CN108434513B

CN108434513B - Wound surface dressing

Info

Publication number: CN108434513B
Application number: CN201810336247.9A
Authority: CN
Inventors: 杜武华; 林栋青; 林艳华; 李焱; 尹翠竹; 高领; 邱新林; 刁盈盈
Original assignee: Shandong Weigao Pharmaceutical Co Ltd
Current assignee: Shandong Weigao Hongrui Medical Technology Co Ltd
Priority date: 2018-04-16
Filing date: 2018-04-16
Publication date: 2020-08-07
Anticipated expiration: 2038-04-16
Also published as: CN108434513A

Abstract

The invention discloses a wound dressing, which comprises hydroxyethyl starch, wherein the molecular weight of the hydroxyethyl starch is 10-70 ten thousand Da. The wound dressing comprises the following components in parts by weight: 20-80 parts of sodium alginate, 20-80 parts of hydroxyethyl starch and 0-5 parts of calcium chloride. The wound dressing can quickly absorb moisture, blood, exudate and other liquids on the surface of a wound to form a gel protective layer, and the gel protective layer stays on the wound for more than 7 days; the influence of wound bleeding on the operation can be reduced, the cleanness of the operation visual field can be kept, and the smooth operation of the operation can be ensured; the wound dressing can be used for filling tissues, preventing pathogenic microorganisms such as helicobacter pylori from contacting the wound surface, effectively preventing infection and reducing the application of antibiotics; can be applied to the wound surface of the mucous membrane of the digestive tract, and effectively resists the attack and erosion of gastric acid, pepsin and other attacking factors to the wound surface; can effectively stimulate the gastrointestinal tract, promote the gastrointestinal tract activity to increase and recover the gastrointestinal tract motor function.

Description

Wound surface dressing

Technical Field

The invention relates to the technical field of sanitary materials, in particular to a wound dressing.

Background

After the operation of the digestive tract, wounds and wound surfaces are usually directly exposed on the surface of the digestive tract and stimulated by harmful substances such as bacteria, gastric acid, digestive enzymes and the like, so that the healing difficulty is increased. In addition, to prevent infection, large amounts of antibiotics are usually injected or taken after surgery, which easily results in the abuse of antibiotics and the generation of drug-resistant strains, thereby forming a vicious circle of antibiotic abuse and increasing the medical burden.

In recent years, in order to promote the rapid healing of wound surfaces, various wound dressings come into operation, and can be divided into traditional dressings, biological dressings, artificially synthesized dressings, growth factor dressings and the like according to different materials. The wound dressings create a wound hypoxia environment by utilizing the characteristics of different materials, promote the generation of capillary vessels and the removal of necrotic tissues and toxins, strengthen the interaction between growth factors and target cells, avoid the adhesion of new epithelial tissues and dressings, and further relieve the pain of patients. Therefore, the wound dressing can shorten the wound healing time, reduce the waste of resources, greatly reduce the medical workload and meet the requirements of patients.

However, the existing wound dressing or the existing wound dressing has poor capability of absorbing seepage, and is easy to cause cross infection; or the wound surface is easy to adhere to, and the mechanical injury of the wound surface is easy to cause during replacement; or the strength is poor, and the wound easily falls off from the wound surface; or is susceptible to gastric fluid erosion; or low transparency, not suitable for observing the wound surface; therefore, the production of wound dressings capable of rapidly absorbing moisture, blood, exudate and other liquids on the surface of a wound to form a gel protective layer, and having strong elasticity, good viscosity and gastric acid erosion resistance is a problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the invention provides a wound dressing, which can be applied to endoscopic surgery, surgical operation and postoperative interstitial tissue adhesion prevention and can promote wound healing.

In order to achieve the purpose, the invention adopts the following technical scheme:

a wound dressing comprises hydroxyethyl starch, wherein the molecular weight of the hydroxyethyl starch is 10-70 ten thousand Da.

The wound dressing comprises the following components in parts by weight: 20-80 parts of sodium alginate, 20-80 parts of hydroxyethyl starch and 0-5 parts of calcium chloride.

The hydroxyethyl starch has good blood volume expanding effect, and can be used for treating traumatic, hemorrhagic, toxic and septic shock, and thromboangiitis obliterans. The invention adopts hydroxyethyl starch with the molecular weight of 10-70 ten thousand Da as the wound dressing, and can quickly absorb moisture, blood, exudate and other liquids on the surface of the wound after contacting with the wound of the digestive tract.

The sodium alginate is contacted with the wound surface, absorbs water and swells to form gel, and the formed gel can block further diffusion of water molecules, so that the sodium alginate on the outer layer of the wound dressing cannot absorb water to form a gel layer. The hydroxyethyl starch used in the invention contains a large amount of hydroxyl, has strong affinity with water molecules, can be rapidly combined with water to form a netted water molecule channel, and the water molecules can rapidly reach the surface of sodium alginate along the channel, so that the sodium alginate on the outer layer of the wound dressing can absorb water to form a gel layer.

Calcium ions in the wound dressing are crosslinked with a large number of carboxyl groups on sodium alginate molecular chains to form gel with a compact network structure, so that a plurality of sodium alginate molecular chains are connected, and the strength of the gel layer is improved.

Furthermore, gel molecular chains formed by calcium ions and sodium alginate form a polymer network structure due to the interaction of entanglement and hydrogen bonds, and the existence of chain links and free chain ends in the polymer network structure can cause the non-uniform gel structure, so that cavities exist in the structure, and the gel protective layer is very easy to disintegrate under the action of digestive enzymes in the digestive tract, and cannot play a continuous protection role. Hydroxyethyl starch in the wound dressing can be combined with holes in gel formed by sodium alginate and calcium ions through coordination bonds, so that a network staggered structure with extremely high crosslinking degree is presented, the mechanical property and the biological property of the gel are improved, and the degradation of gastric acid and digestive enzyme to a gel protective layer is effectively resisted.

Further preferably, a wound dressing as described above, comprises, in parts by weight: 40-80 parts of sodium alginate, 20-60 parts of hydroxyethyl starch and 0-4 parts of calcium chloride.

Further preferably, a wound dressing as described above, comprises, in parts by weight: 60-80 parts of sodium alginate, 20-40 parts of hydroxyethyl starch and 1-3 parts of calcium chloride.

In addition, the molecular weight of hydroxyethyl starch in the wound dressing can influence the formation process of gel, when the molecular weight of hydroxyethyl starch is too large or too small, water molecules cannot be rapidly diffused to the surface of sodium alginate molecules, and a gel protective layer cannot be normally generated.

Preferably, the hydroxyethyl starch has a molecular weight of 10-65 ten thousand Da.

Further preferably, the hydroxyethyl starch has a molecular weight of 12-38 ten thousand Da or 50-65 ten thousand Da.

Further preferably, the hydroxyethyl starch has a molecular weight of 13.5-22 ten thousand Da or 50-58 ten thousand Da.

In addition, the molecular weight of sodium alginate in the wound dressing can influence the flexibility of the gel.

Preferably, the sodium alginate has a molecular weight of 5000-. Further preferably, the molecular weight of the sodium alginate is 5000-.

Further preferably, the molecular weight of the sodium alginate is 5000-.

Preferably, the ratio G/M of β -D-guluronic acid to α -L-mannuronic acid in the sodium alginate is more than or equal to 1.5.

The ratio of β -D-guluronic acid (G unit) to α -L-mannuronic acid (M unit) in sodium alginate has a very important influence on the strength of the formed gel, and the binding capacity of β -D-guluronic acid (G unit) and α -L-mannuronic acid (M unit) to calcium ions are different, so that if the content of β -D-guluronic acid (G unit) is too low, the formed gel is too weak to be effectively adhered to the surface of a wound surface.

If the content of β -D-guluronic acid (G units) is too high, the hardness of the formed gel is too high, resulting in insufficient flexibility of the gel and the formed gel easily falling off from the surface of the digestive tract.

Further preferably, the ratio of β -D-guluronic acid to α -L-mannuronic acid in the sodium alginate is 1.50-2.0.

Preferably, the particle size of the sodium alginate is 40-120 meshes.

When the particle size of the sodium alginate is larger than 40 meshes, a water molecule channel formed by the hydroxyethyl starch is easily blocked by the gelatinized sodium alginate, so that water molecules cannot be further diffused; when the particle size is less than 120 meshes, the specific surface area of the wound dressing is too small to be effectively combined with the wound surface of the digestive tract, and an effective gel protective layer cannot be formed; when the particle size is between 40 and 120 meshes, the formed gel has the strongest viscosity, can be firmly adhered to the surface layer of the wound surface and avoids falling off.

Further preferably, the particle size of the sodium alginate is 40-80 meshes.

Further preferably, the particle size of the sodium alginate is 40-60 meshes.

Preferably, the absorptivity of the wound dressing is more than 10 times of the self weight, and the tensile strength of the formed gel protection layer is more than or equal to 2.0 MPa.

The wound dressing further comprises 2-10 parts of adhesive by weight.

Preferably, the binder is deionized water.

Preferably, the wound dressing is granular, and the particle size is 0.1-1.0 mm; the specific surface area is 30-300m²/g。

Preferably, the preparation process of the wound dressing comprises the following steps:

(1) weighing the ingredients in proportion;

(2) adding hydroxyethyl starch, sodium alginate and calcium chloride into a preheated boiling granulator, and starting a fan of the boiling granulator to boil the hydroxyethyl starch, the sodium alginate and the calcium chloride into a fluidized state; the preheating temperature is 70-90 ℃, and the frequency of the fan is adjusted to be 25-75 HZ.

(3) Adding a binder into a boiling granulator through a spray gun for granulation, and controlling the air speed of the boiling granulator to mix hydroxyethyl starch, sodium alginate, calcium chloride and the binder for granulation; the motor speed is 100-500rpm and the pressure is 0.05-0.4MPa when the spray gun sprays; adjusting the frequency of a fan of the boiling granulator to 25-75 HZ; the inlet temperature of the boiling granulator is 70-90 ℃, and the outlet temperature is 40-50 ℃; the time for boiling granulation is 2-10 min.

(4) Packaging and sealing the granulated wound dressing;

(5) the wound dressing is placed in a sealed sterilization cabinet, ethylene oxide gas is injected into the sterilization cabinet, so that the concentration of ethylene oxide in the sterilization cabinet reaches 600-1000 mg/L, the sterilization is kept for more than 6 hours, and after the sterilization is finished, the ethylene oxide is extracted for sterilizing agent analysis.

Has the advantages that:

(1) although pathogenic microorganisms such as helicobacter pylori and the like cannot be directly killed by the wound dressing provided by the invention, the gel protective layer formed by the wound dressing can effectively prevent the helicobacter pylori from being combined with epithelial cells and glycoprotein and sugar ester target positions of mucus; because the gel layer has stronger physical strength and higher viscosity, pathogenic microorganisms can not directly penetrate through the gel barrier, thereby providing a good protection place for the wound surface of the digestive tract.

(2) The wound dressing provided by the invention can effectively resist the attack and erosion of gastric acid, pepsin and other attacking factors to the wound. After the operation of the digestive tract is finished, the wound surface can be directly exposed to the action of gastric acid, pepsin and other attacking factors, the wound surface dressing provided by the invention forms a barrier on the wound surface after forming gel, and the self digestion of gastric acid and pepsin mucosa can be prevented due to the lubricating and mechanical protection effects of the wound surface dressing.

(3) The wound dressing provided by the invention can effectively absorb harmful substances such as histamine and the like generated in the recovery process of the wound and accelerate the healing of the wound. In addition, sodium alginate can stimulate the mucosa to HCO^3-And mucus secretion, promotes the regeneration mucous membrane cells to secrete neutral mucus, promotes tissue repair and regeneration, and is favorable for wound healing.

(4) The wound dressing provided by the invention can promote gastrointestinal function recovery, effectively relieve symptoms such as nausea, vomiting, abdominal distension, abdominal pain, abnormal air and excrement discharging, fatigue and the like after operation, and shorten the time of first anus air discharging and excrement discharging of a patient. The first anal exsufflation of a patient with digestive tract operation is one of important marks for postoperative gastrointestinal function recovery; the postoperative enteroparalysis and gastrointestinal dysfunction are caused by the reduction and lack of coordination of gastrointestinal peristalsis due to trauma, anesthesia or operation caused by operation, the original anatomical structure of the gastrointestinal tract is changed, the general condition and other factors, and the postoperative enteroparalysis and gastrointestinal dysfunction are mainly clinically manifested as the weakening or disappearance of bowel sound, abdominal distension, abdominal pain, anus exhaust and defecation abnormality and the like. The hydroxyethyl starch and the sodium alginate are high molecular compounds, and can interact with a stimulation target on the surface of a mucous membrane after being adhered to the surface of the gastrointestinal tract, so that the gastrointestinal tract is effectively stimulated, the gastrointestinal tract activity is promoted to be increased, the movement function of the gastrointestinal tract is recovered, and further, the occurrence of irreversible serious complications such as adhesive intestinal obstruction, poor wound healing, malnutrition, dysbacteriosis, multiple uterine function failure and the like caused by the fact that the gastrointestinal tract function cannot be recovered for a long time is effectively avoided.

In conclusion, the wound dressing can rapidly absorb moisture, blood, exudates and other liquids on the surface of the wound to form a gel protective layer, and the gel protective layer stays on the wound for more than 7 days; the influence of wound bleeding on the operation can be reduced, the cleanness of the operation visual field can be kept, and the smooth operation of the operation can be ensured; the wound dressing can be used for filling tissues, preventing pathogenic microorganisms such as helicobacter pylori from contacting the wound surface, effectively preventing infection and reducing the application of antibiotics; can be applied to the wound surface of the mucous membrane of the digestive tract, and effectively resists the attack and erosion of gastric acid, pepsin and other attacking factors to the wound surface; can effectively stimulate the gastrointestinal tract, promote the gastrointestinal tract activity to increase and recover the gastrointestinal tract motor function.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a sample A1 gel according to example 1 of the present invention.

FIG. 2 is a sample A2 gel according to example 1 of the present invention.

FIG. 3 is a sample A3 gel according to example 1 of the present invention.

FIG. 4 is a sample A4 gel according to example 1 of the present invention.

FIG. 5 is a sample A5 gel according to example 1 of the present invention.

FIG. 6 is a sample A6 gel according to example 1 of the present invention.

FIG. 7 is a sample A7 gel according to example 1 of the present invention.

FIG. 8 is a sample A8 gel according to example 1 of the present invention.

FIG. 9 is a graph showing a gel of a test group of example 5 of the present invention.

FIG. 10 is a graph showing the gel form of the test group of example 5 after addition of simulated gastric fluid.

FIG. 11 is a drawing showing a control gel of example 5 of the present invention.

FIG. 12 is a graph showing the appearance of control gels in accordance with example 5 after addition of simulated gastric fluid.

FIG. 13 is a graph showing bleeding points in a rabbit model hemostasis test (minor bleeding) in accordance with example 6 of the present invention.

Fig. 14 is a drawing showing wound dressings covering bleeding sites in a rabbit model hemostasis test (minor bleeding) in accordance with example 6 of the present invention.

FIG. 15 is a graph showing bleeding points in a rabbit model hemostasis test (massive hemorrhage) in accordance with example 6 of the present invention.

Figure 16 is a drawing showing wound dressings covering bleeding sites in a rabbit model hemostasis test (massive hemorrhage) in accordance with example 6 of the present invention.

FIG. 17 is a drawing showing bleeding points in a pig model hemostasis test in accordance with example 6 of the present invention.

Fig. 18 is a drawing showing a wound dressing covering a bleeding point in a pig model hemostasis test in accordance with example 6 of the present invention.

FIG. 19 is a photograph showing the form of the gastric mucosa of the control group in accordance with example 8 of the present invention.

FIG. 20 is a graph showing the degree of wound healing in the control group in example 8 of the present invention.

FIG. 21 is a graph showing the morphology of the gastric mucosa in the test group of example 8 of the present invention.

Fig. 22 is a schematic view of a wound dressing covering a wound in the test group of example 8 of the present invention.

FIG. 23 is a graph showing the degree of wound healing in the test group of example 8 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1: evaluation of gel tensile Strength in different formulations

The preparation method comprises the steps of respectively adding the raw materials shown in the table 1 into a boiling granulator preheated at 70 ℃, enabling the molecular weight of hydroxyethyl starch to be 13.5 ten thousand Da, enabling the molecular weight of sodium alginate to be 6000Da, enabling the G/M ratio to be 1.50, enabling the particle sizes of the sodium alginate and the hydroxyethyl starch to be 40 meshes, starting a fan of the boiling granulator, enabling the hydroxyethyl starch, the sodium alginate and calcium chloride to be in a fluidized state, adding 50G of deionized water into the boiling granulator through a spray gun for granulation, controlling the motor speed when the spray gun sprays to be 200rpm, the pressure to be 0.2MPa, the wind speed to be 75HZ, the inlet temperature to be 70 ℃, the outlet temperature to be 40 ℃, and enabling the boiling granulation time to be 10min, packaging and sealing wound dressing after granulation, placing the wound dressing into a sterilization cabinet, injecting ethylene oxide gas to enable the concentration of the ethylene oxide to reach 600 mg/L, keeping for 7 hours, extracting the ethylene oxide after sterilization, and carrying out sterilization agent analysis to obtain.

TABLE 1

1.0g of each formulation sample was swollen in 10.0g of water to form a gel, and the gel strength was measured by an extensional rheometer, and the test results are shown in Table 2.

The tensile strength calculation formula is that sigma t is p/(b × d), wherein:

σ t is tensile strength (MPa); p is the maximum load (N); b is the specimen width (mm); d is the specimen thickness (mm).

TABLE 2

Sample numbering	Maximum pulling force (N)	Tensile Strength (MPa)	Picture frame
				A1	2.35	0.28	FIG. 1 shows a schematic view of a
A2	0	0	FIG. 2
				A3	5.47	0.66	FIG. 3
A4	18.44	2.21	FIG. 4
				A5	20.15	2.36	FIG. 5
A6	16.48	1.92	FIG. 6
				A7	22.36	2.74	FIG. 7
A8	13.69	1.74	FIG. 8

The test result shows that:

the gel layer obtained with the formulation sample containing only sodium alginate had a certain hardness but no elasticity (figure 1);

when the hydroxyethyl starch is added into water, the hydroxyethyl starch is completely dissolved by water, and the solution has no viscosity and can not form gel (figure 2);

when calcium chloride is added into sodium alginate, gel with certain hardness can be obtained, but the obtained gel has weak elasticity and cannot resist large stretching force (figure 3);

when hydroxyethyl starch is added into the formula of sodium alginate and calcium chloride, the formed gel has high elasticity and good hardness and can resist strong external tension, the hydroxyethyl starch has very important influence on the strength and elasticity of the gel, and the physical properties of the gel can be obviously improved (figures 4-8).

Example 2: effect of G/M ratio in sodium alginate on gel tensile Strength

800G of sodium alginate, 400G of hydroxyethyl starch and 10G of calcium chloride, wherein the molecular weight of the hydroxyethyl starch is 22 ten thousand Da, the molecular weight of the sodium alginate is 6000Da, and the particle sizes of the sodium alginate and the hydroxyethyl starch are 40 meshes, and the ratio of β -D-guluronic acid (G) to α -L-mannuronic acid (M) in the sodium alginate is adjusted, and the preparation method is as shown in example 1.

Each formulation sample, 1.0g, was swollen in 10.0g of water to form a gel, and the gel strength was measured by an extensional rheometer, with the results shown in Table 3.

TABLE 3

Sample numbering	G/M value	Maximum pulling force (N)	Tensile Strength (MPa)
				B1	0.5	3.36	0.40
B2	1.0	5.27	0.63
				B3	1.5	17.85	2.14
B4	2.0	19.36	2.32
				B5	2.2	14.38	1.70
B6	2.5	6.12	0.75

Test results show that the ratio of β -D-guluronic acid (G) to α -L-mannuronic acid (M) in sodium alginate has a large influence on the strength of gel, the strength of gel formed by too low a G/M ratio is weak and cannot resist the stretching action of external force, when the ratio of G/M is 1.5 or more, the formed gel has good stretching strength, and when the ratio of G/M is more than 2.0, the hardness of formed gel is too high, which results in insufficient flexibility of gel and failure of resisting the stretching action of external force.

Example 3: influence of particle size on Water absorption time and Water absorption

800G of sodium alginate, 400G of hydroxyethyl starch and 10G of calcium chloride, wherein the molecular weight of the hydroxyethyl starch is 13.5 ten thousand Da, the molecular weight of the sodium alginate is 6000Da, the ratio of β -D-guluronic acid (G) to α -L-mannuronic acid (M) in the sodium alginate is 2.0, the granularity of the sodium alginate is adjusted, and the preparation method is as shown in example 1.

1g of the sample was uniformly sprinkled into a petri dish containing 40g of water, the diameter of the petri dish was 9cm, the gel was taken out after 30 seconds, weighed, and the weight of the sample absorbing water was calculated, and the results are shown in Table 4.

TABLE 4

Sample numbering	Particle size (mesh)	Time of Water uptake(s)	Absorbent weight (g)	Specific surface area (m)²/g)
					C1	20	30	9.5	60
C2	40	30	14.4	160
					C3	60	30	16.5	200
C4	80	30	15.8	120
					C5	100	30	13.6	100
C6	120	30	12.8	80
					C7	200	30	6.7	40

The test result shows that: when the particle size of the sodium alginate is within 40-120 meshes, the sodium alginate can quickly absorb water to form gel, and the water absorption capacity of each gram of sample is more than 12.0 g; when the particle size of the sodium alginate is smaller than 120 meshes, the water absorption capacity of the sample in 30s is rapidly reduced, so that the exudate and blood cannot be absorbed in time; when the particle size is larger than 40 mesh, the particles are too large, which results in inconvenience in use.

Example 4: effect of hydroxyethyl starch molecular weight on gel tensile Strength

800G of sodium alginate, 400G of hydroxyethyl starch and 10G of calcium chloride, wherein the molecular weight of the sodium alginate is 5000Da, the particle sizes of the sodium alginate and the hydroxyethyl starch are 40 meshes, the ratio of β -D-guluronic acid (G) to α -L-mannuronic acid (M) in the sodium alginate is 2.0, and the molecular weight of the hydroxyethyl starch is adjusted, and the preparation method is as shown in example 1.

Each formulation sample, 1.0g, was swollen in 10.0g of water to form a gel, and the gel strength was measured by an extensional rheometer, with the results shown in Table 5.

TABLE 5

Sample numbering	Molecular weight (Wanda)	Maximum pulling force (N)	Tensile Strength (MPa)
				D1	10	17.47	2.09
D2	15	19.62	2.23
				D3	20	21.33	2.36
D4	30	17.66	2.12
				D5	40	17.29	2.06
D6	50	18.01	2.17
				D7	60	19.40	2.26
D8	70	16.75	2.04
				D9	80	12.01	1.68
D10	90	7.33	0.84

The test result shows that: when the molecular weight of the hydroxyethyl starch is 10-70Da, the formed gel protective layer has better tensile strength.

Example 5: simulating the influence of gastric juice on the formation of gel in wound dressing

The test group comprises 800G of sodium alginate, 400G of hydroxyethyl starch and 10G of calcium chloride, the molecular weight of the hydroxyethyl starch is 15 ten thousand Da, the molecular weight of the sodium alginate is 6000Da, the particle sizes of the sodium alginate and the hydroxyethyl starch are 40 meshes, the ratio of β -D-guluronic acid (G) to α -L-mannuronic acid (M) in the sodium alginate is 2.0, the preparation method is shown in example 1, the average particle size of the prepared wound dressing is 0.45mm, the average specific surface area is 120M²/g。

Control group: the wound dressing is a commercially available product which takes chitosan as a main component.

The corrosiveness of the simulated gastric juice to the gel was observed by comparing the test group with the control group.

The preparation method of the simulated gastric fluid comprises the following steps:

taking 16.4ml of dilute hydrochloric acid (equivalent to 3.84ml of hydrochloric acid), adding about 800ml of water and 10g of pepsin, shaking uniformly, and adding water to dilute into 1000ml to obtain simulated gastric fluid.

Test groups: the sample 1.0g was swollen in 10.0g water to form a gel (FIG. 9), then 10.0g of simulated gastric fluid was added and left to stand for 24h to observe the change in gel morphology (FIG. 10).

Control group: a commercially available sample, 1.0g, was swollen in 10.0g of water to form a gel (FIG. 11), and then 10.0g of simulated gastric fluid was added and left to stand for 24 hours to observe the change in gel morphology (FIG. 12).

And (3) test results: after the gel prepared by the wound dressing provided by the invention is added into simulated gastric juice, the simulated gastric juice can be completely absorbed, the shape of the gel is not obviously changed, the gel still keeps integrity, and the gel has good elasticity and viscosity. After simulated gastric fluid is added into gel prepared by a commercially available sample, the shape of the gel is obviously changed, the gel is completely disintegrated, separated out and broken, and the gel loses viscosity and elasticity and cannot be attached to the surface of a culture dish. Therefore, the wound dressing has good gastric acid lysis resistance and can prevent gastric acid from corroding.

Example 6: blood absorption function of wound dressing

800G of sodium alginate, 400G of hydroxyethyl starch and 10G of calcium chloride, wherein the molecular weight of the hydroxyethyl starch is 15 ten thousand Da, the molecular weight of the sodium alginate is 6000Da, the particle sizes of the sodium alginate and the hydroxyethyl starch are 40 meshes, the ratio of β -D-guluronic acid (G) to α -L-mannuronic acid (M) in the sodium alginate is 2.0, the preparation method is shown in example 1, the average particle size of the prepared wound dressing is 0.45mm, and the average specific surface area is 120M²/g。

The hemostatic effect of the wound dressing on a rabbit model and the hemostatic effect of a pig model are studied.

Rabbit model hemostasis test (minor bleeding): after the rabbit ears are disinfected by using a disinfectant, a needle head of a sterile syringe is used for puncturing veins of the rabbit ears, then the syringe needle head is pulled out, blood seeps out of the veins (figure 13), then the wound dressing provided by the invention is used for covering bleeding points (figure 14), and the hemostasis time is observed and recorded.

Rabbit model hemostasis test (massive bleeding): after the rabbit ears are disinfected by using a disinfectant, a needle head of a sterile syringe is used for puncturing veins of the rabbit ears, then the syringe needle head is stirred in the veins, the needle head is pulled out after massive bleeding occurs, blood is gushed out from the veins in a large amount (figure 15), then the wound dressing provided by the invention is used for covering bleeding points (figure 16), and the bleeding stopping time is observed and recorded.

The pig model hemostasis test: the stomach is sprayed and cleaned with the digestive tract mucus cleaning agent before operation, mucus and foam are removed, endoscope observation is facilitated, the part to be cut is marked by using an electric knife after the stomach is cleaned, and then mucosa filling agent under the endoscope is injected to the submucosa of the part to be cut, so that the mucosa layer is separated from the mucosa muscle layer. The site was marked using an electrotome loop to effect bleeding at the wound site (fig. 17), and the bleeding site was then covered with a wound dressing provided by the invention (fig. 18) and observed to record the time to hemostasis.

And (3) test results: in a rabbit model hemostasis test (a small amount of bleeding), the wound dressing provided by the invention can stop bleeding within 15s, and in a rabbit model hemostasis test (a large amount of bleeding), the wound dressing provided by the invention can stop bleeding within 30 s; therefore, the wound dressing provided by the invention can rapidly absorb blood and form gel to block bleeding points. In a pig model hemostasis test, the wound dressing provided by the invention can stop completely absorbing the blood seepage of an mucosa layer within 30s, keeps the wound surface dry and clean, and facilitates smooth operation.

Example 7: research of wound dressing on recovery of gastrointestinal tract movement function

Test animals: 4-head pig for test

Weight: 32-36 kg

The test method comprises the following steps:

before operation, the stomach is sprayed and cleaned with a digestive tract mucus cleaning agent to remove mucus and foam, so that endoscope observation is facilitated; after cleaning, the electric knife is used for marking the part to be cut off, then the disposable endoscopic mucosa filler is injected to the submucosa of the part to be cut off, the mucosa layer is separated from the mucosa muscle layer, the electric knife is used for cutting off the marked position in a ring shape,

control group: the control group was not treated after removal of gastric mucosa and the time to first defecation was recorded after postoperative observation.

Test groups: the test group sprayed the wound dressing shown in example 6 on the position of the removed gastric mucosa, completely covered the wound, and observed and recorded the first defecation time of the pigs after the operation, and the results are shown in table 6.

TABLE 6

Animal numbering	Time (h) for first defecation of pig
		Control group No. 1	45
Control group No. 2	52
		Test group No. 1	19
Test group No. 2	16

The test result shows that: the control group did not perform any treatment after cutting off the gastric mucosa, and the first defecation time of 2 pigs after operation was 45h and 52h respectively; the test group sprays wound dressing at the position of cutting the gastric mucosa to completely cover the wound, and the first defecation time of 2 pigs after operation is 19h and 16h respectively. Therefore, the wound dressing provided by the invention can restore the gastrointestinal tract movement function and promote gastrointestinal metabolism.

Example 8: research on wound healing function of wound dressing after endoscopic wound excision

Test animals: pig 1 head for test

Weight: 35 kg of

The test method comprises the following steps:

the stomach is sprayed and cleaned with the digestive tract mucus cleaning agent before operation, mucus and foam are removed, endoscope observation is facilitated, the part to be cut is marked by using an electric knife after the stomach is cleaned, and then mucosa filling agent under the endoscope is injected to the submucosa of the part to be cut, so that the mucosa layer is separated from the mucosa muscle layer. The positions of the circular excision markers of the electric knife are used for excision of gastric mucosa of the control group and the test group at the similar positions of the stomach of the same pig.

Control group: the control group was left without any treatment after removal of the gastric mucosa (fig. 19), and pigs were sacrificed 14 days later to observe the degree of wound healing (fig. 20).

Test groups: the test group was sprayed with the wound dressing shown in example 6 (fig. 22) at the site of removal of the gastric mucosa (fig. 21), the wound was completely covered, and the pigs were sacrificed 14 days later to observe the degree of wound healing (fig. 23).

And (3) test results: the control group did not perform any treatment after the gastric mucosa was removed, and after 14 days, the wound surface appeared red and swollen, the wound healing degree was poor, and the wound surface was infected obviously. The test group sprays wound dressing at the position of cutting the gastric mucosa, the wound healing condition is good after 14 days, and no obvious red and swollen phenomenon and no obvious infection appear at the wound. Therefore, the wound dressing provided by the invention can effectively promote the healing of the wound, reduce the using amount of antibiotics, avoid the abuse of the antibiotics and the generation of drug-resistant strains, and reduce the medical expense.

The wound dressing provided by the invention is convenient to use, does not need repeated administration after being used for one time, simplifies the treatment procedure and reduces the pain of patients in the treatment process.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wound dressing is characterized by comprising 20-80 parts of sodium alginate, 20-80 parts of hydroxyethyl starch and 0-5 parts of calcium chloride, wherein the molecular weight of the hydroxyethyl starch is 10-70 ten thousand Da, the molecular weight of the sodium alginate is 5000-10000Da, the ratio of β -D-guluronic acid to α -L-mannuronic acid in the sodium alginate is more than or equal to 1.50 and less than or equal to G/M and less than or equal to 2.0, the particle size of the sodium alginate is 40-120 meshes, the wound dressing is granular, the particle size is 0.1-1.0mm, and the specific surface area is 30-300M²/g。

2. A wound dressing according to claim 1, comprising, in parts by weight: 40-80 parts of sodium alginate, 20-60 parts of hydroxyethyl starch and 0-4 parts of calcium chloride.

3. A wound dressing according to claim 2, characterised in that the rate of absorption of the wound dressing is not less than 10 times its weight.

4. A wound dressing according to claim 1 or 2, further comprising 2 to 10 parts by weight of a binder.

5. A wound dressing according to claim 4, wherein the adhesive is deionised water.