Alginate and hemostatic material containing the same

Abstract

A purpose of the present invention is to provide an alginic acid salt superior in hemostatic effect to conventional alginic acid salts. This alginic acid salt has a carboxyl-group calcium salt and another carboxyl (salt) group, and is characterized in that, when structural units containing the calcium salt group, among the repeating units (structural units) constituting the alginic acid salt, are referred to as calcium alginate and structural units containing the other carboxyl (salt) group are referred to as sodium alginate and when the alginic acid salt is regarded as a mixture of the sodium alginate and the calcium alginate, then the mass proportion (calcium content) of the calcium alginate is 1-99 mass%.

Description

[Technical field]

[0001] The present invention relates to an alginate and a hemostatic material containing the same. [Background technology]

[0002] Alginic acid is a polysaccharide found in brown algae and is a polymer composed of mannuronic acid and / or guluronic acid. Although alginic acid is insoluble in water, salts of alginic acid such as sodium alginate and potassium alginate dissolve easily in water and exhibit a thickening effect, and also gel easily in the presence of calcium ions. Therefore, they are widely used as thickeners, gelling agents, stabilizers, etc. in the fields of food, pharmaceuticals, medical materials, cosmetics, etc.

[0003] Alginic acid and alginates have been considered as medical materials for use in, for example, stopping bleeding, based on their property of reacting with water to form a gel. For example, Patent Document 1 discloses a solid pharmaceutical composition comprising (A) a gelling agent, (B) a salt of at least one acid selected from the group consisting of organic acids and inorganic acids and a divalent metal, and (C) polyethylene glycol. Patent Document 2 discloses a kit for producing an alginate gel, which comprises a first container containing a soluble alginate and a second container containing an insoluble alginate / gel-forming ion particles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2013 / 077414 [Patent Document 2] Special Publication No. 2008-515927 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, alginates have conventionally been used for various purposes, including as hemostatic materials, but there is room for improvement to further enhance the hemostatic effect.

[0006] The present invention has been made in consideration of the above-mentioned current situation, and has an object to provide an alginate having a more excellent hemostatic effect than conventional alginates. [Means for solving the problem]

[0007] The inventors conducted extensive research on alginates and discovered that alginates having a calcium salt of a carboxyl group, in which the calcium content in the carboxyl (salt) group is within a specified range, have excellent hemostatic effects. They then came to the realization that the above-mentioned problems could be solved admirably, and arrived at the present invention.

[0008] The present invention includes the following alginates, etc. [1] An alginate having a calcium salt of a carboxyl group and other carboxyl (salt) groups, the calcium base-containing structural unit in the repeating units (structural units) constituting the alginate being calcium alginate, the other carboxyl (salt) group-containing structural units being sodium alginate, and the mass proportion of calcium alginate (calcium content) of the alginate being 1 to 99 mass% when the alginate is converted into a mixture of sodium alginate and calcium alginate. [2] The alginate according to [1] above, having a mass average molecular weight of 10,000 or more. [3] An alginate according to [1] or [2] above, which has structural units derived from mannuronate and structural units derived from guluronic acid, and in which the ratio of structural units derived from mannuronate and structural units derived from guluronic acid (mannuronic acid / guluronic acid) when all cations in the alginate are replaced with protons is 0.6 or more. [4] Bulk density is 0.2 g / cm 3 The alginate according to any one of the above [1] to [3]. [5] A hemostatic material comprising the alginate salt according to any one of [1] to [4] above. Effect of the Invention

[0009] The alginate of the present invention has the above-mentioned constitution and has excellent hemostatic effect, and therefore can be suitably used as a hemostatic material, etc. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing wounds of Grades A to D in the “Evaluation criteria for the degree of hemostasis” in Table 2. [Diagram 2] FIG. 2 is a photograph showing the result of microscopic observation of a cross section of a portion where hemostasis was confirmed 5 minutes after the alginate salt 9 obtained in Example 9 was sprayed on a bleeding site. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The preferred embodiments of the present invention are specifically described below, but the present invention is not limited to the following description, and can be modified as appropriate within the scope of the present invention. In addition, a combination of two or more of the individual preferred embodiments of the present invention described below also falls within the preferred embodiments of the present invention.

[0012] <Alginate> The alginate of the present invention is an alginate having a calcium salt of a carboxyl group, in which calcium salt of a carboxyl group and other carboxyl (salt) groups such as sodium salt of a carboxyl group are mixed in one molecule. For example, Patent Document 1 discloses a mixture of sodium alginate and a calcium salt, and Patent Document 2 discloses a mixture of sodium alginate and calcium alginate. However, these do not contain a mixture of calcium salts of carboxyl groups and other carboxyl (salt) groups in one molecule, and therefore the alginate of the present invention is different from such mixtures. It is believed that the alginate of the present invention quickly comes into contact with water in the blood, plugs the bleeding site, and exerts a local hemostatic effect.

[0013] The alginate of the present invention has structural units derived from mannuronic acid (salt) and / or guluronic acid (salt) as repeating units, and is composed of calcium base-containing structural units which are structural units derived from calcium salts of mannuronic acid or guluronic acid, and other carboxyl (salt) group-containing structural units which are structural units derived from mannuronic acid or guluronic acid or other salts thereof other than calcium. In the alginate of the present invention, the calcium base-containing structural unit in the repeating units (structural units) constituting the alginate is defined as calcium alginate, and the other carboxyl (salt) group-containing structural units are defined as sodium alginate, and the alginate is converted into a mixture of sodium alginate and calcium alginate, the mass proportion of calcium alginate (calcium content) is 1 to 99 mass%. The alginate of the present invention contains a mixture of calcium salts of carboxyl groups and other carboxyl (salt) groups in one molecule, i.e., a mixture of calcium base-containing structural units and other carboxyl (salt) group-containing structural units. In calculating the calcium content, the calcium base-containing structural units are replaced with calcium alginate, which has the same number of structural units, and the other carboxyl (salt) group-containing structural units are replaced with sodium alginate, which has the same number of structural units, and the alginate is calculated as a mixture of sodium alginate and calcium alginate. The hemostatic effect in the present invention is exerted based on the ionic strength of calcium ions contained in the alginate at a predetermined ratio, and therefore, so long as the calcium content is within the above range, the type of cations other than calcium in the alginate is not particularly limited. The calcium content can be measured by X-ray fluorescence analysis as described in the Examples. For example, when the alginate is potassium / calcium alginate, potassium alginate is used instead of sodium alginate as the standard substance in the fluorescent X-ray measurement to measure the intensity of the fluorescent X-rays of the potassium element, but when calculating the mass ratio, the potassium in the alginate is calculated as sodium. Specifically, the mass ratio of calcium alginate and potassium alginate was calculated based on the intensity of the fluorescent X-rays of calcium and potassium elements, and then the mass ratio of potassium alginate was converted to the chemical equivalent of potassium, and sodium alginate (NaC 6 H 7 O 6 The mass proportion of calcium alginate is determined by multiplying the value obtained by multiplying the chemical formula weight of (a) by the mass proportion of calcium alginate, and setting the sum of these values ​​to 100. Furthermore, when the alginate has an acid carboxyl group, acid alginic acid is used instead of sodium alginate as the standard substance in the fluorescent X-ray measurement, but the protons in the alginate are calculated as sodium when calculating the mass ratio.

[0014] The calcium content of the alginate is preferably 10 to 95% by mass, which allows the alginate to have a more excellent hemostatic effect. The calcium content is more preferably 20 to 90 mass%, further preferably 25 to 85 mass%, even more preferably 30 to 80 mass%, still more preferably 40 to 80 mass%, and particularly preferably 50 to 80 mass%.

[0015] As long as the calcium content of the alginate is within the above range, the cation of the carboxyl (salt) group other than the calcium base is not particularly limited and may be, for example, a sodium ion, a potassium ion, an ammonium ion, a proton, etc., and may have two or more types of monovalent cations. Sodium ions and potassium ions are preferred, and sodium ions are more preferred. A form in which the carboxyl (salt) group in the above alginate is a calcium base or a sodium base, that is, a form of sodium / calcium alginate, is one of the preferred embodiments of the present invention.

[0016] The mass average molecular weight of the alginate is not particularly limited, but is preferably 10,000 or more. This allows the alginate to have a more excellent hemostatic effect. The mass average molecular weight is more preferably 10,000 to 10 million, even more preferably 20,000 to 5 million, even more preferably 30,000 to 3 million, still more preferably 40,000 to 2 million, even more preferably 50,000 to 1.6 million, particularly preferably 100,000 to 1 million, particularly preferably 200,000 to 800,000, and most preferably 300,000 to 600,000. In one embodiment, the alginate may have a mass average molecular weight of 500,000 or less. The mass average molecular weight can be measured by the method described in the Examples.

[0017] The above-mentioned alginate has structural units derived from mannuronate and / or structural units derived from guluronic acid salt, and may be a polymer consisting only of structural units derived from mannuronate or a polymer consisting only of structural units derived from guluronic acid salt, but is preferably a copolymer having structural units derived from mannuronate and structural units derived from guluronic acid salt. As used herein, a mannuronate-derived structural unit refers to a structural unit in which at least one hydroxyl group of a mannuronate is replaced with an ether group, and a guluronic acid-derived structural unit refers to a structural unit in which at least one hydroxyl group of a guluronic acid is replaced with an ether group.

[0018] When the alginate is a copolymer having a structural unit derived from mannuronate and a structural unit derived from guluronic acid, the ratio of the structural unit derived from mannuronate to the structural unit derived from guluronic acid is not particularly limited, but when all cations in the alginate are replaced with protons, that is, when the alginate is regarded as alginic acid, the ratio of the structural unit derived from mannuronate to the structural unit derived from guluronic acid (mannuronate / guluronic acid ratio, hereinafter also referred to as M / G ratio) is preferably 0.6 or more. This makes the alginate more excellent in hemostatic effect. The M / G ratio is more preferably 0.6 to 5, even more preferably 0.67 to 4, even more preferably 0.7 to 4, even more preferably 0.8 to 3, even more preferably 0.9 to 2, and particularly preferably 0.9 to 1.5. The ratio of the structural units derived from mannuronic acid to the structural units derived from guluronic acid can be measured as follows according to the method described in Carbohydrate Research, 32 (1974), 217-225. Alginic acid is a complex block copolymer consisting of a random combination of an MM fraction having only structural units derived from mannuronic acid, a GG fraction having only structural units derived from guluronic acid, and an MG fraction having structural units derived from mannuronic acid and guluronic acid. The resistance to hydrolysis and solubility in acid vary depending on the quantitative ratio and arrangement of these components. Based on these properties of alginic acid, alginic acid is decomposed using weak hydrochloric acid under conditions that allow it to be cleaved into MM, GG, and MG fractions, and each fraction is then fractionated by a commonly used method. The sugar content of each fraction obtained is measured by the phenol-sulfuric acid method, and the M / G ratio is calculated using the following formula. M / G = (sugar amount in MM fraction + (sugar amount in MG fraction / 2)) / (sugar amount in GG fraction + (sugar amount in MG fraction / 2))

[0019] The alginate has a bulk density of 0.2 g / cm 3 The bulk density is preferably 0.2 to 3.0 g / cm or more. This allows the alginate to have a more excellent hemostatic effect. 3and more preferably 0.25 to 2.5 g / cm 3 and more preferably 0.3 to 2.0 g / cm 3 and more preferably 0.4 to 1.5 g / cm 3 and particularly preferably 0.5 to 0.9 g / cm 3 It is. The bulk density can be measured by the following method. <Method of measuring bulk density> After coating a punch and die (φ8 mm, corner), fill the die with alginate (filling depth 10 mm). Press the tablets using a manual benchtop tablet molding machine. Measure the weight of the resulting tablets and determine the bulk density based on the following formula. Bulk density (g / cm 3 )=W / V W: tablet weight (g) V: Volume inside the die (0.5024 cm 3 )

[0020] The alginate preferably has a particle ratio of 80% or more that passes through a sieve with a mesh size of 2000 μm but does not pass through a sieve with a mesh size of 10 μm. The particle ratio is more preferably 90% or more. When the particle ratio of the alginate that does not pass through a sieve with a mesh size of 10 μm is 80% or more, scattering of the alginate into space can be sufficiently suppressed when the alginate is used as a hemostatic material. By passing the alginate through a sieve with a mesh size of 2000 μm, spraying of the alginate becomes easier and treatment of the bleeding point becomes easier. The mesh size of the sieve through which the alginate passes is more preferably 1000 μm, further preferably 800 μm, even more preferably 600 μm, and particularly preferably 500 μm. The mesh size of the sieve through which the alginate does not pass is more preferably 20 μm, further preferably 50 μm, even more preferably 80 μm, and particularly preferably 100 μm.

[0021] The alginate preferably has a swelling degree of 80% or more, more preferably 100% or more, as measured by the following method. <Method of measuring swelling degree> Weigh out 0.1 g of sample into a vial and measure the height of the sample in the vial using a caliper or similar (initial height h0). Next, slowly pour in 2 mL of saline and leave to stand at room temperature. Two minutes after the addition of saline is complete, turn the vial upside down and measure the swelling height (ht) of the sample remaining at the bottom of the vial. Calculate the degree of swelling using the following formula. Swelling degree (%) = (ht-h0) / h0 x 100 h0: Filling height of sample before swelling (mm) ht: swelling height of sample after swelling (mm)

[0022] The form of the alginate is not particularly limited, and examples thereof include powder, fiber (cotton, sheet, etc.), gel, solution, putty, etc., but powder is preferred. In the case of powder, the alginate can quickly cover the bleeding site regardless of the site and shape of the wound, and since the alginate is likely to remain at the bleeding site, it can come into contact with the moisture in the blood more quickly, resulting in a more excellent hemostatic effect.

[0023] <Method of producing alginate> The method for producing the alginate of the present invention is not particularly limited, and the alginate can be produced by a commonly used method, such as by substituting alginic acid with a monovalent cation and calcium ions, substituting a monovalent salt of alginic acid with calcium ions, or substituting the calcium ions in calcium alginate with a monovalent cation. However, it is preferable to produce the alginate by carrying out a step (A) of mixing a monovalent salt of alginic acid with a calcium salt and a step (B) of desalting and dehydrating the product obtained in the step (A).

[0024] The monovalent salt of alginic acid in step (A) of the method for producing an alginate salt is not particularly limited, but examples thereof include alkali metal salts such as sodium and potassium, ammonium salts, etc. Sodium alginate and potassium alginate are preferred, and sodium alginate is more preferred. Sodium alginate, potassium alginate, and ammonium alginate are water-soluble, commercially available, and easily available.

[0025] The calcium salt used in step (A) of the above-mentioned method for producing an alginate salt is not particularly limited as long as it is a compound containing calcium element, but examples thereof include calcium chloride, calcium sulfate, calcium nitrate, calcium carbonate, calcium phosphate, calcium bicarbonate, calcium hydroxide, etc. The calcium salt is preferably calcium chloride.

[0026] Step (A) of the above-mentioned method for producing an alginate is not particularly limited as long as a monovalent salt of alginic acid and a calcium salt are mixed, but it preferably includes a step of mixing an aqueous solution of sodium alginate and an aqueous solution of a calcium salt.

[0027] In the above step (A), when an aqueous solution of a monovalent salt of alginic acid is used, the concentration of the monovalent salt of alginic acid is not particularly limited, but is preferably 0.1 to 50 wt / v%, more preferably 0.5 to 30 wt / v%, and even more preferably 1 to 20 wt / v%, calculated as sodium alginate. The concentration of the monovalent salt of alginic acid is a sodium alginate equivalent concentration. When the monovalent salt of alginic acid is, for example, potassium alginate, the concentration is calculated by substituting sodium for potassium.

[0028] In the above step (A), when an aqueous solution of a calcium salt is used, the concentration of the calcium salt can be appropriately adjusted depending on the desired calcium content.

[0029] In the above step (A), it is preferable to mix the monovalent salt of alginic acid and the calcium salt and then stir them. The stirring time is not particularly limited, but is preferably 1 to 30 minutes, and more preferably 5 to 10 minutes.

[0030] The above step (A) preferably includes a step of mixing a monovalent salt of alginic acid with a calcium salt, optionally stirring the mixture, and then adding an organic solvent, which makes it easier to filter the resulting crude alginate. The organic solvent is not particularly limited, but examples thereof include lower alcohols such as methanol, ethanol, and propanol, among which ethanol is preferred.

[0031] The concentration of the ethanol is not particularly limited, but is preferably 30 to 100 vol %, and more preferably 50 to 100 vol %.

[0032] The above step (A) preferably includes a step of mixing a monovalent salt of alginic acid with a calcium salt, stirring the mixture as necessary, adding an organic solvent, and then filtering the resulting crude alginate.

[0033] The filtration step is not particularly limited and can be carried out by a commonly used method, but a preferred filtration method is filter filtration.

[0034] In the above filtration step, it is preferable to use a glass filter. The pore size of the glass filter is preferably from 5 to 120 μm, and more preferably from 20 to 50 μm. As the glass filter, it is preferable to use a 2G or 3G glass filter.

[0035] Step (B) in the method for producing an alginate of the present invention is a step of desalting and dehydrating the product obtained in step (A).

[0036] The desalting and dehydrating method in the above step (B) is not particularly limited, and examples thereof include commonly used methods such as filtration, dialysis, etc. Filtration is preferred. In the above step (B), it is preferable to add a desalting solvent to the product obtained in step (A), stir the mixture, and then filter it.

[0037] The above-mentioned desalting solvent includes water, organic solvents such as methanol, ethanol, propanol, and mixed solvents thereof. Preferred are water, ethanol, and mixed solvents of water and ethanol, and more preferred is 50 to 80 vol % ethanol.

[0038] The method for producing the alginate preferably includes a step of drying the product obtained in the step (B). The drying step is not particularly limited as long as it is possible to evaporate the solvent from the obtained product, but is preferably carried out by air drying, drying under reduced pressure, spray drying, or the like.

[0039] The drying temperature in the drying step is not particularly limited, but is preferably 30 to 200°C.

[0040] The drying time in the drying step is not particularly limited, but is preferably 1 to 24 hours.

[0041] The method for producing the alginate preferably includes a step of grinding and / or sieving the product obtained in the drying step. The pulverization method is not particularly limited, but for example, a pulverizing mill or the like can be used. The sieve openings used in the above sieving are not particularly limited, but are preferably 10 to 2000 μm.

[0042] <Hemostatic material> The alginate of the present invention has an excellent hemostatic effect and can therefore be suitably used as a hemostatic material. In this specification, the term "hemostatic material" is used to include pharmaceuticals and medical devices as defined in Article 2 of the Pharmaceutical and Medical Device Act. Therefore, the hemostatic material in the present invention includes hemostatic agents. The present invention also relates to a hemostatic material comprising the alginate of the present invention. The hemostatic material promotes hemostasis and is used in mammals (livestock animals, pet The composition can be used in various applications for the purpose of local hemostasis in animals (including animals and humans). For example, the composition can be used as a hemostatic material for wound sites, a hemostatic material for surgery, etc. Preferably, the composition is used as a hemostatic material for surgery. The hemostatic material of the present invention is preferably applied by scattering it on an affected area accompanied by bleeding during surgery, and such a method of using the hemostatic material also constitutes one aspect of the present invention. The present invention also includes a method for using the alginate of the present invention, which comprises the step of spraying the alginate of the present invention on an affected area accompanied by bleeding during surgery.

[0043] The content of the alginate in the hemostatic material is not particularly limited, but is preferably 50 to 100% by mass relative to 100% by mass of the hemostatic material, more preferably 60 to 100% by mass, even more preferably 70 to 100% by mass, still more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, particularly preferably 95 to 100% by mass, and most preferably 100% by mass.

[0044] The hemostatic material may contain other components in addition to the alginate. Other components are not particularly limited as long as they do not interfere with the hemostatic effect and are applicable to the living body, and examples of such other components include pharmacological components such as antibacterial agents, antibiotics, anti-inflammatory agents, blood circulation improvers, steroids, enzyme inhibitors, growth factors, and various vitamins, as well as additives such as excipients, binders, lubricants, pH adjusters, buffers, preservatives, antioxidants, colorants, and moisture-proofing agents.

[0045] The content of the other components in the hemostatic material is not particularly limited, but is preferably 0 to 50% by mass relative to 100% by mass of the hemostatic material, more preferably 0 to 40% by mass, even more preferably 0 to 30% by mass, still more preferably 0 to 20% by mass, even more preferably 0 to 10% by mass, particularly preferably 0 to 5% by mass, and most preferably 0% by mass. EXAMPLES

[0046] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0047] The methods for measuring the various physical properties of the alginate are as follows. <Calcium content> The alginate was pressure molded into a disk shape, and the intensity of the calcium elemental fluorescent X-rays was measured using an energy dispersive X-ray fluorescence spectrometer (JSX-3100RII, manufactured by JEOL Ltd.) under the following conditions. A calibration curve was prepared based on the intensity of fluorescent X-rays from calcium element in the mixture of the following standard substances, and the calcium content (%) was calculated from the obtained calibration curve and the intensity of fluorescent X-rays from calcium element in the above alginate salt. Tube voltage: 30kV Collimator: 7mmφ Atmosphere: Vacuum Measurement time: 120 seconds Standard material: Sodium alginate (Kimika Co., Ltd., molecular weight: 300,000, M / G ratio: 1.1) and calcium alginate (synthesized from the above sodium alginate, molecular weight: 300,000, M / G ratio: 1.1) were mixed uniformly at arbitrary mass ratios (10, 20, 40, 60, 80, 90% by mass) and pressurized into a disk shape.

[0048] <Mass average molecular weight> The alginate was dissolved in a 0.1 w / v % sodium carbonate solution, and then the mass average molecular weight was measured by gel filtration chromatography under the following conditions. Column: TSKgel GMPW XL2 pieces (Tosoh Corporation, diameter 7.8 mm x 300 mm) Column temperature: 40℃ Eluent: 200mM sodium nitrate solution Sample concentration: 0.1% Flow rate: 0.7mL / min Injection volume: 50μL Detector: RI (differential refractometer) Standard substance: pullulan (molecular weight 739,000, 334,000, 216,000, 107,000, 49,700, 22,000, 0,980,000, 0,630,000)

[0049] <Bulk density> Magnesium stearate was applied to a punch and die (φ8 mm, corner), and then the die was filled with alginate (filling depth 10 mm) and rubbed off. After tableting at 600 kgf using a manual tabletop tablet molding machine (Ichihashi Seiki Co., Ltd., HANDTAB-200), the weight of the obtained tablets was measured, and the bulk density was measured according to the following formula. Bulk density (g / cm 3 )=W / V W: tablet weight (g) V: Volume inside the die (0.5024 cm 3 )

[0050] <Swelling degree> 0.1 g of sample was weighed into a vial, and the filling height of the sample in the vial was measured using a caliper or the like (initial height h0). Next, 2 mL of physiological saline was slowly poured into the vial, and the vial was left to stand at room temperature. The vial was turned upside down 2 minutes or 5 minutes after the end of the addition of physiological saline, and the swelling height (ht) of the sample remaining at the bottom of the vial was measured, and the swelling degree was calculated using the following formula. Swelling degree (%) = (ht-h0) / h0 x 100 h0: Filling height of sample before swelling (mm) ht: swelling height of sample after swelling (mm)

[0051] <Hemostasis evaluation> A pig (fasted since the previous day, no water intake restrictions) was given general anesthesia (induction: isoflurane 5%, oxygen flow rate approximately 3.0 L / min, maintenance: isoflurane 1-3%, oxygen flow rate approximately 3.0 L / min) and then underwent laparotomy. A biopsy trephine (Kai Industries, single-use tissue biopsy needle) was inserted into the liver to create a wound 4 mm wide and 3 mm deep. The time it took for the wound to fill with blood was measured and scored according to the "Evaluation criteria for the degree of bleeding" in Table 1, and wounds with a grade of 0.5 to 4 were used in the test. Next, 0.2 g of each test substance was sprayed onto the wound using an Altoshooter (a mechanical needleless drug / vaccine injector manufactured by Kaigen Pharma Co., Ltd.), and the degree of hemostasis at the wound was judged 2 and 5 minutes after spraying according to the "Evaluation Criteria for Hemostasis" shown in Table 2, with A and B being deemed effective. Figure 1 shows a schematic diagram of wounds with Grades A to D according to the "Evaluation Criteria for Hemostasis" in Table 2. When it was difficult to judge, the presence or absence of bleeding was judged after absorbing the blood with gauze. If the degree of hemostasis 2 minutes after application was rated as C or D, no further evaluation was performed. Each test substance was evaluated at multiple wound sites (oozing bleeding), and the rate of results A or B was defined as the effectiveness rate. In addition, blood pressure was measured in the pigs throughout the study, and for each test substance, blood pressure at the time of wound creation was recorded, with blood pressures below 80 mmHg being excluded. In the bleeding sites where hemostasis was not achieved, hemostasis was performed with an electrocautery.

[0052] [Table 1]

[0053] [Table 2]

[0054] <Example 1> A calcium chloride solution prepared by dissolving 920 mg of calcium chloride dihydrate in 500 mL of water was added to 1 L of a 1.5 w / v% aqueous solution of sodium alginate (Kimika Co., Ltd.), and stirred at room temperature for 7 minutes. Then, 3 L of absolute ethanol was added, stirred for 3 minutes, and allowed to stand for 30 minutes. The resulting gel-like crude alginate was filtered under suction using a 2G glass filter. 1.5 L of 70% ethanol was added to the filtered crude alginate, and the mixture was stirred for 3 minutes and then filtered under suction. This desalting operation was repeated once more, and the mixture was air-dried at room temperature overnight, and then dried under reduced pressure at 40°C for 5 hours. The obtained alginate was pulverized, and the particles that passed through a sieve with a mesh size of 250 μm were further sieved through a sieve with a mesh size of 150 μm, and the particles that did not pass through were collected to obtain alginate 1. The obtained alginate 1 was subjected to various physical properties and hemostatic evaluation, and the results are shown in Table 3.

[0055] <Examples 2 to 10> Alginates 2 to 10 were prepared in the same manner as in Example 1, except that sodium alginate (manufactured by Kimika Co., Ltd.) with various molecular weights and M / G ratios was used and the amount of calcium chloride was changed so as to obtain the calcium content shown in Table 3. The obtained alginates 2 to 10 were evaluated for various physical properties and hemostatic properties. The results are shown in Table 3.

[0056] <Comparative Examples 1 to 5> As Comparative Examples 1 to 5, various physical properties and hemostatic evaluations were performed on sodium alginate (Kimika Co., Ltd.), cellulose (Sigma-Aldrich Co., Ltd.), microporous starch (Medicon Co., Ltd., Bird (registered trademark) Arysta (registered trademark) AH), and oxidized regenerated cellulose (Johnson & Johnson Co., Ltd., Surgicel (registered trademark) Powder Absorbable Hemostat). The results are shown in Table 3. Cellulose was evaluated twice in Comparative Examples 2 and 5. As for Comparative Example 4, in the above evaluation method, when the vial was turned upside down, no sample remained at the bottom due to dissolution of the sample, etc., 2 minutes and 5 minutes after the end of the addition of physiological saline, and the swelling height (ht) of the sample became zero, so that it could not be evaluated by this test method.

[0057] <Pathological examination of the bleeding site (wound)> In the hemostasis evaluation of Example 9, alginate 9 was sprayed on the bleeding site, and after confirming that the bleeding had stopped 5 minutes after spraying, the liver including the bleeding site was excised to an appropriate size. The excised liver was fixed in Bouin's solution (Fujifilm Wako Pure Chemical Industries, Ltd.), sliced ​​in the usual manner, stained with hematoxylin and eosin, and observed under a microscope. The micrographs are shown in Figure 2. In FIG. 2, the area enclosed by the dashed line is alginate, which is thought to have come into contact with water in the blood and embolized the bleeding site, thereby exerting a local hemostatic effect.

[0058] [Table 3]

[0059] The results in Table 3 make it clear that the alginate of the present invention has a superior hemostatic effect to sodium alginate and cellulose. [Explanation of symbols]

[0060] 1. Test substances 2 blood 3. Liver

Claims

1. A powdered hemostatic material containing an alginate having a calcium salt of a carboxyl group and another carboxyl (salt) group, the alginate comprises a calcium base-containing structural unit which is a structural unit derived from a calcium salt of mannuronic acid or guluronic acid, and another carboxyl (salt) group-containing structural unit which is a structural unit derived from mannuronic acid or guluronic acid or another salt thereof other than calcium; when the calcium base-containing structural unit in the repeating units (structural units) constituting the alginate is calcium alginate and the other carboxyl (salt) group-containing structural unit is sodium alginate and the alginate is converted into a mixture of sodium alginate and calcium alginate, the mass proportion of calcium alginate (calcium content) is 20 to 90 mass%, The hemostatic material is characterized in that the cation of the other carboxyl (salt) group is at least one selected from the group consisting of sodium ion, potassium ion, ammonium ion and proton.

2. The hemostatic material described in Claim 1, characterized in that the alginate has a mass average molecular weight of 10,000 or more.

3. The alginate salt, a hemostatic material as described in claim 1 or 2, characterized in that it has structural units derived from mannuronate and structural units derived from guluronic acid, and the ratio of structural units derived from mannuronate and structural units derived from guluronic acid (mannuronate / guluronic acid) when all cations in the alginate salt are replaced with protons is 0.6 or more.

4. The alginate has a bulk density of 0.2 g / cm ３ The hemostatic material according to claim 1 or 2, characterized in that:

5. The alginate has a bulk density of 0.2 g / cm ３ The hemostatic material according to claim 3, characterized in that:

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