JP2022126909A - Perforated site closing material, and method for producing perforated site closing material - Google Patents

Abstract

To provide a perforated site closing material having reduced burden on the surrounding tissue.SOLUTION: A perforated site closing material contains particles containing crosslinked gelatin derivatives. The gelatin derivatives have a structure represented by the following formula (1): Gtln-NH-L-CHR1R2 (1) [where, 'Gltn' is a residue of gelatin, L is a single bond or a divalent linking group, R1 is a C1-20 hydrocarbon group, R2 is a hydrogen atom or a C1-20 hydrocarbon group].SELECTED DRAWING: None

Description

The present invention relates to puncture closures and methods of making puncture closures.

Endoscopic submucosal dissection (ESD) has been developed as a minimally invasive treatment for early gastrointestinal cancers of the esophagus, stomach, duodenum, and colon. ESD is gaining in popularity because it can resect superficial neoplasms while minimizing the effects on submucosal tissue and muscle tissue.

However, perforation may occur during ESD, or after a certain period of time has passed after ESD (tardive perforation), and the contents of the gastrointestinal tract may leak into the abdominal cavity, resulting in secondary or serious diseases such as peritonitis. known to cause serious illness. In particular, the duodenum has a thin wall, a narrow lumen, and insufficient bulging of the mucous membrane, resulting in a high perforation rate during surgery.

As an instrument for closing such a perforation, Patent Document 1 describes, "A perforation and an artificial ulcer formed in the inner wall of a patient's body canal after excision of the affected tissue on the inner wall of the body canal. A medical ring used for treatment of covering and suturing an artificial ulcer using normal mucous membrane tissue, comprising at least a pair of ring portions respectively engaged with a clip indwelling in a body canal. ring."

JP 2007-282841 A

The use of endoscopic clips to close the perforation may further damage muscle layers already weakened by ESD, resulting in additional perforations. Also, the duodenum is particularly fragile, making it difficult to apply endoscopic clips to duodenal perforations.

Accordingly, an object of the present invention is to provide a perforated portion closure material that places less burden on surrounding tissue. Another object of the present invention is to provide a method of manufacturing a hole closure.

As a result of intensive studies aimed at achieving the above object, the inventors of the present invention have found that the above object can be achieved with the following configuration.

[1] A hole closing material comprising particles containing a crosslinked gelatin derivative, wherein the gelatin derivative is represented by the following formula (1): Gtln-NH-L-CHR ¹ R ² (1) [ In formula (1), "Gltn" represents a residue of gelatin, L represents a single bond or a divalent linking group, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and R ² represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms].
[2] The perforation closure material according to [1], which is for closing a perforation caused by endoscopic submucosal dissection.
[3] The perforation closure material according to [2], wherein the perforation is a perforation in the digestive tract.
[4] The perforation closure material according to [3], wherein the digestive tract is the duodenum.
[5] Any one of [1] to [4], wherein the average sphericity of the particles is 1.45 or less, and the standard deviation of the sphericity of the particles is 0.25 or less. A perforation closure as described.
[6] In the above formula 1, the hydrophobic group represented by *-L-CHR ¹ R ² [* represents the bonding position] has a total number of carbon atoms of 4 to 16 [1]- [5] The perforated portion closing material according to any one of [5].
[7] The perforated part closing material according to [6], wherein the hydrophobic group has 6 to 12 carbon atoms in total.
[8] The perforated part closing material according to [6], wherein the hydrophobic group has 6 to 10 carbon atoms in total.
[9] The perforated portion closing material according to any one of [6] to [8], wherein the introduction rate of the hydrophobic group is 5 to 60 mol%.
[10] The perforated portion closing material according to any one of [6] to [8], wherein the introduction rate of the hydrophobic group is 25 to 60 mol%.
[11] The following formula (1): Gtln-NH-L-CHR ¹ R ² (1) [In formula (1), "Gltn" represents a residue of gelatin, L is a single bond, or represents a divalent linking group, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and R ² represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms]. in a good solvent to obtain a gelatin solution containing the gelatin derivative and the good solvent; adding a poor solvent to the gelatin solution to obtain intermediate particles containing the gelatin derivative; precipitating in a solution; freeze-drying the gelatin solution after the precipitation to obtain an intermediate powder containing the intermediate particles; and cross-linking the gelatin derivative of the intermediate particles to obtain a cross-linked obtaining a hole closure material comprising particles containing said gelatin derivative.
[12] The method for producing a perforated portion closing material according to [11], wherein the intermediate powder is heated to crosslink the gelatin derivative.
[13] The method for producing a hole closing material according to [12], wherein the intermediate powder is heated at 100 to 200° C. for 2.5 to 5 hours to crosslink the gelatin derivative in the intermediate particles.
[14] Further, according to any one of [11] to [13], the hole closing material containing the particles containing the crosslinked gelatin derivative is irradiated with ultraviolet rays to make the surface of the particles hydrophilic. method of manufacturing a pierced hole closure.

ADVANTAGE OF THE INVENTION According to this invention, the perforation closure material with few burdens to the surrounding tissue|tissue can be provided. The present invention also provides a method of manufacturing a puncture closure.

The present invention will be described in detail below.
Although the description of the constituent elements described below may be made based on representative embodiments of the present invention, the present invention is not limited to such embodiments.
In this specification, a numerical range represented by "-" means a range including the numerical values described before and after "-" as a lower limit and an upper limit.

[Punched portion closing material]
A hole closing material according to an embodiment of the present invention is a hole closing material comprising particles containing a crosslinked gelatin derivative, the gelatin derivative having a structure represented by Formula 1 described below. The components of the puncture closure are detailed below.

(Gelatin derivative)
The puncture closure material includes particles containing a crosslinked gelatin derivative. This gelatin derivative has a structure represented by the following formula (1).

Gtln-NH-L-CHR ¹ R ² (1)
In formula (1), Gltn represents a residue of gelatin, L represents a single bond or a divalent linking group, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and R ² represents hydrogen. represents an atom or a hydrocarbon group having 1 to 20 carbon atoms. In the following description, *-L-CHR ¹ R ² may be referred to as "hydrophobic group".

The divalent linking group of L is not particularly limited, but -C(O)-, -C(O)O-, -OC(O)-, -O-, -S-, -N(R)- (R represents a hydrogen atom or a monovalent organic group (preferably a hydrocarbon group having 1 to 20 carbon atoms)), an alkylene group (preferably an alkylene group having 2 to 10 carbon atoms), an alkenylene group (preferably is an alkenylene group having 2 to 10 carbon atoms), and combinations thereof, among which -C(O)- is preferred. Therefore, L is preferably a single bond or -C(O)-.

The hydrophobic group preferably binds to the ε-amino group of gelatin as a raw material, and more preferably binds to the ε-amino group of lysine (Lys) in gelatin. As a method for binding a hydrophobic group to an amino group, preferably an amino group of lysine, via a linking group or not (directly in other words), for example, a so-called reductive amination reaction (aldehyde, Alternatively, a method using a ketone), and a method using the Schotten-Baumann reaction (a method using an acid chloride).

The —NH— structure of formula (1) can be detected by a band near 3300 cm ⁻¹ in the FT-IR (Fourier transform infrared absorption) spectrum, for example.

The hydrocarbon group having 1 to 20 carbon atoms is not particularly limited, and examples thereof include chain hydrocarbon groups having 1 to 20 carbon atoms, alicyclic hydrocarbon groups having 3 to 20 carbon atoms, There are 14 aromatic hydrocarbon groups and groups that are combinations thereof.

When R ² is 1 to 20 hydrocarbon groups, R ² may be the same as or different from R ¹ . Also, the alkyl groups of R ¹ and R ² may be linear or branched.

The chain hydrocarbon group having 1 to 20 carbon atoms is not particularly limited, but is methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group (or capryl group), nonyl group (or pelargonyl group). , decyl group, dodecyl group (or lauryl group), and tetradecyl group (or myristyl group). Among them, R ¹ is preferably an alkyl group having 1 to 13 carbon atoms, more preferably an alkyl group having 7 to 12 carbon atoms, in that a powder having excellent adhesiveness can be easily obtained. An alkyl group having 8 to 11 carbon atoms is more preferable, and an alkyl group having 9 to 11 carbon atoms is particularly preferable. Although R ² is not particularly limited, it is preferably a hydrogen atom.

Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms include cyclopropyl group, cyclopentyl group, cyclohexyl group, adamantyl group and norbornyl group.

Examples of aromatic hydrocarbon groups having 6 to 14 carbon atoms include, but are not limited to, phenyl, tolyl, and naphthyl groups.

Examples of groups in which the above are combined include, but are not limited to, aralkyl groups having 6 to 12 carbon atoms such as benzyl, phenethyl, naphthylmethyl, and naphthylethyl.

Although the total number of carbon atoms in the hydrophobic groups represented by *-L-CHR ¹ R ² is not particularly limited, it is 3 to 20 from the viewpoint of obtaining a perforated portion closing material having superior effects of the present invention. is preferred, 4 to 16 is more preferred, 6 to 12 is even more preferred, and 8 to 10 is particularly preferred.
*-L-CHR ¹ R ² is preferably an alkyl group in which L is a single bond and R ² is a hydrogen atom. In this case, the number of carbon atoms in the hydrophobic group is synonymous with the number of carbon atoms in the alkyl chain. be.

The gelatin derivative represented by the formula (1) is preferably at least one gelatin derivative selected from the group consisting of the following formulas (2) and (3), and represented by the formula (2) Gelatin derivatives are more preferred.

Gltn-NH-CHR ¹ R ² (2)

In formulas (2) and (3), the meaning of each symbol is the same as in formula (1) already described, and the preferred embodiments are also the same.

Although the introduction rate of the hydrophobic group in the gelatin derivative is not particularly limited, it is generally preferably 1 mol% or more, more preferably 5% or more, still more preferably 10 mol% or more, particularly preferably 15 mol% or more, and 30 mol. % or more is most preferable. Although the upper limit is not particularly limited, it is preferably 80 mol % or less, more preferably 60 mol % or less.
In the present specification, the "introduction rate" of the hydrophobic group is the number of imino groups (*-NH-CHR ¹ R ² ) to which the hydrophobic group is bound in the gelatin derivative relative to the content of amino groups in the raw material gelatin. Defined as the content molar ratio of the content.

The rate of introduction is calculated by the following formula from the values obtained by quantifying the number of amino groups in the raw material gelatin and the number of amino groups in the gelatin derivative by the 2,4,6-trinitrobenzenesulfonic acid method (TNBS method). be done.
Introduction rate (mol%) = [number of amino groups in starting gelatin - number of amino groups in gelatin derivative]/[number of amino groups in starting gelatin] x 100

The gelatin that is the raw material of the gelatin derivative (hereinafter also referred to as "raw gelatin") may be naturally derived or synthesized (including fermentation, genetic recombination, etc.). Alternatively, it may be naturally derived or synthesized gelatin that has undergone some processing.
More specifically, for example, naturally-derived gelatin obtained from the skin, bones, tendons, etc. of mammals, birds, fish, etc., and naturally-derived gelatin treated with acid or alkali ( and processed gelatin, which has been heated and extracted as necessary), and the like.
Among them, alkali-treated gelatin is preferable in that a powder having more excellent effects of the present invention can be obtained.

When the powder is administered to the body and used, for example, when used as a wound dressing, it is preferable to use low endotoxin-treated gelatin with a reduced endotoxin content. Such low endotoxin-treated gelatin is not particularly limited, and known ones can be used. incorporated.

Mammal-derived gelatins include porcine- and bovine-derived gelatins. The gelatin derived from fish is not particularly limited, but gelatin derived from cold water fish (cold water fish) such as salmon, trout, cod, sea bream, tilapia, and tuna (hereinafter also referred to as "cold water fish gelatin") is used. ) is preferred.

Cold-water fish-derived gelatin is a polymer in which two or more amino acids are linked in a linear chain, and contains 190 or less imino acids, more specifically, 80 or less hydroxyprolines ( Hydroxyproline) and 110 or less prolines. It is considered that cold-water fish-derived gelatin has good fluidity at room temperature because the number of hydroxyprolines is 80 or less, or the number of prolines is 110 or less. If any of the conditions are satisfied, the denaturation temperature will be substantially room temperature or below, and normal temperature fluidity will occur.

Thai gelatin has a hydroxyproline number of 73, a proline number of 108, and a denaturation temperature of 302.5K. Tilapia gelatin has a hydroxyproline number of 82, a proline number of 110 and a denaturation temperature of 309K. In contrast, porcine gelatin has a hydroxyproline number of 95, a proline number of 121 and a denaturation temperature of 316K.

Cold-water fish-derived gelatin has an amino acid sequence similar to that of animal-derived gelatin, is easily degraded by enzymes, and has high biocompatibility.

The molecular weight of raw material gelatin is not particularly limited, but the weight average molecular weight (Mw) is preferably 5,000 to 100,000, more preferably 10,000 to 50,000, and still more preferably 20,000 to 40,000. . In addition, in this specification, the weight average molecular weight means the weight average molecular weight determined by gel permeation chromatography (GPC).

(particle)
The puncture closure material comprises particles of a crosslinked gelatin derivative.
As used herein, the term "crosslinked" means a crosslinked structure obtained by an irreversible crosslinking reaction, not including a reversible physical crosslinked structure. Therefore, a "crosslinked gelatin derivative" is a gelatin having an irreversible crosslinked structure obtained by a crosslinking reaction, which is produced by applying energy such as heat, light, energy rays, etc. to a gelatin derivative and/or using a crosslinking agent. It is a derivative. It typically occurs through reactions between gelatin side chain functional groups (—NH ₂ , —OH, —SH, —COOH, etc.).

Particles containing crosslinked gelatin derivatives may be surface-hydrophilized.

The particles only need to contain a crosslinked gelatin derivative, and may contain other components within the scope of the effects of the present invention. The content of the crosslinked gelatin derivative in the particles is not particularly limited, but the crosslinked gelatin derivative is added to the total mass of the particles in order to easily obtain a powder exhibiting superior effects of the present invention. It is preferably contained in an amount of 90% by mass or more, more preferably in an amount of 99% by mass or more.
Other components that the particles may contain are not particularly limited, but include, for example, non-crosslinked gelatin derivatives, solvents, buffering agents, coloring agents, preservatives, excipients, and drugs (antithrombotic agents, antibacterial agents, agents, growth factors, etc.) and the like.

The sphericity of the particles is 1.45 or less, preferably 1.20 or less, more preferably 1.10 or less, from the viewpoint of obtaining superior adhesion to living tissue. In this specification, the sphericity means a value obtained by the following test method.

・Test method Sprinkle the powder to be measured on a scanning electron microscope stage with a carbon tape attached, and then remove the powder that is not adhered to the carbon tape by air spraying. Observe with a microscope, and measure the length of the horizontal axis and the vertical axis for 20 particles randomly extracted from one visual field using "ImageJ (v1.51)". Next, the "horizontal axis/vertical axis" is calculated for each particle, the arithmetic mean is calculated, and the obtained value is rounded off to the second decimal place, and this is taken as the sphericity. . In the above measurement and calculation, it is defined as (vertical axis)≦(horizontal axis). That is, the largest particle diameter among the measured particle diameters of one particle is defined as the horizontal axis. The vertical axis is the diameter at a position rotated 90 degrees from the horizontal axis.

In addition, the standard deviation (SD) of the sphericity of the particles in the powder is 0.25 or less, but 0.20 or less in terms of obtaining superior adhesion to living tissue. is preferred, and 0.15 or less is more preferred.
The standard deviation of the sphericity of the particles in the powder is calculated from the sphericity of the 20 particles, and the calculated value obtained is rounded off to the second decimal place. be the standard deviation.
The average particle size of the particles is usually 0.5-50 μm, preferably 1-40 μm. The "average particle size" in the specification of the present application is a value obtained by randomly measuring the particle size (major axis) of 100 particles with an electron microscope and averaging them.

[Manufacturing Method of Closing Material for Perforated Portion]
As a method for producing the perforated portion closing material, a method of granulating a gelatin derivative and cross-linking the granulated gelatin derivative can be applied. Known methods such as spray drying, pulverization, and coacervation can be applied to granulate the gelatin derivative.

More specifically, first, a gelatin derivative solution is dried with a spray dryer and classified to adjust the sphericity of the particles as necessary, and then heated to crosslink the gelatin derivative to obtain particles. mentioned. Alternatively, a method of pulverizing a solid gelatin derivative, then classifying to adjust the sphericity of particles as required, and heat-crosslinking to obtain particles can also be used. Among them, the method including the following steps is preferable from the viewpoint of easier control of the particle shape.

- Step 1: A step of dissolving a gelatin derivative in a good solvent to obtain a gelatin solution containing the gelatin derivative and the good solvent - Step 2: Adding a poor solvent to the gelatin solution to prepare intermediate particles containing the gelatin derivative in the gelatin solution step of precipitating in the middle Step 3: Freeze-drying the precipitated gelatin solution to obtain an intermediate powder containing intermediate particles Step 4: Cross-linking the gelatin derivative of the intermediate particles to obtain a cross-linked gelatin derivative Step of obtaining a hole closing material containing particles containing Securing Step Below, each of the above steps will be described in detail.

・Process 1 (melting process)
Step 1 is a step of dissolving the already explained gelatin derivative in a good solvent to obtain a gelatin solution. As used herein, a good solvent means a solvent that easily dissolves a gelatin derivative, and is not particularly limited, and includes water, glycerin, acetic acid, and mixtures thereof. preferable. Also, the good solvent may be heated. Although the temperature for heating is not particularly limited, 50 to 70°C is preferable.

The method for dissolving the gelatin derivative in the good solvent is not particularly limited, and known methods can be used. For example, a gelatin derivative is swelled by adding a good solvent at a low temperature (e.g., room temperature) to the gelatin derivative, and the resulting swollen body is heated to obtain a gelatin solution (swelling and dissolving method); A method of adding a gelatin derivative to a solvent to obtain a gelatin solution (direct dissolution method) can be used.

The content of the gelatin derivative in the gelatin solution is not particularly limited, but the content (final concentration) of the gelatin derivative relative to the total volume of the gelatin solution is preferably 0.01 to 30% by mass/volume, and 1 to 25%. % by mass/volume is more preferred, 5 to 20% by mass/volume is even more preferred, and 5 to 15% by mass/volume is particularly preferred.
When the content of gelatin in the gelatin solution is within the above range, the standard deviation of the sphericity of the obtained particles tends to be smaller.

・Step 2 (precipitation step)
Step 2 is a step of adding a poor solvent to the gelatin solution to precipitate intermediate particles containing the gelatin derivative in the gelatin solution.
As used herein, the term "poor solvent" means a solvent in which the gelatin derivative is more difficult to dissolve when compared with the good solvent used in Step 1. That is, in the present specification, a good solvent and a poor solvent are not defined by the absolute amount of solubility of the gelatin derivative, but are relatively defined in relation to the poor solvent and the good solvent, respectively. .

The poor solvent is not particularly limited, but examples thereof include organic solvents, among which water-soluble organic solvents are preferred, and alcohols such as methanol, ethanol, n-propanol, isopropanol, butanol, and t-butyl. Alcohol and the like are more preferred.

When a poor solvent is added to a gelatin solution, intermediate particles are precipitated in the gelatin solution. The intermediate particles are particles containing the gelatin derivative. The particle size of the intermediate particles precipitated in this step is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 1 to 50 μm, even more preferably 1 to 10 μm.

When the particle size is within the above range, the intermediate particles precipitated in the gelatin solution are less likely to settle, and in step 3 described later, the intermediate particles are frozen together with the gelatin solution containing the intermediate particles and then freeze-dried. Aggregation of the body particles is more likely to be suppressed. As a result, the sphericity and the like of the particles obtained in step 4 tend to fall within the desired range.

Although the temperature at which the poor solvent is added is not particularly limited, it is generally preferably 10 to 30°C, more preferably 15 to 25°C. In step 1, when the gelatin derivative is dissolved by heating the solvent, it is preferable to further include a step of cooling the gelatin solution between steps 1 and 2.

It is preferable to stir the gelatin solution when the poor solvent is added dropwise. The stirring method is not particularly limited, and known methods can be used. By adding the poor solvent while stirring the gelatin solution, the precipitated particles are less likely to aggregate and settle. As a result, a hole closure material containing particles with desired properties is more readily available.

・Process 3 (drying process)
Step 3 is a step of freeze-drying the dispersed solution of the uncrosslinked gelatin particles precipitated by the coacervation to obtain an intermediate powder containing intermediate particles containing the uncrosslinked gelatin derivative.
Although the method for freezing the gelatin solution is not particularly limited, it is preferable to freeze more rapidly from the viewpoint of making it more difficult for the particles containing the uncrosslinked gelatin derivative to aggregate during freezing. At this time, the ambient temperature for freezing is not particularly limited, but is preferably −20° C. or less, more preferably −30° C. or less.
Moreover, the freeze-drying method is not particularly limited, and a known method can be used.

An intermediate powder is a powder containing intermediate particles. The intermediate powder may contain ingredients other than the intermediate particles. Examples of such components include the above good solvent and poor solvent.

・Step 4 (crosslinking step)
Step 4 is a step of cross-linking the gelatin derivative of the intermediate particles to obtain a powder containing the cross-linked gelatin derivative. Through this step, the gelatin derivatives of the particles are irreversibly crosslinked intermolecularly and/or intramolecularly. The result is a hole closure material comprising particles containing a crosslinked gelatin derivative.

The method of cross-linking is not particularly limited, but examples thereof include a method of imparting heat energy to a gelatin derivative, or irradiating actinic rays or radiation (eg, electron beams).
Among them, a method of imparting thermal energy (in other words, heating) is preferable (thermal crosslinking) because a crosslinked product of the gelatin derivative can be obtained more easily and there is no generation of impurities derived from the crosslinking agent and it is safe. In this method, for example, an amino group in a gelatin derivative reacts with other reactive groups (eg, carboxy group, mercapto group, etc.) to form a crosslinked structure.

The method of thermal crosslinking is not particularly limited, and known methods can be used. As a method of thermal crosslinking, for example, there is a method in which the container containing the powder precursor is placed in a heated atmosphere (for example, in an oven) together with the container and maintained for a predetermined period of time.

The heating temperature for thermal crosslinking is not particularly limited, but is generally preferably 80 to 200°C, more preferably 100 to 200°C.
The heating time for thermal crosslinking is not particularly limited, but is generally preferably 0.1 to 20 hours, more preferably 0.5 to 10 hours, still more preferably 1 to 6 hours, and even more preferably 2 to 5 hours. Preferably, 2.5 to 4 hours are particularly preferred.
When the heating time is within the above numerical range, the obtained hole closing material has better adhesiveness.

Moreover, the crosslinked product of a gelatin derivative may be obtained by reacting a gelatin derivative with a crosslinking agent. Examples of the cross-linking agent include, but are not limited to, genipin, N-hydroxysuccinimide, polybasic acids activated with N-sulfoxysuccinimide, aldehyde compounds, acid anhydrides, dithiocarbonates, and diisothiocyanates.
As a cross-linking agent, for example, compounds described in paragraphs 0021 to 0024 of WO 2018/079538 can also be used, the contents of which are incorporated herein.

・Step 5 (particle surface hydrophilization step)
Step 5 is a step of further irradiating the particles containing the crosslinked gelatin derivative with ultraviolet rays to make the surfaces of the particles hydrophilic. This surface treatment by UV irradiation reduces the contact angle between the particles and water droplets, making them easier to swell in the presence of moisture. On the other hand, when dry and in contact with tissue, the particles after UV irradiation still have excellent adhesion.
The conditions for ultraviolet irradiation are not particularly limited, but usually irradiation is performed for 1 to 10 hours, more preferably for 2 to 8 hours, and still more preferably for 3 to 6 hours. Irradiate with The ultraviolet intensity is preferably 0.05-50 mW/cm ^{2 , more preferably 0.5-10 mW/cm 2 .} Also, the integrated amount of ultraviolet light is preferably 1 to 100 J/cm ² , more preferably 5 to 100 J/cm ² .
There are no particular restrictions on the ultraviolet irradiation device, and a commercially available ultraviolet irradiation device may be used.
During the irradiation, it is preferable to mix the particles at regular intervals (for example, every 30 minutes) so that the particles are evenly irradiated with the ultraviolet rays. In addition, since the surface of the particles becomes hydrophilic after being irradiated with ultraviolet rays, it is preferable to store the particles in a dry atmosphere such as in the presence of a dehumidifying agent.

<How to use the hole closing material>
By spraying the perforation site closure material, the perforation site absorbs moisture present in the surrounding area and forms a hydrogel. to close.
Because the perforation closure material is a powder and can be sprayed dry from an endoscope, it is particularly preferred for closing perforations caused by ESD. ESD is applied to the esophagus, stomach, duodenum, and large intestine. Especially for the duodenum, which is a fragile tissue, it was difficult to close the perforation with a clip. The perforation can be closed without the burden of

The amount to be applied can be appropriately adjusted depending on the application site and wound, but as one aspect, by spraying 10 to 200 mg to a perforation of 1 to 3 mm, the hydrogel adheres to the perforation and is sufficiently A good perforation closing effect is obtained.

In addition, when the presence of a perforation cannot be visually confirmed due to reasons such as the size of the perforation being small, the perforation closing material is sprayed on the target site for the purpose of preventing the perforation from expanding or forming a perforation. It is also possible to use it as

EXAMPLES The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

(material)
Alaska pollock gelatin (Mw=38,000 Da, amino group content: 303 μmol/g, hereinafter also referred to as "ApGltn" or "Org") was obtained from Nitta Gelatin. Aliphatic aldehydes (hexanal, octanal, decanal, dodecanal), 2,4,6-trinitrobenzenesulfonic acid (TNBS) were purchased from Tokyo Kasei Kogyo (Japan). Ethanol and 2-picoline borane were purchased from Junsei Chemical. Fresh porcine duodenum was purchased from Tokyo Shibaura Organ.

(Preparation of gelatin derivative)
Gelatin derivatives were prepared by reductive amination of gelatin and aldehydes. First, ApGltn (10 g) and 12.5 mL of ethanol were dissolved in 35 mL of ultrapure water while stirring at 50°C.
Under continuous stirring at the same temperature, 6.1 mmol of decanal dissolved in 1 mL of ethanol (equivalent to 2 equivalents of 303 μmol/g of total amine residues in gelatin) was added to the solution, and after 1 hour, A solution of 1.5 equivalents of 2-picoline borane dissolved in 1.5 mL of ethanol was added to bring the final concentration of the mixture to 20 w/v % (water/ethanol=7:3).

The resulting solution was carefully dropped into 500 mL of cold ethanol to precipitate the gelatin. After washing with ethanol three times, the precipitate was vacuum-dried for three days to obtain a gelatin derivative 'hm-ApGltn'. By this method, a plurality of gelatin derivatives having a hydrophobic group introduction ratio ranging from 9 mol % to 62 mol % and different chain lengths (C6 to C12) of the introduced alkyl chains were synthesized.

The introduction rate of hydrophobic groups in gelatin was determined by quantification of residual amino groups using TNBS. Introduction of aliphatic aldehydes into hm-ApGltn was performed by Fourier transform infrared spectroscopy (FT-IR) (ALPHA II; Bruker Corp., USA) and ¹ H nuclear magnetic resonance (1H-NMR, JNM-AL300 ; JEOL).

(Preparation of gelatin derivative particles)
Gelatin derivative particles were prepared by a coacervation method using ethanol as a poor solvent. First, hm-ApGltn (5 g) was dissolved in 100 mL of ultrapure water (5 w/v% of gelatin) at 50° C., and then 100 mL of ethanol was added dropwise at 25° C. with vigorous stirring. The cloudy gelatin solution was frozen (-30°C) and dried to obtain gelatin derivative particles.
The resulting powder of gelatin derivative particles was thermally crosslinked in an oven at 150° C. under reduced pressure (<3 mbar) for 3 hours. The morphology of the obtained gelatin derivative particles was observed using a scanning electron microscope (SEM, S-4800 ultra-high resolution, HITACHI, Japan). Table 1 summarizes the composition of the gelatin derivative particles obtained and the sphericity and standard deviation of the particles calculated by scanning electron microscopy.

[Evaluation of pressure resistance at duodenum perforation closure]
Compressive strength evaluation was performed with modifications to ASTM-F2392-04R. First, fresh porcine duodenal tissue was cut into discs (diameter=30 mm). To mimic the state after ESD surgery, the mucosa in the center of the tissue piece was removed in a disk shape (5 mm in diameter) to expose the submucosal tissue and create a submucosal stripped tissue.

A pinhole (diameter = 1 mm) was then made as a perforation in the center of the tissue with a biopsy punch. After removing excess water with paper, 50 mg of each particle was sprayed on the pinhole and ulcer and allowed to stand for 10 minutes. Next, 300 μL of physiological saline was added dropwise and allowed to stand at 37° C. for 30 minutes to swell and form a hydrogel on the tissue. Next, the hydrogel was placed on the stage with the hydrogel facing down, and 5 mL of saline was added to the headspace of the chamber. Air was applied from the bottom of the tissue at a rate of 2 mL/min using a syringe pump (SPS-1, ASONE, Japan). Pressure was monitored with a Krone digital manometer (Krone CORPORATION, Japan). Table 2 shows the results of the pressure resistance test.

From the description in Table 2, it was shown that the perforation closing materials of Examples 1 to 7 had excellent compressive strength and were able to close perforations.
In addition, the perforated part closing material of Example 4, in which the hydrophobic group introduction rate was 10 mol % or more, had superior pressure resistance strength compared to the perforated part closing material of Example 1.
In addition, the hole closing material of Example 4, in which the hydrophobic group introduction rate was 15 mol % or more, had superior compressive strength as compared with the hole closing material of Example 2.
In addition, the hole closing material of Example 4, in which the hydrophobic group introduction rate was 30 mol % or more, had superior pressure resistance strength compared to the hole closing material of Example 2.

In addition, from the description in Table 2, when comparing the perforated area covering materials of Examples 4 to 7, all of which have a hydrophobic group introduction rate of 45 mol% or more, the number of carbon atoms possessed by the hydrophobic group is 10 or less. The hole closure of Example 4 had better compressive strength compared to the hole closure of Example 7.

(Pinhole diameter of compressive strength, dependence of particle spray amount)
The compressive strength was measured in the same manner as above, except that the pinhole diameters were 1 mm, 2 mm, and 3 mm, respectively, and the particle spray amount was 50 mg, 75 mg, and 100 mg. In addition, "47C10" was used as the particles. Table 3 is the result.

From the results in Table 3, it was confirmed that the desired effect can be obtained by appropriately changing the amount of spray according to the size of the pinhole.

(Preparation of gelatin derivative particles 2)
45C10 dissolved in 60% EtOH (introduction ratio: 45 mol%, hydrophobic group with 10 carbon atoms) was poured into a tray made of polytetrafluoroethylene and air-dried at room temperature to obtain a film of 45C10. Next, the film was crushed with a "wonder crusher (WC-3C)" at 28000 rpm for 1 minute, and this was repeated three times. The resulting powder was sieved and particles of ˜250 μm were recovered. The resulting powder was then further sieved to recover ~53 μm particles. The resulting powder was then further sieved and ˜32 μm was recovered. Each of these particles was thermally crosslinked at 150° C. for 3 hours to obtain gelatin derivative particles. Table 4 shows the sphericity and average particle size of the particles obtained under each condition.

[Pressure test measurement method for duodenum]
50 mg of the perforation closure material was placed on the duodenum with a defect of 1 mm diameter on two silicone sheets with a hole of 1 cm diameter, and the surface was flattened with a spatula. Next, a circular silicone (<1 cm) and a weight (50 g) were placed and allowed to stand for 10 minutes. The 1 cm diameter silicone was removed and replaced with a 1.5 cm diameter silicone, and physiological saline (300 μL×2) was added. After 30 minutes, a pressure resistance test was performed. Table 5 is the result. The results in Table 5 cannot be compared with the results in Table 2 in terms of numerical values. This is because the test methods are different.

From the results in Table 5, it was confirmed that the perforation closing material containing particles obtained by the pulverization method with classification also has the excellent effect of the present invention.

By spraying the perforation site closure material, the perforation site absorbs moisture present in the surrounding area and forms a hydrogel. to close.
Because the perforation closure material is a powder and can be sprayed dry from an endoscope, it is particularly useful for closing perforations caused by ESD. ESD is applied to the esophagus, stomach, duodenum, and large intestine. Especially for the duodenum, which is a fragile tissue, it was difficult to close the perforation with a clip. The perforation can be closed without the burden of

In addition, when the presence of a perforation cannot be visually confirmed due to reasons such as the size of the perforation being small, the perforation closing material is sprayed on the target site for the purpose of preventing the perforation from expanding or forming a perforation. It is also possible to use it as

Claims (14)

A hole closure material comprising particles containing a crosslinked gelatin derivative,
The gelatin derivative has the following formula (1):
Gtln-NH-L-CHR ¹ R ² (1)
[In formula (1), "Gltn" represents a residue of gelatin, L represents a single bond or a divalent linking group, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms]
A perforation closure having a structure represented by 2. The perforation closure material of claim 1 for closing a perforation resulting from endoscopic submucosal dissection. 3. The puncture closure of claim 2, wherein the perforation is a perforation in the gastrointestinal tract. 4. The puncture closure of claim 3, wherein the digestive tract is the duodenum. The perforation according to any one of claims 1 to 4, wherein the average sphericity of the particles is 1.45 or less, and the standard deviation of the sphericity of the particles is 0.25 or less. part closing material. Claims 1 to 5, wherein the total number of carbon atoms in the hydrophobic group represented by *-L-CHR ¹ R ² [* represents the bonding position] in formula (1) is 4 to 16. A perforation closure according to any one of the preceding claims. The perforated part closing material according to claim 6, wherein the total number of carbon atoms possessed by the hydrophobic groups is 6 to 12. 7. The perforated part closing material according to claim 6, wherein the total number of carbon atoms possessed by said hydrophobic groups is 6 to 10. The perforated part closing material according to any one of claims 6 to 8, wherein the introduction ratio of the hydrophobic group is 5 to 60 mol%. The perforated part closing material according to any one of claims 6 to 8, wherein the introduction rate of the hydrophobic group is 25 to 60 mol%. Formula (1) below:
Gtln-NH-L-CHR ¹ R ² (1)
[In formula (1), "Gltn" represents a residue of gelatin, L represents a single bond or a divalent linking group, R represents a hydrocarbon group having 1 to 20 carbon atoms, and R represents represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms]
dissolving a gelatin derivative having a structure represented by in a good solvent to obtain a gelatin solution containing the gelatin derivative and the good solvent;
adding a poor solvent to the gelatin solution to precipitate intermediate particles containing the gelatin derivative in the gelatin solution;
Freeze-drying the gelatin solution after the precipitation to obtain an intermediate powder containing the intermediate particles;
cross-linking said gelatin derivative of said intermediate particles to obtain a hole closure material comprising particles containing said cross-linked gelatin derivative. 12. The method of manufacturing a hole closing material according to claim 11, wherein the intermediate powder is heated to crosslink the gelatin derivative. The method for producing a hole closing material according to claim 12, wherein the intermediate powder is heated at 100 to 200°C for 2.5 to 5 hours to crosslink the gelatin derivative in the intermediate particles. Furthermore, the perforated portion closing material containing the particles containing the crosslinked gelatin derivative is irradiated with ultraviolet rays to make the surface of the particles hydrophilic. A method of manufacturing a closure.