JPH0337165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to contact lens treatment methods and treatment compositions for removing inorganic deposits on lenses and preventing the formation of inorganic deposits.

Soft contact lenses can be divided into two broad categories: hydrophilic lenses and hydrophobic lenses. Hydrophobic contact lenses are usually based on elastic and flexible silicone rubbers (polysiloxanes) and are generally made from cross-linked dimethylpolysiloxanes.

Typical silicone contact lens preparation is disclosed in U.S. Pat. No. 3,228,741, herein incorporated by reference, and includes a suitable polymerization catalyst, up to 40% silica filler and It consists of producing a mixture of coalescence. This mixture is then molded and cured by heating to cross-bond the polysiloxane and produce a finished clean lens. Increased consumer acceptance of flexible silicone rubber lenses has resulted in a need for cleaning fluids that can be effectively used on such lenses.

Hydrophilic soft contact lenses generally contain two hydrophilic organic monomers containing olefinic double bonds.
The present invention is a hydrated gel lens that can be prepared by copolymerizing small amounts of a cross-linking agent containing multiple polymerizable olefinic double bonds. These lenses are usually based on polyhydroxylated alkyl methacrylates and contain polyhydroxylated alkyl methacrylates, such as polyhydroxyethyl methacrylate cross-linked with hydroxyethyl dimethacrylate.

One of the problems associated with these types of lenses is that over a period of time, insoluble mineral deposits form on the lenses. These deposits are believed to be primarily calcium-based, such as calcium phosphate and calcium carbonate, but may also contain other inorganic substances and bound organic substances such as proteins. The presence of such insoluble mineral deposits is a common cause of lens intolerance and loss of visual sharpness.

The inventor has now discovered a method and composition for treating contact lenses, particularly silicone and hydrophilic plastic contact lenses, for removing inorganic deposits on the lenses and preventing the formation of inorganic deposits.

The method of the present invention described above comprises preparing a contact lens with an aqueous solution containing an effective amount of a sequestering agent selected from the group consisting of polymetaphosphate, gluconic acid and salts thereof to remove any inorganic deposits present and contact for a sufficient time to prevent the formation of deposits.

The composition of the present invention described above contains polymetaphosphate,
from about 0.01 to about 20% by weight of a sequestering agent selected from the group consisting of gluconic acid and salts thereof;
It consists of a preserved saline solution containing. The above composition may further contain a lens sterilizing agent, but does not contain the active oxygen generating peroxide described in JP-A-50-67378.

Typical examples of the sequestering agent that can be used in the present invention include calcium sequestering agents such as polymetaphosphate, gluconic acid, and salts thereof. Suitable polymetaphosphates include sodium polymetaphosphate, preferably sodium hexametaphosphate. Salts of gluconic acid that can be used include common inorganic salts such as the sodium salt,
Potassium and calcium salts and other salts such as calcium borogluconate may be mentioned. A preferred sequestering agent is sodium hexametaphosphate. All the compounds mentioned above are compounds well known in the art, are commercially available and are also conventionally used in industrial processes such as leather tanning, dyeing, washing and textile processing, water softening, etc. It is used for metal plating, textile mordanting, and as a photographic processing aid. Therefore, periodic treatment of contact lenses with aqueous solutions of the aforementioned compounds prevents the formation of inorganic deposits on the lenses without causing any harm to the lenses or to the eyes of the lens wearers. The discovery that it could be done was surprising.

The amount of sequestering agent that can be used in the present invention ranges from about 0.01 to about 20% by weight and preferably from about 0.1 to about 5% by weight.

Sequestering agents can be manufactured in a number of convenient forms for use in the processes described herein. For example, the sequestering agent may be presented in a dry, unit dosage form, such as a tablet, which is dissolved in water before use. The sequestering agent can also form part of the buffered or unbuffered preserved or unpreserved sterile isotonic saline solution used to preserve the lens. The sequestering agents described herein can also be formulated into cold disinfection systems containing lens preservatives and disinfectants.

The invention will now be further illustrated by the following examples, which are for illustrative purposes only and the invention is not limited to any of the particular compounds, formulations or conditions described in the examples. It should be understood that this should not be considered as such. Unless otherwise specified, percentages refer to percentages by weight.

Example 1 A hydrophilic contact lens (Polymacon) that had been worn for about two years was tested and found to have heavy film deposits that were visible to the naked eye. The above lens was cleaned with an enzyme cleaner for 24 hours, but there was almost no effect. The lenses were then sterilized in a 20% solution of sodium hexametaphosphate in water for two cycles (15 minutes).
heated to 100℃). The lens still retained some film-like material, but after one additional treatment with the enzymatic cleaner described above, the lens was found to be film-free. This indicates that the deposits were composed of both inorganic and proteinaceous materials. This is because the enzymatic cleaners described above rapidly (usually within 4 hours) and completely remove protein films from hydrophilic lenses.

Example 2 A human-worn hydrophilic lens with an inorganic thin film was cleaned with an enzymatic contact lens cleaning agent for 24 hours. A heavy film remained on the lens that was visible to the naked eye. This lens was split in half and the half was preserved with 0.001% thimerosal at pH 7.4, sodium hexametaphosphate 0.2%, boric acid 0.1%, disodium ederate 0.01%, sodium chloride 0.85.
% (heated to 80° C. for 20 minutes) for 4 cycles. After treatment for an additional 3 hours with the enzymatic detergent solution described above, the lenses were free of visible deposits. The other half of the lenses, treated in a similar manner but omitting the sterilant treatment cycle, still retained the heavy inorganic film.

Example 3 A hydrophilic lens with an inorganic thin film, worn by a person, was cleaned with an enzymatic cleaner for 4 hours. No changes were observed in the thin film. Next, the lens
Sodium gluconate 0.2%, boric acid 0.1 preserved at PH7.4 with 0.001% Thimerosal
%, disodium ederate 0.01%, sodium chloride 0.85% (formulation no. 5945X) for 20 minutes alternately sterilization (heating to 80 °C for 20 minutes) and three of these cycles are completed. Washed with enzyme washing solution for several hours. Microphotographs from the same area of the lens at each step show that the heavy inorganic deposits were almost completely removed after the three cycles described above. No visible deposits remained.

Example 4 Hydrophilic contact lenses are made of calcium chloride.
23.5% in aqueous solution for 30 minutes, then in test solution
Holds time. This was repeated for 80 cycles. Test solution 1 was 0.2% polysorbate 80, 1.92% propylene glycol, 0.033% alkyltriethanolammonium chloride, 0.05% sodium bicarbonate, 0.002% sodium chloride,
It is an aqueous solution containing 0.0023% thimerosal, and test solution 2 contains the same ingredients as above as well as 0.05%.
of sodium hexametaphosphate.

Testing of the test lenses after 80 cycles revealed calcium carbonate deposits on the lenses treated with Test Solution 1. There were no calcium carbonate deposits on the lenses treated with Test Solution 2. This demonstrates that the addition of sodium hexametaphosphate prevented the deposition of insoluble calcium salts on hydrophilic contact lenses.

Claims (1)

[Claims] 1. A contact lens is brought into contact with a saline solution containing 0.01 to 20% by weight of a sequestering agent selected from the group consisting of hexametaphosphate and calcium borogluconate; A contact lens treatment method comprising heating the solution for a sufficient period of time to remove inorganic deposits on the lens and to prevent the formation of inorganic deposits. 2. The method according to claim 1, wherein the saline solution is a preserved saline solution. 3. The method according to claim 1 or 2, wherein the contact lens is selected from silicone contact lenses and hydrophilic soft contact lenses. 4. Claim 1, wherein the effective amount of sequestering agent ranges from about 0.1 to about 1% by weight;
The method according to item 2 or 3. 5. The method according to any one of claims 1 to 4, wherein the sequestering agent is sodium hexametaphosphate. 6. A contact lens heat treatment composition comprising a saline solution containing 0.01 to 20% by weight of a sequestering agent selected from the group of hexametaphosphate and calcium borogluconate. 7 Claim 6 further contains a preservative
A composition for heat treatment of contact lenses as described in 2. 8. The composition for heat treatment of contact lenses according to claim 6 or 7, wherein the solution contains 0.85% by weight of sodium chloride. 9. The composition for heat treatment of contact lenses according to claim 6, wherein the sequestering agent is sodium hexametaphosphate.