IE49362B1

IE49362B1 - Method and composition for treating contact lenses

Info

Publication number: IE49362B1
Application number: IE70/80A
Authority: IE
Original assignee: Allergan Pharma
Priority date: 1979-01-15
Filing date: 1980-01-14
Publication date: 1985-09-18
Also published as: JPS5595926A; NL8000201A; GB2040492B; NZ192499A; AU533669B2; IE800070L; AU5456280A; FR2446499B1; DE3000742C2; CA1136841A; BR8000199A; GB2040492A; MX154425A; IT8019122A0; ES8103394A1; IT1129653B; FR2446499A1; ZA8054B; SE8000157L; ES487679A0

Abstract

The invention relates generally to a method and composition for the treatment of contact lenses, especially silicone and hydrophilic plastic contact lenses, to remove inorganic deposits and to prevent the formation of inorganic deposits on the lenses. One of the problems connected with these types of lenses is the formation, over a period of time, of insoluble inorganic deposits on the lenses. These deposits are thought to be primarily calcium based, e.g., calcium phosphate and calcium carbonate, but may also contain other inorganic materials and associated organic materials, e.g., protein. The presence of these insoluble inorganic deposits is a common cause of lens intolerance and decreased visual acuity. The method comprises contacting a contact lens with an aqueous solution containing an effective amount of a polymetaphosphate, gluconic acid or salts thereof as sequestering agent for a period of time sufficient to remove existing inorganic deposits and to prevent formation of inorganic deposits. The solution may be a preserved saline solution containing 0.01-20% by weight of the sequestering agent.

Description

The invention relates generally to a method and composition for the treatment of contact lenses to remove inorganic deposits and to prevent the formation of inorganic deposits on the lenses.

Soft contact lenses may be divided into two broad categories, namely hydrophilic and hydrophobic lenses. Hydrophobic contact lenses are usually based on elastic and flexible silicon rubber (polysiloxane) and are generally made from cross-linked dimethyl polysiloxane.

A typical preparation of a silicon contact lens is disclosed in U.S. Patent No. 3 228 741, which comprises forming a mixture of a suitable polymerization catalyst, up to 40% of a silica filler, and the silicone polymer. Said mixture is then moulded and cured by heating to cross-link the polysiloxane and to produce a finished clear lens. Increased consumer acceptance of flexible silicone ruhber lenses has created a need for a cleaning solution which can be used effectively with such lenses.

Hydrophilic soft contact lenses are hydrated gel lenses which can be prepared by copolymerizing hydrophilic organic monomers containing an olefinic double bond with a small amount of a cross-linking agent which usually contains two polymerizable olefinic double bonds. These lenses are usually based on polyhydroxylated alkyl methacrylates and contain a polyhydroxylated alkyl methacrylate, such as polyhydroxyethyl methacrylate, cross-linked with, for example, an hydroxyethyl dimethacryl ate. 49363 One of the problems connected with these types of lenses is the formation, over a period of time, of insoluble inorganic deposits on the lenses. These deposits are thought to be primarily calcium based, e.g. calcium phosphate and calcium carbonate, but may also contain other inorganic materials and associated organic materials, e.g. protein. The presence of these insoluble inorganic deposits is a common cause of lens intolerance and decreased visual acuity.

The present invention relates to a method and composition for the treatment of contact lenses, and especially silicone and hydrophilic plastic contact lenses, to remove inorganic deposits and to prevent the formation of inorganic deposits on the lenses.

According to the present invention there is provided a method for the treatment of contact lenses to remove inorganic deposits and to prevent the formation of inorganic deposits on the lenses, comprising contacting a contact lens with an aqueous saline solution containing from 0.01 to 20% by weight of a sequestering agent, selected from a hexametaphosphate, gluconic acid and salts thereof, and calcium borogluconate, and heating the solution in contact with the lens for a period of time sufficient to remove inorganic deposits and to prevent formation of inorganic deposits on the lens.

Further in accordance with the present invention there is provided a method for the propylactic treatment of contact lenses to prevent the formation of inorganic deposits on the lenses comprising periodically contacting a contact lens with an aqueous saline solution containing from 0.01 to 20% by weight of a sequestering agent selected from a hexametaphosphate, gluconic acid and salts thereof, and calcium borogluconate, and heating the solution for a period of time sufficient to prevent formation of inorganic deposits on the lenses.

Still further in accordance with the present invention there is provided a method for the treatment of contact lenses to remove inorganic deposits and to prevent the formation of inorganic deposits on the lenses comprising preparing an aqueous saline solution by combining with salt water, a solid, unit dosage form of a sequestering agent selected from a hexametaphosphate, gluconic acid and salts thereof, and calcium borogluconate, and contacting a contact lens having inorganic deposits with the resulting heated aqueous saline solution containing from 0.01 to 20% by weight of the sequestering agent for a period of time sufficient to remove the inorganic deposits on the lens.

Also in accordance with the present invention there is provided an aqueous saline solution containing from 0.01 to 20% by weight of a sequestering agent selected from a hexametaphosphate, gluconic acid and salts thereof, and calcium borogluconate.

Preferably, the aqueous saline solution is a preserved solution.

The composition may additionally contain an agent for sterilising the lenses.

The sequestering agent is preferably present in an amount of from 0.1 to 1% by weight. The preferred sequestering agents are sodiumhexametaphosphate and salts of fluconic acid such as the sodium, potassium and calcium salts, as well as calcium borogluconate. All of the aforementioned compounds are well known in the art, are commercially available, and have been used heretofore for industrial processes such as, for example, leather tanning, dyeing, laundry and textile processing, water softening, metal plating, mordanting fabrics and as photographic processing aids.

The sequestering agents may be manufactured in a number of convenient forms for use in the treatment described herein. For example, the sequestering agent could be delivered in the form of a dry, unit dosage or such as a tablet which would be dissolved in salt water prior to use. The sequestering agent could also form a part of a buffered or unbuffered preserved or unpreserved sterile, isotonic saline solution used to store the lenses. The sequestering agents described herein may also be incorporated into cold disinfecting systems containing lens preservatives and disinfectants.

The present invention may be further described and illustrated with reference to the following examples. It is to be understood, however, that the following examples are for the purpose of illustration and the invention is not to be regarded as limited to any of the specific compounds or formulations or conditions recited therein. Unless otherwise state, percents are by weight.

EXAMPLE 1 A hydrophilic human worn lens with an inorganic film was cleaned with an enzymatic contact lens cleaner for 24 hours. A heavy visible film remained on the lens. The lens was cut to half and one-half was asepticized (heated to 80° for 20 minutes) for four cycles in an aqueous solution containing 0.2% sodium hexametaphosphate, 0.1% boric acid, 0.01% disodium edetate, 0.85% sodium chloride preserved with 0.001% thimerosal at pH 7.4. Following another three hour treatment with the enzyme cleaner solution, the lens was free of >, 49362 visible deposits. The other half of the lens treated in a similar manner, except that the aseptor cycle was omitted, still retained its heavy inorganic film.

EXAMPLE 11 A hydrophilic human worn lens with an inorganic film was cleaned for four hours with the enzyme cleaner. No change in the film was noted. It was then alternately asepticized (heated to 80°C for 20 minutes) in an aqueous solution containing 0.2% sodium gluconate, 0.1% boric acid, 0.01% disodium edetate, 0.85% sodium chloride preserved with 0.001% thimerosal at pH 7.4 (Formula No. 5945X) for minutes and cleaned for several hours with the enzyme cleaner until three of these cycles had been completed. Photomicrographs taken on the same area of the lens at each step show almost complete removal of the heavy inorganic deposit after the three cycles. No visible deposits remained.

Claims

1. A method for the treatment of contact lenses to remove inorganic deposits and to prevent the formation of inorganic deposits on the lenses, comprising contacting a contact lens with an aqueous saline solution containing from 0.01 to 20% by weight of a sequestering agent selected from a hexametaphosphate, gluconic acid and salts thereof, and calcium borogluconate, and heating the solution in contact with the lens for a period of time sufficient to remove inorganic deposits and to prevent formation of inorganic deposits on the lens.

2. A method as claimed in claim 1, wherein the aqueous saline solution is preserved solution.

3. A method as claimed in claim 1 or 2, wherein the contact lens is selected from a silicone contact lens and a hydrophilic soft contact lens.

4. A method as claimed in claim 1, 2 or 3, wherein the sequestering agent is present in an amount of from 0.1 to 1% by weight.

5. A method as claimed in any preceding claim, wherein the aqueous solution additionally contains an agent for sterilizing the lens.

6. A method as claimed in any preceding claim, wherein the sequestering agent is sodium hexametaphosphate.

7. A method as claimed in any of claims 1 to 5, wherein the sequestering agent is a salt of gluconic acid selected from sodium, potassium and calcium salts.

8. A method for the propylactic treatment of contact lenses to prevent the formation of inorganic deposits on the lenses, comprising periodically contacting a contact lens with an aqueous saline solution containing from 0.01 to 20% by weight of a sequestering agent 4 83 62 selected from a hexametaphosphate, gluconic acid and salts thereof, and calcium borogluconate, and heating the solution for a period of time sufficient to prevent formation of inorganic deposits on the lenses.

9. A method for the treatment of contact lenses to remove inorganic deposits and to prevent the formation of inorganic deposits on the lenses comprising preparing an aqueous saline solution by combining with salt water, a solid, unit dosage form of a sequestering agent selected from a hexametaphosphate, gluconic acid and salts thereof, and calcium borogluconate, and contacting a contact lens having inorganic deposits with the resulting heated aqueous saline solution containing from 0.01 to 20% by weight of the sequestering agent for a period of time sufficient to remove the inorganic deposits on the lens.

10. An aqueous saline solution containing from 0.01 to 20% by weight of a sequestering agent selected from a hexametaphosphate, gluconic acid, and salts thereof, and calcium borogluconate.

11. A solution as claimed in claim 10, additionally containing a preservative.

12. A solution as claimed in claim 10, wherein the solution contains 0.85% sodium chloride by weight.

13. A solution as claimed in claim 10, 11 or 12, wherein the sequestering agent is sodium hexametaphosphate.

14. A solution as claimed in claim 10, 11, 12 or 13, additionally containing an agent for sterilizing the lens.

15. A method for the treatment of contact lenses as claimed in any one of claims 1 to 7, substantially as hereinbefore described.

16. A method for the prophylactic treatment of contact lenses as claimed in claim 8, substantially as hereinbefore described.

17. A method for the treatment of contact lenses as claimed in claim 9, substantially as hereinbefore described.

18. An aqueous saline solution for use in the treatment of contact lenses, substantially as hereinbefore described, with reference to the 5 Examples.

19. Contact lenses when treated by a method according to any one of claims 1 to 9 or 15 to 17.