A composite film powder and a method for preparing the same

Abstract

A composite film powder and a preparation method thereof, wherein a modified sesbania gum is prepared by carboxymethylation modification and grafting of gallic acid on the sesbania gum, and a plurality of plant fine powders and plant extracts are simultaneously prepared; the modified sesbania gum is premixed with calcium L-lactate, and then uniformly mixed with modified corn starch, nano pearl powder, plant components and functional additives through multi-stage equal increment mixing; the mixture is sterilized by using ethylene oxide, analyzed and then packed to obtain a finished product. The product prepared by the method has good powder flowability, excellent film mechanical strength and skin adhesion, good antioxidant activity and active release effect, and good storage stability, and the comprehensive performance is better than that of conventional simple compounded similar products.

Description

Technical Field

[0001] This invention relates to the field of plant extract technology, and in particular to a composite film powder and its preparation method. Background Technology

[0002] As skincare consumption trends towards natural and gentle products, topical mask powders with plant-derived active ingredients have gained widespread market attention due to their convenience and direct effects. Traditional plant-based mask powders often use mineral matrices or ordinary starch as carriers, simply compounded with plant extracts. They generally suffer from poor film-forming properties, low retention of active ingredients, rough skin feel, and short duration of efficacy, making it difficult to meet the needs of refined skincare.

[0003] The film-forming matrix is ​​the core component that determines the performance and efficacy delivery of film powders. Currently, most topical film agents use synthetic polymers such as polyvinyl alcohol and carboxymethyl cellulose as film-forming agents. While these offer good film continuity, they lack biocompatibility and skin affinity, and long-term use can easily lead to discomfort such as dryness and tightness. Some natural polysaccharide film-forming agents, although possessing good biocompatibility and moisturizing potential, suffer from poor cold water solubility, low solution stability, and insufficient film-forming mechanical strength. Furthermore, their loading and sustained-release capabilities for plant-based active ingredients are limited, restricting their extensive application in skincare film powders.

[0004] Guillarin is a natural galactomannan abundant in my country, possessing basic properties such as thickening and film-forming. However, its native structure has limited water solubility and single function, leading to problems such as poor dispersibility, easy degradation, and insufficient storage stability when directly applied to skincare systems. Existing research often modifies natural polysaccharides through carboxymethylation to improve their solubility. However, single carboxymethylation modification still struggles to balance film-forming mechanical properties and active ingredient loading capacity, and lacks effective ways to combine with plant polyphenolic active ingredients, failing to achieve synergistic skincare efficacy of the film-forming matrix itself.

[0005] Furthermore, existing plant-based composite film powders mostly employ a simple process of direct powder mixing, resulting in a lack of stable binding between the plant active ingredients and the film-forming matrix. This leads to excessively rapid release of active ingredients during use, hindering long-lasting skincare effects. Simultaneously, the poor uniformity of multi-component powder mixing and their tendency to absorb moisture and agglomerate negatively impact product storage stability and user experience. Currently, in-situ cross-linked composite film powders that combine excellent film-forming properties, sustained-release activity, and plant-based skincare efficacy are still relatively scarce, and related preparation processes require further improvement. Therefore, developing a topical plant-based composite film powder with modified natural polysaccharides as the core film-forming agent, combined with multiple plant active ingredients, and possessing excellent film-forming properties, skin feel, and skincare efficacy has significant application value. Summary of the Invention

[0006] To address the problems mentioned in the background section, this invention provides a composite film powder and its preparation method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The raw materials for preparing the composite film powder of the present invention include modified guar gum, L-calcium lactate, modified corn starch, nano pearl powder, plant fine powder, plant extract, low molecular weight sodium hyaluronate, and ascorbate glucoside.

[0008] The amounts of each raw material, by weight, are as follows: 10 parts modified guar gum, 0.8-1.2 parts L-calcium lactate, 15-25 parts modified corn starch, 2-5 parts nano pearl powder, 30-50 parts plant powder, 3-8 parts plant extract, 0.5-1.5 parts low molecular weight sodium hyaluronate, and 0.5-1.5 parts ascorbate glucoside.

[0009] Furthermore, the plant powder is prepared from Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica, wherein the mass ratio of Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica is 1:1:1:1:0.8-1.2:0.8-1.2; the licorice powder is prepared from licorice root slices.

[0010] Furthermore, the plant extracts include licorice root extract, chamomile extract, and tea extract, with a mass ratio of 1:0.8-1.2:0.8-1.2.

[0011] Furthermore, the particle size range of the nano pearl powder is 20-100 nm; the modified corn starch is pregelatinized modified corn starch or hydroxypropyl modified corn starch; and the molecular weight range of the low molecular weight sodium hyaluronate is 10000-50000 Da.

[0012] Furthermore, the moisture content of the composite membrane powder is ≤8.0% by mass, and the passing rate through a 200-mesh standard sieve is ≥90%.

[0013] The preparation method of the composite film powder of the present invention includes the following steps: (1) Preparation of carboxymethyl guar gum: The dried guar gum was dispersed in an ethanol-water solution and stirred to form a suspension. Then, a 30% sodium hydroxide solution was added and alkalized at 25-30℃ for 30-45 min. Solid sodium chloroacetate was added and the temperature was raised to 55-65℃ for 1.5-2.5 h. After the reaction, the pH of the system was adjusted to 6.5-7.0 with hydrochloric acid solution. The system was then filtered under reduced pressure, washed, vacuum dried, pulverized and sieved to obtain carboxymethyl guar gum.

[0014] Further, in step (1), the volume fraction of the ethanol-water solution is 80%, the mass-to-volume ratio of guar gum to ethanol-water solution is 1:10-1:15 g / mL; the molar ratio of sodium hydroxide to sodium chloroacetate is 1.1-1.3:1, and the mass ratio of sodium chloroacetate to guar gum is 0.5-0.9:1; the stirring rate during the alkalization process is 150-200 r / min; the pH is adjusted using a 0.5 mol / L hydrochloric acid solution; the washing process uses a 70% volume fraction ethanol-water solution, and the washing is performed 3-4 times; the drying temperature is 50-55℃, the drying pressure is -0.08--0.09 MPa, and the material is dried until the moisture content is ≤8.0%; after pulverization, the material is passed through a 200-mesh standard sieve.

[0015] (2) Preparation of modified guar gum: Carboxymethyl guar gum was prepared into an aqueous solution, and nitrogen gas was introduced to remove dissolved oxygen from the system. The reaction was maintained under positive nitrogen pressure throughout. Then, ascorbic acid and hydrogen peroxide were added, and the mixture was treated at 30-35℃ for 5-10 minutes. Gallic acid was added, and the temperature was raised to 35-40℃ for 2-3 hours. The reaction solution was dialyzed, dried, and sieved to obtain modified guar gum.

[0016] Further, in step (2), the mass fraction of the carboxymethyl guar gum aqueous solution is 1.5%-2.5%; the nitrogen gas is introduced for 10-15 min, and the nitrogen purity is ≥99.99%; the final concentration of ascorbic acid in the system is 0.5-1.0 mmol / L, and the final concentration of hydrogen peroxide is 1.0-2.0 mmol / L; the mass ratio of gallic acid to carboxymethyl guar gum is 0.2-0.4:1; dialysis is performed using a regenerated cellulose dialysis bag with a molecular weight cutoff of 8000-14000 Da, the dialysis time is 48-72 h, the dialysis fluid is deionized water, and the dialysis fluid is replaced every 6-8 h; drying is performed using spray drying, the inlet air temperature is 160-170℃, the outlet air temperature is 80-85℃, and the feed flow rate is 5-8 mL / min; after drying, it is passed through a 200-mesh standard sieve.

[0017] (3) Pretreatment of plant-based functional powders: The slices of Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica were purified, washed, dried, pulverized, and sieved to obtain fine plant powders. The extracts of Glycyrrhiza glabra, chamomile, and tea leaves were sieved separately for later use.

[0018] Further, in step (3), the medicinal slices are first selected to remove moldy, insect-infested individuals and non-medicinal impurities, and then rinsed three times with purified water; the drying temperature of the medicinal slices is 55-60℃, the drying time is 2.5-3h, and the moisture content of the material after drying is ≤8.0%; the pulverization is low-temperature ultra-fine pulverization, the temperature of the pulverizing chamber is ≤40℃, the single pulverization time is 15-20min, and after pulverization, it is graded by 150 mesh and 200 mesh standard sieves, and the fine powder under the 200 mesh sieve is collected; the extracts of licorice root, chamomile, and tea leaves are passed through a 120 mesh standard sieve.

[0019] (4) Premixing of composite matrix powder: Modified guar gum and L-calcium lactate were mixed at a mass ratio of 10:0.8-1.2 to obtain composite matrix powder.

[0020] Further, in step (4), the equal incremental method is used for mixing. The mixing equipment is a three-dimensional motion mixer with a mixing speed of 25-30 r / min. First, take 1 / 3 of the mass of modified guar gum and mix it with all the powdered L-calcium lactate for 10-15 min. Then, add the remaining modified guar gum in two batches, mixing for 10 min after each addition. The relative humidity of the mixing environment is ≤45%.

[0021] (5) Total mixture: Modified corn starch, nano pearl powder and composite matrix powder are premixed, then plant fine powder is added and mixed, then plant extract, low molecular weight sodium hyaluronate and ascorbate glucoside are added and mixed evenly to obtain composite powder.

[0022] Further, in step (5), the premixing speed is 30 r / min and the premixing time is 10-15 min; the plant powder is added in three equal batches, and each batch is mixed for 15-20 min after addition; the plant extract, low molecular weight sodium hyaluronate, and ascorbate glucoside are premixed in equal increments before being added, and then mixed for 20-25 min after addition; the mixing environment temperature is 20-25℃ and the relative humidity is ≤45%.

[0023] (6) Sterilization and dispensing: The composite powder is sterilized with ethylene oxide, desorbed, and then packaged to obtain external plant composite film powder.

[0024] Further, in step (6), the chamber temperature for ethylene oxide sterilization is 35-40℃, the relative humidity is 40%-60%, the concentration of ethylene oxide is 400-600mg / L, and the sterilization time is 4-6h; the desorption temperature is 20-25℃, the desorption time is 24-36h, and ventilation is maintained during the desorption process; after the desorption is completed and the indicators are qualified, it is packaged.

[0025] The beneficial effects of this invention are: 1. This invention modifies virgin guar gum with carboxymethylation, introducing carboxylate anionic groups onto the polysaccharide molecular chain. This significantly enhances the hydration and cold water solubility of the polysaccharide molecules, improves its dispersibility in the aqueous phase and the stability of the solution system, and solves the defects of poor solubility and easy sedimentation of virgin galactomannan. At the same time, the carboxylate groups provide sufficient reaction sites for the subsequent grafting of active components, providing a structural basis for the functional expansion of the polysaccharide matrix.

[0026] 2. This invention utilizes a free radical-initiated grafting process to covalently bond gallic acid to the molecular framework of carboxymethyl guar gum, a method distinct from traditional physical mixing. This structure, on one hand, endows the film-forming matrix itself with the relevant activities of polyphenols, achieving the integration of the film-forming carrier and the active ingredient; on the other hand, the grafted phenolic components can increase the steric hindrance of the polysaccharide molecular chains, optimizing the compactness and flexibility of the continuous film phase. Simultaneously, it can adsorb and encapsulate plant active substances through intermolecular forces such as hydrogen bonding and hydrophobic interactions, delaying the release rate of active ingredients, prolonging their action time on the skin surface, and improving the utilization efficiency of active ingredients.

[0027] 3. This invention uses functionalized modified polysaccharides and L-calcium lactate to form an in-situ cross-linked film matrix. During the dissolution process in water, the calcium ions generated by the dissociation of calcium lactate can coordinate with the carboxylate groups on the polysaccharide molecular chains, quickly forming a three-dimensional network cross-linked structure. This cross-linking system can significantly improve the film formation speed and the mechanical strength of the film, improving the problems of easy drying and peeling of ordinary polysaccharide films, making the film adhere more closely and smoothly to the skin. At the same time, the formed three-dimensional network can physically encapsulate active components such as plant powders and plant extracts, further improving the retention effect of active substances, optimizing the skin feel and the duration of action.

[0028] 4. This invention uses a low-temperature ultra-fine pulverization process to process plant slices, resulting in plant fine powder with uniform particle size and excellent dispersibility in composite powders. This effectively avoids powder agglomeration and improves the smoothness of the skin during use, eliminating the rough and gritty feeling of traditional film powders. The combination of various plant fine powders and standardized plant extracts can achieve synergistic and complementary skin care effects. Combined with the delivery function of the modified polysaccharide matrix, it enhances the overall skin care performance of the product.

[0029] 5. This invention employs a multi-stage, equal-volume incremental mixing process, combined with low-humidity environmental control, to ensure uniform dispersion of trace amounts of functional additives and plant extracts in the powder matrix, avoiding component segregation and improving batch-to-batch uniformity and storage stability. The use of ethylene oxide low-temperature sterilization meets the microbial limits for external use products while avoiding damage to the polysaccharide molecular structure and heat-sensitive active ingredients of plants caused by high-temperature treatment, thus maximizing the preservation of the product's efficacy and activity. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment provides a topical plant composite film powder, which, by mass parts, consists of: 10 parts modified guar gum, 1.0 part L-calcium lactate, 20 parts modified corn starch, 3.5 parts nano pearl powder, 40 parts fine plant powder, 5 parts plant extract, 1.0 part low molecular weight sodium hyaluronate, and 1.0 part ascorbate glucoside; wherein the fine plant powder includes Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica, and the plant extract includes Glycyrrhiza glabra extract, Chamomile extract, and Tea extract.

[0033] The preparation method steps are as follows: (1) Take 100g of dried guar gum to constant weight, add it to 1200mL of ethanol-water solution made of 960mL ethanol and 240mL water, stir to form a uniform suspension system, add 28.8g sodium hydroxide solution made of 67.2g water, control the temperature at 28℃ and the stirring rate at 180r / min, and alkalize for 35min; add 70g solid sodium chloroacetate, raise the temperature to 60℃, and react at a constant temperature for 2h; after the reaction is completed, adjust the pH of the system to 6.8 with dilute hydrochloric acid solution, separate by vacuum filtration, wash the filter cake 3 times with 300mL of ethanol-water solution containing 210mL ethanol; place the washed filter cake in a vacuum environment of 52℃ and -0.085MPa to dry to a moisture content of ≤8.0%, take it out and crush it, and pass it through a 200-mesh standard test sieve to obtain carboxymethyl guar gum.

[0034] (2) Take 50g of the above carboxymethyl guar gum, add it to 2450mL of deionized water, stir until completely dissolved, and prepare a 2500mL homogeneous aqueous solution; transfer the solution to a reaction vessel, and purge with high-purity nitrogen gas (≥99.99%) for 12min to remove dissolved oxygen, maintaining positive pressure protection with nitrogen gas throughout the reaction; add an aqueous solution containing 0.33g of ascorbic acid and an aqueous solution containing 0.13g of hydrogen peroxide to the system, control the temperature at 32℃, and maintain the temperature for 8min; add 15g of gallic acid. The acid solid was stirred until completely dissolved, then heated to 38℃ and reacted at a constant temperature for 2.5 hours. After the reaction, the reaction solution was placed in a regenerated cellulose dialysis bag with a molecular weight cutoff of 8000-14000 Da and purified by dialyzing in sufficient deionized water for 60 hours, with the dialysis solution being replaced every 7 hours. The purified solution was then spray-dried, with the inlet air temperature controlled at 165℃, the outlet air temperature at 82℃, and the feed flow rate at 6 mL / min. The dried powder was collected and passed through a 200-mesh standard inspection sieve to obtain modified guar gum.

[0035] (3) Take 100g each of dried slices of Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis and Centella asiatica. After sorting, remove moldy, insect-infested individuals and non-medicinal impurities. Rinse three times with purified water, drain and place in a constant temperature forced-air drying oven at 58℃ for 2.75h, and control the moisture content of the material to ≤8.0%. After drying, each material is subjected to low-temperature ultrafine pulverization. The temperature of the chamber is controlled at 35℃ and the pulverization time is 18min. After pulverization, the fine powder under a 200-mesh sieve is collected and graded to obtain fine powder of each plant. Take 50g each of dried powder of Glycyrrhiza glabra extract, chamomile extract and tea extract, pass them through a 120-mesh standard inspection sieve to remove lumps and set aside.

[0036] (4) Take 100g of the above modified guar gum and 10g of L-calcium lactate powder and premix them using the equal incremental method; first, take 33.3g of modified guar gum and all of the L-calcium lactate into a three-dimensional motion mixer, set the speed to 28r / min, and mix for 12min; then add the remaining modified guar gum in two batches, 33.3g each time, and maintain the same speed for 10min after each addition to obtain a uniform composite matrix powder; control the relative humidity of the environment to ≤45% throughout the mixing process.

[0037] (5) Take 200g of modified corn starch, 35g of nano pearl powder and all the above composite matrix powders and put them into a three-dimensional motion mixer. Set the speed to 30r / min and premix for 12min to obtain the matrix mixture phase. Then take 400g of plant fine powder and add it to the matrix mixture phase in 3 batches in equal amounts. Mix for 18min after each batch is added to obtain plant-based mixed powder. Finally, add 50g of premixed plant extract, 10g of low molecular weight sodium hyaluronate and 10g of ascorbate glucoside to the mixer and continue mixing for 22min. Control the ambient temperature at 22℃ and the relative humidity at ≤45% throughout the process to obtain composite powder.

[0038] (6) The above composite powder is treated with ethylene oxide low-temperature sterilization process, the sterilization chamber temperature is controlled at 38℃, relative humidity at 50%, ethylene oxide concentration at 500mg / L, and effective sterilization time is 5h; after sterilization, it is decomposed at 22℃ under ventilation conditions for 30h; after decomposition, the sample is tested and qualified, and then sealed and packaged in aluminum-plastic composite bags according to specifications to obtain the finished product of external plant composite film powder.

[0039] Example 2

[0040] This embodiment provides a topical plant composite film powder, which, by mass parts, consists of: 10 parts modified guar gum, 0.8 parts L-calcium lactate, 15 parts modified corn starch, 2 parts nano pearl powder, 30 parts fine plant powder, 3 parts plant extract, 0.5 parts low molecular weight sodium hyaluronate, and 0.5 parts ascorbate glucoside; wherein the fine plant powder includes Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica, and the plant extract includes Glycyrrhiza glabra extract, Chamomile extract, and Tea extract.

[0041] The preparation method steps are as follows: (1) Take 100g of dried guar gum to constant weight, add it to 1000mL of ethanol-water solution made of 800mL ethanol and 200mL water, stir to form a uniform suspension system, add 18.9g sodium hydroxide solution made of 44.1g water, control the temperature at 25℃ and the stirring rate at 150r / min, and alkalize for 30min; add 50g solid sodium chloroacetate, raise the temperature to 55℃, and react at a constant temperature for 1.5h; after the reaction is completed, adjust the pH of the system to 6.5 with dilute hydrochloric acid solution, separate by vacuum filtration, wash the filter cake 3 times with 300mL of ethanol-water solution containing 210mL ethanol; place the washed filter cake in a vacuum environment of 50℃ and -0.08MPa to dry until the moisture content is ≤8.0%, take it out and crush it, and pass it through a 200-mesh standard test sieve to obtain carboxymethyl guar gum.

[0042] (2) Take 50g of the above carboxymethyl guar gum, add it to 3283mL of deionized water, stir until completely dissolved, and prepare 3333mL of homogeneous aqueous solution; transfer the solution to a reaction vessel, and purge with high-purity nitrogen gas (≥99.99%) for 10min to remove dissolved oxygen, maintaining positive pressure protection with nitrogen gas throughout the reaction; add an aqueous solution containing 0.29g of ascorbic acid and an aqueous solution containing 0.11g of hydrogen peroxide to the system, control the temperature at 30℃, and maintain the temperature for 5min; add 10g of gallate The solid guar gum was stirred until completely dissolved, then heated to 35°C and reacted at a constant temperature for 2 hours. After the reaction was completed, the reaction solution was placed in a dialysis bag containing regenerated cellulose with a molecular weight cutoff of 8000-14000 Da and purified by dialysis in sufficient deionized water for 48 hours, with the dialysis solution being replaced every 6 hours. The purified solution was then spray-dried, with the inlet air temperature controlled at 160°C, the outlet air temperature at 80°C, and the feed flow rate at 5 mL / min. The dried powder was collected and passed through a 200-mesh standard sieve to obtain modified guar gum.

[0043] (3) Take 100g each of dried slices of Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis and Centella asiatica. After sorting, remove moldy, insect-infested individuals and non-medicinal impurities. Rinse three times with purified water, drain and place in a constant temperature forced-air drying oven at 55℃ for 2.5h, and control the moisture content of the material to be ≤8.0%. After drying, each material is subjected to low-temperature ultra-fine pulverization. During the pulverization process, control the cavity temperature to be ≤40℃ and the pulverization time to be 15min per pulverization. After pulverization, collect the fine powder through a 200-mesh sieve to obtain fine powder of each plant. Take 50g each of dried powder of Glycyrrhiza glabra extract, chamomile extract and tea extract, and pass them through a 120-mesh standard inspection sieve to remove lumps before use.

[0044] (4) Take 100g of the above modified guar gum and 8g of L-calcium lactate powder and premix them using the equal incremental method; first, take 33.3g of modified guar gum and all of the L-calcium lactate into a three-dimensional motion mixer, set the speed to 25r / min, and mix for 10min; then add the remaining modified guar gum in two batches, 33.3g each time, and maintain the same speed for 10min after each addition to obtain a uniform composite matrix powder; control the relative humidity of the environment to ≤45% throughout the mixing process.

[0045] (5) Take 150g of modified corn starch, 20g of nano pearl powder and all the above composite matrix powders and put them into a three-dimensional motion mixer. Set the speed to 30r / min and premix for 10min to obtain the matrix mixture phase. Then take 300g of plant fine powder and add it to the matrix mixture phase in three equal batches. Mix for 15min after each batch is added to obtain plant-based mixed powder. Finally, add 30g of premixed plant extract, 5g of low molecular weight sodium hyaluronate and 5g of ascorbate glucoside to the mixer and continue mixing for 20min. Control the ambient temperature at 20℃ and the relative humidity at ≤45% throughout the process to obtain composite powder.

[0046] (6) The above composite powder is treated with ethylene oxide low-temperature sterilization process, and the sterilization chamber temperature is controlled at 35℃, relative humidity at 40%, ethylene oxide concentration at 400mg / L, and effective sterilization time at 4h. After sterilization, it is decomposed at 20℃ under ventilation conditions for 24h. After decomposition, the sample is tested and found to be qualified. It is then sealed and packaged in aluminum-plastic composite bags according to specifications to obtain the finished product of external plant composite film powder.

[0047] Example 3

[0048] This embodiment provides a topical plant composite film powder, which, by mass, consists of the following raw materials: 10 parts modified guar gum, 1.2 parts L-calcium lactate, 25 parts modified corn starch, 5 parts nano pearl powder, 50 parts fine plant powder, 8 parts plant extract, 1.5 parts low molecular weight sodium hyaluronate, and 1.5 parts ascorbate glucoside; wherein the fine plant powder includes Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica, and the plant extract includes Glycyrrhiza glabra extract, Chamomile extract, and Tea extract.

[0049] The preparation method steps are as follows: (1) Take 100g of dried guar gum to constant weight, add it to 1500mL of ethanol-water solution made by mixing 1200mL of ethanol and 300mL of water, stir to form a uniform suspension system, add 40.2g of sodium hydroxide solution made by dissolving 93.8g of water, control the temperature at 30℃ and the stirring rate at 200r / min, and alkalize for 45min; add 90g of solid sodium chloroacetate, raise the temperature to 65℃, and react at a constant temperature for 2.5h; after the reaction is completed, adjust the pH of the system to 7.0 with dilute hydrochloric acid solution, separate by vacuum filtration, wash the filter cake 4 times with 300mL of ethanol-water solution containing 210mL of ethanol; place the washed filter cake in a vacuum environment of 55℃ and -0.09MPa to dry until the water content is ≤8.0%, take it out and crush it, and pass it through a 200-mesh standard test sieve to obtain carboxymethyl guar gum.

[0050] (2) Take 50g of the above carboxymethyl guar gum, add it to 1950mL of deionized water, stir until completely dissolved, and prepare 2000mL of homogeneous aqueous solution; transfer the solution to a reaction vessel, and purge with high-purity nitrogen gas (≥99.99%) for 15min to remove dissolved oxygen, maintaining positive pressure protection with nitrogen gas throughout the reaction; add an aqueous solution containing 0.35g of ascorbic acid and an aqueous solution containing 0.14g of hydrogen peroxide to the system, control the temperature at 35℃, and keep it at a constant temperature for 10min; add 20g of gallate The solid guar gum was stirred until completely dissolved, then heated to 40°C and reacted at a constant temperature for 3 hours. After the reaction was completed, the reaction solution was placed in a dialysis bag containing regenerated cellulose with a molecular weight cutoff of 8000-14000 Da and purified by dialysis in sufficient deionized water for 72 hours, with the dialysis solution being replaced every 8 hours. The purified solution was then spray-dried, with the inlet air temperature controlled at 170°C, the outlet air temperature at 85°C, and the feed flow rate at 8 mL / min. The dried powder was collected and passed through a 200-mesh standard sieve to obtain modified guar gum.

[0051] (3) Take 100g each of dried slices of Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis and Centella asiatica. After sorting, remove moldy, insect-infested individuals and non-medicinal impurities. Rinse three times with purified water, drain and place in a constant temperature forced-air drying oven at 60℃ for 3h, and control the moisture content of the material to be ≤8.0%. After drying, each material is subjected to low-temperature ultrafine pulverization. During the pulverization process, control the cavity temperature to be ≤40℃ and the pulverization time to be 20min. After pulverization, collect the fine powder through a 200-mesh sieve and prepare fine powder of each plant. Take 50g each of dried powder of Glycyrrhiza glabra extract, chamomile extract and tea extract, pass them through a 120-mesh standard inspection sieve to remove lumps and set aside.

[0052] (4) Take 100g of the above modified guar gum and 12g of L-calcium lactate powder and premix them using the equal incremental method; first, take 33.3g of modified guar gum and all of the L-calcium lactate into a three-dimensional motion mixer, set the speed to 30r / min, and mix for 15min; then add the remaining modified guar gum in two batches, 33.3g each time, and maintain the same speed for 10min after each addition to obtain a uniform composite matrix powder; control the relative humidity of the environment to ≤45% throughout the mixing process.

[0053] (5) Take 250g of modified corn starch, 50g of nano pearl powder and all the above composite matrix powders and put them into a three-dimensional motion mixer. Set the speed to 30r / min and premix for 15min to obtain the matrix mixture phase. Then take 500g of plant fine powder and add it to the matrix mixture phase in three equal batches. Mix for 20min after each batch is added to obtain plant-based mixed powder. Finally, add 80g of premixed plant extract, 15g of low molecular weight sodium hyaluronate and 15g of ascorbate glucoside to the mixer and continue mixing for 25min. Control the ambient temperature at 25℃ and the relative humidity at ≤45% throughout the process to obtain composite powder.

[0054] (6) The above composite powder is treated with ethylene oxide low-temperature sterilization process, the sterilization chamber temperature is controlled at 40℃, relative humidity at 60%, ethylene oxide concentration at 600mg / L, and effective sterilization time at 6h; after sterilization, it is decomposed at 25℃ under ventilation conditions for 36h; after decomposition, the sample is tested and qualified, and then sealed and packaged in aluminum-plastic composite bags according to specifications to obtain the finished product of external plant composite film powder.

[0055] Example 4

[0056] This embodiment provides a topical plant composite film powder, which, by mass parts, consists of: 10 parts modified guar gum, 1.1 parts L-calcium lactate, 18 parts modified corn starch, 4 parts nano pearl powder, 45 parts fine plant powder, 6 parts plant extract, 0.8 parts low molecular weight sodium hyaluronate, and 1.2 parts ascorbate glucoside; wherein the fine plant powder includes Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica, and the plant extract includes Glycyrrhiza glabra extract, Chamomile extract, and Tea extract.

[0057] The preparation method steps are as follows: (1) Take 100g of dried guar gum to constant weight, add it to 1300mL of ethanol-water solution made of 1040mL of ethanol and 260mL of water, stir to form a uniform suspension system, add 31.6g of sodium hydroxide solution made of 73.7g of water, control the temperature at 26℃ and the stirring rate at 160r / min, and alkalize for 40min; add 80g of solid sodium chloroacetate, raise the temperature to 58℃, and react at a constant temperature for 2.2h; after the reaction is completed, adjust the pH of the system to 6.7 with dilute hydrochloric acid solution, separate by vacuum filtration, wash the filter cake 4 times with 300mL of ethanol-water solution containing 210mL of ethanol; place the washed filter cake in a vacuum environment of 53℃ and -0.088MPa to dry to a moisture content of ≤8.0%, take it out and crush it, and pass it through a 200-mesh standard test sieve to obtain carboxymethyl guar gum.

[0058] (2) Take 50g of the above carboxymethyl guar gum, add it to 2223mL of deionized water, stir until completely dissolved, and prepare 2273mL of homogeneous aqueous solution; transfer the solution to a reaction vessel, and purge with high-purity nitrogen gas (≥99.99%) for 13min to remove dissolved oxygen, maintaining positive pressure protection with nitrogen gas throughout the reaction; add an aqueous solution containing 0.32g of ascorbic acid and an aqueous solution containing 0.14g of hydrogen peroxide to the system, control the temperature at 33℃, and maintain the temperature for 7min; add 17.5g of gallate. The solid guar gum was stirred until completely dissolved, then heated to 37°C and reacted at a constant temperature for 2.8 hours. After the reaction was completed, the reaction solution was placed in a dialysis bag containing regenerated cellulose with a molecular weight cutoff of 8000-14000 Da and purified by dialyzing in sufficient deionized water for 66 hours, with the external dialysis solution being replaced every 7 hours. The purified solution was then spray-dried, with the inlet air temperature controlled at 168°C, the outlet air temperature at 83°C, and the feed flow rate at 7 mL / min. The dried powder was collected and passed through a 200-mesh standard sieve to obtain modified guar gum.

[0059] (3) Take 100g each of dried slices of Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis and Centella asiatica. After sorting, remove moldy, insect-damaged individuals and non-medicinal impurities. Rinse three times with purified water, drain and place in a constant temperature forced-air drying oven at 57℃ for 2.8h, and control the moisture content of the material to be ≤8.0%. After drying, each material is subjected to low-temperature ultra-fine pulverization. The temperature of the chamber is controlled at 38℃ and the pulverization time is 17min. After pulverization, the fine powder under a 200-mesh sieve is collected and graded to obtain fine powder of each plant. Take 50g each of dried powder of Glycyrrhiza glabra extract, chamomile extract and tea extract, pass them through a 120-mesh standard inspection sieve to remove lumps and set aside.

[0060] (4) Take 100g of the above modified guar gum and 11g of L-calcium lactate powder and premix them using the equal incremental method; first, take 33.3g of modified guar gum and all of the L-calcium lactate into a three-dimensional motion mixer, set the speed to 27r / min, and mix for 13min; then add the remaining modified guar gum in two batches, 33.3g each time, and maintain the same speed for 10min after each addition to obtain a uniform composite matrix powder; control the relative humidity of the environment to ≤45% throughout the mixing process.

[0061] (5) Take 180g of modified corn starch, 40g of nano pearl powder and all the above composite matrix powders and put them into a three-dimensional motion mixer. Set the speed to 30r / min and premix for 13min to obtain the matrix mixture phase. Then take 450g of plant fine powder and add it to the matrix mixture phase in three batches. Mix for 16min after each batch is added to obtain plant-based mixed powder. Finally, add 60g of premixed plant extract, 8g of low molecular weight sodium hyaluronate and 12g of ascorbate glucoside to the mixer and continue mixing for 24min. Control the ambient temperature at 23℃ and the relative humidity at ≤45% throughout the process to obtain composite powder.

[0062] (6) The above composite powder is treated with ethylene oxide low-temperature sterilization process, the sterilization chamber temperature is controlled at 37℃, relative humidity at 55%, ethylene oxide concentration at 450mg / L, and effective sterilization time at 4.5h. After sterilization, it is decomposed at 23℃ under ventilation conditions for 28h. After decomposition, the sample is tested and qualified. It is then sealed and packaged in aluminum-plastic composite bags according to specifications to obtain the finished product of external plant composite film powder.

[0063] Comparative Example 1 The difference between this comparative example and Example 1 is that the gallic acid grafting modification step is omitted, and carboxymethyl guar gum is directly used to replace the modified guar gum in the subsequent mixing process.

[0064] Comparative Example 2 The difference between this comparative example and Example 1 is that L-calcium lactate was not added, and modified guar gum was used directly as the film-forming matrix for subsequent mixing.

[0065] Comparative Example 3 The difference between this comparative example and Example 1 is that carboxymethylation and gallic acid grafting modification are not performed; instead, virgin guar gum raw material is used directly to replace the modified guar gum, while the remaining preparation steps remain the same.

[0066] Comparative Example 4 The difference between this comparative example and Example 1 is that no graft copolymerization reaction is performed. Gallic acid and carboxymethyl guar gum are directly and physically mixed evenly at the same mass ratio as in Example 1, and then used to replace the modified guar gum in subsequent processes.

[0067] Comparative Example 5 The difference between this comparative example and Example 1 is that licorice root extract, chamomile extract, and tea extract are not added; only the plant powder is retained as the plant-based active ingredient.

[0068] This embodiment verifies the performance of samples prepared in Examples 1 to 4 and Comparative Examples 1 to 5. The external plant composite membrane powder of Examples 1 to 4 is used as the experimental group, and the composite membrane powder of Comparative Examples 1 to 5 is used as the control group. Three samples are prepared in parallel for each group, and each performance test is performed in triplicate. The arithmetic mean of the test results is taken. The reagents used in the experiment mainly include 1,1-diphenyl-2-trinitrophenylhydrazine, anhydrous ethanol, pH 7.4 phosphate buffer solution, gallic acid reference standard, and purified water. The instruments used mainly include an electric thermostatic drying oven, a 200-mesh standard sieve, an angle of repose measuring device, an electronic universal tensile testing machine, a UV-Vis spectrophotometer, a constant temperature shaking incubator, regenerated cellulose dialysis bags with a molecular weight cutoff of 8000-14000 Da, a rapid moisture analyzer, and a constant temperature and humidity chamber.

[0069] The basic performance test of the powder includes three indicators: moisture content, 200-mesh sieve passing rate, and flowability. Moisture content is determined using the drying method. 2.0g of the sample is accurately weighed and placed in a pre-dried weighing bottle to constant weight. The sample is spread evenly and placed in a 105℃ forced-air drying oven to dry to constant weight. After cooling to room temperature in a desiccator, it is weighed again. The moisture content is calculated based on the difference in mass before and after drying. For the 200-mesh sieve passing rate test, 10.0g of the sample is accurately weighed and placed in a 200-mesh standard test sieve. The sieve is manually sieved at a fixed frequency for 5 minutes. The mass of the powder passing through the sieve is collected and weighed. The percentage of the powder passing through the sieve to the total sample mass is calculated as the 200-mesh sieve passing rate. The powder flowability was characterized by the fixed funnel method using the angle of repose. A standard funnel was vertically fixed above the coordinate paper, and the vertical height between the bottom of the funnel and the paper was controlled to be 5 cm. The powder to be tested was slowly added to the funnel until the top of the cone formed by the powder just touched the bottom of the funnel. The diameter of the bottom surface of the cone was measured, and the angle of repose θ was calculated according to the formula tanθ=2H / D, where H is the height from the bottom of the funnel to the paper and D is the diameter of the bottom surface of the powder cone.

[0070] Film-forming performance testing includes three indicators: film-forming time, film mechanical properties, and film adhesion properties. For film-forming time determination, accurately weigh 5.0g of the sample, add 20mL of room-temperature deionized water, and stir at 300r / min for 3min to form a uniform film solution. Transfer 2mL of the film solution and evenly coat it onto a clean 5cm×5cm glass plate surface, ensuring consistent coating thickness across all groups. Place the glass plate in a constant temperature and humidity environment of 25℃ and 50% relative humidity and allow it to stand. The film-forming endpoint is defined as when the film surface feels non-sticky and shows no powder adhesion when lightly touched with a finger. Record the time from coating completion to reaching the film-forming endpoint. For the mechanical property testing of the membrane layer, the uniform membrane liquid prepared above was poured into a 10cm×10cm polytetrafluoroethylene mold and allowed to dry naturally at a constant temperature of 25℃. After being completely peeled off, it was cut into rectangular test strips with a width of 1cm and a length of 5cm. The thickness of each group of test strips was controlled to be consistent. Tensile tests were conducted using an electronic universal tensile testing machine at a tensile rate of 5mm / min. The tensile strength and elongation at break of the test strips were recorded. The average value was taken after testing 5 test strips in each group. The adhesion performance test of the membrane layer was conducted using ex vivo pigskin. Fresh ex vivo pigskin was flattened and fixed on a flat plate surface. 0.5g of the above membrane liquid was evenly coated on it. After drying naturally, the membrane was placed in an environment with a temperature of 37℃ and a relative humidity of 60%. The time required for the membrane layer to peel off with an area greater than 50% was observed and recorded.

[0071] Antioxidant activity was determined using the DPPH free radical scavenging method. Before the experiment, a 0.2 mmol / L DPPH anhydrous ethanol solution was prepared and used immediately under light-protected conditions. 0.1 g of the sample was accurately weighed, added to 100 mL of deionized water, stirred to dissolve, and centrifuged at 3000 r / min for 10 min. The supernatant was used as the sample test solution. 2 mL of the sample test solution and 2 mL of DPPH solution were thoroughly mixed in a stoppered test tube, allowed to stand in the dark for 30 min, and the absorbance of the mixture was measured at 517 nm, recorded as Ai. Simultaneously, the absorbance of the mixture of 2 mL DPPH solution and 2 mL anhydrous ethanol was measured, recorded as A0. The absorbance of the mixture of 2 mL sample test solution and 2 mL anhydrous ethanol was also measured, recorded as Aj. The DPPH free radical scavenging rate of each sample was calculated using the formula: DPPH free radical scavenging rate = [1 - (Ai - Aj) / A0] × 100%.

[0072] The in vitro release performance was determined using the dialysis bag diffusion method. After pretreatment by thoroughly immersing the regenerated cellulose dialysis bag in deionized water, 5 mL of the above-mentioned sample solution was added. The two ends of the dialysis bag were clamped to ensure a seal, and the bag was completely immersed in a conical flask containing 100 mL of pH 7.4 phosphate buffer solution. The flask was placed in a constant-temperature shaking incubator at 37℃ and a shaking rate of 100 r / min. At time points of 0.5 h, 1 h, 2 h, 4 h, 6 h, 8 h, and 12 h, 2 mL samples were taken from the conical flask. Simultaneously, an equal volume of isothermal fresh phosphate buffer solution was added to the flask to maintain a constant system volume. The absorbance of the sample solution at each time point was measured using ultraviolet spectrophotometry. The concentration of the active substance in the solution was calculated using a pre-plotted gallic acid standard curve. The cumulative release rate at different time points was further calculated, and the in vitro release curve of the active substance was plotted.

[0073] For accelerated storage stability testing, each group of samples was sealed in an aluminum-plastic composite bag and placed in a constant temperature and humidity test chamber at 37℃ and 75% relative humidity for 30 consecutive days. After the period, the samples were removed, and the powder was visually observed for any changes in appearance such as clumping, moisture absorption, or discoloration. The 200-mesh sieve passing rate and DPPH free radical scavenging rate of the samples were re-measured. The activity retention rate was calculated by the ratio of the free radical scavenging rate after storage to the initial free radical scavenging rate. The storage stability of the samples was comprehensively evaluated by combining the changes in powder appearance and sieve passing rate. By comparing the performance data of each group of samples, the effects of polysaccharide modification, polyphenol grafting, in-situ crosslinking systems, and plant component complexes on improving the powder performance, film-forming properties, efficacy, and storage stability of the products can be directly verified.

[0074] The results are shown in Table 1-4: Table 1. Test results of basic powder properties for each sample

[0075] Table 2. Test results of film-forming properties of each sample

[0076] Table 3. Results of antioxidant activity and in vitro release performance tests for each sample.

[0077] Table 4. Accelerated storage stability test results for each sample

[0078] Table 1 shows that the moisture content of Examples 1-4 was controlled between 5.8% and 6.5%, the passing rate through a 200-mesh sieve was all above 94%, and the angle of repose was within the range of 31.8°-33.2°. This indicates that the moisture content of the external plant composite film powder prepared in these examples is suitable, the particle size uniformity is high, and the flowability is good, which can meet the processing requirements of subsequent mixing and packaging. This invention introduces carboxylate anionic groups into the guar gum molecular chain through carboxymethylation modification, increasing the electrostatic repulsion between molecules and weakening the strong hydrogen bond aggregation between native polysaccharide molecules. Combined with subsequent refining, drying, and grading sieving processes, the uniformity of powder particles is significantly improved, while the hydrophilic properties of the powder surface are improved, reducing the tendency to absorb moisture, thus giving the powder excellent processing flowability and storage anti-caking ability. Comparative Example 3, which uses native guar gum directly, has a passing rate of only 82.6% through a 200-mesh sieve, an angle of repose as high as 41.2°, and a moisture content significantly higher than the other groups. This is because the hydrogen bonds between the molecular chains of native galactomannan are strong, leading to easy aggregation and a wide particle size distribution in the native powder particles. Furthermore, the uneven distribution of hydrophilic groups on the surface results in a stronger tendency to absorb moisture, leading to poor powder flowability, low sieving efficiency, and an inability to guarantee the uniformity of multi-component mixing. The basic powder properties of Comparative Examples 1, 2, 4, and 5 are similar to those of the Example, indicating that the addition or subtraction of gallic acid grafting, calcium lactate crosslinking system, and plant extracts has little impact on the macroscopic processing properties of the powder. The basic characteristics of the powder are mainly determined by the carboxymethylation modification of the polysaccharide.

[0079] Table 2 shows that the film-forming time of Examples 1-4 was 3.9-4.8 min, the tensile strength of the film layer reached 2.62-3.01 MPa, the elongation at break was 30.1%-34.6%, and the film adhesion time reached 5.8-7.2 h. This indicates that the composite film powder prepared in the examples has a fast film-forming speed, and the formed film layer has excellent mechanical properties, good flexibility, and more durable adhesion to the skin surface. This invention constructs an in-situ cross-linked film-forming system of modified polysaccharide and L-calcium lactate. During the dissolution process in water, the calcium ions dissociated from calcium lactate can coordinate with the carboxyl groups on the polysaccharide molecular chains to quickly form a three-dimensional network cross-linked structure, which not only effectively shortens the film-forming time but also significantly improves the tensile strength and flexibility of the film layer. At the same time, gallic acid grafted onto the polysaccharide chain can form additional intermolecular hydrogen bonds through phenolic hydroxyl groups, further enhancing the film cohesion, optimizing the film layer's density and skin adhesion, thereby prolonging the film layer's adhesion time on the skin surface. Comparative Example 2, without L-calcium lactate, and Comparative Example 3, using virgin guar gum, showed extended film-forming times of 7.3 min and 10.5 min, respectively, with significant decreases in tensile strength and adhesion time. Comparative Example 2 lacked a calcium ion crosslinking system, relying solely on hydrogen bonds between polysaccharide molecules for film formation. This resulted in a loose network structure, leading to slow film formation, poor mechanical properties, and easy detachment from the skin surface. Comparative Example 3, with its slow hydration and dissolution rate of virgin guar gum, struggled to effectively entangle molecular chains to form a continuous and uniform film. This resulted in a brittle film with poor continuity, and all film-forming indicators were at their lowest levels. Comparative Examples 1 and 4, without covalent grafting of gallic acid, lacked additional hydrogen bond reinforcement within the film layers, resulting in slightly lower overall film-forming performance than the examples, confirming the auxiliary enhancement effect of polyphenol grafting on film performance.

[0080] As shown in Table 3, the DPPH free radical scavenging rate of Examples 1-4 reached 82.4%-90.2%, and the cumulative release rate of active substances over 12 hours was 58.7%-65.1%, indicating that the products of these examples possess both excellent antioxidant activity and long-lasting sustained-release characteristics. This invention utilizes a free radical-initiated grafting process to covalently bond gallic acid to the molecular backbone of carboxymethyl guar gum, fully preserving the bioactivity of the phenolic hydroxyl groups. Simultaneously, it forms a synergistic effect with the natural active components such as polyphenols and flavonoids in plant powders and various plant extracts, jointly enhancing the antioxidant capacity of the system. Furthermore, the three-dimensional polysaccharide network formed by calcium ion cross-linking physically encapsulates and impedes the active components, and the covalently grafted polyphenols require slow dissociation and release. This dual impediment effect delays the diffusion rate of the active substances, achieving long-lasting release of the active ingredients. Comparative Example 3, without modified polysaccharides and grafted polyphenols, showed the weakest DPPH free radical scavenging rate at only 42.8%. Comparative Example 1, without grafted gallic acid, lacked the polyphenolic activity of the film-forming matrix itself, resulting in a significant decrease in free radical scavenging rate. Comparative Example 4, using a physical mixing method to add gallic acid, showed that free phenols were more easily oxidized and deactivated during preparation and storage, resulting in lower activity efficiency than the covalently grafted system. Furthermore, the lack of chemically bonded free active substances led to a faster diffusion rate, with a cumulative release rate as high as 82.3% over 12 hours. Comparative Example 5, lacking plant extract components, relied solely on grafted gallic acid for activity, resulting in a lower antioxidant level than the examples, verifying the synergistic effect of plant extracts and grafted polyphenols. Comparative Example 2, lacking the encapsulation and retardation effect of the cross-linking network, reduced the diffusion resistance of active substances, significantly increasing the cumulative release rate, confirming the sustained-release effect of the in-situ cross-linking system.

[0081] As shown in Table 4, after 30 days of accelerated storage at 37℃ and 75% relative humidity, Examples 1-4 showed no clumping or discoloration. The change rate of the 200-mesh sieve passing rate was between -0.9% and 1.5%, and the activity retention rate reached 91.8%-93.7%, indicating that the composite membrane powder prepared in these examples has excellent storage stability. This invention optimizes the dispersion uniformity of the polysaccharide powder through carboxymethylation modification. Combined with a multi-stage, equal-quantity incremental mixing process under low humidity conditions, liquid bridges are less likely to form between powder particles. Simultaneously, gallic acid covalently grafted onto the polysaccharide backbone can exert an endogenous antioxidant protective effect, inhibiting the oxidative degradation of heat-sensitive plant active ingredients in the system. Therefore, it can maintain a stable powder state and efficacy even under high temperature and high humidity accelerated storage conditions. Comparative Example 3, using virgin guar gum, exhibited significant clumping and yellowing after standing. Its sieve pass rate and activity retention rate were the worst. This is because virgin polysaccharide particles are more prone to hygroscopic aggregation and lack antioxidant protective components, making the active ingredients more susceptible to oxidative degradation. Comparative Example 1, lacking gallic acid grafting, lacked an endogenous antioxidant protective barrier, resulting in a significantly lower activity retention rate than the examples. In Comparative Example 4, the free gallic acid was easily oxidized and deactivated, failing to continuously protect other active ingredients within the system; therefore, its activity retention rate was also low. Comparative Example 2, lacking calcium lactate, slightly exacerbated the powder's tendency to absorb moisture and aggregate, leading to a greater decrease in sieve pass rate.

[0082] In summary, this invention modifies guar gum by carboxylation and covalently grafts it with gallic acid, then constructs an in-situ cross-linked film-forming system using L-calcium lactate. Combined with the compounding and refined mixing process of plant active ingredients, it effectively optimizes the powder processing flowability, significantly improves the film-forming mechanical strength, skin adhesion, and sustained-release effect, while endowing the product with excellent antioxidant activity and storage stability. Its overall performance is significantly better than that of similar products with conventional simple compounding.

[0083] In the description of this specification, the reference to terms such as "embodiment," "various embodiments," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or preparation example is included in at least one embodiment of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0084] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a composite film powder, characterized in that, Includes the following steps: (1) Disperse guar gum in an ethanol-water solution, stir to form a suspension system, add sodium hydroxide solution, and alkalize at 25-30℃ for 30-45 min; add sodium chloroacetate, heat to 55-65℃ and react for 1.5-2.5 h; after the reaction, adjust the pH of the system to 6.5-7.0, filter, wash, dry, pulverize and sieve to obtain carboxymethyl guar gum; (2) Prepare carboxymethyl guar gum into an aqueous solution, pass nitrogen gas through it, add ascorbic acid and hydrogen peroxide, and treat at 30-35℃ for 5-10 min; add gallic acid, heat to 35-40℃ and react for 2-3 h; after dialysis, drying and sieving, the modified guar gum is obtained. (3) The slices of Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica were washed, dried, pulverized and sieved to obtain fine plant powder; the extracts of Glycyrrhiza glabra, chamomile and tea leaves were sieved and set aside. (4) The modified guar gum and L-calcium lactate were mixed at a mass ratio of 10:0.8-1.2 to obtain the composite matrix powder; (5) After premixing the modified corn starch, nano pearl powder and composite matrix powder, add plant fine powder and mix, then add plant extract, low molecular weight sodium hyaluronate and ascorbate glucoside and mix evenly to obtain composite powder. (6) The composite powder is sterilized with ethylene oxide, desorbed and then packaged to obtain external plant composite film powder.

2. The preparation method according to claim 1, characterized in that, In step (1), the volume fraction of the ethanol-water solution is 80%, and the mass-to-volume ratio of guar gum to ethanol-water solution is 1:10-1:15 g / mL; the molar ratio of sodium hydroxide to sodium chloroacetate is 1.1-1.3:1, and the mass ratio of sodium chloroacetate to guar gum is 0.5-0.9:1; washing is performed using a 70% volume fraction ethanol-water solution, and the number of washing cycles is 3-4; the drying temperature is 50-55℃, and the drying pressure is -0.08--0.09MPa; after pulverization, the solution is passed through a 200-mesh standard sieve.

3. The preparation method according to claim 1, characterized in that, In step (2), the mass fraction of the carboxymethyl guar gum aqueous solution is 1.5%-2.5%; the nitrogen gas is introduced for 10-15 min; the final concentration of ascorbic acid in the system is 0.5-1.0 mmol / L, and the final concentration of hydrogen peroxide is 1.0-2.0 mmol / L; the mass ratio of gallic acid to carboxymethyl guar gum is 0.2-0.4:1; dialysis is performed using a dialysis bag with a molecular weight cutoff of 8000-14000 Da, and the dialysis time is 48-72 h; drying is performed using spray drying, with an inlet air temperature of 160-170℃, an outlet air temperature of 80-85℃, and a feed flow rate of 5-8 mL / min; after drying, the sample is passed through a 200-mesh standard sieve.

4. The preparation method according to claim 1, characterized in that, In step (3), the drying temperature of the medicinal slices is 55-60℃ and the drying time is 2.5-3h; the pulverization is low-temperature ultra-fine pulverization, the temperature of the pulverization chamber is ≤40℃, and the single pulverization time is 15-20min; the plant fine powder passes through a 200-mesh standard sieve; the extracts of licorice root, chamomile, and tea pass through a 120-mesh standard sieve.

5. The preparation method according to claim 1, characterized in that, In step (4), the equal incremental method is used for mixing. The mixing equipment is a three-dimensional motion mixer with a mixing speed of 25-30 r / min. First, take 1 / 3 of the mass of modified guar gum and mix it with all of the L-calcium lactate for 10-15 min. Then, add the remaining modified guar gum in two batches, mixing for 10 min after each addition. The relative humidity of the mixing environment is ≤45%.

6. The preparation method according to claim 1, characterized in that, In step (5), the premixing speed is 30 r / min and the premixing time is 10-15 min; the plant powder is added in three equal batches, and each batch is mixed for 15-20 min after addition; the plant extract, low molecular weight sodium hyaluronate, and ascorbate glucoside are premixed in equal increments before being added, and then mixed for 20-25 min after addition; the mixing environment temperature is 20-25℃ and the relative humidity is ≤45%.

7. The preparation method according to claim 1, characterized in that, In step (6), the chamber temperature for ethylene oxide sterilization is 35-40℃, the relative humidity is 40%-60%, the concentration of ethylene oxide is 400-600mg / L, and the sterilization time is 4-6h; the desorption temperature is 20-25℃, and the desorption time is 24-36h.

8. The preparation method according to claim 1, characterized in that, The amounts of each raw material, by weight, are as follows: 10 parts modified guar gum, 0.8-1.2 parts L-calcium lactate, 15-25 parts modified corn starch, 2-5 parts nano pearl powder, 30-50 parts plant powder, 3-8 parts plant extract, 0.5-1.5 parts low molecular weight sodium hyaluronate, and 0.5-1.5 parts ascorbate glucoside.

9. The preparation method according to claim 8, characterized in that, The mass ratio of Atractylodes macrocephala, Bletilla striata, Poria cocos, Portulaca oleracea, Glycyrrhiza uralensis, and Centella asiatica in the plant powder is 1:1:1:1:0.8-1.2:0.8-1.2; the mass ratio of Glycyrrhiza glabra extract, Chamomile extract, and Tea extract in the plant extract is 1:0.8-1.2:0.8-1.

2.

10. A composite film powder, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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