JPS6229773B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contact lens made of a novel material.

More than 20 years have passed since contact lenses were first used, but all the lenses used to date have been made from polymers, such as polymethyl methacrylate, hydroxyethyl methacrylate, and silicone. be.

Among these, soft contact lenses are mainly made of homopolymers or copolymers of acrylic derivatives having OH groups, which have good optical properties as lenses and swelling properties when absorbing water. It is preferred because it is warm and causes less pain when worn.

However, while soft contact lenses made of conventional materials have excellent properties, they are brittle and have low physical strength, so they have the disadvantage of cracking or chipping during handling, or breakage or cracking during cleaning or disinfection. I had something to do.

The present inventors have been conducting various studies on chitin, chitosan, and their derivatives, focusing on their synthesis methods, molecular structures, physical properties, and biochemical properties, and have found that chitin, chitosan, and their derivatives have the above-mentioned drawbacks. We have discovered that this material can be used as an extremely excellent contact lens.

Examples of derivatives of chitin and chitosan include, but are not limited to, acetyl chitin, hydroxyethyl chitosan, hydroxypropyl chitosan, hydroxybutyl chitosan, hydroxybenzyl chitosan, hydroxyhexyl chitosan, and acetyl chitosan.

Contact lenses are made of glass, a solution of the above materials,
It is molded by placing it in a metal mold and removing the solvent. Although the contact lenses of the present invention can be made into either hard or soft lenses depending on the selection of materials and subsequent processing, they are more suitable for soft contact lenses due to the characteristics of the materials. It is something.

Chitin, chitosan, or their derivatives used in the present invention have recently attracted attention for use as dialysis membranes or wound covering materials by forming them into membranes or nonwoven fabrics, but no examples of their use in contact lenses have been reported. do not have.

Chitin is a natural polymer substance found in crab shells, etc., and is widely available in nature. Chitosan is deacetylated chitosan, and both are easily obtained from commercial products. It is a raw material that can be

Chitosan can be produced by dissolving it in acetic acid, formic acid, propionic acid, etc., molding it into a lens, and then treating it with sodium hydroxide.Chitin can also be produced by dissolving it in acetic acid, formic acid, propionic acid, etc. and treating it with sodium hydroxide after forming it into a lens. , N-methylpyrrolidone or other polar organic solvent and molded into a lens.

Derivatives such as hydroxyethyl chitosan are crosslinked by contacting them with a crosslinking agent such as dimethylol urea, tolylene diisocyanate, epichlorohydrin, formaldehyde, acetaldehyde, methylol acrylamide, glutaraldehyde, chromic acid, etc. in a solvent and then heating. It is also possible to make it insoluble in water and have improved strength.

Alternatively, crosslinking can also be effected by irradiation with gamma rays, ultraviolet rays, or the like.

Next, the present invention will be explained by examples.

Example 1 Commercially available chitosan was washed with water, then washed with ethanol and ether, dried, and diluted with 1.5% acetic acid aqueous solution.
Dissolve glutaraldehyde at a rate of 0.1%
It was added at a ratio of This was placed in a lower glass lens mold and spread uniformly, then degassed under reduced pressure overnight, the convex part of the upper lens mold was pressed against the lower mold containing chitosan, and the mold body was placed in a heating oven. Transfer,
Crosslinking was achieved by heating at 70°C for 10 hours. The chitosan lens thus formed was neutralized with a dilute aqueous sodium hydroxide solution (PH8), transferred to physiological saline, left to stand, taken out, frozen, and cut around the lens with a circular cutter. The finished lenses were stored in physiological saline. This lens was optically transparent and highly flexible, and exhibited excellent properties as a contact lens.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the contact lens of the present invention, and FIG. 2 is a sectional view thereof.

Claims (1)

[Claims] 1. A contact lens made of chitin, chitosan, or a derivative thereof. 2. The contact lens according to claim 1, which is crosslinked by treatment with formaldehyde, glutaraldehyde, or epichlorohydrin.