JPH0622559B2 - Porous chitin molding for hemostasis - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel porous chitin molded article, which is useful as a medical device and the like, and has a particularly high protein adsorption ability as compared with a conventional chitin sponge. The present invention relates to a hemostatic porous chitin molded article useful as an external hemostatic sponge in that it has a hemostatic effect.

(Prior Art) A gelatin sponge has been put into practical use as an external hemostatic sponge. Since gelatin is inherently water-soluble, it dissolves quickly when wetted with blood or body fluids, so gelatin sponges modified with protein denaturants such as formaldehyde, diacetyl and glyoxal are commercially available.

As a conventionally known chitin sponge, for example, the 1st International Chitin-Chitosan Conference Record Collection (Proceedin
g of the First International Confer-ence on Chitin
/ Chitosan) p. 300, lines 16-24, there is described a method for producing a sponge in which sodium sulfate is eluted after mixing a chitin solution obtained by a process similar to the cellulose viscose method with sodium sulfate. .

In addition, the inventors of the present invention have a high wet strength, in which a water-soluble polymer substance is added to and mixed with a chitin solution, and the mixture liquid is coagulated to elute and remove the water-soluble polymer substance from the obtained chitin molded body. A method for producing a chitin sponge was established and was previously proposed (Japanese Patent Application No. 59-176952).

(Problems to be solved by the invention) Currently used hemostatic gelatin sponges have the drawbacks of low strength when wet and poor shape retention. The development of a hemostatic sponge with a robust structure that can hold blood has been eagerly awaited.

On the other hand, the chitin sponge previously proposed by the present inventors has high strength when wet and has advantages such as a wound healing promoting effect, but the hemostatic effect was not remarkable. Therefore, an object of the present invention is to provide a chitin sponge that also has a hemostatic effect without impairing the robust structure and the effect of promoting wound healing.

(Means for Solving the Problems) As a result of diligent studies to obtain a new and useful chitin sponge that also has a hemostatic action, the present inventors have found that the porous chitin molded body is treated with an alkali to obtain a protein. The present inventors have completed the present invention by discovering the fact that hemostatic action is manifested as the adsorptive capacity is significantly increased.

That is, the present invention is a porous molded product for hemostatics, which is a porous molded product made of water-insoluble chitin and has a protein adsorption amount of 0.5 mg or more per 1 g of dried molded product.

The water-insoluble chitin in the present invention means poly (N-) obtained by treating crustaceans, insects, etc. with hydrochloric acid and caustic soda to remove proteins and calcium.
(Acetyl-D-glycosamine), or a derivative thereof that does not dissolve in water. Examples of such chitin derivatives include those obtained by partially deacetylating the acetylamino group of chitin, etherified products, esterified products, hydroxyethylated products, O-ethylated products, and the like, and specific examples include poly [N-acetyl]. -6-O- (2-
Hydroxyethyl) -D-glycosamine], poly [N-
Acetyl-6-O- (ethyl) -D-glucosamine] and the like.

The chitin molded product of the present invention having excellent protein adsorption ability can be produced by first molding chitin into a porous material and then subjecting the molded product to alkali treatment.

In the present invention, the term “porous” specifically means sponge-like or sponge-like, and the porosity (B /
A × 100: B; the volume of pores contained in the porous molded body of unit weight, A; the volume of the porous molded body of unit weight) is preferably 80% or more, more preferably 85% or more, optimally Indicates 90% or more. In order to obtain a porous molded body made of chitin, for example, the following method can be adopted.

That is, first, chitin is dissolved in a solvent to obtain a chitin dope. Here, the solvent may be a known chitin solvent, for example, a mixture of trichloroacetic acid and a halogenated hydrocarbon, a mixture of lithium chloride and N-methylpyrrolidone, or a mixture of lithium chloride and dimethylacetamide. The concentration of chitin in the chitin dope varies depending on the degree of polymerization of chitin used, but is preferably 0.05-5.
0, more preferably 0.1 to 25, most preferably 0.3 to
It is in the range of 10 W / W%.

Next, a water-soluble polymer substance is added to and dispersed in the chitin dope. Here, the water-soluble polymer substance refers to a natural or synthetic polymer substance that is solid at room temperature and is soluble in water, such as polyvinyl alcohol, polyethylene glycol, polypropylene glycol, agar,
Soluble starch and the like are preferably used, but polyvinyl alcohol and agar are particularly preferably used. Polyvinyl alcohol, which can be dissolved in water at low or high temperatures, has a saponification degree of 60 mol% or more and a polymerization degree of 50 to 2
000 is preferably used, but high temperature,
For example, those having a saponification degree of 95 mol% or more which can be dissolved in water at 60 ° C. or more are preferably used. The agar means a mucilage existing as a cell membrane component of red soup such as agar beetle or a substance obtained by freeze-drying and drying it, and agarose, agaropectin and derivatives thereof separated therefrom. As polypropylene glycol and polyethylene glycol, those having a molecular weight of 1000 or more are preferably used. It is preferable that all of these water-soluble polymer substances are used by being dispersed in the form of powder. These water-soluble polymer substances are mixed with the chitin dope, but generally, the water-soluble polymer substance does not dissolve in the chitin dope and is present in a dispersed state. The mixing ratio is chitin dope / water-soluble polymer = 1/5 to 5 by weight.
The range of / 1 is preferable.

The chitin dope obtained by dispersing the water-soluble polymer substance obtained as described above is immersed in a coagulating liquid to be molded and coagulated, and then treated with an aqueous solution to elute and remove the water-soluble polymer substance to form a porous structure. A molded body is obtained. As the coagulating liquid, water or alcohols such as methanol, ethanol, propanol and butanol, and ketones such as acetone are preferably used.

Water-soluble for treating a solidified molded article means water or water containing a small amount of salts, and the treatment temperature and time are selected depending on the solubility of the water-soluble polymer substance in water. Generally, for example, a method of treating at a high temperature of 80 to 125 ° C. for a long time of 1 hour or more is preferably used.

By subjecting the porous molded body thus obtained to alkali treatment, the chitin molded body of the present invention can be obtained. The alkali treatment in the present invention includes any method in which a porous molded body made of chitin is brought into contact with an alkaline solution.
An aqueous solution of sodium hydroxide is practical as an alkaline solution, and its concentration is preferably 0.1 w / v% or more, more preferably 10 w / v% or more, most preferably 30 to 60 w / v%.
The preferable treatment temperature is 10 ° C. or higher, more preferably 40 ° C. or higher, most preferably 60 to 120 ° C. The treatment time varies depending on the alkali concentration and the treatment temperature, but is preferably 1 minute to 24 hours, more preferably 15 minutes to 12 hours, and optimally 1 to 6 hours. The bath ratio is preferably 25 parts by weight or more, more preferably 50 parts by weight or more, and most preferably 100 parts by weight or more with respect to 1 part by weight of the dried chitin molding. The alkali solution may be stirred as necessary, and after the treatment, when removing the alkali, operations such as neutralization and washing with water may be carried out, followed by treatment with an organic solvent and drying.
As a drying method, a method such as natural drying, blast drying, or vacuum drying can be adopted, but a freeze-drying method is preferably used in order to prevent shrinkage of the porous chitin molded product due to drying.

The porous molded product obtained by such a method has a protein adsorption amount of preferably 0.5 mg or more, more preferably 1 mg or more, optimally 2 to 100 mg per 1 g of dried porous chitin molded product. It has the ability to adsorb the protein that is present. The amount of adsorbed protein here can be measured by the following method.

The calf serum for cell culture is diluted 500 times with distilled water to prepare a diluted serum, and 20 ml of this diluted serum is used as a specimen 1
After adding 00 mg and gently stirring at 37 ° C for 10 minutes, the protein concentration in the diluted serum was set to Amg / ml, and the protein concentration in the case of performing the same operation without adding the sample was B.
If it is mg / ml, it means that (BA) × 20 mg of protein is adsorbed on 100 mg of the sample.

The protein concentration is determined by the phenol reagent method (published by The University of Tokyo Press, Biochemistry Experimental Method Series A-3, protein quantification method,
Pp. 86-103).

(Example) Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 Chitin powder (manufactured by Shin Nippon Chemical Co., Ltd.) was crushed to 100 mesh, treated with 1N-HCl at 4 ° C. for 1 hour, and further 3%.
Treat with NaOH aqueous solution at 90-100 ° C for 3 hours,
The ash content and protein were removed, and washing with water was repeated and drying was performed to obtain purified chitin powder.

2 g of the purified chitin powder was dissolved in 98 g of dimethylacetamide containing 8% w / w of LiCl at room temperature to obtain a transparent chitin dope. To this chitin dope, polyvinyl alcohol [Poval UF-170GS, Unitika Chemical Co., Ltd.]
Manufactured, polymerization degree 170, saponification degree 95 mol% or more] 50 g was added and mixed, and uniformly dispersed. This dispersion was cast on a glass plate in a size of 5 cm square and a thickness of 5 mm, immersed in tap water and solidified into a sheet. After peeling from the glass plate, it was immersed in a sufficient amount of water, and the treatment at 100 ° C. for 2 hours was repeated 3 times while exchanging water to obtain 6 sheet-shaped porous chitin moldings.

The sheet thus obtained was thoroughly squeezed with water, dipped in 40 w / v% NaOH aqueous solution of 1 and treated at 80 ° C. for 5 hours. After cooling, the sheet was transferred into about 1 water, neutralized with concentrated hydrochloric acid, washed with running water, further washed with distilled water, and then freeze-dried to obtain a sheet-shaped chitin molded article of the present invention.

The amount of protein adsorbed per 1 g of the dried molded product of the obtained chitin molded product was 33 mg, and the tensile strength when wet was 13.5 g.
/ Mm ² , and the porosity was 97%.

Example 2 2 g of the purified chitin powder obtained in Example 1 was mixed with LiCl
Was dissolved in 98 g of N-methylpyrrolidone containing 8 w / w% to obtain a transparent chitin dope. To this chitin dope, 50 g of agar powder was added and mixed, and dispersed uniformly. This dispersion was pressurized from a circular nozzle with a diameter of 7 mm, extruded into methanol, solidified to a length of about 5 cm, immersed in a sufficient amount of water, and treated at 120 ° C. for 30 minutes while exchanging water. By repeating the process, a cylindrical porous chitin molded body was obtained.

Thoroughly squeeze the water of the chitin molded product obtained in this way,
Soak in 500 ml of 40 w / v% NaOH aqueous solution for 12
It was treated at 0 ° C. for 1 hour. After cooling, the sponge was transferred to about 1 water, neutralized with concentrated hydrochloric acid, washed with running water, further washed with distilled water, and then freeze-dried to obtain a cylindrical chitin molded product of the present invention.

The amount of protein adsorbed per 1 g of the dried molded product in the obtained chitin molded product was 36 mg, and the tensile strength when wet was 12.8 g.
/ Mm ² , and the porosity was 98%.

Examples 3 to 7 and Comparative Example 1 The relationship between the conditions of alkali treatment and the protein adsorption amount when obtaining the chitin molded product of the present invention was investigated. That is, when the sheet-like porous chitin molded body obtained by the method described in Example 1 was treated with alkali, the temperature was fixed at 120 ° C. and the time was fixed at 60 minutes, and the treatment was performed while changing the concentration of the NaOH aqueous solution. The protein adsorption capacity of the obtained chitin molded body was measured.

As a result, as shown in Table 1, the amount of protein adsorbed increases with the increase of the alkali concentration during the treatment.

Reference Examples 1 and 2 The hemostatic effects of the conventional chitin sponge and the porous chitin molded product of the present invention were compared.

As the conventional chitin sponge, the sheet-like porous molded article (protein adsorption amount: 0.3 mg / g) obtained in Example 1 which is not subjected to alkali treatment is used, and the porous chitin molded article of the present invention is The one obtained in Example 1 was used.

Rabbits with a body weight of about 2.5 kg were shaved, and the back muscle surface was punctured to a depth of 5 to 6 mm using a puncture device in which 10 insect pins were bundled in a diameter of about 8 mm to cause bleeding. The conventional chitin sponge and that of the present invention were separately pressed against two such stab wounds and bleeding parts, fixed with adhesive tape, and after about 2 hours, the areas of the colored parts due to bleeding were compared. As a result, the conventional chitin sponge was colored in a circular shape having a diameter of about 35 mm, and the porous chitin of the present invention was colored only in a portion having a diameter of about 20 mm.

From the above results, it can be seen that the porous chitin molded product of the present invention is superior in the hemostatic effect as compared with the untreated product.

(Effects of the Invention) The hemostatic porous chitin molded article of the present invention has a robust structure and excellent biocompatibility, and also has a hemostatic effect that is not present in conventional chitin sponges. The manufacturing method is an extremely simple operation of preparing a chitin sponge and treating it with an alkaline solution, and is applicable to industrial production.

In addition to the hemostatic effect, the hemostatic porous chitin molded article of the present invention has a very smooth feel when contacted, as compared with that before treatment, and is also suitable as a wound cover material from this point.

Claims (1)

[Claims] 1. A porous molded article composed of water-insoluble chitin, wherein the amount of protein adsorbed per 1 g of dried molded article is 0.5 mg.
The porous chitin molded body for hemostasis characterized by the above.