IE55346B1 - Process for cleaning and decontamination of contact lenses and composition for its operation - Google Patents

Abstract

1. Process for the sterilization and the cleaning of contact lenses of type consisting in treating the lens by a first agent, with oxidizing feature, having the effect to destroy the germs that are presents on the lens, then by a second agent, with reducing feature, having the effect by reaction with the first agent to generate degradation by products that are harmless for eyes, the process being characterized in that the oxidizing agent is selected amongst the products able to discharge in situ hydrogen peroxide while the reducing agent is selected amongst the products able to generate hypochlorous acid in aqueous solution and stable in the dry state, the respective proportions of oxidizing agent and of reducing agent being about 0,005% to 5% and about 0,02% to 6% with regard to weight of the involved compositions.

Description

55346 The present invention is directed to a process for the cleaning and the decontamination of contact lenses, as well as compositions for the operation of this process.

The process of the invention is applicable to most S of the known contact lenses, for instance in polymethacrylate, in hydroxyethylmethacrylate, in acetobutyrate of cellulose, etc... It is equally applicable to the decontamination of the storage oases of the lenses and the nozzles of hearing aids.

Processes of this type, being aimed to decontaminate lenses by elimination of undesirable miro-organisms, just as to clean them, are already known and numerous compositions have been proposed to this end.

For' example, the French patent 7500237 describes 11 a sterilization process of hydrophile contact lenses, characterized in that it comprises the putting in contact of the lens through a compound solution freeing a non toxic hypochlorite in sufficient amount for the destruction of the pathogenic micro-organisms that are present, then the reduc- 20 tion of. the hypoclorite into chloride through a non toxic reducing agent which is in a sufficient quantity for the v 4 reduction of the whole hypochlorite.

However the process remains inefficient on a certain number of pathogenic germs, and above all it has no -2- action on the proteinic deposits responsible for the "veil" that troubles the transparency of the lens at end of some hours.

The present invention allows to remedy these dis-<5 advantages, that is to achieve simultaneously the complete decontamination and an efficient cleaning of the lenses.

To this end, the invention is directed to a process for the sterilization and the cleaning of contact lenses of type consisting in treating the lens by a first agent, with oxidizing feature, having the 10 effect to destroy the germs that-are present on the lens, then by a second agent, with reducing feature, having the effect by reaction with the first agent to generate degradation by products that are harmless for eyes, the oxidizing agent is selected from products able to discharge in situ hydrogen peroxide while the reducing a gent.'is selected from products able to generate is" hypochlorous acid in aqueous solution and stable in the dry state, the MO respective proportions of oxidizing agentAof reducing agent being 0,005% to 5% and 0.02% to 6% with regard to weight of the involved compositions.

Preferably the oxidizing compound of the oxide-reducing system is oxygenated water freeed in situ by the %0 putting in solution of a precursor constituted of the first or the second compound.

The oxido-reducing systems of the invention achieve in the same operation the progressive decomposition of the peroxide of hydrogen by the following reaction : 1 S' 2 Hj 0j + Reducer-» 2 H20 + 2 (0)-»02 Thus the contact lens is efficiently cleaned and decontaminated by the action of the hydrogen peroxide during the suitable time. However the treated lens must not necessarily be removed from the container in which the treatment 3d has been performed, for the reducing agent, that was present at departure, is active so that HgOg is broken down and -3- eliminates it thus by transformation into harmless reactive products, water and nascent oxygen. The last one, of course, has a cleaning effect and an additional decontamination action.

It is remarked that the amount of H202 that is found in the medium after decontamination and before reduction is almost identical to the initial amount that was present in the medium.

Appropriated oxidizing agents are for instance peroxide of urea, perphosphates, perborates, percarbonates, persulfates of alkaline metals, the list being not limitative and the peroxide of urea being the preferred compound according to the invention.

The amount of oxidant to be used can vary about from 0.005 % up to 5 % and preferably about 0.01 % to 0.1 %.

Besides the reducing compound can be any hypochlorite or any chlorinated agent generating hypochlorite anions at the moment of the use in aqueous medium.

The hypochlorite can be any mineral organic hypochlorite with the general formula Α(001)χ in which A represents a metal or an organic group, for instance an alkaline metal such as sodium, potassium and lithium, an alkalino-earthy metal such as baryum, magnesium and calcium, an hypochlorite of alkyle, for instance of tertio-butyl, of tertio-amyl, of ethyl, of methyl, of propyl, of isopropyl and similar, and x represents the absolute charge of the mineral or organic substituent. Thus one can employ for instance hypochlorite of sodium, hypochlorite of potassium, hypochlorite of lithium, hypochlorite of calcium, hypochlorite of tertio-butyl or hypochlorite of tertio-amyl.

Instead of adding the hypochlorite in the state, one can employ substances that produce hypochlorous acid in aqueous solution and that are stable when held in dry condition. These substances are, for instance, N,N-dichlorotaurine (sodium salt), Ν,Ν-dichloro-beta-alanine, N,Nldichloro- isocyanuric acid (potassium salt), N,N' -dichloroisocyanuric acid (sodium salt), N-chlorinated, N,N'-dichloro-2,5-pipera-zinedione, N,N'-1,3-dichloro-5,5-dimethylhydantoine, trichlo-roisocyanuric acid, N-chlorosyccinamide, N,N'-dichloro-glyco-•Γ cyamine, N,N-dichloroglycine.

With the same effect, one can also use the complex of hydrated trisodium phosphate and sodium hypochlorite of the formula n(Na3PC>4, xHgO) NaOCl, where n=4 to 7 and x= 11 to 12, designated by P.T.C. in the following.

AO The amount of reducer, that has to be employed for reducing the hydrogen peroxide according to favourable kinetics, varies about from 0.02 % up to 6 %, and preferably about 0.04 % to 1 %.

According to an important feature of the invention, iS" the process consists of the intervention of the two compounds sequentially, owing to the specific structural display of the compounds of the invention, such as for instance multilayer tablet, multi-nucleus tablet, capsule holding the two compounds in the state of micro-granules, one of the com-10 pounds being isolated from the other by the appropriated coating, or by a separate display of the two compounds in a distinct container, for instance double sachet or mechanical system (tipping up container).

Therefore the invention is equally directed to the compounds for sterilization and cleaning of the contact lenses, of the type described above wherein each agent is present in the form of a powder or of micro-granules in two separated packagings which are then put in aqueous solution to liberate the active products.

These compositions are operated as following. The lenses are arranged by the user in whatever container, for instance the case of the lenses, in which was previously put a quantity of water, that is in relation with the volume of the container and in which is added a sufficient quantity of the composition according to the invention. The lenses are put into contact with the composition for a time in relation with the peculiar used system, at ambient temperature. The system provides a complete security, for the lenses can stay there several days without danger, the decomposition products of the oxido-reducing system being harmless for eyes.

Advantageously the compositions according to the invention contain additives such as the solution, in which soak the lenses after treatment, either isotonic or iso-pH (7.0-7.6).

At end of the operation of cleaning and decontamination, the holder can put down his suitably treated lenses directly on to his eyes, without any ulterior treatment or rinse.

The process described above allows the cleaning and the decontamination of the lenses daily, while keeping them in their initial state. It allows to do it in a situation of complete security for the user. Such are the products and method of operation of the product that the user has no possibility to making an error of operation, the decontamination and the cleaning being made in a single action.

The substances used in the present invention, namely oxidants and reducers, are elected so that they do not affect the physical features of the lens and are not toxic for the eyes of the user of the lenses and do not generate such toxic products.

The final solution after cleaning and decontamination is isotonic and iso-pH for tears by reason of tolerance of the ocular tissues that are put into contact with £ the products and by reason of compatibility with the polymer of the lens.

One can insert in the above described substances buffer-excipents, suitable stabilization agents such as ήΟ sodium benzoate, disodic edetate, sodium chloride or sodium citrate, potassium chloride or potassium citrate, phosphates and bicarbonates of sodium and potassium.

It was pointed out previously that the belated setting into contact of two compounds could be performed if either inside specific displays (multi-nucleus or multilayer tablets), or by a physical separation (several sachets for instance, or products held in a porous paper support).

In the second case, there is no peculiar problem to be resolved, for the compounds may not come into contact before their utilization.

On the contrary, in the first case, it is compulsory that the external displays secure the good preservation of the products, because they are reactive with each other within a time. ii As for example, appropriated non toxic excipents allowing the belated freeing of the reducer, on one hand, and allowing to prevent the chemical insompatibility between the oxidant and the reducer during the preservation of the product, on the other hand, are employed combined with the \o compositions of the invention.

Thus the treatment can be realized with a doublenucleus tablet, or multi-layer tablet with coating of the reducer, freeing sequentially programmed in the time : - the oxidizing compound -¾ ζ - then the reducing product of neutralisation, all in the same medium, rendered isotonic by the excipients of -7- the tablet, or conversely the reducing compound, and then the oxidizing compound.

A coating product allowing to isolate either the grains of the two compounds in a single granulated composition or the central nucleus of a tablet comprising the first compound coated inside the second compound, one can indicate the salt of polymethylmethacrylate soluble at pH 7, commercialized by the firm ROHM PHARMA under the brand "EUDRAGIT L-100".

The action of the compositions according to the invention can be strenghtened if an effervescent mixture is used, that comprises, moreover the above described compounds, a product emitting, after being put in solution, carbon dioxide that produces a mechanical action of cleaning. This product can be chosen, for instance and non limitatively, in the group comprising the sodium bicarbonate, the citric acid, the sodium bicarbonate and the glycine carbonate of sodium (CGS), the monosodic sodium citrate, the monosodic phosphate.

Example I. Compositions pursuant to the invention are for instance as following : Composition 1 Composition 2 Composition 3 - urea peroxide 1.5 mg 1.05 mg 2.25 mg - coated P.T.C. 24.0 mg 16.8 mg 36.0 mg - anhydrous disodic citrate 30.0 mg 21.0 mg 45.0 mg - C.G.S. 10.0 mg 7.0 mg 15.0 mg - sodium chloride 70.0 mg 49.0 mg 105.0 mg These compositions are to be dissolved respectively in 10 ml, 7 ml and 15 ml of water.

This formulation prevents the possibility of reaction between the oxidizing compound and the trisodic phosphate (PTC) in an environment charged with humidity.

This difficulty is diverted by preventing the direct contact between oxidant and reducer, by use of coating polymers of the type methacrylic acid and methylic ester of methacrylic acid. Consequently this polymer has double function : 1) to prevent the immediate freeing of the reducer in solution by deferring it with regard to the peroxide of urea, 2) to prevent the physio-chemical incompatibility between the oxidant and the reducer, on one hand, and between the reactive products and certain excipients, on the other hand.

These mixtures are displayed under form of fine powder non sticking. Their time of dissolving is lower than 30 minutes. They produce in water light effervescence due to the disodic citrate and the C.G.S. (glycine carbonate of sodium).

Example II. In order to stabilize the tablet still more and to prevent contingent incompatibilities : - PTC / peroxide of urea, - PTC / acids, - CGS / citric acid, a three-layer tablet is advantageously realized.

To this end, it has been sought a tablet that is destined for dissolving in 7 ml of purified water, on one hand, and a three-layer tablet destined for dissolving in 7 ml of physiological water, on the other hand. a) Tablet dissolved in purified water.

The agreed formulation is as following : 1st layer : Peroxide of urea 1.05 mg Anhydrous citric acid 5.6 mg Sodium chloride 20.0 mg Lactose 20.0 mg 2nd layer : Lactose 23.0 mg CGS 7.0 mg 3rd layer : Coated PTC 16.8 mg Sodium chloride 29.0 mg 122.45 mg Each layer is lubricated by sodium benzoate, PEG 6000 and Maltodextrine.

This tablet is to be dissolved in 7 ml of purified ζ water.

The amine functions of the urea peroxide cause the browning neither of the lactose nor of the Maltodextrine (reaction of Maillard). This is verified on tablets having more than 5 months. It is therefore possible to employ the ήΰ lactose.

The effervescence of these three-layer tablets can be obtained by putting the CGS in the central layer (a pronounced delay effect of the 3rd layer is got) or by inserting the CGS in the layer containing the PTC (in this case, the 1S" amount of lactose in the 2nd layer is increased). b) Tablet dissolved in physiological water (7 ml).

An advantageous formulation is as following : 1st layer Peroxide of urea 1.05 mg Anhydrous citric acid 5.6 mg Lactose 40.0 mg 2nd layer : Lactose 30.0 mg CGS 7.0 mg 3rd layer : Coated PTC 16.8 mg Lactose 25.0 mg xs Example III. This example shows that the pretreatment with peroxide of urea according to the invention destroys retro- actively the hypochlorite or the hypochlorous acid. The redox system with programmed freeing, where the reducer is freeed in solution within a certain time after the oxidant 1° so as to allow the action of the same, is preferably under the form of a two- or three-layer tablet.

The hypochlorite freeed from the complex PTC is itself oxidized by the oxygenated water generated by the urea peroxide. The kinetics of neutralisation of the free -10- Cl^ shows that, after a contact of 5 mn between the oxidant and the reducer, half of the freeed Clg is already destroyed by the urea peroxide. After 1 hour, it remains only 0.1 mg %, that is 1 ppm, of Cl2 that is free in the solution. This amount of chlorine is perfectly bi-compatible.

Example IV. This example illustrates tha antimicrobial efficiency of a composition according to the invention, used under the form of two separate tablets.

The tablet A has the following composition : 10 Peroxide of urea coated with EUDRAGIT L-100 corresponding to pure urea peroxide 1.18 mg Lactose 50.00 mg Sodium benzoate 5.00 mg The tablet B has the following composition : Dichloroisocyanurate of sodium 2H20 1.00 mg Anhydrous monosodic phosphate 32.00 mg Anhydrous disodic phosphate 50.00 mg Sodium bicarbonate 57.00 mg 3.0 Lactose 30.00 mg Sodium benzoate 15.00 mg The two tablets are introduced in 10 ml of suspen- g sion or of germs with 10 germs/ml. %f Germs employed Staphylococcus aureus Pseudomonas aeruginosa Escherichia coli + Candida albicans Aspergillus niger Ίο ATCC 6538 P ATCC 19429 ATCC 8739 ATCC 10231 ATCC 16404 Determination of the antimicrobial efficiency of the tablet. -Π- Type sample t = 0 Tests t = 0 Tests t =lh Tests t = 2h Type sample t = 18h Tests t = 18h Candida albicans 41,000 0 0 0 460,000 0 Aspergillus Niger 200,000 0 0 0 200,000 0 Staphylo coccus aureus 4,000,000 0 0 0 200,000 0 Pseudo monas aeruginosa 3,000,000 0 0 0 2,700,000 0 Escherichia Coli 530,000 0 0 0 300,000 0 "Powder A" - Peroxide of urea 1.5 mg - Sodium benzoate 3.5 mg - Sodium chloride 40.0 mg 10 - Lactose 80.0 mg "Powder B" - P.T.C. 24.0 mg - Sodium benzoate 3.5 mg - Sodium chloride 17.0 mg -if - Lactose 60.5 mg The powder "A" is put in solution in 10.0 ml o purified water held in a suitable container allowing to receive the lenses. After waiting 10 minutes, the powder "B" is added. A light effervescence is observed, the final \o solution is obtained clear and limpid, presenting a pH of 7.3, and a cryoscopic point of - 0.56°C. -12- r 1o % The dosage after 15 minutes of putting in solution of the powders makes appear a concentration of hydrogen peroxide inferior to 2 ppm and a concentration of chlorine inferior to 1 ppm. Bacteriological test : The powder "A" is put in solution in 10 ml of g suspension of germs with 10 germs/ml. After 10 minutes, the powder "B" is added, and one picks up after 1, 2 and 5 minutes so as to carry out the counting of the surviving germs. Germs tested : Escherichia Coli ATCC 8739 Pseudomonas aeruginosa ATCC 9027 Staphylococcus aureus ATCC65380 Results : xo •jo Concentration of germes Surviving after· Time of contact (mu) 1 2 3 E. Coli < 10 A O ^ 10 Ps. aeruginosa 1.9 x 104 7 x 102 < 10 St. aureus 2.9 x 104 10 ^10 Example VI This example illustrates the antimicrobial efficiency of two compositions according to the invention, each composition being used under the form of a single tablet. Tablet A Internal nucleus : Peroxide of urea 1, .05 mg Anhydrous citric acid 5, ,60 mg Sodium chloride 15, ,00 mg Lactose 22 .15 mg -13- 5 5 6.40 mg 2.40 mg 2.40 mg Carboxylmethylcellulose Sodium Salt Sodium benzoate P.E.G. 6000 + Eudragit L 100 coating of nucleus 1.5 mg + 55.00 mg Internal nucleus of 56.50 mg 40 ir Tablet B External cover : P.T.C. 16.80 mg Socium chloride o o o mg Lactose 48.70 mg Carboxymethylcellulose 6.00 mg Sodium benzoate 8.50 mg P.E.G. 6000 8.50 mg External cover of 128.50 mg Ίΰ Biconvex double nucleus tablet, colour white 0 7.5 mm, thickness : 4 mm Coated internal nucleus 0 5.0 mm, thickness : 2.5 mm Composition : Internal nucleus : Raw material Unitary amount Coated urea peroxide 3.16 mg Lactose 41.09 mg Sodium benzoate 5.00 mg Sodic carboxymethylstarch 1.25 mg Eudragit L 100 (coating) 1.50 mg For tablet of 52.00 mg -14- Cover : Raw material Unitary amount Dichlorocyanurate of Na.2H20 1.00 mg S' Anhydrous disodic phosphate 63.50 mg Anhydrous monosodic phosphate 26.50 mg 10 Sodium bicarbonate 40.00 mg Sodium chloride 15.00 mg Sodium benzoate 8.00 mg P.E.G. 6000 15.00 mg For a cover of 169.00 mg —► Double nucleus tablet of 221.00 mg ^ The tablets A and B are destined for dissolving in 10 ml of water.

The tablets thus realized present a very regular surface, non sticking. Their time of dissolving is less than 20 minutes. They produce in water an effervescence 30 due to the monosodic phosphate and the sodium bicarbonate.

The solution realized is limpid and colourless, giving a pH of 7.2 and a cryoscopic point of - 0.57°C.

Bacteriological test : For demonstration of the antimicrobial efficiency of the tablet B°.

Suspensions with 10 germs/ml are prepared and a tablet is put into contact with 10 ml of suspensions. One picks up, after dissolving of the tablet that is formed, after 1, 2 and 18 hours, and the surviving germs are counted.

Micro-organisms used : Candida albicans ATCC 10.231 Aspergillus Niger ATCC 16404 -15- s' Escherichia Coli Pseudomonas aeruginosa Staphylococcus aureus Results : Concentration after counting.

ATCC 8739 ATCC 19429 ATCC 6538 of the micro-organisms to αο Organisms T = 0 in the sample type of physiological solution T = 0 in the product to be Concentration of the org/ml in the product, after lh 2h 18h C. albicans (ATCC 10231) 370,000 0 0 0 0 Asp. Niger (ATCC 16404) 100,000 0 0 0 0 St. Aureus (ATCC 6538) 2,600,000 0 0 0 0 Ps. Aeruginosa (ATCC 14429) 1,540,000 0 0 0 0 E. Coli (ATCC 8937) 1,970,000 0 0 0 0 Example VII : This example illustrates the antibacterial efficiency of a composition according to the invention used under the form of a single powder in which the grains of one of the two agents are coated with EUDRAGIT L 100.

Compositions I II Peroxide of urea 2.0 mg 2.0 mg Sodium dichloroiso cyanurate coated (EUDRAGIT L 100) 2.0 mg 2.0 mg -16- 30 Anhydrous disodic phosphate 60.1 mg 120.2 mg Anhydrous monosodic phosphate 19.7 mg 39.4 mg Lactose 92.0 mg 92.0 mg Sodium benzoate 10.0 mg 10.0 mg r Sodium chloride 44.2 mg 6.0 mg 1o This compositions are to be dissolved in 10 ml of water and bring after dissolving to a solution of pH 7.18 and cryoscopic point - 0.56°C for the composition I, and a solution of pH 7.0 and cryoscopic point - 0.57°C for the composition II.

This formulation prevents the possibility of reaction of the urea peroxide with the sodium dichloroiso-cyanurate and allows the belated freeing of the DCCNa in solution. 1C lo 10 The mixtures so got are displayed under the form of fine powders, non sticking. Bacteriological test : The tests are performed on the above composition II. g On 10 ml of suspension of germs with 10 germs/ml, the suitable amount of tested powder is added at time 0, after 1, 3, 5 and 10 minutes following the putting into contact, the surviving germs are demonstrated. Tested germs : Escherichia Coli ATCC 8739 Pseudomonas aeruginosa ATCC 9027 Staphylococcus aureus ATCC 65380 Results : Concentration of the surviving micro-organisms with regard to the time of contact and the dilutions carried out when at counting them. a) Escherichia Coli -17- Dilutions/Time of contact 1/10 1/100 1/1000 1/10000 1 minute <10 <10 <10 <10 3 minutes <10 contami- contami- <10 nated nated 5 minutes <10 <10 <10 <10 10 minutes <10 <10 <10 <10 b) Staphylococcus aureus Dilutions/Time of contact 1/10 1/100 1/1000 1/10000 1 minute 3 minutes 5 minutes 10 minutes <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 c) Pseudomonas aeruginosa K Dilutions/Time of contact 1/10 1/100 1/1000 1/10000 1 minute <10 <10 <10 <10 3 minutes <10 <10 <10 <10 5 minutes <10 <10 <10 <10 10 minutes <10 <10 <10 - <10 Example VIII : Three solutions in physiological serum are prepared. The solution 1 is prepared from the association of the two substances, the solution 2 contains only peroxide of urea, the solution 3 contains only PTC. To each of the -18- said solutions are added three types of different bacteria 5 6 with concentration of 10 to 10 germs/ml. The number of living bacteria per culture on solid nutritional medium after 1 h 30 mn of contact is observed. The achieved re-f suits are reported hereafter : Experiment 1.

The tested formula is the complete formula : peroxide of urea and PTC put in the same time into contact with the bacteria. The concentration of the micro-organisms 10 is measured after counting.

Organisms Number of germs per ml of product at inoculation Number of germs per ml of product after lh30 mn in contact E. Coli 780,000 2,900 Ps. aeruginosa 590,000 3,400 St. aureus 1,080,000 4,000 Experiment 2.

Peroxide of urea and PTC put into contact after each other : urea peroxide + inoculum in contact for 15 mn, xo then the rest of the formula.

Organisms Number of germs per ml of product at inoculation Number of germs per ml of product after lh30 mn in contact E. Coli 980,000 3,000 Ps. aeruginosa 770,000 0 St. aureus 890,000 190 Experiment 3.

PTC + inoculum in contact for 15 mn, then the rest of the formula.

Organisms Number of germs per ml of product at inoculation Number of germs per ml of product after lh30 mn in contact E. Coli 980,000 90 Ps. aeruginosa 770,000 660 St. aureus 890,000 0 In the experiment 1, there is no effect of delay : the two substances are put into contact immediately. In the experiment 2, the effet of delay is simulated by making firstly the peroxide of urea act for 15 mn, then the rest of the composition.

The experiment 3 is identical, the PTC being put into contact with germs firstly, then the rest of the composition.

These results give prominence to the antibacterial synergic effect of the association of the urea peroxide with the PTC, peculiarly useful when the two substances are put into contact with the bacteria after each other. The activity of the complete redox system is appreciably superior to the one of each of the compounds taken separately.

Finally, concerning the efficiency of the compositions according to the invention, as cleaning products of lenses, eliminating the proteinic deposits that are responsible for the veil formed at end of some hours, the test employed consists of causing the dirtying of lenses by immersion during 24 to 48 h in a solution at 10 % of attenuated bovine serum in which a drop of oil of cod liver is added. The formation of a veil is reported. After treatment of the veiled lenses by means of compositions according to the invention, and particularly by application of the ones matter of the examples IV and VI, without neutali- sation or rinse, subjectively the disappearance of this veil and the return of the lenses to a perfect transparency are reported. The test has been carried out together on flexible lenses and on hard lenses. < It is supposed that the efficiency of the compo sitions according to the invention, together as antimicrobial compositions and as cleaning agents, comes from the action of the nascent oxygen freeed at the moment of their use, that exerts a very strong oxidizing action peculiarly ή 0 efficient on anaerobic germs and on proteinic deposits, while the reducing agent and especially the sodium dichlo-rocyanurate exerts its own antibacterial action on all kinds of germs.

Claims (6)

1. Process for the sterilization and the cleaning of contact lenses of type consisting in treating the lens by a first agent, with 5 oxidizing feature, having the effect to destroy the germs that are present on the lens, then by a second agent, with reducing feature, having the effect by reaction with the first agent to generate degradation by products that are harmless for eyes, the oxidizing agent is selected from products able to discharge in situ hydrogen peroxide 10 while the reducing agent is selected from products able to generate hypochlorous acid in aqueous solution and stable in the dry state, the respective proportions of oxidizing agent and of reducing agent being 0.005% to 5% and 0.02% to 6% with regard to weight of the involved compositions. 15

2. Process according to claim 1, wherein the oxidizing agent is selected from the group constituted by: peroxide of alkaline perphosphates, alkaline percarbonates, alkaline perborates and alkaline persulfates. 20

3. Process according to any one of the claims 1 or 2, wherein the reducing agent is selected from the group consisting of : a mineral or organic hypochlorite, a complex of hydrated trisodium phosphate and sodium hypochlorite, sodium dichlorisocyanurate. 25

4. Process according to any one of the claims 1 to 3, wherein the two agents are employed under the form of a solid dosed composition displayed with known excipients, so as to determine, in aqueous medium, sequentially the freeing of the first and then of the second agent. 30 5. Compositions for the sterilization and cleaning of contact lenses, such as obtained by the process of any one of the claims 1 to 4, wherein each agent is present in the form of a powder or of micro-granuales in two separate packagings which are then put in 35 aqueous solution to liberate the active products. 6. Compositions obtained by the process of any one of the claims 1 to 4, wherein one of the two agents is isolated from the other by a -22- coating product in water soluble at about pH 7, the two agents being associated in a single form of utilization such as a double nucleous table or a mixed powder. 7. Compositions according to claim 6, wherein the coating product is a soluble salt of polymethylmethacrylate. 8. A process for the sterilization and cleaning of contact lenses substantially as described with reference to the Examples. 10 9. A composition for the sterilization and cleaning of contact lenses substantially as described herein with reference to the Examples. 15 Dated this the 18th day of April, 1984. (Signed) BY:

5. , Dartmouth Road, DUBLIN

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