Aqueous solution

Details Aqueous solution Aqueous solution

1998-05-05

2001-03-27

Einsmann, Margaret (Department: 1751)

Cleaning compositions for solid surfaces, auxiliary compositions

Cleaning compositions or processes of preparing

For cleaning a specific substrate or removing a specific...

C510S421000, C510S470000, C510S471000, C510S475000, C510S504000

Reexamination Certificate

active

06207628

ABSTRACT:

The present invention relates generally to an aqueous solution for maintaining contact lenses, in particular hard contact lenses.
Aqueous solutions for maintaining contact lenses generally have the function of decontaminating and cleaning the lenses.
To be effective, these solutions need to have a combination of several properties.
Firstly, they need to ensure effective decontamination of the lenses for a broad spectrum of microorganisms, and effective cleaning of the surfaces of the lenses, without their active principles being absorbed by the lenses.
Moreover, in order to simplify the maintenance of lenses, it is desirable for them to be re-usable directly after soaking in the maintenance solution, i.e. without it being necessary to carry out one or more rinses with water. In this case, it is particularly important, since the maintenance solution must remain in contact with the user's eye, that this solution is not irritant, is well tolerated and leaves the lenses comfortable to wear throughout the period of continuous use, generally a day.
An important factor for the comfort of use of treated lenses is the viscosity of the maintenance solution. This viscosity should not be too low or too high. If the viscosity of the solution is too low, the solution will not wet the surfaces of the lens correctly; the user will perceive the lens as a foreign body in the eye, and if the viscosity is too high, the solution can give rise to cloudy vision and lead to a greasy feel on the lens, which users find uncomfortable.
Another important factor for the comfort of use of lenses treated with a maintenance solution is the ability of the maintenance solution to retain a relatively large amount of water on the surfaces of the lens treated, such that the surfaces of the lens are humidified throughout a prolonged period and the wettability of the surfaces of the lens is retained. This characteristic, which will be denoted hereinbelow as “the humidity-retaining ability” is an important factor for the user's comfort. This humidity-retaining ability is a particularly important factor in the case of hard contact lenses, which generally have a low ability to retain water on their surfaces.
In order to improve the wettability of contact lens surfaces, in particular for hard lenses, it has been proposed to incorporate hydrophilic monomers into the maintenance solutions. However, these hydrophilic monomers generally have the drawback of affecting the other physical properties of the lenses.
To solve this problem it has also been proposed to incorporate wetting polymers into the maintenance solutions, but the action of these polymers is weak and disappears rapidly.
To overcome the abovementioned drawbacks, document WO 95/00616 proposes adding to the maintenance solutions a water-soluble poly(ethylene oxide) which is a star polymer containing a hydrophobic core having at least three carbon atoms and at least three hydrophilic poly(ethylene oxide) chains (arms) attached to the core. In addition, the star polymers in document WO 95/00616 must not contain hydrophobic arms attached to the core.
In a preferred embodiment of document WO 95/00616, a second surfactant polymer component, a cationic cellulose polymer, is added to the maintenance solution. This cationic component complexes with the poly(ethylene oxide) star polymer and the complex formed is strongly adsorbed onto the surface of the lenses.
Although the maintenance solutions of document WO 95/00616 are satisfactory, it would be desirable to have available maintenance solutions which afford the contact lens wearer even better comfort.
The object of the present invention is thus to provide a maintenance solution for contact lenses, in particular for hard contact lenses, which overcomes the abovementioned drawbacks.
The subject of the present invention is, more particularly, a maintenance solution as defined above, which gives treated lenses improved humidity-retaining ability.
The subject of the present invention is also a maintenance solution as defined above, which is easy to use, in particular which allows treated lenses to be used directly, i.e. without rinsing, and makes the treated lenses comfortable for the user to wear.
The aims listed above are achieved, according to the present invention, by providing an aqueous maintenance solution for contact lenses, in particular hard contact lenses, characterized in that it comprises an effective amount of polyethylene glycol 120 methylglucose dioleate of formula:
in which x+y=120.
The incorporation of polyethylene glycol 120 methylglucose dioleate into the maintenance solution not only increases the wettability of the lenses by the maintenance solution but also appreciably improves the humidity-retaining ability of the treated lenses. In addition, the maintenance solutions according to the invention make the treated lenses particularly comfortable for the user.
Preferably, the amount of polyethylene glycol 120 methylglucose dioleate present in the solution is between 0.05 and 5% by weight, better still between 0.1 and 2% by weight, relative to the total weight of the aqueous maintenance solution.
As is well known, the aqueous maintenance compositions according to the invention comprise a decontaminating agent. This decontaminating agent, generally an antimicrobial agent, is well known in the art and can consist of a single compound or a mixture of several compounds. Compounds which are useful as decontaminating agents can be any known compounds which are useful as decontaminating agents in aqueous maintenance solutions for contact lenses.
Among these compounds, mention may be made of chlorhexidine (1,1′-hexamethylenebis[5-(p-chlorophenyl)biguanide]) or water-soluble salts thereof, such as chlorhexidine gluconate; polyhexamethylene biguanide (a hexamethylene biguanide polymer also known under the name polyaminopropyl biguanide) or water-soluble salts thereof, such as polyhexamethylene biguanide hydrochloride sold under the trade name Cosmocil CQ® (ICI Americas Inc.); alkylammonium halides, in particular alkyltrimethylammmonium bromides such as tetradecyltrimethylammonium bromide, dodecyltrimethyl-ammonium bromide, hexadecyltrimethylammonium bromide (cetrimonium bromide) sometimes known as “Cetrimide”; benzalkonium halides such as benzalkonium chloride; polymeric quaternary ammonium salts; and mixtures of these compounds.
The recommended decontaminating agents according to the invention are polyaminopropyl biguanide and the water-soluble salts thereof, in particular the product sold under the brand name Cosmocil CQ®, and alkylammonium bromides, in particular cetrimonium bromide, and mixtures thereof.
A decontaminating agent which is particularly preferred according to the invention is a mixture of polyhexamethylene biguanide hydrochloride (Cosmocil CQ®) and cetrimonium bromide.
The amount of decontaminating agent in the maintenance solution according to the invention is an effective amount, i.e. an amount sufficient to decontaminate lenses. In general, the amount of decontaminating agent present in the maintenance solution according to the invention is from 10
−6
to 5% by weight, preferably 0.01 to 0.05% by weight, relative to the total weight of the maintenance solution.
Preferably, the maintenance solutions according to the invention contain an effective amount of one or more nonionic surfactants. Among these nonionic surfactants, mention may be made of fatty acid esters of polyethylene glycol, for example of coconut oil, polysorbates, polyoxyethylene ethers and polyoxypropylene ethers of higher alkanes (C
12
-C
18
). Examples of the above nonionic surfactants comprise polysorbate 20 (sold under the brand name Tween 20®), polyoxyethylene lauryl ether (Brij® 35), polyoxyethylene (40) stearate (Myrj® 52), polyoxyethylene (25) propylene glycol stearate (Atlas® G 2612).
A particularly recommended class of nonionic surfactants comprises poly(oxypropylene)-poly(oxyethylene) adducts of ethylenediamine and poly(oxyethylene)-poly(oxypropylene) block polymers.
The pre

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