JPS63283650A - Material for intraocular lens - Google Patents

Abstract

PURPOSE:To make various inflammatory cells, the emergence of deposit, the precipitation of fibrin and secondary cataract hard to generate, by treating copolymer being a specific resin having good bio-compatibility with alkali. CONSTITUTION:A copolymer subjected to alkali treatment is based on methyl methacrylate (component A) and acrylic acid or methacrylic acid (component B). A crosslinking agent or a known other vinyl monomer as the copolymerizing component of a material for a lens is added thereto if necessary. When the total amount of the component A and the component B is set to 100pts.wt., the use amount of the component B is desirably set to about 3-30pts.wt. When the use amount of the component B becomes below 3pts.wt., the effect (bio- compatibility) using the component B is not sufficiently obtained and, when said amount exceeds 30pts.wt., material quality becomes brittle and a machining property becomes inferior.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an intraocular lens material, and particularly to an intraocular lens material with good biocompatibility.

(Prior art and its problems) Intraocular lenses, which have traditionally been used as vision correction lenses after cataract surgery, have been used in many clinical experiments in Japan in recent years as lenses have been improved and surgical techniques have developed. Under,
Their use has been increasing, and it has been recognized that they are extremely functionally superior to conventional cataract glasses and contact lenses.

Incidentally, such an intraocular lens is an optical element (artificial crystalline lens) that is used as a substitute for the crystalline lens surgically removed from the eye and is inserted into the anterior chamber or retrograde part of the eye. It consists of a biconvex or plano-convex disc-shaped lens body and a support portion for holding the lens body at a predetermined position within the eye.

1. Conventionally, polymethyl methacrylate has been mainly used as a material for providing the lens body and support portion of such an intraocular lens. This is because polymethyl methacrylate has also been widely used as a material for contact lenses.

However, with intraocular lenses made of polymethyl methacrylate, although the material itself is unlikely to deteriorate, various inflammatory cells and deposits are likely to appear around the lens after it is inserted into the eye. Furthermore, there were inherent problems in that fibrin was deposited and the development of secondary cataracts was likely to occur.

(Object of the Invention) The present invention has been made against the background of the above, and its object is to provide an intraocular lens material capable of correcting visual acuity after cataract surgery. Intraocular lenses with good biocompatibility that suppress the reactions of surrounding cells in the eye, specifically those that are less likely to cause the appearance of various inflammatory cells, deposits, fibrin precipitation, secondary cataracts, etc. The purpose is to provide materials.

(Structure of the Invention) In order to achieve the above object, the present invention provides an intraocular lens material obtained by alkali-treating a copolymer mainly composed of methyl methacrylate and acrylic acid or methacrylic acid. That is.

(Operation/Effect) In this way, the present invention does not use polymethyl methacrylate as a material for intraocular lenses, but uses methyl methacrylate, which has a long track record of safety for living organisms, and charged The material obtained by copolymerizing the component acrylic acid or methacrylic acid and then treating the copolymer with an alkali can be used as a material for intraocular lenses. It was possible to obtain an intraocular lens with good quality, and the reason for this is probably that the methyl methacrylate-(meth)acrylic acid copolymer becomes electrically charged due to alkali treatment. It is thought that this is due to

For example, when methacrylic acid is used for copolymerization with methyl methacrylate, the methacrylic acid component in the copolymer reacts with an alkali to form a salt such as sodium methacrylate, and the surface becomes charged. This is thought to be the case. Since charged materials have little fibrin precipitation and cell reactions, the above-mentioned charged copolymers according to the present invention also suppress surrounding cell reactions in the eye and prevent various types of inflammation. It is believed that this material will be a material for intraocular lenses with good biocompatibility that will not cause the appearance of cells and deposits, the precipitation of fibrin, and secondary cataracts.

(Specific Structure of the Invention) In the present invention, the copolymer to be subjected to alkali treatment has methyl methacrylate (component A) and acrylic acid or methacrylic acid (component B) as main components, It consists of a crosslinking agent added accordingly and other vinyl monomers known as copolymerization components of lens materials, among which the amount of component B used is the same as the amount of component A and B described above. If the total amount of the components is 100 parts by weight, it is desirable that the proportion be within the range of approximately 3 to 30 parts by weight. When the amount of component B used is less than 3 parts by weight, the effect of using component B (
(biocompatibility) could not be obtained sufficiently, and 3.
This is because if the amount exceeds 0 parts by weight, the material will be poor and machinability will deteriorate. In addition, here, the main component means, as long as it does not have an adverse effect on the purpose of the present invention.
It should be understood that proportions of approximately 50% by weight or more are generally contemplated.

In addition, the crosslinking agent is used in the same way as in the production of ordinary lens materials, and specifically, the following commonly used monomers are exemplified, and one or two of these can be used. More than one species is selected and used. Such a crosslinking agent is added for the purpose of imparting good shape stability to the material and making the material insoluble in various solvents. The amount added is preferably within the range of approximately 0.1 to 10 parts by weight per 100 parts by weight of the total copolymer components. Examples of this crosslinking agent include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, allyl(meth)acrylate, Examples include methacryoyloxyethyl acrylate, trimethylolpropane tri(meth)acrylate, divinylbenzene, diallyl phthalate, diallyl adipate, and triallyl isocyanurate.

Then, predetermined amounts of component A and component B and various components such as a crosslinking agent are uniformly mixed as necessary, and appropriate amounts of additives such as dyes and ultraviolet absorbers are added as necessary. By copolymerizing them according to a conventional method, a copolymer which is a raw material for the intended intraocular lens material can be obtained.

In this copolymerization, the polymerization is usually carried out by radical polymerization by heating or irradiation with ultraviolet rays, and in that case, a polymerization method such as bulk polymerization or solution polymerization is selected as appropriate. The Rukoto. In addition, in order to carry out radical polymerization, a radical polymerization initiator is added to a polymerization reaction liquid which is a mixed liquid formed by mixing the above-mentioned various monomer components, and polymerization is carried out. Examples of the polymerization initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, benzoyl peroxide, and the like, and one or more of these may be used. In the case of thermal polymerization, heating is carried out for several hours to several tens of hours while gradually raising the temperature in a temperature range of about 20° C. to 130° C., thereby completing the polymerization.

Further, prior to the alkali treatment to provide the intraocular lens material according to the present invention, the above-mentioned copolymer is molded into the shape of the intended intraocular lens member, particularly into the shape of a lens. In addition, the molding method at this time is to cut the copolymer obtained by the above polymerization method into the desired shape in a dry state,
Methods such as polishing, or injecting a liquid mixture of the monomer components into a mold and polymerizing it, and molding at the same time as the polymerization are employed as appropriate. In addition, during molding, after molding only the lens body, a support member may be attached to form an intraocular lens, or the lens body and support member may be molded at the same time to form an integrated intraocular lens. If the present invention is applied only to the supporting member, only the supporting member will be formed of the above-mentioned copolymer.

Next, the thus obtained material in a predetermined shape made of a copolymer mainly composed of the above-mentioned components A and B is subjected to an alkali treatment, so that the surface becomes electrically charged. However, this alkaline treatment
Generally, this is carried out by using an alkaline solution (preferably pH 13 or higher) such as sodium hydroxide or potassium hydroxide, and immersing the material in this alkaline solution for a predetermined period of time. Note that the concentration of alkali in such an alkaline solution is lower than 1% (at which point it is difficult to obtain the desired effect;
Moreover, if it exceeds 15%, although the effectiveness remains the same, the workability becomes poor (generally 1 to 15%).
It is said that the concentration is about 100%.

The immersion time is related to the concentration of the alkaline solution and is appropriately determined so as to obtain the desired effect, but is generally about 15 minutes to 2 hours.

In the thus obtained intraocular lens material according to the present invention, the B component in the copolymer reacts with the alkali by the alkali treatment as described above, and becomes a carboxylic acid salt, so that it exhibits charging characteristics. Therefore, at least the surface exhibits a charged state, which suppresses the appearance of various inflammatory cells and deposits within the eye, and makes it difficult for fibrin precipitation and secondary cataracts to occur (thus suppressing the reaction of surrounding cells. This results in a material for intraocular lenses with good biocompatibility that can effectively suppress the effects.

(Examples) Below, some examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited in any way by the description of such examples. Needless to say, it is not something that can be accepted.

In addition to the following examples and the above-mentioned specific description, the present invention may include various changes and modifications based on the knowledge of those skilled in the art, as long as they do not depart from the spirit of the present invention.
It should be understood that modifications, improvements, etc. may be made.

Note that all parts and percentages in the following examples are expressed on a weight basis unless otherwise specified.

Examples 1 to 4 First, polymerization was initiated with respect to 100 parts of a mixture of methyl methacrylate (MMA), methacrylic acid (MAA), and ethylene glycol dimethacrylate (EDMA) in various proportions shown in Table 1 below. After mixing 0.1 part of azobisisobutyronitrile as an agent, the mixture was poured into a polypropylene test tube and heated at a temperature of 35 to 50°C.
Heated for 7 hours, then gradually raised the temperature to 110°C for 21 hours to perform polymerization, producing various rod-shaped copolymers with different copolymerization ratios of A component and B component. did.

Table 1: Monomer blending ratio (parts) Next, each of the obtained rod-shaped copolymers was cut in a dry state into a shape with a diameter of 3M and a thickness of approximately 0.2mm, and then 10% Various test pieces corresponding to the intraocular lens materials of the present invention were obtained by performing alkali treatment by immersing them in an aqueous sodium hydroxide solution for 30 minutes, and then washing with physiological saline.

Using the various test pieces thus obtained, the biocompatibility of each was evaluated by the following test method. First, the test piece of the comparative example was implanted in one eye of a domestic rabbit, and the test piece of Example 1 was implanted in the other eye so that they were located in the anterior chamber of the rabbit, and after - weeks, they were removed.2. After fixing the deposits adhering to each test piece with a mixture of 5% geltaraldehyde and 5% formalin, they were immersed in physiological saline and examined under a stereomicroscope at 32x magnification to a diameter of 100 μm.
The number of attached giant cells was measured. As a result, the number of cell-like deposits attached to the test piece of Comparative Example was 33, while the number of deposits on the test piece of Example 1 was 1, overwhelmingly. As a result, the test piece of Example 1 according to the present invention was recognized to have excellent biocompatibility. Similarly, the test pieces of Examples 2 to 4 were examined for their biocompatibility by applying the above test method, and it was found that all of the test pieces had similar excellent biocompatibility. It was recognized that

Claims (1)

[Claims] An intraocular lens material obtained by treating a copolymer mainly composed of methyl methacrylate and acrylic acid or methacrylic acid with an alkali.