 2,425,714). After treatment of the contact lenses with these solutions, relatively large residual amounts of hydrogen peroxide solution adhere to the lens. When lenses so t t treated are inserted, these residual amounts lead to varying degrees of irritation of the mucous membrane. Therefore, after treatment with a S hydrogen peroxide solution, it is necessary to treat the lens with a S neutralizing solution, by means of which the hydrogen peroxide is split into water and oxygen. The elimination after the sterilization treati ment of residual amounts of hydrogen peroxide by decomposition with the S help especially of heavy metal catalysts is known from the aforementioned German Patent 2,425,714. The use of two different treatment steps is required here, namely, first of all, the treatment step of sterilizing the lens and, after discarding the sterilizing solution, the treatment step of eliminating the residual hydrogen peroxide in an aqueous system containing the catalyst. The handling of the lens during the care and cleaning operations therefore is relatively complicated.

The choice of suitable catalysts, which are used for the decomposition of residual amounts of hydrogen peroxide, also presents difficulties.

As catalysts for the decomposition of the hydrogen peroxide, used to disinfect and clean contact lenses, after the cleaning and disinfecting L I

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treatments have been carried out, the use of enzymatic peroxidases, especially catalase, is known from the EP-A-82 798. In this case also, however, the hydrogen per'oxide solution is poured off after its disinfecting treatment and replaced by a neutralizing solution which contains the peroxide-neutralizing catalyst or catalysts peroxidases). Here also, therefore, two different, successive treatment steps are employed, so that the care treatment of the lens remains complicated.

In both cases, a contact lens care treatment simultaneously using hydrogen peroxide and a neutralizing solution with a decomposition catalyst, for example, has been impossible because, in such case, the hydrogen peroxide is decomposed into oxygen and water by the neutralizing solution via its decomposition catalyst, for example, before it can have a sufficient sterilizing action to kill the germs on the lens which requires from about one to about four hours, especially for a soft lens.

Summary of the Invention It is, therefore, an object of the invention to provide a contact lens care set which, in one step, keeps hydrogen peroxide active sufficiently long at least for substantially sterilizing the lens and then neutralizes at least residual hydrogen peroxide on the lens at least substantially so that the lens can then be worn, at least generally, without discomfort.

2 To this and other end, the invention provides a contact lens care set having at least two agents: hydrogen peroxide and a neutralizing agent. The hydrogen peroxide is sufficient to be effective at least for substantially sterilizing at least one of a hard or soft contact lens and, preferably, either. The neutralizing agent is sufficient to be effective at least for decomposing any residual amount of the hydrogen peroxide on the lens into oxygen and water after the hydrogen peroxide has so sterilized the lens at least substantially, whereby the lens can then be worn, at least generally, without discomfort. The neutralizing agent has at least two constituents: a catalyst or enzyme, preferably for so decomposing the residual hydrogen peroxide, and a retarding agent. The retarding agent delays the time of release of at least so much of the neutralizing agent as decomposes the residual hydrogen peroxide, e.g., 4 Ut t the catalyst, into the hydrogen peroxide until the hydrogen peroxide has so sterilized the lens.

tt Ut t ~The invention therefore substantially facilitates t the care of the contact lens, whether hard or soft, because only a one-step treatment is required. The lens and the neutralizing agent with the catalyst and the retarding agent ~that controls the time-delayed release of at least part of the neutralizing agent such as the catalyst, for example, are placed into a sterilizing hydrogen peroxide solution.

The regarding agent, which comes into contact with the hydrogen peroxide during the immersion, then releases at least the neutralizing portion of the catalyst-containing neutralizing agent after the hydrogen peroxide has acted on the contact lens that is to be treated for a time sufficient for the lens sterilization.

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For this, the neutralizing agent may be coated with its retarding -brnn- 1 dor'ez .t agent for immersion in the hydrogen peroxide in a water solution with the lens. The delayed release time then can be adjusted (especially up to four hours), for example, by the thickness of the coating which dissolves into the hydrogen peroxide solution. As a result of the release of the catalyst-containing neutralizing agent when the coating dissolves, the neutralizing acts automatically, without further help from the contact-lens wearer taking care of the contact lens, on the hydrogen peroxide solution. The hydrogen peroxide solution is acidic (with a pH of less than 4) in the stable state for effecting both the sterilization and the dissolving. The catalyst, for example, inside the coating then decomposes the sterilizing hydrogen peroxide solution in a treatment container therefore in which the lens to be treated and the neutralizing agent have also been placed at the same time.

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V V Examples of the composition of the hydrogen peroxide solution and of the catalyst- or enzyme-containing neutralizing agent are given in the German Offenlegungsschrift 3,410,400.

Moreover, the following composition is suitable as neutralizing agent: 0.05 weight percent 0.05 weight percent 0.05 weight percent 0.25 weight percent 0.75 weight percent catalase concentrate, 260,000 units/mL hydroxypropylmethylcellulose USP XX NaH 2

PO

4 x 2H 2 0 DAB 8 Na 2

HPO

4 x 2H 2 0 sodium chloride EP I The following is a further suitable composition of the neutralizing agent: t I 3 12 mg suitable buffer substance(s) or mixture, for example, alkali 0, phosphate, borate or citrate, glycine 40 70 mg neutral electrolyte (for example, NaCl, KC1) 10 mg alkali hydrogen carbonate 10 mg water-soluble polymer, for example, polyvinylpyrrolidone 0.2 1 mg catalyst (catalase, peroxidase) per single dose.

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e This amount is sufficient to decompose, to neutralize and to adjust to an osmolarity of 270 320 mosmol 7 mL of an hydrogen peroxide.solution.

These 7 mL correspond to the volume of a standard contact lens case or contact lens treatment body.

An example of a further special composition of the neutralizing agent is the following: 5.6 mg potassium hydrogen phosphate 8 mg disodium hydrogen phosphate 52.4 mg NaCl 7 mg sodium hydrogen carbonate 4.8 mg polyvinylpyrrolidone 0.3 mg catalyst 0o The compositions of the neutralizing agent, given above, can be used as o" capsule fillings, the capsule being fashioned as the retarding agent, which surrounds the catalyst-containing neutralizing agent. The capsule comprises a water-soluble polymer, especially a polyvinyl alcohol.

S The neutralizing agent may also be formed into a tablet, which is provided with a water-soluble coating for the time-delayed dissolution of 0 0e a 0 the tablet. The water-soluble coating may comprise a polymer, soluble S .in an acidic medium, such as a polymer of dimethylaminomethacrylate and neutral methacrylate esters. The coating may also comprise a pH-neutral, soluble polymer. Polymers, suitable for this purpose, are, for example, soluble cellulose ethers such as methylcellulose, methylhy- 0" droxypropylcellulose, methylhydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, sodium carboxymethylcelluloses; cellulose acetate phthalate; hydroxypropylmethylcellulose phthalate; polymers of methacrylic acid and methacrylate esters; a coating of an aqueous dispersion of a copolymer of methacrylic acid and methacrylate esters; a coating of an aqueous dispersion of cellulose acetate phthalate; copolymers of methyl vinyl ether and maleic anhydride and polyvinyl alcohols.

Suitable polyalcohols, especially in an amount of 0.2 1 mg/tablet, can be added to these polymers to control the time delay, 1,2-propyleneglycol, polyethylene glycols and citrate esters being suitable as polyalcohols.

The coating can be produced from the water-soluble polymer by known processes, for example, by spray-coating a film in the coating pan, by the fluidized bed process (Wurster process) or in closed systems. The preferred amount of polymer, coating a tablet, is 2.0 to 5.0 mg.

The following is an example of a tablet composition, which forms the catalyst-containing neutralizing agent: 11.2 mg disodium hydrogen phosphate 55.8 mg NaC1 4.8 mg polyvinylpyrrolidone 0.2 mg catalyst (catalase, peroxidase) The following is an example of an acid-soluble polymer, suitable as a coating: 1.9 mg methacrylate ester 0.4 mg hydroxypropylmethylcellulose 0.2 mg polyethylene glycol (1000) The following is an example of a coating film of a neutral-soluble polymer: 2.2 mg hydroxypropylmethylcellulose phthalate 0.3 mg polyethylene glycol (1000) It is also possible to seal a catalyst-containing neutralizing agent, 'which has been formed into a tablet, in a water-soluble film, for example, of polyvinyl alcohol, which acts as a'retarding agent. Plasticiz- 7 p 1 1 -i ers of multihydric alcohols and water are added in an amount of 3.5% to to the polyvinyl alcohol film, as a result of which a time-delayed dissolution of the film is effected. The films may be as thick as 30 150 m. The gas permeability (DIN 53 380) is 0.9 1.4 cc/m 2 /d/bar.

The films can be welded at temperatures ranging from 140 0 C 190 0 C with a contacting pressure of 4 5 bar.

The catalyst-containing neutralizing .agent, formed into a tablet, may also be coated with an insoluble, yet semipermeable membrane. This membrane may also be applied by known coating processes, such as spraycoating the film, by the fluidized bed process or in closed systems, and moreover in an amount of 3 to 10 mg/tablet. The semipermeable membrane may be formed, for example, as follows from an organic solution of ethylcellulose, an aqueous dispersion of ethylcellulose, a copolymer of acrylate/methacrylate esters with trimethylammoniummethacrylate, an aqueous dispersion of mixed methyl methacrylates and ethyl methacrylates; to control the diffusion rate, suitable plastic'sers can be added, especially in an amount of 1.0 5.0 mg/tablet. As plasticizer, 1,2-propyleneglycol, polyethylene glycols and citrate esters are suitable. An example of the composition of a semipermeable membrane is as follows: 3.8 mg ethylcellulose N22 1.2 mg polyethylene glycol (6,000) A further example of a retarding agent, by means of which a time-delayed release of the catalyst, which decomposes hydrogen peroxide, and of the neutralizing agent can be attained, is a swellable, yet sparingly soluble or insoluble matrix, especially in tablet form, in which the catalyst-containing neutralizing agent is distributed. The catalyst-containing neutralizing agent may have one of the aforementioned compositions, which is incorporated in the matrix that may comprise natural or partly synthetic polymers. The matrix, especially in tablet form, can be produced by conventional processes, for example, by granulating and .molding the starting materials. It is of course also possible to pro-

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cess the mixture of starting materials directly into tablets without prior granulation. Polymers, suitable for the formation of the matrix, are the soluble cellulose ethers, such as those given by way of example above, the alkali salts of alginic acid, methacrylic acid derivatives, especially acrylate/methacrylate esters, acrylic acid derivatives, dextrans (MW 1,000 75,000) and polyvinyl alcohols. The following is an example of the matrix, in which the catalyst-containing neutralizing agent is incorporated: 0.3 mg 10.2 mg 55.8 mg 4.7 mg mg catalyst (catalase, peroxidase) disodium hydrogen phosphate NaCI polyvinylpyrrolidone hydroxypropylmethylcellulose *r 1$r 1 *r I li ft I r I I Tablets are molded to have, for example, a weight of 86 mg and a 6 mm round format.

It is also possible to incorporate the components of the catalyst and the neutralizing agent in a highly-concentrated, aqueous polymer solution and, after casting and drying, to produce from this sectile films 3.0 mm thick. By cutting the film to size, appropriate dosage units can be produced in precalculated superficial dimensions. The water-soluble polymers act as retarding agent, through which the timedelayed release of catalyst and neutralizing agent is attained. Suitable polymers are water-soluble cellulose ethers, like those given above by way of example, alkali alginates, dextrans and polyvinyl alcohols.

It is known in the medical sector concerned with the administration of drugs that therapeutic systems may be used in the form of tablets, semipermeable membranes and matrices, which are brought into a particular target area of a biosystem in order to bring about a constant delivery of drug over a prolonged period of time. In contrast to this, the invention accomplishes that the hydrogen peroxide-decomposing catalyst, together with the sterilizing hydrogen peroxide, can be used 9 Ir C It I 1 j

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i I simultaneously in the treatment of contact lenses without adverse effect by the catalyst, which decomposes the hydrogen peroxide, on the desired sterilizing action of the hydrogen peroxide over a period of, for example, four hours. The decomposing action of the catalyst on the hydrogen peroxide sets in only at the end of the desired treatment time.

A delayed release of the catalyst can also be achieved by immobilizing the catalyst on particulate carrier substances, especially acrylic resin pellets, for example, by bonding over reactive oxiran groups. The carrier substances, with the catalyst, especially an enzymatic catalyst, immobilized thereon, are disposed in an adequate amount, for example in a bottom part or a lid with screw thread of a contact lens treatment container or a contact lens case and are separated from the treatment solution, which contains the pH-neutralizing materials and the neutral salts together with the hydrogen peroxide, by permeable, inert sieve netting. In this version, the catalyst is disposed in a part of the treatment container without mixing with the treatment solution. By these means the danger is avoided, that the catalyst material will collect or accumulate in the soft lens material during the treatment of soft contact lenses. For example, an amount of ca'rier substances with an immobilized enzymatic catalyst, sufficient for 30-day repeated use, can be accommodated in the container part.

~t r t ie rr t etx i S The treatment solution, in which the release neutralizing agent takes place, may have a pH especially of 7.3 and an osmolarity of about 300 of catalyst-containing of about 7 to 7.5 and mosmol.

A color change, especially the use of a color indicator (pH/redox indicator), changing color at a pH of 7.0 to 7.5 and especially at 7.3, S indicates to the user that the hydrogen peroxide, used for the sterilizing treatment, has been decomposed. For this purpose, high molecular weight dyes, which do not penetrate into the lens material, are especially suitable.

So that the catalyst, which preferably is an enzymatic catalyst, exerts

II

i its action only after the disinfecting or sterilizing treatment of the lens, this catalyst additive, together with auxiliary materials, which are present in the neutralizing agent and which serve to neutralize the hydrogen peroxide, may be packaged in a coating, which ensures that the catalyst for decomposing the hydrogen peroxide is released only after the necessary treatment time (up to four hours). There are a number of possibilities for accomplishing this.

The coating or packaging of the catalyst and the auxiliary materials has the shape of a capsule, which is water-soluble at the pH, at which the hydrogen peroxide solution is stable, that is, at a pH of 4 to about yet does not flocculate or precipitate in neutral solution, that is, at a pH of about 7.3.

It is, moreover, advantageous if the capsule is provided with one or two or optionally even more laser perforations, through which the auxiliary materials are released on contact with the hydrogen peroxide solution, the capsule dissolving completely when a pH of about 7 is reached in order to release the catalyst then.

The catalyst may also be present as an enzyme prill which, together with the auxiliary materials, is filled into the capsule, which has the aforementioned dissolving properties.

The catalyst-containing neutralizing agent may also be fashioned as a coated tablet, from which, with delayed dissolution of the coating, first of all the auxiliary materials are set free to change the pH of the hydrogen peroxide solution and then, at a pH of about 7, the catalyst is set free.

Furthermore suitable for the catalyst-containing neutralizing agent is a two-layer tablet, one of the layers of which, comprising'soluble salts, serves to neutralize the hydrogen peroxide solution and the other layer of which contains the catalyst, it being possible to release either the auxiliary materials or the catalyst first.

The neutralizing agent may also be present as a basic gel in a coating, ,which is soluble at a PH of 7. The catalyst may also be present as a viscous solution in a coating, which surrounds the auxiliary materials, Moreover, the neutralizing agent may have a semipermeable membrane as coating, through which the water to dissolve the auxiliaries penetrates into the interior and out of which the dissolved salts reach the outside due to osmotic pressure. For this pu-pose, the semipermeable membrane may have a perforation or it may be destroye? by osmotic pressureo ,whereby then the auxiliary materials and the catalyst are set free. The catalyst may be present here as an enveloped enzyme product, Moreover, a two-layer system with a soluble and a semipermeable membrane is suitable for the time-displaced release of the auxiliary materials and the catalyst, An insoluble membrane system could be exchanged on renewed use.

A suitable two-lhar system may be constructed so that the catalyst is enveloped by the semipermeable membrane, at the outside of which the auxiliary materials lie* A coating, water soluble at the PH (less than 4) of the stable hydrogen peroxide solution, moreover envelops the auxiliary materials and the semipermeable membrane enclosing the cata- 1 ysto *1 4; *1 I

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III,

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4*11 1* 19 a 4 Trhe decomposition of the hydrogen Peroxide can be detected by a color indicator* In thi-o connection, it it a question of the addition of a pR/redox indicator$ which does not penetrate into the soft hydrophilic contact lenses and which is physiologically safe, The color indicator may also be so Oasignedo that it is colored at PH 7 in the presence of hydrogen peroxide and colorless at pH 7 in the absence of hydrogen peroxide.

The container, in which the contact lens care or treatment is carried out,, may have facilities for venting, for example, in the form of a I It Bunsen valve or the like, through which the oxygen released during the neutralization and decomposition of the hydrogen peroxide can escape.

The attached Figures serve to explain the invention further.

Figures 1 to 5 Figure 6 show different examples of the systems containing hydrogen peroxide and the decomposition catalyst.

shows the timewise course of the treatment of a contact lens with an example of the operation of the contact lens care set.

shows a treatment container in side view.

shows a plan view of a container part, which can be screwed onto the treatment container and which contains particulate carrier substances, to which an enzymatic, hydrogen peroxide-decomposing catalyst is bound.

Figure Figure Ir 4 4 In the example shown in Fig. 1, the auxiliary materials 1 and a hydrogen peroxide-splitting catalyst 2, for example in the form of catalase, are randomly distributed in the outer casing 3. The outer casing 3 may be water soluble or semipermeable after it has been acted upon for a certain period of time by the hydrogen peroxide, which has a sterilizing effect in contact lens care on the contact lens to be treated. The thickness of the casing controls the length of time (up to four hours) that the hydrogen peroxide acts on the lens, before sufficient catalase and auxiliary materials are released by the dissolution of the outer casing 3 or by the semipermeability of this casing, so that the sterilizing hydrogen peroxide is neutralized and eliminated by catalytic decomposition In this example of the operation, the auxiliary materials and the catalyst may be released simultaneously.

In the example shown in Fig. 2, the auxiliary materials 1 are released first, as a result of which the sterilizing hydrogen peroxide solution is neutralized. After this, the hydrogen peroxide-destroying catalyst 2, for example In the form of catalase, comes to be used. For this purpose, the outer casing 3 is provided which, after the hydrogen peri~ A oxide has acted fo a certain period of time, is soluble or which is appropriately semipermeable and which surrounds the auxiliary materials 1. The auxiliary materials 1 surround the catalyst 2, which, for its part, is surrounded by an internal casing 4, which may also be constructed so as to be soluble or semipermeable.

In the example shown in Fig. 3, the catalyst 2 and the auxiliary materials 1 are next to each other and are surrounded by a common outer casing 3, which is water soluble or semipermeable. In this case, the auxiliary materials 1 and the catalyst 2 may be separated by a partition In the example shown in Fig. 4, the catalyst 2, which may be present in the form of a viscous solution, is released first, after which the auxiliary materials 1 are released. The catalyst 2 is surrounded here by the outer casing 3 and the auxiliary materials 1 by the inner casing 4. In this version, the auxiliary materials 1 lie on the inside and are surrounded by the catalyst 2.

In the example shown in Fig. 5, the catalyst 2, as catalyst prill, and the auxiliary materials 1 are randomly distributed in the outer casing 3, which may be soluble or semipermeable.

Fig. 6 graphically shows the timewise course of the treatment of the contact lens with the hydrogen peroxide and the subsequent destruction of the hydrogen peroxide, after it has acted for the desired time t The length of time, that the hydrogen peroxide acts, can be fixed, for example, by the thickness of the coating or by an appropriate selection of the material of the coating. The hydrogen peroxide content is plotted on the ordinate, the initial hydrogen peroxide content essentially remaining constant until the end of the time of action tl. After the release of the auxiliaries and/or the catalyst, the hydrogen peroxide content in the treatment container decreases rapidly.

Figs. 7 and 8 schematically shown an example of the operation of a 1 1 i treatment container 1, in which in a bottom part 2 particulate carrier substances 3, on which an enzymatic hydrogen peroxide-decomposing catalyst is immobilized, are disposed in a recess 4 of the bottom part 2.

The bottom part 2 may, for example, may be attached by a screw thread to the treatment vessel part 5, as described, for example, in the German Offenlegungsschrift 3,410,400. The carrier substances 3, coated with the catalyst, are separated from the interior 7 of the container by means of an inert sieve netting 6, which is impermeable to the treatment solution present in the interior 7 of the container. The color of the lid 8, which is also screwed-on and to which the cups 9 for the contact lenses to be treated are attached, as shown in the German Offenlegungsschrift 3,410,400, may be different from the color of screwed-on base part 2, so that the danger of confusion is precluded.

It will be understood that the specification and examples are illustrative but not limitative of the present invention and that other embodiments within the spirit and scope of the invention will suggest themselves to those skilled in the art.

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Claims

1. A method of caring for a contact lens with a container for receiving a neutralizing agent, the lens and a liquid com- prising hydrogen peroxide in an amount effective at least for substantially sterilizing the lens, wherein the method com- nrises addina the neutralizing aaent, the licuid comprising hydrogen peroxide and the lens to the container, characterised in that the neutralizing agent comprises catalytic decomposing means which are effective at least for decomposing residual hydrogen peroxide on the lens into oxygen and water after the hydrogen peroxide has so sterilized the lens; and retarding agent means for delaying, after the neutralizing agent is received in the container, the time of release into the hydrogen peroxide of at least so much of the decomposing catalyst as decomposes the residual hydrogen peroxide until after the hydrogen peroxide has so sterilized the lens.

2. A catalyst-containing neutralizing agent for use in a con- tact lens care set having a container for receiving the neutralizing agent, the lens and a liquid comprising hydrogen peroxide in an amount effective at least for substantially sterilizing the lens, wherein the neutralizing agent comprises catalytic decomposing means which are effective at least for decomposing residual hydrogen peroxide on the lens into oxygen and water after the hydrogen peroxide has so sterilized the lens; and retarding agent means for delaying, after the neutra- lizing agent is received in the container, the time of release into the hydrogen peroxide of at least so much of the decompo- sing catalyst as decomposes the residual hydrogen peroxide until after the hydrogen peroxide has so sterilized the lens. 16

3. Contact lens care set with two treating agents, one of which is a sterilizing hydrogen peroxide and the other a catalyst-containing neutralizing agent for neutralizing and decomposing the hydrogen peroxide after the sterilizing treatment of a contact lens, wherein the neutralizing agent and/or the catalyst, which decomposes the hydrogen peroxide, are/is combined with a retarding agent, which controls the time-delayed release.

4. Contact lens care set as defined in Claim 3, wherein the catalyst-containing neutralizing agent is enclosed by a coating which, in contact with the hydrogen peroxide solution, releases the neutralizing agent after the hydrogen peroxide has acted for a specified time on the contact lens that is to be treated. it

5. Contact lens care set as defined in Claim 3, wherein the neutralizing agent, aside from the catalyst to decompose the hydrogen peroxide, contains auxiliary materials, which neutralize the acidic hydrogen peroxide solution.

6. Contact lens care set as defined in Claim wherein the catalyst to decompose the hydrogen peroxide is S released before or after the neutralization of the hydrogen peroxide solution.

7. Contact lens care set as defined in Claim 6, wherein the retarding agent has the form of a water soluble coating for the catalyst-containing neutralizing agent and comprises a polymer, which is water-soluble in an acidic or neutral medium.

8. Contact lens care set as defined in Claim 7, wherein the polymer, which is soluble in an acidic medium, is a polymer of dimethylaminomethacrylate and neutral methacrylate esters. -T -nscc

9. Contact lens care set as defined in Claim 7, wherein the polymer, which is soluble in a neutral medium is a compound from the group of soluble cellulose ethers, cellulose acetate phthalate, hydroxypropylmethylcellulose phthalate, a polymer from methacrylic acid and methacrylate esters, a copolymer from methacrylic acid and methacrylate esters, a copolymer from methyl vinyl ether and maleic anhydride and polyvinyl alcohols.

Contact lens care set as defined in Claim 9, wherein the soluble cellulose ethers are methylcellulose, methylhydroxypropylcellulose, methylhydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose and sodium carboxymethylcellulose.

11. Contact lens care set as defined in Claim 7, wherein polyalcohols are added to the water-soluble polymer for controlling the retarding time.

12. Contact lens care set as defined in Claim 11, wherein the polyalcohols are 1,2-propyleneglycol, polyethylene glycol, citrate esters. i r r ri 1 f I ,e r

13. wherein the film.

14. wherein the wherein the multihydrix Contact lens care set as defined in Claim 12, coating is present in the form of a water-soluble Contact lens care set as defined in Claim 7, coating comprises polyvinyl alcohol.

Contact lens care set as defined in Claim 13, polyvinyl alcohol film contains plasticizers of alcohols and water in an amount of 3.5% to ;ii i~

16. Contact lens care set as defined in Claim 3, wherein the retarding agent is present in the form of a semipermeable membrane, which envelops the catalyst-containing neutralizing agent and comprises ethylcellulose or a copolymer of acrylate and methacrylate esters with trimethylammonium- methacrylate or a mixture of methyl methacrylates and ethyl methacrylates.

17. Contact lens care set as defined in Claim 16, wherein plasticizers are added to control the diffusion rate of the membrane.

18. Contact lens care set as defined in Claim 17, wherein the plasticizers are 1,2-propyleneglycol or poly- ethylene glycols or citrate esters. 4t o

19. Contact lens care set as defined in Claim 7, *t wherein the coating is water-soluble or semipermeable at the #Eit SpH (less than 4) at which the hydrogen peroxide solution is stable.

Contact lens care set as defined in Claim Swherein the auxiliary materials are NaH 2 PO 4 Na 2 HPO 4 and NaCl buffer substances, film-forming materials and wetting agents.

21. A catalyst- containing neutralizing agent for use in a contact lens care set substantially as herein described with reference to any one of the Examples.

22. A catalyst-containing neutralizing agent for use in i a contact lens care set substantially as herein described with reference to any one of Figures 1 to 5 in the drawings. 19 A'. '~Nr I I ~I--LL

23. A contact lens care set substantially as herein described with reference to any one of the examples and/or Figures 7 or 8 of the drawings. DATED this 23rd day of February, 1990. CIBA-GEIGY AG By Its Patent Attorneys ARTHUR S. CAVE CO. X7 A4- 20 3038F/AC