Patent Application
20230241283
The present disclosure relates to the technical field of hemostatic materials, and more particularly, relates to a starch-based fluffy particle, a preparation method and use thereof.
A hemostatic procedure in surgical trauma and operation is an important factor in clinic, in which a hemostatic material plays an important role. At present, a starch-based material is widely used as the hemostatic material due to a good biological safety, a high water absorption rate, a degradability, and the like. An original particle size of starch particles derived from plants such as corns and potatoes generally ranges from 10 μm to 50 μm, and the particle size of most of the particles is less than 30 μm. The particle size of the starch particles does not change greatly even after chemical modification (etherification, gelatinization, crosslinking or carboxymethylation). When these small-sized starch particles are aggregated, a capillary phenomenon occurs due to a small gap after aggregation of the particles, which leads to easy aggregation during water absorption, thus resulting in difficult subsequent water penetration, so that a whole starch particle aggregate has a slow water absorption speed and a greatly reduced water absorption rate. When used in special occasions, for example, when used as hemostatic powder for spraying hemostasis, the starch particles have a poor hemostatic effect due to slow water absorption speed and low total water absorption rate.
Existing researches show that the particle size of the starch particles and the chemical structure of starch may both affect the water absorption speed and the water absorption rate of the starch aggregate. Generally, carboxymethylated starch or etherified starch with the same particle size has a higher water absorption rate and a faster water absorption speed than original starch. Starch aggregate with different particle sizes or aggregation forms prepared from the starch with the same chemical structure also have difference in water absorption speed and water absorption rate. Arista™ modified starch hemostatic powder produced by Medafor Company of America has a particle diameter less than 50 μm, and although the hemostatic powder has a porous particle surface, the hemostatic powder has a low water absorption speed and a low water absorption rate. In Chinese Patent CN200710141944.0 to Xin Ji, et al., a porous spherical aggregate having a particle size ranged from 10 μm to 1,000 μm, and preferably ranged from 50 μm to 500 μm is prepared by using original particles of modified starch, and it is found that a water absorption speed and a water absorption rate were greatly improved in the case of large particles.
There are many related starch hemostatic particle products, for example, HaemoCer starch particle hemostatic powder (composed of carboxymethylated potato starch) from BIOCER Company of Germany, whose particle size is 10 μm to 50 μm, although a water absorption speed is fast in an initial stage and a water absorption rate is high (20 times), a water retention capacity is insufficient in a later stage, and gel is easy to be thin to flow. Natural polysaccharide microspheres invented by Wenzhou Institute of Biomaterials and Engineering in China are prepared by emulsifying and dispersing, physically crosslinking into spheres, and vacuum drying at 60° C. to obtain microspheres with an adjustable particle size of 20 μm to 50 μm for hemostasis, but the hemostatic effect of the microspheres is still insufficient.
Although existing starch-based hemostatic materials have been improved by various methods, the prepared large-particle modified starch-based hemostatic materials still cannot fully meet actual clinical hemostatic requirements. Therefore, it is urgent to develop a starch-based hemostatic material that has a high hemostatic performance, and can implement hemostasis of traumatic wounds by coating or spraying, or is used for hemostasis of in-vivo micro-leakage under endoscope/minimal invasion.
The present disclosure aims to solve at least one of the technical problems in the prior art above. Therefore, the present disclosure provides a starch-based fluffy particle, a preparation method and use thereof. The starch-based fluffy particles provided are porous and fluffy with a large particle gap, have excellent water absorption speed, water absorption rate and degradation rate, and can achieve the purpose of rapid and efficient hemostasis. In addition, the starch-based fluffy particles are free of dispersing agent, emulsifying agent or cross-linking agent, have the characteristics of safety and reliability, and can meet the hemostatic requirement of in-vivo environment.
A preparation method of a starch-based fluffy particle, comprises the following steps of:
(1) adding water into starch or modified starch for gelatinization to obtain a starch paste;
(2) adding the starch paste into an organic solvent, stirring, standing and centrifuging to collect a precipitate; and
(3) freeze-drying, crushing and sieving the precipitate in sequence to prepare the starch-based fluffy particle.
In the related prior art, the prepared starch paste is usually directly freeze-dried to prepare a hemostatic sponge-like or lumpy aggregate structure, and then crushed to finally prepare hemostatic particles. However, after adding water into starch or modified starch for gelatinization, starch particles swell, molecular chains on particle surfaces stretch after water absorption and contact with each other, and diffuse to entangle partially, and at the moment, the starch particles lean against each other to form a whole adhesive body. The strength of the formed starch paste before freeze-drying is not high, and a flexible lumpy or sponge-like product may be formed during freeze-drying, so starch molecules in the formed hemostatic sponge are entangled with each other and difficult to be dispersed, which is not beneficial for subsequent crushing into uniform small particles. Moreover, the water absorption speed and the water absorption rate of the prepared particles are poor, so that the hemostatic requirement of practical use cannot be met.
In addition, there are some starch hemostatic materials on the market, which are formed into spheres by adding the crosslinking agent and the emulsifying agent into the starch paste. The starch molecules can be linked in a form of chemical bond by introducing the cross-linking agent to form a compact and stable structure, which can reduce the swelling rate and the in-vivo degradation rate. However, since the cross-linking agent is insoluble in water, it is necessary to add the organic solvent as an assistant to dissolve the cross-linking agent to make it work. The organic solvent also plays a role of adjusting the polarity of the reaction solution, which is convenient for the cross-linking agent to fully react with main ingredients of hemostatic powder. The hemostatic particles prepared by this method have the advantages of a long in-vivo retention time, a slow degradation speed and a stable property, and the disadvantages of more compact original starch particles caused by cross-linking, an enhanced hydrophobicity of the starch, and small pores inside and between particles, leading to a greatly reduced water absorption rate and a slow water absorption speed. Meanwhile, the degradation time of the hemostatic particles is prolonged due to cross-linking, which leads to the prepared hemostatic particles not meeting regulations of finishing hemostasis and degradation within 48 hours in a digestive tract or minimally invasive operation, so that the use of the hemostatic particles is limited. Thus, it can be seen that when the cross-linking agent, the emulsifying agent and other ingredients are not used in a starch material, there is no motivation or reason for adding the organic solvent.
However, the present disclosure first discovers and points out that, by using the organic solvent to stir and disperse the starch paste before freeze-drying, the following effects can be achieved: 1. by introducing the organic solvent insoluble with the starch paste, and then stirring, the starch paste may be dispersed into aggregates with a small particle size, which is convenient for dispersion after drying, and uniform particles may be obtained through crushing. 2. The organic solvent has a dehydration effect, which can effectively reduce a water content between the precipitates during freezing to avoid adhesion phenomenon caused by the re-entanglement of the precipitates due to the presence of water during freezing and drying. The precipitates are stable and hard, which is convenient for subsequent crushing and ball milling. 3. Furthermore, the organic solvent may penetrate inside the precipitate to further swell the precipitate, so that pores are also formed inside the dried precipitate to form a porous fluffy structure, thus effectively improving the water absorption speed and the water absorption rate of the starch-based material.
In the preparation method, after finishing the stirring in step (2), by standing for a period of time, water molecules are diffused into the starch particles to swell the starch particles, and molecular chains of the starch on surfaces between non-cross-linked starch particles are mutually diffused, entangled and aggregated in a water swelling state, thus further improving the fluffy degree.
Preferably, in step (1), the modified starch is at least one selected from the group consisting of etherified starch, carboxymethylated starch, esterified starch and crosslinked starch.
Preferably, in step (1), a mass ratio of the starch or the modified starch to the water in the starch paste is 1:(3-40).
Preferably, in step (2), the organic solvent is at least one selected from the group consisting of methanol, ethanol, propanol, butanol, acetone, isopropanol, and dimethyl sulfoxide. More preferably, the organic solvent is isopropanol, methanol, ethanol or a combination of isopropanol and methanol. Experiments show that when the organic solvent is isopropanol, methanol, ethanol or the combination of isopropanol and methanol, the prepared starch-based fluffy particle has a higher fluffy degree and a better water absorption effect.
Preferably, the starch-based fluffy particle further comprises a hydrophilic polymer material. Addition of the hydrophilic polymer material may affect the stability, adhesion and hemostasis properties of the product to a certain extent, and the hydrophilic polymer material includes but is not limited to at least one of sodium carboxymethyl cellulose, hyaluronic acid, polyoxyethylene or collagen.
Preferably, in step (2), the organic solvent further comprises water. Due to an actual preparation requirement or the difficulty in obtaining a pure organic solvent, the volume of the water in the organic solvent may range from 0% to 50%.
Preferably, in step (2), the stirring is performed at a rotating speed of 100 r/min to 3,000 r/min, and lasts for 0.5 hour to 2 hours.
Preferably, in step (2), the centrifuging is performed at a rotating speed of 2,000 r/min to 5,000 r/min. The centrifuging is intended to remove a part of organic solvent and a part of water.
Preferably, in step (3), the freeze-drying comprises the steps of: freezing the precipitate at −30° C. to −10° C. for 3 hours to 24 hours first, and then freeze-drying the precipitate in a freeze dryer at −50° C. to −30° C. for 15 hours to 36 hours. Solid ice (bound water) and residual organic solvent may be directly removed by using the vacuum freeze-drying process, and freezing of the water under the freezing condition may further swell the particles, thus improving the fluffy degree. In addition, the original fluffy state of the particles may be kept by low-temperature vacuum drying, which can better keep the porous structure inside and between the starch particles.
A starch-based fluffy particle prepared by the preparation method above is provided, wherein a particle size of the starch-based fluffy particle is from 20 μm to 500 μm.
Use of the starch-based fluffy particle above as a medical hemostatic material is provided. The starch-based fluffy particle may be coated or sprayed on a traumatic wound as hemostatic powder for hemostasis, and may also be applied to a digestive tract wound and a minimally invasive operation for hemostasis.
Compared with the prior art, the present disclosure has the following beneficial effects:
(1) In the present disclosure, the organic solvent and the water are used to prepare the starch-based fluffy particle, and the organic solvent and the water have a strong volatility, thus being easy to remove during freeze-vacuum drying, and having little residue. In addition, in the present disclosure, the chemical dispersing agent, the emulsifying agent, the cross-linking agent and other ingredients are not added, thus the starch-based fluffy particle is safer and more reliable, and capable of meeting hemostatic requirements of the digestive tract wound and the minimally invasive operation.
(2) By using the organic solvent, the precipitate collected is brittle after freeze-drying, and is easy to be crushed into the starch-based fluffy particles of a required size. Compared with the starch aggregates with the same chemical structure, the finally obtained starch-based fluffy particle is also significantly improved in water absorption speed and water absorption rate.
(3) In the present disclosure, the modified starch may be used as the starch raw material to further improve the water absorption rate, the water absorption speed, the adhesion property, the gel strength and other properties of the starch-based fluffy particles.
In order to make those skilled in the art better understand the technical solutions of the present disclosure, the following examples are now provided for description. It should be pointed out that the following examples do not limit the scope of protection claimed in the present disclosure.
Unless otherwise specified, the raw materials, reagents or devices used in the following examples may all be obtained in conventional commercial ways, or obtained by existing known methods.
The example provided a carboxymethyl corn starch-based fluffy particle, and a preparation method of the carboxymethyl corn starch-based fluffy particle comprised the following steps.
(1) 1 g of carboxymethyl corn starch with a degree of substitution of 0.24 was added into 10 mL of distilled water, and stirred evenly at room temperature to prepare a carboxymethyl corn starch paste.
(2) An aqueous solution containing 95% methanol was prepared, and the carboxymethyl corn starch paste was transferred into 20 mL of methanol solution at a stirring speed of 1,000 r/min and room temperature, continuously stirred for 0.5 hour after finishing transferring, and then stood for 3 hours. The supernatant liquid was dumped, the lower layer containing the solvent and the starch-based precipitate was centrifuged at a rotating speed of 3,000 r/min to remove most of the solvent adsorbed on the starch-based precipitate, and the starch-based precipitate was collected.
(3) The collected starch-based precipitate was frozen in a refrigerator at −20° C. for 15 hours, and then freeze-dried in a freeze dryer at −50° C. for 20 hours to obtain dried carboxymethyl corn starch-based precipitate.
(4) The dried carboxymethyl corn starch-based precipitate was crushed, and then sieved with an 80-mesh sieve to obtain crushed precipitates with a particle size less than 200 μm. Then, the obtained crushed precipitates were sieved with a 300-mesh sieve to remove the crushed precipitates with a particle size less than 50 μm, so as to obtain carboxymethyl corn starch-based fluffy particles with a particle size of 50 μm to 200 μm.
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The example provided a carboxymethyl potato starch-based fluffy particle, and a preparation method of the carboxymethyl potato starch-based fluffy particle comprised the following steps.
(1) 1 g of carboxymethyl potato starch with a degree of substitution of 0.3 was added into 10 mL of distilled water, and stirred evenly at room temperature to prepare a carboxymethyl potato starch paste.
(2) An aqueous solution containing 90% ethanol was prepared, and the carboxymethyl potato starch paste was transferred into 20 mL of ethanol solution at a stirring speed of 600 r/min and room temperature, continuously stirred for 0.5 hour after finishing transferring, and then stood for 3 hours. The supernatant liquid was dumped, the lower layer containing the solvent and the starch-based precipitate was centrifuged at a rotating speed of 2,000 r/min to remove most of the solvent adsorbed on the starch-based precipitate, and the starch-based precipitate was collected.
(3) The collected starch-based precipitate was frozen in a refrigerator at −28° C. for 20 hours, and then freeze-dried in a freeze dryer at −50° C. for 24 hours to obtain dried carboxymethyl potato starch-based precipitate.
(4) The dried carboxymethyl potato starch-based precipitate was crushed, and then sieved with an 80-mesh sieve to obtain crushed precipitates with a particle size less than 200 μm. Then, the obtained crushed precipitates were sieved with a 350-mesh sieve to remove the crushed precipitates with a particle size less than 30 μm, so as to obtain carboxymethyl potato starch-based fluffy particles with a particle size of 30 μm to 200 μm.
When the carboxymethyl potato starch-based fluffy particles prepared in this example were used in a hemostasis experiment of a broken tail of a mouse. The bleeding volume of the mouse during hemostasis was low, and the hemostasis time was short. Complete hemostasis could be realized within 100 seconds on average, and the hemostasis speed was much faster than that of Chinese and foreign hemostatic powder products that have a hemostasis time of more than 210 seconds.
The example provided a polyoxyethylene/carboxymethyl potato starch-based fluffy particle, and a preparation method of the polyoxyethylene/carboxymethyl potato starch-based fluffy particle comprised the following steps.
(1) 0.1 g of polyoxyethylene powder with a molecular weight of 50,000 was dispersed in 20 mL of distilled water, and then 1 g of carboxymethyl potato starch with a degree of substitution of 0.3 was added, and stirred evenly at room temperature to prepare a polyoxyethylene/carboxymethyl potato starch paste.
(2) 50 mL of aqueous solution containing 95% isopropanol was prepared, and the polyoxyethylene/carboxymethyl potato starch paste was transferred into the 50 mL isopropanol solution at a stirring speed of 1,500 r/min and room temperature, continuously stirred for 0.5 hour after finishing transferring, and then stood for 3 hours. The supernatant liquid was dumped, the lower layer containing the solvent and the starch-based precipitate was centrifuged at a rotating speed of 3,000 r/min to remove most of the solvent adsorbed on the starch-based precipitate, and the starch-based precipitate was collected.
(3) The collected starch-based precipitate was frozen in a refrigerator at −30° C. for 10 hours, and then freeze-dried in a freeze dryer at −50° C. for 24 hours to obtain dried polyoxyethylene/carboxymethyl potato starch-based precipitate.
(4) The dried polyoxyethylene/carboxymethyl potato starch-based precipitate was crushed, and then sieved with an 80-mesh sieve to obtain crushed precipitates with a particle size less than 200 μm. Then, the obtained crushed precipitates were sieved with a 300-mesh sieve to remove the crushed precipitates with a particle size less than 50 μm, so as to obtain polyoxyethylene/carboxymethyl potato starch-based fluffy particles with a particle size of 50 μm to 200 μm.
In this example, the flexibility of carboxymethyl potato starch gel was further improved by adding polyoxyethylene into the carboxymethyl potato starch.
The example provided a carboxymethyl potato starch-based fluffy particle, and a preparation method of the carboxymethyl potato starch-based fluffy particle comprised the following steps.
(1) 1 g of carboxymethyl potato starch with a degree of substitution of 0.3 was added into 10 mL of distilled water, and stirred evenly at room temperature to prepare a carboxymethyl potato starch paste.
(2) An aqueous solution containing 50% isopropanol and 45% methanol (i.e., an isopropanol-methanol aqueous solution) was prepared, and the carboxymethyl potato starch paste was transferred into 20 mL of isopropanol-methanol solution at a stirring speed of 600 r/min and room temperature, continuously stirred for 0.5 hour after finishing transferring, and then stood for 3 hours. The supernatant liquid was dumped, the lower layer containing the solvent and the starch-based precipitate was centrifuged at a rotating speed of 2,000 r/min to remove most of the solvent adsorbed on the starch-based precipitate, and the starch-based precipitate was collected.
(3) The collected starch-based precipitate was frozen in a refrigerator at −28° C. for 20 hours, and then freeze-dried in a freeze dryer at −50° C. for 24 hours to obtain dried carboxymethyl potato starch-based precipitate.
(4) The dried carboxymethyl potato starch-based precipitate was crushed, and then sieved with an 80-mesh sieve to obtain crushed precipitates with a particle size less than 200 μm. Then, the obtained crushed precipitates were sieved with a 350-mesh sieve to remove the crushed precipitates with a particle size less than 30 μm, so as to obtain carboxymethyl potato starch-based fluffy particles with a particle size of 30 μm to 200 μm.
Product Effect Test
Tests, including water absorption, gel strength and adhesion work were performed on the starch-based fluffy particles prepared in Examples 1 to 4, the carboxymethyl corn starch, the carboxymethyl potato starch and three comparative products (which were namely comparative products 1 to 3). Test results are shown in Table 1. The comparative product 1 is hemostatic powder prepared from potato starch by a cross-linking technology; the comparative product 2 is a product prepared according to the Chinese patent CN200610045441.9; and the comparative product 3 is a product prepared according to the Chinese patent CN200610053680.9.
Water absorption rate=water absorption capacity (g or mL)/powder weight (g);
water absorption speed: time required for adsorbing 10 g of water with 0.5 g of powder (second);
gel strength: gel strength measured after the product is saturated with water and sealed standing for 48 hours; and
adhesion work (g·mm): adhesion work of gel after saturated with water.
It can be seen from Table 1 that, compared with the carboxymethyl corn starch without any treatment and the carboxymethyl potato starch without any treatment, the starch-based fluffy particles prepared in Examples 1 to 4 of the present disclosure all have significantly better effects in water absorption, gel strength and adhesion work. Although the property of the German product is superior to those of the Chinese products 1 and 2, the property of the German product is inferior to those of the starch-based fluffy particles prepared in Examples 1 to 4, which indicates that the product prepared by the present disclosure has a better hemostatic property than conventional Chinese and foreign market products, and can be widely used in vivo and in vitro as a medical hemostatic material to achieve the purpose of fast and efficient hemostasis.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202110008377.1 | Jan 2021 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2021/075416 | 2/5/2021 | WO |
