JPH0113085B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for cleaning contaminated or yellowed contact lenses. Contact lenses are broadly divided into hard types and soft types. Conventionally, materials such as polymethyl methacrylate (PMMA), dextran, or cellulose derivatives have been used for hard type lenses, all of which are non-hydrophilic and hard lenses. Disinfection of hard lenses is carried out by immersing the lenses in a storage solution containing mainly benzalkonium chloride as a disinfectant, but in this case, even if the drug adheres or adsorbs to the lenses, the amount is small. be. On the other hand, soft type lenses are mainly made of polyhydroxyethyl methacrylate (PHEMA), which absorbs water in an aqueous solution and turns into a gel.
A feature of this device is that even beginners can continue wearing it without feeling a foreign body when wearing it on the eye. and,
In Japan, boiling sterilization is compulsory for sterilization before or after wearing soft lenses, but this method is not desirable as it is cumbersome to operate and accelerates the aging of the lens material. Therefore, disinfection methods using chemicals for soft lenses are being developed, but these include benzalkonium chloride, p-
It is said that bactericidal agents such as oxybenzoic acid esters and chlorobutanol are adsorbed and accumulated on soft lenses and cause eye damage if they are worn directly on the eyes. In the United States, Canada, and Europe, soft lenses are disinfected with a mixed solution containing both chlorhexidine gluconate and thimerosal. In this case, a considerable amount of chlorhexidine is adsorbed and accumulated on the soft lens, but when the lens is worn on the eye, it is said that there is no problem because the amount of chlorhexidine eluted is small compared to the adsorbed amount. In any case, it is desirable for both the lens and the wearer to remove the disinfectant that is intermittently adsorbed and accumulated on the lens. Additionally, contact lenses tend to yellow when worn for a long period of time. This yellowing is thought to occur when sugars, amino acids, etc. in tear fluid components are adsorbed to the lens and then oxidized by light. The present inventors have conducted research on cleaning methods for contaminated or yellowed lenses as described above, and have found that chlorhexidine adsorbed from lenses can be eluted and removed using a urea solution, and that urea solutions can be used to decolorize yellowed lenses. The present invention was achieved by discovering that it is also effective. The present invention uses urea to treat contact lenses that have been contaminated with chlorhexidine or yellowed due to wear.
This is a method for cleaning drug-contaminated contact lenses, which is characterized by immersing them in a 10-50 (W/V)% aqueous solution. Chlorhexidine, either as it is or in the form of its acid salt, is added to lens cleaning and preservation solutions as a disinfectant, but no matter what form chlorhexidine comes into contact with the lens, the lens that has adsorbed it will be permanently damaged. It can be the subject of invention. Representative examples of chlorhexidate salts are chlorhexidine gluconate or chlorhexidine hydrochloride. Urea is generally used as an aqueous solution. Although isotonic solutions of urea have a concentration of about 2% (V/W), hypertonic solutions are preferred for the method of the present invention. A hypertonic solution of urea generally has the property of swelling a soft lens, and when washed with water, the lens shrinks and returns to its original shape, so the urea solution penetrates inside the lens and is then expelled. It is believed that this movement of urea solution aids in cleaning lens contamination. The higher the concentration of urea in the urea solution, the greater the lens cleaning effect, but it is approximately 10%
(W/V) or more, and more preferably 20 to 50 (W/V)%. Contact lenses targeted by the present invention are mainly soft-type lenses, but the method of the present invention can also be applied to hard-type lenses, if necessary. The urea solution used for lens cleaning may be a solution of urea alone, or may be a solution containing urea alone, or may contain urea containing sodium chloride, potassium chloride and other salts, enzymes such as lipase and protease, and chelating agents such as sodium ethylenediaminetetraacetate as necessary. A solution may also be used. For yellowing lenses, cleaning with a urea solution one or two times does not produce a significant effect, but as the number of cleanings increases, the color gradually decolorizes. Further, by washing the lens with a urea solution after wearing it, yellowing of the lens can be prevented. Example 1 After immersing a soft contact lens in an aqueous solution of chlorhexidine gluconate to adsorb chlorhexidine onto the lens, the lens was taken out from the solution, and 5 ml of a urea solution of each concentration based on physiological saline was added thereto. After shaking briefly for an hour, the amount of chlorhexidine eluted into the aqueous solution was determined. The results are shown in Table 1.

[Table] As can be seen from Table 1, the elution rate of chlorhexidine adsorbed to soft contact lenses differs slightly depending on the type of lens, but the elution rate of chlorhexidine adsorbed to soft contact lenses is There was a significant increase in comparison. Example 2 2.5 g of urea, 0.06 g of sodium chloride, 0.06 g of sodium sulfite, 0.09 g of sodium bisulfite,
Sodium edetate 6mg and polysorbate 80
A contact lens adsorbed with chlorhexidine is soaked in a solution of 0.05 g dissolved in 5 ml of purified water and washed. Example 3 2.0 g of urea, 0.06 g of sodium chloride, 0.06 g of sodium sulfite, 0.09 g of sodium bisulfite,
Dissolve 6 mg of sodium edetate and 0.05 mg of bioplase (proteolytic enzyme) in 5 ml of purified water. A contact lens that has yellowed due to long-term wear is soaked in this solution, left overnight, washed with physiological saline, and worn, and the same soaking, washing, and wearing process is repeated several times.
In some cases, soaking and washing may be repeated without wearing the product. Example 4 2.0 g of urea, 0.06 g of sodium chloride, 0.04 g of polysorbate 80, and 0.04 g of sodium polyoxyethylene alkyl sulfate are dissolved in 5 ml of purified water, and the lens adsorbed with chlorhexidine is washed with this solution.

Claims (1)

[Claims] 1. A contact lens cleaning method characterized by immersing a contact lens contaminated with chlorhexidine in a 10 to 50 (W/V)% aqueous solution of urea.