Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1996-09-03
2001-01-09
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S470000, C510S474000
Reexamination Certificate
active
06172017
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of this invention is cleaning contact lenses using carbohydrate compositions. More particularly, the invention relates to compositions and methods that combine cleaning using certain carbohydrates with thermal or chemical disinfecting of contact lenses.
2. Description of the Art
In the normal course of wearing contact lenses, tear film and debris consisting of proteinaceous, oily, sebaceous and related organic manner have a tendency to deposit and build up on lens surfaces. As part of a routine care regimen, contact lenses must be cleaned to remove these film deposits and debris. Without proper cleaning and removal of deposits, wettability and optical quality of the lenses are reduced causing discomfort for the wearer and reduced visual clarity, respectively.
Further, contact lenses, especially those made from hydrophilic materials, must be frequently disinfected to kill harmful microorganisms that collect or grow on lens surfaces. A number of methods for disinfecting contact lenses have been used, such as subjecting the lenses to high temperature, oxidative chemicals or various antimicrobial agents.
Conventionally, the cleaning of contact lenses is accomplished by one or both of two general classes of cleaners, based on surfactants or enzymes. Surfactant cleaners are effective for the removal of some carbohydrate and lipid derived matter and are typically recommended for daily use. However, these cleaners are only slightly effective in the removal of proteinaceous matter, such as lysozyme, a principal component of tears. Typically, proteolytic enzymes, derived from plant, animal or microbial sources, are used to remove proteinaceous deposits. These enzyme cleaners are typically recommended for cleaning lenses once per week at ambient temperatures. As evident from the following description, the present invention is directed to a composition that is not an enzyme cleaner, but rather a composition that can remove protein without the use of an enzyme.
The process of cleaning and disinfecting contact lenses conventionally requires two or more steps. Cleaning typically requires soaking in a cleaning solution of surfactant or enzyme at ambient temperature for a sufficient period to effectively remove deposits. Disinfection involves contacting the lenses with a solution containing antimicrobial agents at ambient temperatures or exposing the lenses in an aqueous solution to elevated temperatures for a time sufficient to achieve disinfection.
Those developing contact lens care products seek to simplify lens care regimens used by lens wearers. As indicated above, a lens care regimen will typically include a number of steps in combination that must be followed to effectively clean and disinfect. It is commonly known that lens wearers often fail to follow complex cleaning and disinfecting methods. Since many of the chemicals utilized in the process, as well as contaminating microorganisms, are harmful to the eye, compliance is an important concern. It is also a goal that the cleaned and disinfected lens, at the end of a one-step regimen, reside in a substantially isotonic solution of such a character that the lens may be inserted directly into the eye without further rubbing and rinsing to remove potentially harmful materials. Ideally, contact lens cleaning/disinfecting regimens would be reduced to a single step. However, combining cleaning and disinfecting in a single step has proved to be difficult to achieve because of competing reactions involved and the nature of the chemicals conventionally used.
Cleaning of proteinaceous deposits from contact lenses has evolved primarily into the use of enzymes that effectively remove this type of contaminant that binds to lens surfaces. Since enzymes may not be safely placed in the eye at the end of the lens cleaning step, they must be removed or deactivated prior to wearing. Since enzymatic cleaners do not substantially disinfect contact lenses, there must be a disinfection step in the regimen. As described above, the disinfection step may be chemical in nature or employ elevated temperature.
At the completion of chemical disinfection, it is generally necessary to either neutralize or rinse residual chemicals from the lens surfaces before they may be safely inserted in the eye. For example, in Huth et al, U.S. Re 32,672, contact lenses are simultaneously cleaned and disinfected by placing them in a solution containing an enzyme and hydrogen peroxide. At completion of the cleaning/disinfecting cycle, residual hydrogen peroxide must be decomposed or neutralized before the lenses can be placed on the eye. A rub and rinse step with an isotonic buffered saline solution is often recommended after neutralization as a final step before insertion of the cleaned and disinfected lenses into the eye.
In U.S. Pat. No. 5,096,607, contact lenses are simultaneously cleaned and disinfected by contacting the lenses with an aqueous system containing a disinfecting amount of an antimicrobial agent, such as a polymeric quaternary ammonium salt or biguanide, and an effective amount of a proteolytic enzyme. The osmotic value of this system is adjusted such that the activity of the antimicrobial agent is not inhibited. While the lenses do not need a separate chemical neutralizing step, they must be rinsed with a suitable isotonic aqueous solution prior to insertion in the eye to remove any residual enzyme therefrom.
Another commonly accepted technique for disinfecting contact lenses after cleaning employs a thermal disinfection process in which the lenses are placed in a solution and elevated in temperature for a period of time sufficient to effect the disinfection. In Ogunbiyi et al, U.S. Pat. No. 4,614,549, cleaning and disinfection are accomplished simultaneously by placing the lenses in a solution comprising a proteolytic enzyme dissolved in water at about room temperature and then heating the solution and lenses to an elevated temperature of about 60-100° C. for about 60 minutes or less. The temperature increase first activates the enzyme to accomplish the cleaning. As the process proceeds, the enzyme is deactivated and removed protein denatured to form a suspended particulate precipitate. The lenses must be rubbed and rinsed prior to insertion in the eye to remove any precipitated protein therefrom. The thermal disinfection technique, of course, requires a special electrical disinfecting apparatus.
There is a continuing need for new cleaning and disinfecting compositions and methods that permit simple cleaning regimens. The formulation of one-step cleaning and disinfecting systems that would allow one to place the cleaned and disinfected lens directly in the eye without prior rinsing or rubbing is always a principal goal.
SUMMARY OF THE INVENTION
It has now surprisingly been found that certain carbohydrate cleaning solutions that are safe for use in the human eye are effective for cleaning proteinaceous deposits from contact lenses. Preferred carbohydrates are certain mono or disaccharides, or an alcohol or a partially hydrolyzed ester of such saccharides or mixtures thereof. Such preferred carbohydrates include, but are not limited to, sorbitol, glucose, maltose, sucrose, dulcitol, dextran, dextrin, mannitol, maltitol, mannose or mixtures thereof in an aqueous solution in an effective amount.
An effective amount of said carbohydrates of the invention is about 0.001 to about 10 weight percent in an aqueous solution. The solution may include buffer compounds such as borate or phosphate buffers to regulate pH. A preferred composition for cleaning comprises sorbitol in an amount of about 0.1% to about 1% by weight in an aqueous solution.
The invention also comprises a method for simultaneously cleaning and disinfecting contact lenses comprising contacting said lenses with a composition comprising a carbohydrate that is a mono or disaccharide, or an alcohol or a partially hydrolyzed ester of such saccharide or mixtures thereof. Preferably, said carbohydrate comprises sorbitol, glucose, maltose, sucrose,
Groemminger Suzanne F.
Panicucci Rick
Bausch & Lomb Incorporated
Furr, Jr. Robert B.
Ogden Necholus
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