A healing powder composition and its preparation method

Abstract

This invention relates to a healing powder prepared using starch as the main matrix and oxidized starch and diamino polyethylene glycol as modifiers.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical technology and biomedicine, specifically relating to a composition and its preparation method. This composition has the effect of accelerating hemostasis and promoting wound healing during trauma and surgery. Background Technology

[0002] Starch is a typical and commonly used naturally sourced polymer. It is a polysaccharide composed of D-glucan units. Its molecular formula can be represented as (C6H...). 11 O5) n In the formula, C6H 11 O5 represents a dehydrated glucose unit (AGU), where n is the AGU number, i.e., the degree of polymerization. Due to the heterogeneity of starch molecular weight, n in the formula represents the average degree of polymerization of starch molecules. Starch is composed of amylose and amylopectin. Amylose is a linear polymer of AGU linked by α-1,4 glycosidic chains, and its n value is generally between 100 and 6000, mostly in the hundreds. Amylopectin is a highly branched polymer of AGU linked by α-1,6 glycosidic chains. Its n value is generally between 10 million and 3 million, mostly above 6000. Regardless of the plant from which starch originates, its amylopectin content is usually above 70%. Common starches used as pharmaceutical excipients include corn starch, cassava starch, potato starch, and wheat starch.

[0003] Oxidized starch is a widely used and extensively applied type of modified starch. Different types of hydroxyl groups in the starch molecule can be oxidized. The C1 hemiacetal hydroxyl group can be oxidized to a carboxyl group, the C6 primary hydroxyl group can be oxidized to an aldehyde or carboxyl group, and the C2 and C3 primary hydroxyl groups form an ethylene glycol structure, which can be oxidized to a carbonyl or carboxyl group. Furthermore, the C2-C3 inter-bond can be broken. Although the oxidation process is often accompanied by the breaking of a certain amount of molecular bonds, the oxidation of hydroxyl groups has the greatest impact on starch properties. Currently, the oxidants used in the industrial oxidation process to prepare oxidized starch from starch are mainly hydrogen peroxide, hypochlorous acid (sodium hypochlorite), sodium periodate, and potassium permanganate. The preparation of oxidized starch using ozone oxidation has also been reported.

[0004] Polyethylene glycol, abbreviated as PEG, is a high molecular weight polymer widely used in biomedicine, medical aesthetics, and chemical materials. PEG contains polar end groups, exhibits excellent molecular chain flexibility, and is easily synthesized with controllable molecular weight. It possesses good biocompatibility and physicochemical properties. Various molecular weight grades of PEG are available commercially or can be custom-made. PEG is amphiphilic and biocompatible, with no toxic side effects, and is currently widely used in the pharmaceutical field to modify peptides, proteins, liposomes, nanoparticles, and other drugs or carriers.

[0005] Diamino polyethylene glycol, also known as NH2-PEG-NH2, is a modified polyethylene glycol (PEG) obtained by structural modification and alteration of PEG. The two amino groups are located at opposite ends of the linear polymer chain. The PEG being modified can be any commercially available PEG product with various molecular weights, or researchers can customize PEG with specific molecular weights for diamino modification according to their needs. Summary of the Invention

[0006] The purpose of this invention is to provide a healing powder prepared by using starch as the main matrix and oxidized starch and diamino polyethylene glycol as modifiers.

[0007] A pure starch-based healing powder can be prepared using starch as the sole matrix. This healing powder, when in contact with a suitable solvent or the patient's skin exudate, can be used for wound healing, and its therapeutic effect is equivalent to commonly used wound dressings. It has advantages such as being more suitable for skin wounds of varying depths and allowing for easy adjustment of dosage according to the wound condition. However, healing powders made solely with starch as the matrix have less than ideal viscosity, formability, and film-forming properties upon contact with liquids. This makes it impossible for a simple starch-based healing powder to replace various commercially available dermatological dressings. This invention provides a novel healing powder formulation and preparation method for the first time. Using starch as the main matrix and oxidized starch and diamino polyethylene glycol as modifiers, this healing powder exhibits better viscosity and film-forming properties when added to an appropriate solution or when absorbing wound exudate, thus accelerating hemostasis and promoting wound healing. Furthermore, experimental verification has shown that this healing powder has good safety, effectiveness, and controllable quality.

[0008] According to one aspect of the present invention, a healing powder is provided, which is made of starch, oxidized starch and diamino polyethylene glycol.

[0009] Preferably, the weight ratio of starch, oxidized starch, and diamino polyethylene glycol is (10-20):1:(1-3), more preferably (13-18):1:(1.5-2.8).

[0010] Preferably, the average molecular weight of the starch is 20,000-600,000, more preferably 200,000-400,000.

[0011] Preferably, the starch is selected from one or a mixture of more than one of corn starch, tapioca starch, potato starch, and wheat starch.

[0012] Preferably, the average molecular weight of the oxidized starch is 2500-12000, more preferably 4000-6000.

[0013] Preferably, the oxidized starch is selected from one or a mixture of more than one of oxidized corn starch, oxidized cassava starch, oxidized potato starch, and oxidized wheat starch.

[0014] Preferably, the average molecular weight of the diamino polyethylene glycol is 1,000-10,000, more preferably 2,500-5,000.

[0015] Preferably, the average particle size of the healing powder is 0.1mm-0.5mm.

[0016] Preferably, the healing powder of the present invention is prepared by the following method: starch, oxidized starch, diamino polyethylene glycol and an appropriate amount of water are mixed under heating conditions, frozen and the hard outer skin is removed during thawing, the liquid is squeezed out, placed in an ethanol aqueous solution, the liquid is squeezed out again, dried, pulverized and sterilized to obtain the product.

[0017] Preferably, the healing powder of the present invention is prepared by the following method: oxidized starch and diamino polyethylene glycol are mixed, water is added, and the mixture is heated to 60-80°C (preferably 65-75°C) with stirring, and kept at this temperature for 10 min-1 h (preferably 20-45 min). After cooling, starch (preferably starch and water) is added, and the mixture is heated to 60-80°C (preferably 65-75°C) with stirring, and kept at this temperature for 10 min-1 h (preferably 20-45 min). The mixture is then frozen, and upon thawing, the hard outer skin is scraped off, and the liquid is squeezed out. The mixture is then placed in an ethanol aqueous solution for 12-36 h (preferably 18-30 h), the liquid is squeezed out, and the mixture is dried, pulverized, and sterilized to obtain the final product.

[0018] Preferably, the amount of water used is 4-8 times the total weight of the solid raw materials, more preferably 5.5-6.5 times. Preferably, the water is water for injection.

[0019] Preferably, the sample is frozen at -20 to 0°C (more preferably -18°C) for 12 to 72 hours (more preferably 24 to 48 hours).

[0020] Preferably, the amount of hardened epidermis removed is about 5%-15% of the total amount, more preferably 10%.

[0021] Preferably, the concentration of the ethanol aqueous solution is 85%-98%, more preferably 95%.

[0022] Preferably, the drying temperature is 30-70℃, more preferably 40-65℃. Those skilled in the art will understand that drying can be performed under normal pressure or reduced pressure.

[0023] According to another aspect of the present invention, the present invention provides a method for preparing a healing powder, comprising the following steps: mixing oxidized starch and diamino polyethylene glycol, adding water, heating to 60-80°C (preferably 65-75°C) with stirring, keeping warm for 10 min-1 h (preferably 20-45 min), cooling, adding starch (preferably starch and water), heating to 60-80°C (preferably 65-75°C) with stirring, keeping warm for 10 min-1 h (preferably 20-45 min); freezing, then scraping off the hard outer skin upon thawing, squeezing out the liquid; placing in an ethanol aqueous solution for 12-36 h (preferably 18-30 h), squeezing out the liquid, drying, pulverizing, and sterilizing to obtain the product.

[0024] Preferably, the weight ratio of starch, oxidized starch, and diamino polyethylene glycol is (10-20):1:(1-3), more preferably (13-18):1:(1.5-2.8).

[0025] Preferably, the average molecular weight of the starch is 20,000-600,000, more preferably 200,000-400,000.

[0026] Preferably, the starch is selected from one or a mixture of more than one of corn starch, tapioca starch, potato starch, and wheat starch.

[0027] Preferably, the average molecular weight of the oxidized starch is 2500-12000, more preferably 4000-6000.

[0028] Preferably, the oxidized starch is selected from one or a mixture of more than one of oxidized corn starch, oxidized cassava starch, oxidized potato starch, and oxidized wheat starch.

[0029] Preferably, the average molecular weight of the diamino polyethylene glycol is 1,000-10,000, more preferably 2,500-5,000.

[0030] Preferably, the amount of water used is 4-8 times the total weight of the solid raw materials, more preferably 5.5-6.5 times. Preferably, the water is water for injection.

[0031] Preferably, the sample is frozen at -20 to 0°C (more preferably -18°C) for 12 to 72 hours (more preferably 24 to 48 hours).

[0032] Preferably, the amount of hardened epidermis removed is about 5%-15% of the total amount, more preferably 10%.

[0033] Preferably, the concentration of the ethanol aqueous solution is 85%-98%, more preferably 95%.

[0034] Preferably, the drying temperature is 30-70℃, more preferably 40-65℃. Those skilled in the art will understand that drying can be performed under normal pressure or reduced pressure.

[0035] Preferably, the average particle size of the healing powder is 0.1mm-0.5mm.

[0036] According to another aspect of the present invention, the present invention provides a healing powder prepared by the above method.

[0037] When using the healing powder of the present invention, it can be directly applied to the wound surface, or it can be mixed with an appropriate amount of water, preferably sterile water or water for injection, before application to the wound surface.

[0038] The healing powder of this invention has good film-forming properties, promotes coagulation to accelerate hemostasis, promotes wound healing, has a simple composition, is inexpensive, safe, and can be degraded and absorbed. Detailed Implementation

[0039] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by this invention.

[0040] The numbers in parentheses in the following examples represent the average molecular weight.

[0041] Example 1: Formula and preparation method of healing powder A

[0042] The prescription is as follows:

[0043]

[0044] The preparation method is as follows:

[0045] Weigh out the prescribed amounts of oxidized starch and diamino polyethylene glycol, mix them thoroughly, add 30% of the prescribed amount of water for injection, stir well, heat in a water bath to 70°C, let stand and keep warm for 30 minutes, and then cool naturally to room temperature. Add the prescribed amount of starch and the remaining 70% of the prescribed amount of water for injection, stir until it becomes a transparent viscous liquid, heat in a water bath to 70°C again, and keep warm for 30 minutes with stirring. Then pour the mixture into a square dish and freeze at -18°C for 36 hours. After that, take it out and place it at room temperature. When slightly thawing, scrape off the hard skin formed during freezing. The amount of hard skin removed is about 10% of the total amount. After thawing completely, wrap it in gauze and gently press out the water. Cut it into suitable small pieces and place it in a 95% ethanol aqueous solution. After 24 hours, take it out and squeeze out the ethanol and water. Then dry it at 45°C. After the ethanol has evaporated, dry it under reduced pressure at 60°C until the water is removed. Crush the resulting small pieces into powder with an average particle size of about 0.3 mm. 60 Sterilization by irradiation with 15 kGy of Co-γ rays yields healing powder A.

[0046] Example 2: Formula and preparation method of healing powder B

[0047] The prescription is as follows:

[0048]

[0049] The preparation method is as follows:

[0050] Weigh out the prescribed amounts of oxidized starch and diamino polyethylene glycol separately, mix them evenly, add 35% of the prescribed amount of water for injection, stir well, heat in a water bath to 75°C, let stand and keep warm for 35 minutes, and then cool naturally to room temperature. Add the prescribed amount of starch and the remaining 65% of the prescribed amount of water for injection, stir until it becomes a transparent viscous liquid, heat in a water bath to 65°C again, and keep warm with stirring for 45 minutes. Then pour the mixture into a square dish and freeze at -18°C for 24 hours. After that, take it out and place it at room temperature. When slightly thawing, scrape off the hard skin formed during freezing. The amount of hard skin removed is about 10% of the total amount. After thawing completely, wrap it in gauze and gently press out the water. Cut it into suitable small pieces and place it in a 95% ethanol aqueous solution. After 18 hours, take it out and squeeze out the ethanol and water. Then dry it at 50°C. After the ethanol has evaporated, dry it under reduced pressure at 65°C until the water is removed. Crush the resulting small pieces into powder with an average particle size of about 0.21 mm. 60 Sterilization by irradiation with 20 kGy Co-γ rays yields Healing Powder B.

[0051] Example 3: Formula and preparation method of healing powder C

[0052] The prescription is as follows:

[0053] Tapioca starch (250000) 13.5g

[0054] Oxidized starch (4000) 0.90g

[0055] Diamino polyethylene glycol (5000) 1.85g

[0056] 100mL of water for injection

[0057] The preparation method is as follows:

[0058] Weigh out the prescribed amounts of oxidized starch and diamino polyethylene glycol separately, mix them evenly, add 25% of the prescribed amount of water for injection, stir well, heat in a water bath to 65°C, let stand and keep warm for 25 minutes, and then cool naturally to room temperature. Add the prescribed amount of starch and the remaining 75% of the prescribed amount of water for injection, stir until it becomes a transparent viscous liquid, heat in a water bath to 75°C again, and keep warm with stirring for 20 minutes. Then pour the mixture into a square dish and freeze at -18°C for 48 hours. After that, take it out and place it at room temperature. When slightly thawing, scrape off the hard skin formed during freezing. The amount of hard skin removed is about 10% of the total amount. After thawing completely, wrap it in gauze and gently press out the water. Cut it into suitable small pieces and place it in a 95% ethanol aqueous solution. After 30 hours, take it out and squeeze out the ethanol and water. Then dry it at 40°C. After the ethanol has evaporated, dry it under reduced pressure at 55°C until the water is removed. Crush the resulting small pieces into powder with an average particle size of about 0.5 mm. 60 Sterilization by 11 kGy Co-γ irradiation yields healing powder C.

[0059] Comparative Example 1: Formulation and Preparation of Starch-Oxidized Starch-Based Healing Powder

[0060] The prescription is as follows:

[0061] Wheat starch (350000) 15.0g

[0062] Oxidized starch (4000) 1.5g

[0063] 100mL of water for injection

[0064] The preparation method is as follows:

[0065] Weigh out the prescribed amounts of starch and oxidized starch, mix them thoroughly, add the prescribed amount of water for injection, stir well, heat in a water bath to 70°C and keep warm for 30 minutes with stirring. Then pour the transparent paste-like mixture into a square dish and freeze at -18°C for 36 hours. After freezing, remove it and place it at room temperature. When slightly thawing, scrape off the hardened skin formed during freezing. The amount of hardened skin removed is about 10% of the total amount. After complete thawing, wrap it in gauze and gently press out the water. Cut it into suitable small pieces and place it in a 95% ethanol aqueous solution. After 24 hours, remove it and squeeze out the ethanol and water. Then dry it at 45°C. After the ethanol has evaporated, dry it under reduced pressure at 60°C until the water is removed. Crush the resulting small pieces into powder with an average particle size of about 0.25 mm. 60 Sterilization by 11 kGy Co-γ irradiation yields starch-oxidized starch-based healing powder.

[0066] Comparative Example 2: Formulation and Preparation of Starch-Diamino Polyethylene Glycol-Based Healing Powder

[0067] The prescription is as follows:

[0068] Tapioca starch (250000) 15.0g

[0069] Diamino polyethylene glycol (4000) 2.0g

[0070] 100mL of water for injection

[0071] The preparation method is as follows:

[0072] Weigh out the prescribed amounts of starch and diamino polyethylene glycol, mix them thoroughly, add the prescribed amount of water for injection, stir well, heat in a water bath to 70°C and keep warm for 30 minutes with stirring. Then pour the transparent paste-like mixture into a square dish and freeze at -18°C for 36 hours. Afterward, remove it and place it at room temperature. When slightly thawing, scrape off the hardened skin formed during freezing. The amount of hardened skin removed is about 10% of the total amount. After complete thawing, wrap it in gauze and gently press out the water. Cut it into suitable small pieces and place it in a 95% ethanol aqueous solution. After 24 hours, remove it and squeeze out the ethanol and water. Then dry it at 45°C. After the ethanol has evaporated, dry it under reduced pressure at 55°C until the water is removed. Crush the resulting small pieces into powder with an average particle size of about 0.25 mm. 60 Sterilization by irradiation with 20 kGy Co-γ rays yields starch-diamino polyethylene glycol-based healing powder.

[0073] Comparative Example 3: Formulation and Preparation of Starch-Oxidized Starch-Polyethylene Glycol-Based Healing Powder

[0074] The prescription is as follows:

[0075]

[0076] The preparation method is as follows:

[0077] Weigh out the prescribed amounts of oxidized starch and polyethylene glycol, mix them thoroughly, add 30% of the prescribed amount of water for injection, stir well, heat in a water bath to 70°C, let stand and keep warm for 35 minutes, and then cool naturally to room temperature. Add the prescribed amount of starch and the remaining 70% of the prescribed amount of water for injection, stir until it becomes a transparent viscous liquid, heat in a water bath to 70°C again, and keep warm for 30 minutes with stirring. Then pour the mixture into a square pan and freeze at -18°C for 36 hours. After that, take it out and place it at room temperature. When slightly thawing, scrape off the hard skin formed during freezing. The amount of hard skin removed is about 10% of the total amount. After thawing completely, wrap it in gauze and gently press out the water. Cut it into suitable small pieces and place it in a 95% ethanol aqueous solution. After 24 hours, take it out and squeeze out the ethanol and water. Then dry it at 45°C. After the ethanol has evaporated, dry it under reduced pressure at 66°C until the water is removed. Crush the resulting small pieces into powder with an average particle size of about 0.25 mm. 60 Sterilization by 15 kGy Co-γ irradiation yields starch-oxidized starch-polyethylene glycol-based healing powder.

[0078] Comparative Example 4: Formulation and Preparation of Pure Starch-Based Healing Powder

[0079] The prescription is as follows:

[0080] Corn starch (300,000 g) 16.5 g

[0081] 100mL of water for injection

[0082] The preparation method is as follows:

[0083] Weigh the prescribed amount of starch, add the full prescribed amount of water for injection, stir well, heat in a water bath to 70°C and keep warm for 30 minutes with stirring. Then pour the transparent, viscous starch solution into a square dish and freeze at -18°C for 36 hours. After freezing, remove and place at room temperature. When slightly thawing, scrape off the hardened outer skin formed during freezing. The amount of hardened outer skin removed is about 10% of the total amount. After complete thawing, wrap in gauze and gently press to squeeze out the water. Cut into suitable small pieces and place in a 95% ethanol aqueous solution. After 24 hours, remove and squeeze out the ethanol and water. Then dry at 45°C. After the ethanol has evaporated, dry under reduced pressure at 60°C until the water is removed. Crush the resulting small pieces into powder with an average particle size of about 0.25 mm, and then... 60 Sterilization by irradiation with 15 kGy of Co-γ rays yields pure starch-based healing powder.

[0084] Example 4: Water Absorption Test

[0085] The healing powders prepared in Examples 1-3 and Comparative Examples 1-4 were used respectively, and their water absorption was measured according to the following water absorption test method. This water absorption corresponds to the amount of water absorbed.

[0086] Water Absorption Test Method: Take 1.0g of the sample to be tested and add it to 50mL of water at 20℃. Gently stir to ensure the sample and water are thoroughly mixed, obtaining a sample suspension. Care should be taken not to break the sample particles. After the sample has fully absorbed the water, filter the sample suspension through a dry G4 sintered glass funnel. The filtration endpoint is defined as when no more water droplets drip from the funnel after more than 1 minute. Weigh the filtered material and the sintered glass funnel together to obtain the total weight. Subtract the weight of the sintered glass funnel from the total weight, and then subtract the weight of the sample to obtain the water absorption capacity of the sample. This water absorption capacity is the characterization of the sample's water absorption capacity, generally expressed as: Water Absorption Capacity = Water Absorption Capacity / Sample Weight. The sintered glass funnel used in this test does not absorb any water itself.

[0087] After three batches of testing, the water absorption capacity of healing powder A was between 22.9 and 23.4 times, that of healing powder B was between 25.0 and 25.3 times, and that of healing powder C was between 23.5 and 24.0 times. In comparison, the water absorption capacity of the starch-oxidized starch-based healing powder used as a control was between 16.9 and 17.5 times, the water absorption capacity of the starch-diamino polyethylene glycol-based healing powder used as a control was between 16.7 and 17.2 times, the water absorption capacity of the starch-oxidized starch-polyethylene glycol-based healing powder used as a control was between 17.2 and 17.6 times, and the water absorption capacity of the pure starch-based healing powder used as a control was between 14.1 and 14.6 times. Therefore, healing powders A, B, and C, which use starch as a matrix and add appropriate amounts of oxidized starch and diamino polyethylene glycol as modifiers, exhibit significantly superior water absorption properties compared to other healing powders.

[0088] Example 5 Film-forming property test

[0089] The healing powders prepared in Examples 1-3 and Comparative Examples 1-4 have very similar properties, all being white to off-white powder granules. They can be used for hemostasis during trauma and surgery, as well as for wound healing. Therefore, the film-forming properties of the healing powder after combining with a certain amount of liquid during use play a key role in the ease of clinical use and patient compliance.

[0090] Film-forming test 1: Take 0.5g of each of the healing powders prepared in Examples 1-3 and Comparative Examples 1-4, add 2.5mL of physiological saline as the liquid medium to each, stir to mix thoroughly and evenly, and then evenly coat the resulting viscous liquid onto the surface of a petri dish. Then blow nitrogen gas for 10 minutes and observe that the state of each healing powder viscous liquid gradually becomes nearly dry and close to a film. Then try to peel off the film formed by the healing powder viscous liquid from each petri dish. The part that can form a film accounts for 70% of the total coating area, and is peeled off in a form that is almost an integral film, which means that the film-forming property is good.

[0091] Film-forming test 2: Refer to the above film-forming test 1, but replace the liquid medium with serum. The rest of the test content is the same as the above film-forming test 1.

[0092] Film-forming test 3: Referring to film-forming test 1 above, the liquid medium is replaced with simulated wound exudate, and the rest of the test content is the same as film-forming test 1 above. The simulated wound exudate is prepared by adding a small amount of calcium chloride, magnesium chloride, human serum albumin, human fibrin, and thrombin to physiological saline and then mixing the simulated wound exudate.

[0093] Experimental results: In the three film-forming tests, the healing powders prepared in Examples 1-3 all had excellent film-forming properties, all exceeding 70%, while the healing powders prepared in Comparative Examples 1-4 had very poor film-forming properties and could not be peeled off in a near-whole film form.

[0094] Experimental conclusion: The healing powders prepared in Examples 1-3 all have good film-forming properties, while the healing powders prepared in Comparative Examples 1-4 have basically no film-forming properties.

[0095] Example 6 In vitro coagulation test

[0096] Weigh 5 mg of healing powder A prepared in Example 1, add it to a centrifuge tube, add 100 μL of physiological saline for injection, and mix well to prepare a dressing. Healing powders B and C, as well as dressings prepared with the healing powders from Comparative Examples 1-4, were prepared using the same method.

[0097] In vitro coagulation test: After preparing each dressing as described above, approximately 20 mg of the dressing was taken from each dressing sample. 2 mL of fresh blood was added to each sample, and after shaking, the blood clotting time was recorded. The clotting time results are shown in Table 1 below. 20 mg of commercially available chitosan gel was used as a control sample, and 20 mg of physiological saline was used as a blank sample. All clotting times in the table are in minutes.

[0098] Table 1 Clotting Time

[0099]

[0100]

[0101] Experimental results showed that dressings made from healing powders A, B, and C prepared in Examples 1-3 all exhibited good hemocoagulant effects, showing significant differences compared to the blank sample, control sample, and comparative examples 1-4. Dressings made from healing powders prepared in comparative examples 1-4 also had some hemocoagulant effects, but their performance was weaker than that of dressings made from healing powders A, B, and C.

[0102] Example 7 Wound Healing Experiment

[0103] Weigh 50 mg of the healing powder A prepared in the example, add 1000 μL of physiological saline for injection and mix well to prepare a dressing. The same method was used to prepare dressings of healing powders B and C, as well as the healing powders prepared in comparative examples 1-4.

[0104] SD rats were used as experimental animals, with 10 rats in each group. After hair removal from the back of the rats, sodium pentobarbital was administered intraperitoneally for anesthesia. A full-skin incision of approximately 1 cm in diameter was made on the back of the rats using surgical scissors. After disinfection with 75% alcohol solution, dressings made from healing powders A, B, C, and the healing powders from comparative examples 1-4 were evenly applied to the wounds on the rats' backs. The wounds were then covered with paraffin-coated gauze and bandaged. The positive control group received a commercially available chitosan gel dressing treated and bandaged using the same method. A blank control group received only paraffin-coated gauze and bandaged. Wound healing was observed on days 4, 7, 10, and 14 after wound modeling, and the wound healing rate was calculated at each time point. The formula for calculating the wound healing rate is: (Wound area at modeling - Unhealed wound area) ÷ Wound area at modeling = Wound healing rate (%)

[0105]

[0106]

[0107] The results of the healing rate at 14 days post-surgery showed that SD rats treated with dressings made from healing powders A, B, and C experienced faster wound healing on their backs. The healing rate was significantly better than that of dressings made from the healing powders in Comparative Examples 1-4, and also significantly better than the positive control group and the blank control group, with statistically significant differences. In conclusion, healing powders A, B, and C have a therapeutic effect in promoting skin wound healing.

[0108] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A healing powder, characterized in that, It is made of starch, oxidized starch, and diamino polyethylene glycol, with a weight ratio of starch, oxidized starch, and diamino polyethylene glycol of (10-20):1:(1-3); the starch is selected from one or more of corn starch, cassava starch, potato starch, and wheat starch, and the average molecular weight of the starch is 20,000-600,000; the oxidized starch is selected from one or more of oxidized corn starch, oxidized cassava starch, oxidized potato starch, and oxidized wheat starch, and the average molecular weight of the oxidized starch is 2,500-12,000; the average molecular weight of the diamino polyethylene glycol is 1,000-10,000. The healing powder is prepared by the following method: oxidized starch and diamino polyethylene glycol are mixed, water is added, and the mixture is heated to 65-75°C with stirring and kept at that temperature for 20-45 minutes. After cooling, starch and water are added, and the mixture is heated to 65-75°C with stirring and kept at that temperature for 20-45 minutes. The mixture is then frozen, and the hard outer skin is scraped off during thawing, and the liquid is squeezed out. The mixture is then placed in an ethanol-water solution for 18-30 hours, the liquid is squeezed out, and the powder is dried, pulverized, and sterilized to obtain the final product.

2. The healing powder as described in claim 1, characterized in that, The weight ratio of starch, oxidized starch, and diamino polyethylene glycol is (13-18):1:(1.5-2.8).

3. The healing powder as described in claim 1, characterized in that, The average molecular weight of starch is 200,000-400,000.

4. The healing powder as described in claim 1, characterized in that, The average molecular weight of oxidized starch is 4000-6000.

5. The healing powder as described in claim 1, characterized in that, The average molecular weight of diamino polyethylene glycol is 2500-5000.

6. The healing powder as described in claim 1, characterized in that, The average particle size of the healing powder is 0.1mm-0.5mm.

7. The healing powder as described in claim 1, characterized in that, The amount of water used is 4-8 times the total weight of the solid raw materials; freezing is carried out at -20 to 0℃ for 12-72 hours; the amount of hard skin scraped off is 5%-15% of the total amount; the concentration of the ethanol aqueous solution is 85%-98%; and the drying temperature is 30-70℃.

8. The healing powder as described in claim 7, characterized in that, The amount of water used is 5.5-6.5 times the total weight of the solid raw materials; freezing is carried out at -18℃ for 24-48 hours; the amount of hard skin scraped off is 10% of the total amount; the concentration of the ethanol-water solution is 95%; and the drying temperature is 40-65℃.

9. A method for preparing a healing powder, characterized in that, The process includes the following steps: Mix oxidized starch and diamino polyethylene glycol, add water, heat to 60-80℃ with stirring, keep warm for 10 min-1 h, cool, add starch and water, heat to 60-80℃ with stirring, keep warm for 10 min-1 h; freeze, then scrape off the hard outer skin during thawing and squeeze out the liquid; place in an ethanol-water solution for 12-36 h, squeeze out the liquid, dry, pulverize, and sterilize to obtain the final product; The weight ratio of starch, oxidized starch, and diamino polyethylene glycol is (10-20):1:(1-3); the starch is selected from one or more of corn starch, cassava starch, potato starch, and wheat starch, and the average molecular weight of the starch is 20,000-600,000; the oxidized starch is selected from one or more of oxidized corn starch, oxidized cassava starch, oxidized potato starch, and oxidized wheat starch, and the average molecular weight of the oxidized starch is 2,500-12,000; the average molecular weight of diamino polyethylene glycol is 1,000-10,000.

10. The preparation method according to claim 9, characterized in that, Mix oxidized starch and diamino polyethylene glycol, add water, heat to 65-75℃ with stirring, keep warm for 20-45 minutes, cool, add starch and water, heat to 65-75℃ with stirring, keep warm for 20-45 minutes; freeze, then scrape off the hard outer skin when thawing, squeeze out the liquid; place in an ethanol-water solution for 18-30 hours, squeeze out the liquid, dry, pulverize, and sterilize to obtain the final product.

11. The preparation method according to claim 9, characterized in that, The weight ratio of starch, oxidized starch, and diamino polyethylene glycol is (13-18):1:(1.5-2.8).

12. The preparation method according to claim 9, characterized in that, The average molecular weight of starch is 200,000-400,000.

13. The preparation method according to claim 9, characterized in that, The average molecular weight of oxidized starch is 4000-6000.

14. The preparation method according to claim 9, characterized in that, The average molecular weight of diamino polyethylene glycol is 2500-5000.

15. The preparation method according to claim 9, characterized in that, The average particle size of the healing powder prepared by the method is 0.1 mm to 0.5 mm.

16. The preparation method according to claim 9, characterized in that, The amount of water used is 4-8 times the total weight of the solid raw materials; freezing is carried out at -20 to 0℃ for 12-72 hours; the amount of hard skin scraped off is 5%-15% of the total amount; the concentration of the ethanol aqueous solution is 85%-98%; and the drying temperature is 30-70℃.

17. The preparation method according to claim 16, characterized in that, The amount of water used is 5.5-6.5 times the total weight of the solid raw materials; freezing is carried out at -18℃ for 24-48 hours; the amount of hard skin scraped off is 10% of the total amount; the concentration of the ethanol-water solution is 95%; and the drying temperature is 40-65℃.

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