JPH04364839A - Rod for closing lacrimal duct - Google Patents

Abstract

PURPOSE:To provide a rod for closing lacrimal ducts with uniform dissolubility free of secondary disorder. CONSTITUTION:Material herein used for a rod is polyglycolate. The rod thus obtained reduces the acuteness of eye drying disease and facilitates the management of an insertion schedule with a uniform dissolving rate and also reduces uncertainty pertaining to biocompatibility.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lacrimal duct closure rod. More specifically, the present invention relates to a dissolvable lacrimal duct closing rod.

0002

BACKGROUND OF THE INVENTION Tears play an important role in human daily life. In addition to preventing dryness of the eyes and washing away foreign substances such as dust that have entered the eyes, it also has a bactericidal effect, and it is well known that when tear production decreases, these functions decrease, making you more susceptible to diseases such as keratitis and conjunctivitis. This is a fact.

Additionally, as a recent trend, computer workers who stare at television screens for long periods of time are experiencing dry eye (
It is also said that the number of patients with lachrymal hypolacrima is increasing. After wetting the corneal surface, the lacrimal fluid secreted by the lacrimal gland flows toward the nose, enters the lacrimal punctum, and flows out into the lower nasal passage through the lacrimal canaliculus, lacrimal sac, and nasolacrimal duct. The area from this lacrimal punctum to the inferior nasal meatus is called the lacrimal duct.

[0004] For the dry eye patients described above, methods have been proposed to reduce the amount of lachrymal fluid flowing out from the lacrimal duct. For example, there are punctal plugs, such as those described in US Pat. No. 3,949,750. This method involves placing a plug at the entrance of the tear duct to stop the flow of tear fluid. According to this method, since the upper part of the plug protrudes from the lacrimal punctum, this part comes into contact with the cornea, which may cause corneal abrasion, and it also has the disadvantage that it is easily removed from the lacrimal punctum. Furthermore, Japanese Patent Application Laid-open No. 115559/1983 proposes inserting a catgut rod into the lacrimal duct. Catgut or collagen is inserted into the lachrymal canal for 10~
This method dissolves in 15 days, so there is no need to worry about the problems caused by long-term retention like when inserting a plastic rod. However, since collagen is made from natural animal intestines, it depends on the nature of the tissue used. Disadvantages include large variations in texture and dissolution rate due to natural biological changes. In addition, it is a well-known fact that collagen is susceptible to antigen-antibody reactions and has biocompatibility problems.

[0005]

[Problems to be Solved by the Invention] The present invention provides a rod for lacrimal duct closure that does not cause the secondary adverse effects that occur during use, has uniform solubility, and has small variations in dissolution rate. The purpose is to provide.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present inventors conducted intensive studies on various materials, and as a result, they discovered that polyglycolic acid dissolves within the lachrymal duct, leading to the present invention. Polyglycolic acid is a relatively well-known material for sutures, and is known to dissolve in living tissue. However, it was surprising that it dissolves in the lacrimal duct, which is not necessarily in living tissue.

That is, the present invention is a lacrimal duct closing rod made of polyglycolic acid. The lacrimal duct closure rod is inserted through the lacrimal punctum, and its size is usually 0.5 to 5 m in length.
m, selected from the range of 0.1 to 1.5 mm in diameter,
The most common length is 1.0-3.0 mm and the diameter is 0.2-0.8 mm. This should be selected depending on the size of the puncta of each individual, and the optimal length and radius of the rod may be determined depending on the person using the rod.

[0008] Polyglycolic acid, which is a compound according to the present invention, is produced by ring-opening polymerization of glycolide using a generally known method. This can be expressed as a reaction formula as shown in Chemical Formula 1 below.

[0009]

[Chemical formula 1]

The molecular weight of the polyglycolic acid used here is at least about 10,000 (degree of polymerization
90 to 1200) is preferred. If the molecular weight is less than 10,000, melt molding is impossible;
When it exceeds 70,000, the viscosity increases and molding becomes difficult. A method for producing polyglycolic acid having a molecular weight of 10,000 to 100,000 is described, for example, in US Pat. No. 266,816.
It is described in the specification of No. 2, Japanese Patent Publication No. 43-5192, and the like, and the outline of the commonly practiced method is as follows.

When glycolide prepared from oxyacetic acid (glycolic acid) is heated in the presence of an antimony trifluoride catalyst (0.03% to glycolide) at 195°C for over 1 hour and then further heated at 230°C for 30 minutes, poly Glycolic acid is obtained. The molecular weight is between 10,000 and 100,000, and the melt viscosity at 245°C of a polymer of such molecular weight is between about 400 and 27,000 poise.

[0012] The molecular weight of polyglycolic acid is determined by dissolving it in a mixed solvent of phenol and trichlorophenol.
It can be measured as an average molecular weight using the terminal group quantitative method. A polyglycolic acid rod can be obtained by melt-spinning the thus obtained polyglycolic acid using a plunger extruder or the like, cooling and solidifying it, and then cutting it into a desired length.

[0013] Since the rod for lacrimal duct closure obtained in this manner is not made of natural products such as collagen, it is free from disadvantages caused by biological influences in nature, such as non-uniform solubility. has been greatly improved. In addition, for the purpose of stabilizing polyglycolic acid, for example,
Needless to say, the present invention also includes a lacrimal duct closing rod made of a compound obtained by esterifying the terminal group of polyglycolic acid as described in Japanese Patent No. 2-41525.

[0014] Also, for the purpose of improving handling during insertion,
It can also be used by coating with various surfactants, for example, coating agents such as calcium stearate. Further, stabilizers such as triphenyl phosphite, dialkylphenol sulfide, and disulfide aromatic phenol may be added.

[0015] Furthermore, it is also possible to color with a suitable coloring agent if desired.

[0016]

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples.

[0017]

[Example 1] Polyglycolic acid powder with a number average molecular weight of 30,000 obtained from glycolide by the method described in US Pat. No. 2,668,162 was inserted into a plunger extruder, melt-spun at 230°C, and then introduced into water and cooled. The solidified material is cut continuously using a cutter with a rotating blade, and the diameter is 0.3.
A lacrimal duct closure rod made of polyglycolic acid and having a length of 2 mm and a length of 2 mm was obtained.

[0018] This rod was cut into two, each having a length of 1 mm, and the rods were inserted into the left and right lacrimal puncta of two white rabbits weighing 3.5 kg and 3.4 kg. When the lacrimal duct was incised 1.5 months later, the inserted rod had dissolved and disappeared.

[0019]

[Effects of the Invention] By using the lacrimal duct closure rod of the present invention, dry eye symptoms are alleviated, and the dissolution rate is uniform, making it easy to manage insertion schedules, and in addition, concerns regarding biocompatibility are alleviated. Reduced.

Claims (1)

[Claims] Claim: 1. A lacrimal duct closure rod made of polyglycolic acid.