JPH06312943A - Biodegradable scleral plug - Google Patents

Abstract

PURPOSE:To provide a biodegradable scleral plug capable of effectively plugging orifices in corpus vitreum operations and needless to be removed after operation. CONSTITUTION:The scleral plug made of a lactic acid copolymer, designed to contain a medicine and ensure it to be sustainedly released into a corpus vitreum, and intended to cure or prevent retinopathy taking advantage of the sustained release action for medicine and to promote curing after corpus vitreum operation. This scleral plug enables safe and effective administration of a medicine through sustainedly releasing it over a long period into the intraocular tissue highly difficult in medicine migration thereinto.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a biodegradable scleral plug and a technique for containing a drug in the scleral plug to achieve a sustained release effect of the drug on the vitreous body, and further to a sustained release action of the drug. The present invention provides a scleral plug for treating or preventing retinal diseases and promoting healing after vitreous surgery.

[0002]

BACKGROUND OF THE INVENTION The vitreous body is a type of internal tissue of the eye,
Most of it is water, but it contains a solid component mainly composed of collagen fibers and hyaluronic acid, and is a transparent gel-like tissue with high viscosity. The retina is the innermost tissue of the eye that is in contact with the vitreous body in a form that wraps the vitreous body. Many retinal diseases are generally intractable, and include retinal hemorrhage due to various causes, proliferative vitreoretinopathy accompanied by proliferative changes in new blood vessels and retinal cells, retinal detachment, retinoblastoma, etc. , Depending on the disease, turbidity of the vitreous body is involved.

Eye diseases are most commonly treated by instillation of a drug, but the drug hardly migrates to the retina or vitreous. In addition, even if an attempt is made to administer by systemic administration such as intravenous administration, the concentration does not shift to a normal effective concentration due to the aqueous humor fence. Although it is possible to inject the drug directly into the vitreous, injecting a high-concentration substance at a time may cause damage to the intraocular tissues, and frequent injection is practical due to the risk of infection and the troublesome procedure. Not.
Under such circumstances, treatment by surgery is performed for some diseases. For example, in the case of vitreous hemorrhage, the vitreous body that is turbid due to hemorrhage is excised, and in the case of proliferative vitreoretinopathy, the vitreous body is excised and the proliferating tissue is excised. For retinal detachment, the vitreous body may be excised and the vitreous body made of silicon or the like may be used to hold down the retina. In vitreous surgery, the sclera, which is the wall of the eye,
A small incision is added to form a site for perfusion of physiological perfusate into the eye, a site for inserting a guide for irradiating the eye, and a site for inserting instruments such as a cutter for vitrectomy. A metal scleral plug may be used temporarily for inserting and removing the instruments into and from the eye (Am.
J. Ophthalmol. 91 , 797 (1981)), and finally the operation is completed by suturing the small incision. As a drug therapy for the retina and vitreous diseases, a method of directly injecting a drug into the vitreous is currently taken, but a method of using microspheres or liposomes is being studied in order to slowly release the drug ( Invt. Ophthalmol. Vis. Sci. 3
2 , 1785 (1991)). Recently, polymers using lactic acid have been studied as biodegradable polymers. For example, a method used for a bone joint member (Japanese Patent Laid-Open No. 3966/1993)
3), a method for use in surgical suture (Japanese Patent Laid-Open No. 4-5011)
09), a method for use as an intraocular implant material (JP-A-63-
22516) and the like. Also, the effect of polylactic acid on sustained drug release has been studied (J. Med. Chem. 16 , 897).
(1973)). Further, a sustained-release intraocular implant preparation using low-molecular weight polylactic acid has been reported (Japanese Patent Laid-Open No. H5-5980).
-17370).

[0004]

As a method for gradually releasing a drug into the vitreous body, a method of injecting the drug into the vitreous body using microspheres or liposomes is known, but it is more convenient and releases the drug over a long period of time. It was desired to develop a technology that can control this. Therefore, the present inventors
The problem was solved by paying attention to the above-mentioned metal scleral plug which is used to temporarily block the opening in the vitreous surgery. The problems to be solved by the present invention are basically the following problems. The first is to develop a scleral plug that effectively closes the opening in vitreous surgery and does not need to be removed after surgery. Next, it is to allow safe and effective administration by gradually releasing the drug over a long period of time to the intraocular tissue where transfer of the drug is extremely difficult. Further, it is to find a simple and clinically applicable administration method by utilizing a scleral wound created at the time of vitreous surgery.

[0005]

[Means for Solving the Problems] First, as a result of research on the material of the scleral plug that does not need to be removed after the operation, when the lactic acid copolymer is used, it is gradually decomposed and absorbed by the eye tissue and is very sensitive. It was found that a highly safe plug can be obtained even for an eye tissue which is a tissue with a high degree of damage. However, there are additional requirements for scleral plugs. That is, the required time is such that it has a function of closing the scleral opening, is decomposed and absorbed within an appropriate time, and is easy to handle during surgery. In order to satisfy these conditions, the molecular weight of the lactic acid copolymer and the composition ratio of the lactic acid unit were examined. As a result, the weight average molecular weight of the copolymer was 10,000 to 1,000,000, and the composition ratio of the lactic acid unit was 50 to 100 mol%. I found it to be good. Next, as a result of research on the shape of the scleral plug, a nail-shaped one composed of a head portion that prevents the plug from falling into the eye and a shaft portion that is inserted into the scleral opening is preferable. It has been found that it is preferable that the tip end of the is a pyramid or a cone with an acute angle such as a cone in order to prevent complications during insertion.

[0006] Next, as a result of research on a method for gradually releasing the drug into the vitreous body, the drug was contained in a scleral plug using a lactic acid copolymer, the plug was inserted into the scleral opening, and the tip portion thereof was inserted. It has been found that the purpose can be achieved by inserting the into the vitreous body. The insertion of the scleral plug into the scleral opening and the insertion of the distal end into the vitreous body are usually performed at the site of the pars plana of the ciliary body. This scleral plug can be designed so that the drug can be released for a desired period by changing the molecular weight of the lactic acid copolymer, the composition ratio of the lactic acid unit, and the like. Moreover, since the scleral plug of the present invention is made of a biodegradable polymer, it has been found that the object does not need to be removed even after the release of the drug is completed, and the purpose is extremely effectively achieved. Furthermore, since the scleral plug of the present invention can be easily inserted into the vitreous through the sclera, it can be inserted not only through the opening at the time of vitreous surgery but also by directly making micropores in the sclera and inserting it into the vitreous. I found what I could do. That is,
The scleral plug of the present invention can be applied to the treatment or prevention of retinal diseases even without performing vitrectomy, and can be additionally pierced when drug release is required for a very long period of time. It has been found that it is possible to insert and use a plurality of drugs at the same time when a higher drug concentration is required.

[0007]

The present invention is a scleral plug made of lactic acid copolymer,
And a drug, and a scleral plug designed to gradually release the drug into the vitreous body, and a strong scleral plug for treating or preventing retinal diseases and promoting healing after vitrectomy using the sustained release effect of the drug. Regarding membrane plugs. The lactic acid copolymer is a copolymer having lactic acid and glycolic acid as main unit components, but malic acid, glyceric acid, tartaric acid, etc. can be used instead of glycolic acid. The lactic acid copolymer in the present invention means that the composition ratio of lactic acid units is 100%, that is, polylactic acid is also contained. still,
As the lactic acid unit component, L-form, D-form or DL-form can be used.

[0008] The scleral plug has such strength that it will not be broken or chipped even if it is manipulated by a scissors during an operation, and has a function of gradually releasing the drug for a period necessary for treatment, etc., and then decomposed and absorbed. Characteristics are required. These characteristics are
It is determined by the composition ratio of the lactic acid unit and the glycolic acid unit and the like (hereinafter, the composition ratio is shown by a molar ratio unless otherwise specified), the weight average molecular weight and the like. In order to simplify the description, a copolymer composed of a lactic acid unit and a glycolic acid unit will be described below as an example. The degradability of a copolymer depends mainly on its crystallinity and water absorption. As either the composition ratio of the lactic acid unit or the composition ratio of the glycolic acid unit becomes higher, the crystallinity increases and the decomposition rate becomes slower. When the composition ratio of each is 50/50, decomposition is fastest. In addition, polyglycolic acid is more hydrophilic than polylactic acid, and when the glycolic acid unit composition ratio in the copolymer is high, the properties of polyglycolic acid appear and the hydrophilicity is increased, and the water absorption is increased, so decomposition is faster. Become. Furthermore, an organic solvent is used to make the plug, but the glycolic acid unit composition ratio is 50%.
If it exceeds the range, it becomes difficult to dissolve it in an ordinary organic solvent, which makes it difficult to form a plug. Considering the characteristics of glycolic acid as described above, the composition ratio of the glycolic acid unit is preferably 50% or less.

Further, the weight average molecular weight of the copolymer and the decomposition rate of the plug are in a proportional relationship, and the larger the molecular weight, the slower the decomposition rate. In producing the plug, the composition ratio of the lactic acid unit and the glycolic acid unit and the molecular weight of the copolymer can be selected in consideration of these characteristics and the function required for the plug. The composition ratio of lactic acid units in the scleral plug of the present invention is preferably 50-100 mol%, and the composition ratio of glycolic acid units is preferably 0-50 mol%. The molecular weight of the copolymer also affects the strength of the plug, and the higher the molecular weight, the higher the strength tends to be. Considering the strength required for the above-mentioned plug, the molecular weight is preferably 10,000 or more. However, if the molecular weight becomes too high, the decomposition rate of the plug becomes slow and molding becomes difficult, so the molecular weight is preferably 1,000,000 or less. That is, the weight average molecular weight is preferably in the range of 10,000 to 1,000,000, and the molecular weight can be appropriately selected according to the purpose of use of the scleral plug.

The composition ratio of the lactic acid unit and the glycolic acid unit and the weight average molecular weight of the copolymer are selected mainly on the basis of the required effective concentration maintaining period of the drug. Also,
The effective concentration maintenance period of the drug, that is, the required release period, is selected mainly based on the type of disease, the symptoms and the effect of the drug. The scleral plug of the present invention can be preferably used for various retinal diseases, acceleration of healing after vitreous surgery, and proliferative vitreoretinopathy, for example.
Viral infection, postoperative inflammation, postoperative infection. The drug release period can be adjusted to about 1 week to 6 months by appropriately selecting the molecular weight and the composition ratio.

When the release is required for a relatively short period of about 1-2 weeks, a molecular weight of about 10,000 to 100,000, preferably about 10,000 to 50,000, more preferably about 20,000 to 40,000. It is possible to select one having a molecular weight of. When release is required for about 2 weeks to 1 month, a molecular weight of about 10,000 to 200,000, preferably about 20,000 to 100,000, more preferably about 20,000 to 50,000 is selected. can do. When a long-term release of 1 month or more, for example, 1 month to 6 months is required, a molecular weight of about 10,000 to 1,000,000, preferably about 20,000 to 400,000, and more preferably about 40,000 to 200,000. One with a molecular weight can be selected.

The release period of the drug can also be controlled by changing the composition ratio of the lactic acid unit and the glycolic acid unit as described above. That is, the appropriate molecular weight and composition ratio are selected in consideration of the drug release period and the degradability of the plug. The range of the composition ratio is lactic acid unit /
100 / 0-50 / 5 as the molar ratio of glycolic acid units
It is 0.

More specifically, although it depends on the condition, in the case of doxorubicin hydrochloride which can be used for proliferative vitreoretinopathy, a release period of usually about 2 weeks-1 month is preferable. Has a molecular weight of about 10,000 to 200,000, preferably about 20,000 to 100,000,
More preferably, about 20,000-50,000 is used, and the composition ratio of the lactic acid unit and the glycolic acid unit is 100 / 0-50 /.
50, preferably 80 / 20-50 / 50, more preferably about 80 / 20-70 / 30 is used. In the case of ganciclovir that can be used for viral infection, a release period of 1 month or more, for example, 1 month-6 months, usually 4 months-6 months is preferable, and the molecular weight of the scleral plug is 10,000-1,000,000. Degree, preferably 20,000-4
About 100,000, and more preferably about 40,000-200,000 is used, and the composition ratio of the lactic acid unit and the glycolic acid unit is 100.
/ 0-50 / 50, preferably 80 / 20-50 / 5
0, more preferably about 80 / 20-70 / 30 is used.

A plurality of scleral plugs of the present invention can be used at the same time or can be additionally used. Therefore, when the therapeutic need requires the drug to be released at a higher concentration, multiple drugs should be used at the same time, and when it is required to further extend the drug release period, additional drugs should be added. Can be used. Even if it is difficult to contain a desired amount of drug in one scleral plug, this difficulty can be overcome by using a plurality of scleral plugs simultaneously or additionally.

Although polylactic acid is used in the sustained release intraocular implant preparation of JP-A-5-17370, it is a low molecular weight polylactic acid having an average molecular weight of up to about 7,000. As mentioned above, the characteristics required for the plug cannot be obtained, and the plug cannot be used as a scleral plug.

The scleral plug preferably has a nail-like shape composed of a head portion which prevents the plug from falling into the eye and a shaft portion which is inserted into the scleral opening.
In particular, the tip of the shaft portion is preferably a pyramid or a cone with an acute angle such as a cone in order to prevent complications during insertion. Preferably, the head portion is formed in a hemispherical shape, a disk shape, a polygonal plate shape such as a hexagonal plate,
The shaft portion is formed in a prismatic shape such as a quadrangular prism, a cylindrical shape, or the like. To make it easier to understand the form of the plug,
Explaining the size of the plug, it usually has a length of about 6 mm, the diameter of its head portion is about 2 mm, the diameter or width of the shaft portion is about 1 mm, and the total weight of the plug is about 9 mg. . Of course, this size can be appropriately changed depending on the amount of the drug contained and the like. The release of the drug into the vitreous
Accomplished by diffusion with hydrolysis of the scleral plug.
The scleral plug is disassembled and absorbed, so there is no need to remove it again. The retina is prone to damage when exposed to high concentrations of drug, and the amount of drug released is such that it does not cause retinal damage.
And it is designed so that the effective concentration of the drug is maintained. This release amount can be controlled by the content of the drug, the molecular weight of the copolymer and the composition ratio of the lactic acid unit and the glycolic acid unit. The amount of the drug to be contained in the plug is appropriately selected based on the period for which the effective concentration of the drug is maintained based on the type of disease required, symptoms, action of the drug, characteristics, etc.
It is about 6 months. For example, in the case of an antitumor agent such as doxorubicin hydrochloride used for treatment of proliferative vitreoretinopathy, 2
Week-about 1 month, for antiviral agents such as ganciclovir used for treatment of viral infections, 1 month or more, for example, about 1 month-6 months, anti-inflammatory agents such as steroids used for treatment of postoperative inflammation For 2 weeks-1 month, for antibiotics used to treat postoperative infections 1 week-2 weeks, for antifungal agents used to treat fungal infections 1 month or more For example, about 1 month to 2 months is a standard. As the drug, a drug useful for treatment and prevention of various diseases of the retina and promotion of healing after vitrectomy can be used. The present invention is characterized by using a biodegradable lactic acid copolymer, and is not limited by the type of drug, an antitumor agent, an antibiotic,
Drugs in various fields such as anti-inflammatory agents, antiviral agents, antifungal agents are applied.

A general method for producing a plug is obtained by dissolving a lactic acid copolymer synthesized according to a known method in an organic solvent such as methylene chloride, acetonitrile, acetic acid, adding a drug and removing the solvent. The plug is molded from powder. The lactic acid copolymer is obtained by polymerizing lactic acid or a cyclic dimer thereof and a comonomer such as glycolic acid or a cyclic dimer thereof in the presence of a catalyst system such as tin octylate and lauryl alcohol. Is prepared by.
The polymerization method is preferably, but not limited to, bulk polymerization.

[0018] In the following Examples, examples of the production of a drug sustained-release scleral plug using doxorubicin hydrochloride useful for proliferative vitreoretinopathy or ganciclovir useful for viral infections are shown as examples of drugs. The manufacturing examples are for better understanding of the present invention, and do not limit the scope of the invention.

[0019]

【Example】

Production Example 1 First, L- having a copolymer composition ratio of 75/25 (mol)
A lactic acid / glycolic acid copolymer was synthesized by bulk ring-opening polymerization in the presence of a catalyst system consisting of tin octylate and lauryl alcohol. The weight average molecular weight of the obtained copolymer was 38,000. 198 mg of this copolymer was added to 2
After dissolving in ml of methylene chloride, 2 mg of doxorubicin hydrochloride was stirred and dispersed in this solution, and the obtained dispersion was cast on a Teflon sheet to prepare an L-lactic acid / glycolic acid copolymer sheet containing doxorubicin hydrochloride. Next, the scleral plug shown in FIG. 1 was formed from this sheet by cutting.

This scleral plug (4) is formed into a nail shape consisting of a disk-shaped head portion (1) and a square columnar shaft portion (3), and the tip portion (2) of the shaft portion (3) is It has a quadrangular pyramid shape.

Production Example 2 Copolymer synthesized in the same manner as in Production Example 1 (L-lactic acid / glycolic acid: 75/25 (mol), weight average molecular weight 4
1000 mg and doxorubicin hydrochloride 5 mg were dissolved in acetonitrile / water (9: 1) 5 ml, and the solvent was removed from this solution by freeze-drying. The obtained powder was molded into a scleral plug under heating. Thus, the scleral plug shown in FIG. 2 was obtained.

This scleral plug (14) is formed into a nail shape consisting of a hemispherical head portion (11) and a cylindrical shaft portion (13), and the tip portion (12) of the shaft portion (13) is conical. It is in the shape of.

A weight average molecular weight of about 1 is obtained in the same manner as described above.
10,000, 20,000, 50,000, 70,000, 100,000, 200,000, L-lactic acid / glycolic acid molar ratio 50/50, 70/30, 80/2
0, content of doxorubicin hydrochloride 0.1%, 0.3%,
0.5%, 1%, 2% scleral plugs can be obtained. A similar scleral plug can be obtained by using D- or DL-lactic acid instead of L-lactic acid.

Production Example 3 A copolymer synthesized in the same manner as in Production Example 1 (DL-lactic acid /
Glycolic acid: 75/25 (mol), weight average molecular weight 1
22,000) 900 mg and ganciclovir 100 mg
Was dissolved in 15 ml of acetic acid and freeze-dried. The obtained powder was molded into a scleral plug under heating.

The weight average molecular weight is about 1 in the same manner as above.
10,000, 20,000, 40,000, 200,000, 400,000, 1,000,000, DL-lactic acid / glycolic acid molar ratio 50/50, 70/30, 8
0/20, Ganciclovir content 1%, 2%, 5%,
10%, 15%, 20% scleral plugs can be obtained. A similar scleral plug can be obtained by using L- or D-lactic acid instead of DL-lactic acid.

Production Example 4 900 mg of L-polylactic acid (weight average molecular weight 95,000) and 100 mg of ganciclovir were dissolved in 15 ml of acetic acid and freeze-dried. The obtained powder was molded into a scleral plug under heating.

The weight average molecular weight is about 1 in the same manner as above.
10,000, 20,000, 40,000, 200,000, ganciclovir content 1
%, 2%, 5%, 10%, 15%, 20% scleral plugs can be obtained. In place of L-polylactic acid, DL
Similar scleral plugs can be obtained by using -or D-polylactic acid.

[0028]

EFFECTS OF THE INVENTION Using doxorubicin hydrochloride as an example of the drug, the sustained release effect of the drug, the safety and degradability of the scleral plug were investigated.

As the scleral plug containing doxorubicin hydrochloride, that of Production Example 1 was used.

1) In Vitro Test A scleral plug was placed in an isotonic pH 7.4 phosphate buffer solution and kept at 37 ° C. for 1 day, 3 days, 7 days, 14 days, 21 days. After 28 days and 28 days, the elution amount of doxorubicin hydrochloride was measured by a fluorescence spectrophotometer. The results are shown in Table 1. In Table 1, the elution amount is shown by weight% with the total amount contained in the scleral plug of doxorubicin hydrochloride as 100%. The numerical value is the average value of 3 cases.

[0031]

[Table 1] As shown in Table 1, doxorubicin hydrochloride was gradually eluted over 4 weeks, which confirms the sustained drug release effect of the present invention.

During this time, no collapse of the plug was observed.

2) In Vivo Test One eye of a colored rabbit (10 birds) was subjected to a vitreous surgery, and two weeks later, a scleral plug was inserted from a scleral wound and covered with a conjunctiva. On the 1st, 3rd, 5th, 14th and 28th days after the insertion, 0.2 ml of aqueous humor was collected from the vitreous cavity and stored at -80 ° C. The concentration of doxorubicin hydrochloride in the aqueous humor was measured by high performance liquid chromatography. The results are shown in Table 2.

[0034]

[Table 2] As shown in Table 2, doxorubicin hydrochloride was gradually released into the vitreous body for 4 weeks, and the effective concentration (2-10 ng / ml) was maintained on each measurement day. Also,
There was no temporary high concentration and no accumulation of the drug in the vitreous body was observed, confirming the safety as well as the drug sustained-release effect of the present invention.

3) Toxicity test Tissue change A scleral plug was inserted from a scleral wound of a colored rabbit and covered with conjunctiva. When the eyeball was extracted after 1 month and 3 months and the tissue change in the eye was observed with an optical microscope, no tissue change was observed and safety was confirmed. When the state of the scleral plug was observed after enucleation of the eye, decomposition of the scleral plug was observed, and it was also confirmed that the scleral plug of the present invention gradually decomposed in vivo.

Changes in retinal function One eye of a colored rabbit (2 birds) was subjected to a vitreous surgery, and a scleral plug was inserted from a scleral wound and covered with a conjunctiva. One month later, an electroretinogram was taken and compared with the preoperative electroretinogram. At the same time, it was also compared with the electroretinogram of the other eye that had not undergone vitrectomy. As a result, no change was observed in the b-wave in any case, and it was confirmed that the scleral plug of the present invention does not affect the retinal function.

[Brief description of drawings]

1 is a perspective view showing a scleral plug obtained in Production Example 1. FIG.

2 is a perspective view showing a scleral plug obtained in Production Example 2. FIG.

[Explanation of symbols]

 (1) (11): Head part (2) (12): Tip part (3) (13): Shaft part (4) (14): Scleral plug

Claims (28)

[Claims] 1. A scleral plug formed from a lactic acid copolymer. 2. The scleral plug according to claim 1, wherein the composition of the lactic acid copolymer is a lactic acid unit and a glycolic acid unit. 3. The weight average molecular weight of the lactic acid copolymer is 10,000-
The scleral plug according to claim 1, which is 1 million. 4. The scleral plug according to claim 1, wherein the composition molar ratio of the lactic acid unit and the glycolic acid unit is 50 / 50-100 / 0. 5. A scleral plug made of a lactic acid copolymer, which is formed into a nail shape composed of a head portion and a shaft portion, and has a sharp tip at the shaft portion. 6. A scleral plug formed of a copolymer of lactic acid units and glycolic acid units, the copolymer having a weight average molecular weight of 10,000 to 1,000,000, and a lactic acid unit and a glycolic acid unit. Compositional molar ratio of 50 / 50-100 /
0, a lactic acid copolymer scleral plug that is formed in a nail shape composed of a head portion and a shaft portion, and has a sharp tip at the shaft portion. 7. A lactic acid copolymer scleral plug containing a drug, wherein the drug is gradually released into the vitreous body. 8. The scleral plug according to claim 7, wherein the composition of the lactic acid copolymer is a lactic acid unit and a glycolic acid unit. 9. The weight average molecular weight of the lactic acid copolymer is 10,000-
The scleral plug according to claim 7, which is 1 million. 10. The weight average molecular weight of the lactic acid copolymer is 10,000 to 100,000, and the effective concentration maintaining period of the drug is 1 week-2.
The scleral plug according to claim 7, which is set for about a week. 11. The scleral plug according to claim 7, wherein the lactic acid copolymer has a weight average molecular weight of 20,000 to 40,000, and the effective concentration maintaining period of the drug is set to about 1 week to 2 weeks. 12. The weight average molecular weight of the lactic acid copolymer is 10,000 to 200,000, and the effective concentration maintaining period of the drug is 2 weeks-1.
The scleral plug according to claim 7, which is set to about a month. 13. The scleral plug according to claim 7, wherein the lactic acid copolymer has a weight average molecular weight of 20,000 to 50,000, and the effective concentration maintaining period of the drug is set to about 2 weeks to 1 month. 14. The scleral plug according to claim 7, wherein the lactic acid copolymer has a weight average molecular weight of 10,000 to 1,000,000 and an effective concentration maintaining period of the drug is set to 1 month or more. 15. The scleral plug according to claim 7, wherein the lactic acid copolymer has a weight average molecular weight of 40,000 to 200,000, and the effective concentration maintaining period of the drug is set to 1 month or more. 16. The composition molar ratio of the lactic acid unit and the glycolic acid unit is 50 / 50-100 / 0.
The described scleral plug. 17. The composition molar ratio of the lactic acid unit and the glycolic acid unit is 50 / 50-80 / 20.
The described scleral plug. 18. The composition molar ratio of lactic acid unit and glycolic acid unit is 70 / 30-80 / 20.
The described scleral plug. 19. A scleral plug containing a drug, comprising:
A scleral plug made of lactic acid copolymer, which is formed into a nail shape composed of a head portion and a shaft portion, and the tip of the shaft portion has an acute angle. 20. A drug-containing scleral plug formed of a copolymer of lactic acid units and glycolic acid units, wherein the lactic acid copolymer has a weight average molecular weight of 10,000 to 1,000,000. And the compositional molar ratio of glycolic acid unit is 5
A lactic acid copolymer scleral plug having a diameter of 0 / 50-100 / 0, formed in a nail shape composed of a head portion and a shaft portion, and having a sharp tip at the shaft portion. 21. A lactic acid copolymer scleral plug containing a drug, wherein the drug is gradually released into the vitreous body. A lactic acid copolymer sclera for treating or preventing retinal diseases. plug. 22. A lactic acid copolymer-made scleral plug containing a drug, wherein the drug is gradually released into the vitreous body, which is made of a lactic acid copolymer for promoting healing after vitreous surgery. Scleral plug. 23. The lactic acid unit component is L-form, D-form or DL-form
The scleral plug according to claim 1, which is a body. 24. The scleral plug according to claim 12, wherein the drug is an antitumor agent. 25. The drug according to claim 14, which is an antiviral agent.
Or the scleral plug according to item 15. 26. The scleral plug according to claim 12 or 13, wherein the drug is an anti-inflammatory agent. 27. The scleral plug according to claim 10 or 11, wherein the drug is an antibiotic. 28. The scleral plug according to claim 14 or 15, wherein the drug is an antifungal agent.