Compositions and methods to disinfect contact lenses

Details Compositions and methods to disinfect contact lenses Compositions and methods to disinfect contact lenses

1994-02-28

2002-01-15

Witz, Jean C. (Department: 1651)

Drug, bio-affecting and body treating compositions

Enzyme or coenzyme containing

Multienzyme complexes or mixtures of enzymes

C424S094400, C424S094600, C424S094610, C424S094620, C424S094630, C424S094640, C424S094650, C424S094660, C424S094670, C422S030000, C252S062200, C252S182280, C252S175000, C252S175000

Reexamination Certificate

active

06338847

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to compositions and methods to disinfect contact lenses. More particularly, the invention relates to such compositions and methods which are useful to facilitate the action of hydrogen peroxide in disinfecting contact lenses and in destroying residual hydrogen peroxide present in a liquid aqueous medium containing a contact lens which has been disinfected by the action of hydrogen peroxide.
Contact lenses should be periodically cleaned and disinfected by the user to prevent infection or other deleterious effects on ocular health which may be associated with contact lens wear. Currently, there are several different conventional systems and methods which enable the user to clean and disinfect their contact lenses between wearing times. These conventional cleaning and disinfection systems can be divided into “hot” and “cold” systems. Hot systems require the use of heat to disinfect the contact lenses, whereas cold systems use chemical disinfectants at ambient temperatures to disinfect the lenses.
Within the realm of cold disinfection systems are hydrogen peroxide disinfection systems. Disinfecting hydrogen peroxide solutions are effective to kill many of the bacteria, fungi and yeasts which may contaminate contact lenses. However, certain microorganisms are resistant to the action of hydrogen peroxide.
One microorganism which is resistant to the killing effects of hydrogen peroxide is the cyst form of acanthamoeba. It has been reported, in an article entitled “The Efficacy of Disinfection System Using Hydrogen Peroxide Against Acanthamoeba”, by Y. Izumi et al, J. Japanese Contact Lens Society 1991; 33(4): 282-6, that such cysts exposed to hydrogen peroxide for two hours survived after two weeks. This article discloses that inclusion of lysozyme in the hydrogen peroxide solution resulted in killing all the cysts within 30 minutes. This article does not suggest any specific contact lens disinfecting system to take advantage of this observation. Since lysozyme is a primary tear protein, the purposeful addition of this enzyme to a liquid medium containing a contact lens may disadvantageously result in the formation of proteinaceous deposits on the contact lens. In effect, treatment of a contact lens with a hydrogen peroxide solution containing lysozyme may result in the lens being soiled with proteinaceous deposit material and/or being otherwise detrimentally affected. In addition, disinfecting a contact lens with a hydrogen peroxide solution containing lysozyme does nothing to destroy the potentially harmful residual hydrogen peroxide which remains after the lens is disinfected.
Residual hydrogen peroxide on a disinfected contact lens may cause irritation, burning or trauma to the eye unless this hydrogen peroxide is destroyed, i.e., decomposed, neutralized, inactivated or chemically reduced. Therefore, the destruction of the residual hydrogen peroxide in the liquid medium containing the disinfected contact lens is needed to enable safe and comfortable wear of the disinfected contact lens.
Associated with the problem of hydrogen peroxide destruction in contact lens disinfection systems are the problems of easy use and user compliance. To enhance user compliance and ease of use, several efforts have focused on one-step disinfection and hydrogen peroxide destruction. In this regard, various time release tablets containing a core tablet and a coating have been suggested. Kruse et al U.S. Pat. No. 4,767,559 discloses a one-step contact lens cleaning and disinfecting tablet designed to be totally dissolved in water. A core containing a hydrogen peroxide reducing agent and a catalyst is provided. A jacket mixture containing a hydrogen peroxide generating component is provided and envelopes the core. In this case, the jacket mixture dissolves to form hydrogen peroxide to disinfect the contact lens. Subsequently, a thin lacquer coating surrounding the core of the tablet is dissolved, resulting in the release of the reducing agent and catalyst.
Kay United Kingdom Patent Application GB 2 151 039 A discloses a sustained-release tablet composition from which a hydrogen peroxide inactivator, e.g. sodium sulphite, is gradually leached in the presence of a hydrogen peroxide-containing solution used to disinfect contact lenses. The entire tablet, other than the leached hydrogen peroxide inactivator, remains unaffected, i.e., is insoluble in the solution.
Kaspar et al U.S. Pat. No. 4,568,517 discloses a system in which a contact lens is disinfected in an aqueous hydrogen peroxide solution and, after disinfection, the peroxide is reduced by adding a tablet containing a core having a hydrogen peroxide reducing component, e.g. sodium sulfite or sodium thiosulfate, and a coating which slowly totally dissolves in the peroxide solution to release the reducing agent.
A number of other alternatives for a combination tablet or the like containing a hydrogen peroxide sterilizing agent and a hydrogen peroxide reducing agent are disclosed in Schafer et al European Patent Application 86-109,361.5. None of these patents and patent applications disclose the use of components which facilitate the antimicrobial action of hydrogen peroxide.
Accordingly, a need exists for novel, safe and efficacious systems for killing hydrogen peroxide-resistant microorganisms contaminating contact lenses without detrimentally affecting, e.g., soiling and/or otherwise harming, the contact lenses being disinfected and for destroying residual hydrogen peroxide in liquid media used for disinfecting contact lenses.
SUMMARY OF THE INVENTION
New compositions and methods useful to disinfect contact lenses have been discovered. The present invention facilitates the killing of hydrogen peroxide-resistant microorganisms by the action of hydrogen peroxide. Moreover, this is achieved substantially without detriment to the contact lens being disinfected. Further, the residual hydrogen peroxide remaining after the disinfecting takes place is effectively and conveniently destroyed, thus allowing the lens to be safely and comfortably worn.
In one broad aspect, the present invention is directed to compositions which comprise an effective amount of a cellulose and/or chitin decomposing enzyme component, hereinafter referred to as CDEC, for example, lysozyme, and an effective amount of a hydrogen peroxide destroying component, hereinafter referred to as HPDC. Such compositions are structured so that the CDEC is released in a liquid medium before the HPDC is released in the liquid medium. The CDEC is preferably present in an amount effective to render acanthamoeba cysts present in the liquid medium more susceptible to being killed by hydrogen peroxide in the liquid medium than by hydrogen peroxide in a substantially identical liquid medium in the absence of the CDEC. The HPDC is preferably present in an amount effective to destroy all the hydrogen peroxide contained in the liquid medium. Methods for disinfecting contact lenses are also provided in which a contact lens is contacted with a liquid medium containing an effective contact lens disinfecting amount of hydrogen peroxide in the presence of a composition, as described herein.
The present invention preferably allows the CDEC/HPDC-containing composition to be initially contacted with the hydrogen peroxide-containing liquid medium, hereinafter referred to as HPLM, at the same time the contact lens to be disinfected is initially contacted with the liquid medium. For example, the present compositions and the contact lens to be disinfected can be added to the HPLM at substantially the same time. This feature greatly reduces the amount of user time and care required to effectively disinfect his/her lens and destroy the residual hydrogen peroxide. Better user compliance and a greater degree of user eye safety is provided. The present invention preferably includes a delayed release feature so that the contact lens is effectively disinfected, even from hydrogen peroxide-resistant microorganisms, by the action of hydrogen peroxide prior to the release of th

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