Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2002-09-16
2004-10-19
Boyer, Charles (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S384000, C510S488000, C510S499000
Reexamination Certificate
active
06806243
ABSTRACT:
This application is based on Japanese Patent Applications Nos. 2001-281471 filed on Sep. 17, 2001 and 2002-224761 filed on Aug. 1, 2002, the contents of which are incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to an ophthalmic solution and a solution for a contact lens. In particular, the invention is concerned with such a solution used as a contact lens sterilizing or germicidal solution, a contact lens sterilizing and cleaning solution, a contact lens sterilizing and storing solution, a contact lens sterilizing, cleaning, and storing solution, a contact lens cleaning and/or storing solution, a collyrium or eye drops, or a preservative in cosmetics. More specifically, the invention is concerned with such a solution which exhibits an excellent germicidal (or sterilizing) or preservative effect or assures excellent compatibility with the contact lens without causing a change of the size of the contact lens, while exhibiting a sufficiently high degree of safety to the eye and the skin of the user.
2. Discussion of the Related Art
A solution for a contact lens (hereinafter referred to as “contact lens solution”) contains a germicidal or preservative component to prevent contamination of the contact lens by molds and microorganisms such as bacteria, in addition to a cleaning component to remove deposits adhering to the contact lens such as protein and lipid which derive from tear fluid and lipid of the eye.
Although various compounds are conventionally proposed as the germicidal component contained in the contact lens solution (contact lens sterilizing solution), it is necessary to use those compounds in relatively high concentrations for permitting the solution to exhibit practically sufficient germicidal characteristics. For instance, biguamide compounds whose typical example is polyhexamethylene biguamide (PHMB) as an organic nitrogen germicide and quaternary ammonium compounds whose typical examples are benzalkonium chloride and polyquaternium have been widely used as the germicidal component included in the contact lens solution since the biguamide compounds and the quaternary ammonium compounds exhibit particularly effective germicidal characteristics superior to those of conventional germicidal components. A recent study, however, reveals that the biguamide compounds or the quaternary ammonium compounds alone do not provide a sufficiently high degree of germicidal or preservative effect unless those compounds are used in relatively high concentrations.
For assuring a practically useful germicidal or preservative effect, it is necessary to increase the amount of the germicidal component to be included in the contact lens solution. The biguamide compounds or the quaternary ammonium compounds if used in high concentrations, however, are toxic to the eye, and likely to be adsorbed on the contact lens, especially the soft contact lens. In this case, the germicidal component undesirably may irritate the mucous membranes of the eye to cause trouble with the eye, giving rise to a problem of insufficient safety. In view of this, various studies have been made to provide a contact lens solution capable of exhibiting a higher germicidal effect while reducing the required amount of the germicidal component.
For instance, JP-A-10-108899 discloses a contact lens solution which assures safety to the eye while exhibiting an excellent germicidal effect. In the disclosed solution, the polyhexamethylene biguamide as the biguamide germicide is used in combination with a nonionic tonicity adjusting agent such as glycerin or propylene glycol. JP-A-11-249087 discloses a contact lens solution which assures safety to the eye while exhibiting an excellent disinfecting effect. In the disclosed solution, the polyquaternium is used in combination with the nonionic tonicity adjusting agent and/or amino acid. Although the germicidal efficacy of each of the disclosed contact lens solutions is improved to some extent owing to the combined use of the compounds described above, there is still room for improvement in the characteristics of the solutions.
Even if the germicidal component such as the polyhexamethylene biguamide or the polyquaternium is used in low concentrations, the germicidal component which adheres to or is adsorbed on the contact lens may cause various troubles with the user's eye, such as inflammation of the eye and staining of the cornea over the substantially entire surface with fluorescein. The staining of the cornea with the fluorescein indicates that the cornea suffers from some trouble such as a wound or an ulcer. Depending upon the kind of the nonionic tonicity adjusting agent and/or the amino acid to be used in combination with the germicidal component, the size of the contact lens may be undesirably changed, in other words, the contact lens may suffer from swelling or shrinkage, resulting in an undesirable change of the specifications of the contact lens.
SUMMARY OF THE INVENTION
The present invention was developed in the light of the background art situations described above. It is therefore a first object of the present invention to provide an ophthalmic solution and a solution for a contact lens, which assure an excellent germicidal or preservative effect while assuring a sufficiently high degree of safety to a living subject or body (human body) by minimizing toxicity to the living subject.
It is a second object of the invention to provide a solution for a contact lens which assures a considerably high degree of safety to the eye of the contact lens user by inhibiting adhesion and adsorption of the germicidal or preservative component to and on the contact lens.
It is a third object of the invention to provide a solution for a contact lens which prevents swelling or shrinkage of the contact lens so as not to cause a change of the size of the contact lens and which assures excellent compatibility with the contact lens.
An extensive study made by the inventors of the present invention to attain the above-indicated first object has revealed that the germicidal activity exhibited by the biguamide germicide or the quaternary ammonium salt germicide included in the ophthalmic solution is inhibited by an electrolyte such as sodium chloride generally included in the solution for adjusting its osmotic pressure, or an inorganic salt buffer such as phosphate, which is generally included in the solution for adjusting its pH and which shows a relatively high degree of ionic strength when dissolved in water. It was also found that the ophthalmic solution exhibits a considerably higher germicidal or preservative effect than the conventional solution if concentrations of the sodium chloride and the phosphate in the solution are made zero or minimized and if at least one amino-acid-based component selected from the group consisting of selected amino acids, salts of the amino acids, and derivatives of the amino acids is used as a tonicity adjusting agent, in place of the sodium chloride.
The above-indicated first object of the present invention may be attained according to a first aspect of the invention, which provides an ophthalmic solution which comprises at least one germicidal/preservative component selected from the group consisting of biguamides and quaternary ammonium salts, further comprising: at least one amino-acid-based component selected from the group consisting of amino acids each having an isoelectric point of not smaller than 4 and a molecular weight of not smaller than 89, salts of the amino acids, and derivatives of the amino acids; and sodium chloride concentration of which in the ophthalmic solution is adjusted to be held in a range of 0-0.2 wt. % and phosphate concentration of which in the ophthalmic solution is adjusted to be held in a range of 0-0.5 wt. %.
In the present ophthalmic solution wherein the concentrations of the sodium chloride and the phosphate are made as low as possible, the biguamide germicide or the quaternary ammonium salt germicide exhibits its germicidal characte
Hozumi Kentaro
Mori Osamu
Tsuzuki Akira
Boyer Charles
Burr & Brown
Menicon Co. Ltd.
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