GB2055579A

GB2055579A - Treating contact lenses

Info

Publication number: GB2055579A
Application number: GB8025706A
Authority: GB
Original assignee: Contact Lenses Manufacturing Ltd
Current assignee: Contact Lenses Manufacturing Ltd
Priority date: 1979-08-16
Filing date: 1980-08-06
Publication date: 1981-03-11
Also published as: GB2055579B

Abstract

There are disclosed contact lens sterilizing solutions of pharmaceutically acceptable strength which contain dichloroisocyanurate, together with tablets and capsules containing dichloroisocyanurate for making up into such solutions with a predetermined quantity of a carrier liquid.

Description

SPECIFICATION Sterilizing contact lenses This invention relates to compositions for use in sterilizing a contact lens and to a method of sterilizing a contact lens.

Many substances are used to sterilize contact lenses among which may be mentioned benzalkonium chloride, chlorobutol, methylparaben, chlorhexidine, propylparaben, phenol, phenylethyl aicohol, phenylmercuric nitrate and thiomersalate.

In view of the conflicting requirements of pharmaceutical acceptability on the one hand and adequate lens sterilizing ability on the other, most of these substances possess disadvantages and there is still required an effective contact lens sterilizing agent which may be used at very low concentrations so as to be acceptable to the eye of a wearer of the contact lens.

It is known to decolourize contact lenses using high concentrations of sodium dichloroisocyanurate but rigorous decontamination procedures are subsequently required to render the lens safe which make the product unsatisfactory for use by the general public. Sodium dichloroisocyanurate is a white solid containing about 64% available chlorine. In water it liberates hypochlorous acid as follows:

According to a first aspect of the present invention, there is provided a method of sterilizing a contact lens which comprises treating the lens with an effective amount of a pharmaceutically acceptable dichloroisocyanurate solution.

According to a further aspect of the present invention there is provided a pharmaceutically acceptable contact lens sterilizing solution containing an effective amount of a dichloroisocyanurate.

According to a third aspect of the present invention there is provided a tablet or capsule for dissolution in a predetermined quantity of a pharmaceutically acceptable carrier liquid to produce a pharmaceutically acceptable contact lens sterilizing solution, which tablet or capsule contains an effective amount of a dichloroisocyanurate.

According to a fourth aspect of the present invention there is provided a two part pack which comprises on the one hand a plurality of sterile sachets each containing a predetermined quantity of a pharmaceutically acceptable carrier liquid and on the other hand a plurality of lens treating tablets or capsules, each of which is soluble in the quantity of liquid contained within a said sachet and each of which contains dichloroisocyanurate in an amount to produce with said quantity of liquid a contact lens sterilizing solution of pharmaceutically acceptable strength.

According to a fifth aspect of the present invention there is provided a method of producing a pharmaceutically acceptable contact lens-sterilizing solution which comprises dissolving in a predetermined quantity of a sterile pharmaceutically acceptable carrier liquid, a tablet or capsule containing dichloroisocyanurate in an amount to produce with said quantity of liquid a lens steriling solution of pharmaceutically acceptable strength.

Preferably the sodium salt of dichloroisocyanurate is employed although other pharmaceutically acceptable metal salts may be used as well or instead.

Generally the dichloroisocyanurate solution has a concentration therein of dichloroisocyanurate of from 0.5 to 100 ppm preferably from 0.5 to 3 ppm, measured as available chlorine.

The solution, tablet or capsule may contain other ingredients such as are generally required to achieve satisfactory contact lens sterilising solution such as chelating agents, wetting agents, catalysts, sodium chloride to assist tonicity, and buffering agents. In the case of tablets or capsules there may also be included effervescing agents to aid dissolution thereof in the carrier liquid.

Preferably the sachets contain water or saline solution which may be buffered and are made of a synthetic plastics material. The liquid may be inserted into the sachets in a sterile condition or may be subsequently sterilized therein, for example, by heat treatment or gamma-ray irradiation; the preferred material for the sachets is polypropylene since it is practically inert to gamma-ray irradiation and is substantially free from components which may be leached into the liquid contained within the sachet.

Preferred liquid dosages to be contained within a single sachet are 10 ml, 20 ml or 18 ml. It is envisaged that the sachets may be sold singly or in strips of sheets from which a single sachet may be torn off for use as required.

The tablets or capsules are preferably sold individually separated in blister packs but may be loose or in sealed containers.

As a non-limitative example ofthe present invention tablets were prepared each including the follow ing ingredients: Sodium dichloroisocyanurate : 0.051 Imgltab (active lens-treating ingredient) Adipic acid (effervescent) 140.30/mg/tab Sodium bicarbonate agent) A blister or bubble pack containing 25 isolated tab lets was prepared.

A polypropylene sachet or envelope was filled with 10 mls of sterile buffered saline solution of pharmaceutically acceptable strength and was then heat-sealed. Subsequently the sachet was irradiated with 2.5 Mrads of gamma-ray radiation to ensure the sterility of its contents.

One tablet was extracted from the blister pack, the sachet was opened and its contents poured into a clean container for containing a contact lens for treatment and the tablet was dissolved in the buf fered saline to produce a lens-treating solution hav ing a concentration therein of sodium dich loroisocyanurate of 1 ppm measured as available chlorine.

When contact lenses of various sorts (including hard lenses made of polymethyl methacrylate and soft lenses made of hydroxyethylmethacrylate polymers or copolymers e.g. with polyvinyl pyrrolidone or made of silicones) were immersed in this solution, they were found to be satisfactorily sterilised after 3 period of 2 hours and it was found that after rinsing with sterile saline the so-sterilized lenses could be inserted into the eyes of a wearer without causing discomfort or irritation.

In another embodiment of the invention a strippack was prepared containing a plurality of isolated tablets each containing 0.051 mg sodium dichloroisocyanurate and 49.949 mg of effervescent base containing adipic acid. When dissolved in 10 ml of water or saline each tablet produced a solution having 3 ppm by weight of available chlorine. The solution was found to have satisfactory lens sterilizing properties and to be physiologically safe.

It will be appreciated that the invention may be preformed otherwise than as specifically described and the invention includes within its scope all methods, solutions, tablets and capsules as defined by the appendant Claims.

Claims

1. A method of sterilizing a contact lens which comprises treating the lens with an effective amount of a pharmaceutically acceptable dichloroisocyanurate solution.

2. A method according to Claim 1, wherein the dichloroisocyanurate solution contains from 0.5 to 100 ppm by weight of dichloroisocyanurate measured as available chlorine.

3. A method according to Claim 2, wherein the dichloroisocyanurate solution contains from 0.5 to 3 ppm by weight of dichloroisocyanurate measured as available chlorine.

4. A method of sterilizing a contact lens, substantially as hereinbefore described.

5. A pharmaceutically acceptable contact lens sterilizing solution containing an effective amount of a dichloroisocyanurate.

6. Asolution according to Claim S,whereinthe dicliloroisocyanurate is sodium dich loroisocyanu- rate

7. A solution according to Claim 6 or7 wherein the solution contains from 0.5 to TOO ppm by weight of dichioroisocyanurate measured as available chlorine.

8. A solution according to any of Claims. 5 to 8, which captains from 0.5 to 3 ppm of the dicks loroisocyanurate measured as available chlorine.

9. A solution according to any of Claims 5 to 8, which also contains one or more of a chelating agent, a wetting agent, a catalyst, sodium chloride and a buffer

10. A pharmaceutically acceptable contact lens sterilizing solution, substantially as hereinbefore described.

11. A tablet or capsule for dissolution in a predetermined quantity of a pharmaceutically acceptable carrier liquid to produce a pharmaceutically acceptable contact lens sterilizing solution, which tablet or capsule contains an effective amount of dichloroisocyanurate.

12. A tablet or capsule as claimed in Claim 11, which further contains an effervescing agent to aid dissolution thereof in said liquid.

13. Atablet or capsule containing dichloroisocyanurate and substantially as hereinbefore described.

14. Atwo part pack which comprises a plurality of sachets each containing a predetermined quantity of a sterile, pharmaceutically acceptable carrier liquid, and a plurality of tablets or capsules as claimed in anyone of Claims 11 to 13, each of said tablets or capsules heing soluble in the quantity of liquid contained within a said sachet and containing dichloroisocyanurate in an amount to produce with said quantity of liquid a lens treating solution of pharmaceutically acceptable strength.

15. A pack according to Claim 14, wherein the sachets anesupplied in the form of a conjoined strip or sheet from which individual sachets may. be sepa--, rated.

16. A pack according to Claim 14 or 15, wherein the sachets are made of polypropylene.

17. A pack according to any one of Claims 74 to 16, wherein each sachet contains sterile water or sterile saline solution.

18. A pack according to anyone of claims 14 to 17, wherein the tablets or capsules are housed in a bubble or blister pack from which each tablet is individually separable.

19. A two part pack substantially as hereinbefore described.

20. A method of producing a pharmaceutically acceptable contact lens sterilizing solution which comprises dissolving in a predetermined quantity of a sterile pharmaceutically acceptable carrier liquid a tablet or capsule containing dichloroisocyanurate in an amount to produce with said quantity of liquid a lens treating solution of pharmaceutically acceptable strength.

21. A method of producing a pharmaceutically acceptable contact lens sterilizing solution substantially as hereinbefore described.

22. The features hereinbefore disclosed, or their equivalents, in any novel selection.