An anthocyanin oral fiber film and a preparation method and application thereof

Abstract

This invention relates to an anthocyanin oral fiber membrane, its preparation method, and its application, belonging to the field of oral delivery materials technology. The anthocyanin oral fiber membrane is a nanofiber membrane prepared by electrospinning from a spinning solution comprising polyvinyl alcohol, hydroxypropyl methylcellulose, tannic acid, and anthocyanins. In the spinning solution, the mass ratio of polyvinyl alcohol to hydroxypropyl methylcellulose is 4:1 to 1:4, the mass concentration of tannic acid is 0.5% to 1.5%, and the mass concentration of anthocyanins is 1.0% to 3.0%. The oral membrane obtained by this invention exhibits good adhesion stability under humid conditions. Furthermore, after treatment with sodium bicarbonate solution, the peeling force can be reduced, enabling on-demand peeling, thereby improving the membrane's suitability for local oral delivery applications.

Description

Technical Field

[0001] This invention relates to an anthocyanin oral fiber membrane, its preparation method, and its application, belonging to the field of oral delivery material technology. Background Technology

[0002] Anthocyanins (ACNs) are a class of water-soluble polyphenolic compounds widely found in plants, possessing antioxidant, anti-inflammatory, and local microenvironment-regulating bioactivities. They hold significant potential for application in functional foods, oral health products, and the delivery of related active ingredients. However, during routine oral ingestion, anthocyanins typically pass through the gastrointestinal tract, making them susceptible to changes in acid-base conditions, digestive enzyme activity, and intestinal microbial metabolism. This can lead to decreased structural stability, reduced activity, and even degradation and inactivation, thus limiting their practical utilization efficiency. Therefore, developing anthocyanin delivery systems that minimize adverse gastrointestinal effects and are suitable for local oral application is of significant importance.

[0003] Oral membranes, with their short pathways of action, well-defined local effects, convenient administration, and avoidance of partial gastrointestinal degradation, represent a potential interface for the local delivery of anthocyanins. Among existing oral local delivery systems, oral membranes have attracted attention due to their small size, portability, relatively uniform component distribution, and ease of adhesion to the oral mucosa. Electrospun fiber membranes, in particular, possess a large specific surface area, abundant pore structure, and good dispersion of active ingredients, which are beneficial for improving the release and utilization of active substances at the oral interface.

[0004] However, the oral environment is constantly moist and subjected to mechanical disturbances such as saliva rinsing, tongue movement, and chewing. In practical use, oral membranes not only need a certain level of wet adhesion to prevent premature slippage, detachment, or damage, but also need to maintain appropriate structural integrity and user comfort. Existing technologies often improve the adhesion between the oral membrane and the mucosal surface by introducing adhesive polymers or other adhesives. However, the oral environment is constantly moist, accompanied by mechanical disturbances such as saliva rinsing, tongue movement, and chewing. For anthocyanin-based oral fiber membranes, if the membrane lacks sufficient interfacial adhesion in the moist oral environment, problems such as unstable adhesion, slippage, detachment, or insufficient action time can easily occur, thus affecting the sustained effect of anthocyanins on the local mucosal surface. However, for membrane materials that directly act on the oral mucosal surface, stronger adhesion is not necessarily better. In actual use, oral membranes not only need to have a certain wet adhesion ability, but also need to match the structural stability, wet integrity, oral comfort, and peeling or disappearance behavior of the membrane to avoid premature slippage, detachment or damage.

[0005] Therefore, in order to meet the practical application needs of anthocyanin oral delivery membranes, how to further improve their adhesion stability on the moist oral mucosa surface without affecting the user experience, while ensuring good film-forming properties, structural stability and active ingredient loading performance of the oral membrane, and thus improve the local delivery effect of anthocyanins in the oral cavity, is an urgent technical problem to be solved in the current research on this type of delivery system. Summary of the Invention

[0006] To address the technical challenges of existing oral films in achieving a balance between film-forming stability, wet adhesion, and peelability in a moist oral environment, this invention provides an anthocyanin oral fiber membrane, its preparation method, and its applications. This invention uses a composite film-forming matrix composed of polyvinyl alcohol (PVA) and hydroxypropyl methylcellulose (HPMC) as its structural basis. While achieving film-forming properties and structural stability, tannic acid is introduced as a wet adhesion-enhancing component, and the anthocyanin oral fiber membrane is prepared using electrospinning technology. The resulting oral membrane exhibits good adhesion stability under moist conditions, and the peeling force is reduced after treatment with sodium bicarbonate solution, thereby improving the membrane's suitability for local oral delivery applications.

[0007] An anthocyanin oral fiber membrane, wherein the anthocyanin oral fiber membrane is a nanofiber membrane prepared by electrospinning technology from a spinning solution comprising polyvinyl alcohol, hydroxypropyl methylcellulose, tannic acid and anthocyanins; wherein in the spinning solution, the mass ratio of polyvinyl alcohol to hydroxypropyl methylcellulose is 4:1 to 1:4, the mass concentration of tannic acid is 0.5% to 1.5%, and the mass concentration of anthocyanins is 1.0% to 3.0%.

[0008] Tannic acid, a natural polyphenol rich in phenolic hydroxyl groups, forms hydrogen bonds, hydrophobic interactions, and multi-point interfacial bonds with hydrophilic polymers and mucosal surfaces in this invention, enhancing the interfacial adhesion of the membrane in humid environments. Electrospinning technology enables rapid solidification of the spinning solution to form a high specific surface area nanofiber structure, which is beneficial for increasing the contact area between the membrane and the oral mucosa. This invention introduces tannic acid based on optimized film-forming properties and structural support capabilities of the PVA / HPMC composite matrix, enabling the resulting oral membrane to form a relatively stable wet adhesion to the oral mucosa during use. Furthermore, after treatment with sodium bicarbonate solution, it allows for convenient and controllable peeling, thereby improving practical compatibility.

[0009] Furthermore, the wet adhesion of the anthocyanin oral fiber membrane is 33~45 kPa; the peel strength of the anthocyanin oral fiber membrane after treatment with NaHCO3 solution is 6~9 kPa.

[0010] Another object of the present invention is to provide a method for preparing the above-mentioned anthocyanin oral fiber membrane, comprising the following steps: heating and dissolving polyvinyl alcohol and hydroxypropyl methylcellulose separately and mixing them evenly to obtain an electrospinning precursor solution; then adding tannic acid solution to the above-mentioned electrospinning precursor solution, followed by adding anthocyanin solution, stirring at room temperature to form a homogeneous spinning solution; injecting the spinning solution into the injection pump of the electrospinning equipment, turning on the electrospinning equipment, adjusting the parameters and starting spinning to obtain a nanofiber membrane, drying to obtain the anthocyanin oral fiber membrane.

[0011] Furthermore, the parameters of the electrospinning equipment are set as follows: the injection pump flow rate is 0.6~1.0 mL / h, the spinning voltage is 12~20 kV, the distance between the needle tip and the collector is 10~20 cm, the ambient temperature is 20~30℃, and the relative humidity is 60%~85%.

[0012] Preferably, the flow rate of the syringe pump is 0.8 mL / h, the spinning voltage is 16 kV, the distance between the needle tip and the collector is 15 cm, the ambient temperature is 25℃, and the relative humidity is 80%.

[0013] Furthermore, the stirring conditions are magnetic stirring at a rate of 500-800 rpm for 1-3 hours.

[0014] Furthermore, the drying conditions are equilibrium drying at 20~30℃ for 12~48 h.

[0015] Preferably, the drying conditions are equilibrium drying at 25°C for 24 hours.

[0016] Furthermore, the tannic acid solution uses a 70% (v / v) aqueous ethanol solution as the solvent.

[0017] Furthermore, the anthocyanin solution uses a citrate-sodium citrate buffer solution at pH 3.0 as the solvent.

[0018] Another object of the present invention is to provide the application of the above-mentioned anthocyanin oral fiber membrane in the preparation of oral topical active ingredient delivery carriers.

[0019] Another object of the present invention is to provide the application of the above-mentioned anthocyanin oral fiber membrane in the preparation of oral care membranes.

[0020] The beneficial effects of this invention are as follows: First, this invention constructs a composite matrix with good film-forming properties and structural support by adjusting the PVA / HPMC ratio. Based on this, an appropriate amount of tannic acid is introduced as a wet adhesion enhancing component, and anthocyanin-loaded nanofiber membranes are prepared using electrospinning technology. The resulting fiber membranes exhibit more uniform fiber morphology, more suitable hydration behavior, and better wet structural stability, which can improve the adhesion stability of the membrane in a moist oral environment. Tests show that compared with membranes without tannic acid or with low tannic acid content, the wet adhesion of the anthocyanin oral fiber membrane obtained in this invention is increased from 8-15 kPa to 33-45 kPa. Simultaneously, after treatment with NaHCO3 solution, the membrane peel force is reduced to 6-9 kPa, which facilitates easier assisted peeling and reduces discomfort that may result from excessive adhesion. Furthermore, when the tannic acid concentration is too high, the viscosity of the spinning solution becomes too high and easily clogs the needle, making it difficult to form a continuous and stable fiber membrane. This indicates that the amount of tannic acid added is not necessarily better the higher it is, but should be controlled within an appropriate range. Furthermore, this invention can improve the storage stability, release behavior, and delivery performance of anthocyanins in membranes and mucus environments, thereby enhancing the practical application value of anthocyanin local oral delivery systems. Attached Figure Description

[0021] Figure 1 Scanning electron microscope (SEM) images of film-forming matrices with different PVA / HPMC mass ratios are shown. In the figures, HPMC represents hydroxypropyl methylcellulose as the single matrix, PVA represents polyvinyl alcohol as the single matrix, and P / H represents the mass ratio of PVA to HPMC. P / H=4 / 1, P / H=3 / 2, P / H=2 / 3, and P / H=1 / 4 represent PVA to HPMC mass ratios of 4:1, 3:2, 2:3, and 1:4, respectively.

[0022] Figure 2 Figures show the hydration diffusion behavior, wet deformation behavior, and mechanical property evaluation of fiber membranes with different PVA / HPMC mass ratios. Specifically, A shows the diffusion of water droplets on the surface of different membranes over time; B shows the tensile deformation of different membranes under wet conditions; C shows the variation of water droplet diffusion diameter for PVA single-matrix fiber membranes; D shows the variation of water droplet diffusion diameter for P / H=4 / 1 fiber membranes; E shows the variation of water droplet diffusion diameter for P / H=3 / 2 fiber membranes; F shows the variation of water droplet diffusion diameter for P / H=2 / 3 fiber membranes; G shows the variation of water droplet diffusion diameter for P / H=1 / 4 fiber membranes; H shows the elongation at break for different membranes; I shows the tensile strength for different membranes; and J shows the tensile length for different membranes.

[0023] Figure 3 Scanning electron microscopy morphology and fiber diameter distribution of anthocyanin-loaded oral fiber membranes with different tannin addition amounts.

[0024] Figure 4 The graphs show the mechanical properties, wet adhesion properties, structural support properties, and NaHCO3-assisted peeling properties of anthocyanin-loaded anthocyanin oral fiber membranes with different tannic acid addition amounts. Specifically, A shows the elongation at break and tensile strength of different membranes; B shows the Young's modulus and wet adhesion force of different membranes; C shows physical observations of the sealing performance, peeling process, and support properties of different membranes; and D shows the peeling force and support height of different membranes after treatment with NaHCO3 solution.

[0025] Figure 5 UV shielding performance of anthocyanin-loaded oral fiber membranes with different tannin additions. In the figure, BK represents the blank control group; UV-A represents long-wave ultraviolet light with a wavelength range of 320~400 nm; UV-B represents medium-wave ultraviolet light with a wavelength range of 280~320 nm.

[0026] Figure 6 Anthocyanin-loaded anthocyanin oral fiber membranes with different tannin additions are evaluated for color stability, anthocyanin retention rate, degradation kinetics, and appearance changes during light storage. In the figures, a represents the red-green hue value, L represents the brightness value, and b represents the anthocyanin luminance value. The value represents the yellow-blue tint, ΔE represents the overall color difference, and 0 day and 14 day represent 0 days and 14 days of light storage, respectively.

[0027] Figure 7 Anthocyanin release curves in artificial saliva for anthocyanin-loaded oral fiber membranes with different tannin addition amounts.

[0028] Figure 8 The graphs show the performance evaluation of anthocyanin-loaded oral fiber membranes with different tannin additions in the artificial mucus layer. A represents the physical images of different membranes in the artificial mucus layer; B represents the anthocyanin concentration results in the artificial mucus layer; and C represents the physical images and statistical results of the transfer height of different membranes in the artificial mucus layer. Detailed Implementation

[0029] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0030] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0031] Example 1 To obtain a film-forming matrix with good spinnability, fiber morphology, and wet structural stability, this embodiment pre-screened the mass ratio of PVA to HPMC. The specific operation is as follows: PVA and HPMC were dissolved separately by heating at 85°C, and then mixed evenly according to different mass ratios of PVA and HPMC (0:1, 1:0, 4:1, 3:2, 2:3, and 1:4, respectively) to obtain an electrospinning precursor solution. The obtained electrospinning precursor solution was injected into the syringe of the electrospinning equipment for spinning. The feed rate was set to 0.8 mL / h, the applied voltage to 16 kV, the distance from the needle tip to the receiver to 15 cm, the ambient temperature to 25°C, and the relative humidity to 80%. After spinning, the obtained fiber membrane was equilibrated and dried at 25°C for 24 h to remove residual solvent, thus obtaining the fiber membrane.

[0032] The microstructure of the fiber membranes obtained by each formulation was observed by scanning electron microscopy (SEM), and their hydration diffusion behavior, wet deformation behavior, and mechanical properties were evaluated. The results are shown in [Figure number missing]. Figure 1 and Figure 2 .

[0033] Figure 1 Scanning electron microscope (SEM) images of the film-forming matrices with different PVA / HPMC mass ratios. Figure 1 It can be seen that pure HPMC is difficult to form a continuous and uniform fiber structure, mainly exhibiting a granular or bead-like structure; although pure PVA can form fibers, the fiber diameter distribution is relatively wide, and local adhesion occurs. With the adjustment of the PVA / HPMC composite ratio, the fiber morphology changes significantly. Specifically, when P / H = 2:3, the resulting fiber network is more uniform and dense, with better fiber continuity and a relatively narrower diameter distribution. This indicates that at this ratio, the polymer system can better balance chain entanglement, solution viscoelasticity, and electrostatic stretching behavior, overcoming the problems of wide fiber diameter distribution and local adhesion in pure PVA, as well as the uneven fiber morphology at high HPMC ratios.

[0034] Figure 2 Figures show the hydration diffusion behavior, wet deformation behavior, and mechanical property evaluation of fiber membranes with different PVA / HPMC mass ratios. Figure 2 A shows the diffusion of water droplets on different membrane surfaces over time. Figure 2 B is a diagram showing the wet stretching and deformation process of different membranes. Figure 2 CG represents the variation in the diffusion diameter of water droplets on the membrane surface for different groups. Figure 2 HJ represents the test results of elongation at break, tensile strength, and tensile length of membranes from different groups. Figure 2It can be seen that when P / H = 2:3, the water diffusion behavior of the membrane is easier to control, which can slow down instantaneous swelling and maintain structural integrity in a humid environment, thereby improving the shortcomings of pure PVA, which is too hydrophilic and swells too quickly. Mechanical property test results further show that when P / H = 2:3, the membrane has both high tensile strength and moderate elongation, indicating that this ratio can achieve a good mechanical balance between strength and flexibility, avoiding the problem of easy breakage or excessive deformation of a single material during wet use. Therefore, when P / H = 2:3, the resulting electrospinning precursor solution has good continuous spinning performance, the resulting fiber membrane has a more uniform fiber distribution, and has suitable hydration behavior and relatively balanced mechanical properties. Therefore, a PVA to HPMC mass ratio of 2:3 is determined as the preferred composite film-forming matrix for subsequent anthocyanin-loaded anthocyanin oral fiber membranes.

[0035] Example 2 This embodiment provides an anthocyanin oral fiber membrane, the preparation method of which is as follows: (1) Preparation of electrospinning precursor solution: PVA and HPMC were heated and dissolved at 85°C, and then mixed evenly at a mass ratio of 2:3 to obtain electrospinning precursor solution; (2) Tannic acid (TA) was dissolved in a 70% (v / v) ethanol-water mixed solvent to obtain a tannic acid solution; anthocyanin (ACN) was dissolved in a citrate-sodium citrate buffer solution at pH 3.0 to obtain an anthocyanin solution. The tannic acid solution was then added to the electrospinning precursor solution, followed by the anthocyanin solution. The mixture was magnetically stirred at 600 rpm for 2 h at room temperature to form a homogeneous spinning solution. The mass ratio of PVA to HPMC in the spinning solution was 2:3, the TA mass concentration was 1.0%, and the ACN mass concentration was 2.0%.

[0036] (3) The obtained spinning solution was injected into the syringe of the electrospinning equipment. The feed rate was set to 0.8 mL / h, the applied voltage was 16 kV, the distance from the needle tip to the receiver was 15 cm, the ambient temperature was 25℃, and the relative humidity was 80%. After spinning, the obtained fiber membrane was equilibrated and dried at 25℃ for 24 h to remove residual solvent, and anthocyanin oral fiber membrane was obtained, denoted as H-PVA-1TA / ACN.

[0037] Example 3 The difference between this embodiment and Example 2 is that the TA mass concentration in the spinning solution is 1.5%, while the other steps are the same as in Example 1. The resulting anthocyanin oral fiber membrane is denoted as H-PVA-1.5TA / ACN.

[0038] Comparative Example 1 The difference between this comparative example and Example 2 is that no TA is added to the spinning solution, while the remaining steps are the same as in Example 1. The resulting fiber membrane is denoted as H-PVA / ACN.

[0039] Comparative Example 2 The difference between this comparative example and Example 2 is that the TA mass concentration in the spinning solution is 0.5%, while the other steps are the same as in Example 1, and the resulting fiber membrane is denoted as H-PVA-0.5TA / ACN.

[0040] Comparative Example 3 The difference between this comparative example and Example 2 is that the TA mass concentration in the spinning solution is 2.0%, while the other steps are the same as in Example 1, and the resulting fiber membrane is denoted as H-PVA-2.0TA / ACN.

[0041] Structural and performance tests were performed on Examples 2 and 3, as well as Comparative Examples 1, 2, and 3: Figure 3 Scanning electron microscopy (SEM) morphology and fiber diameter distribution of anthocyanin-loaded oral fiber membranes with different tannin additions. Figure 3 It can be seen that the H-PVA / ACN group without added tannic acid (Comparative Example 1) was able to form a continuous fiber structure. After adding tannic acid, the fiber morphology still maintained good continuity and uniformity, but the average fiber diameter increased with the increase of tannic acid content, from about 0.213 μm (Comparative Example 1) to about 0.577 μm (Example 2). This result indicates that the introduction of tannic acid can affect the inter-chain interactions and apparent viscosity of polymers in the spinning solution, thereby regulating the fiber formation behavior during electrospinning, resulting in a coarser fiber structure and a more stable fiber network in the obtained membrane. In the actual preparation process, it was found that when the TA mass concentration increased to 2.0% (Comparative Example 3), the viscosity of the electrospinning precursor solution increased significantly, the system fluidity decreased, and phenomena such as needle blockage, droplet accumulation, and jet interruption easily occurred during spinning, making it difficult to form a continuous and stable fiber membrane. Therefore, excessively high TA mass concentration is not conducive to the stable progress of the electrospinning process.

[0042] Figure 4 Evaluation figures show the mechanical properties, wet adhesion properties, structural support properties, and NaHCO3-assisted peeling properties of anthocyanin-loaded oral fiber membranes with different tannin addition amounts. Figure 4 A represents the test results of the membrane's elongation at break and tensile strength. Figure 4 B represents the results of Young's modulus and wet adhesion test. Figure 4 C is a physical observation diagram of the membrane's sealing performance, peeling process, and support performance. Figure 4 D represents the test results of peel force and support height after treatment with NaHCO3 solution. Figure 4It can be seen that the wet adhesion of the membranes without added tannic acid (Comparative Example 1) and with low content (Comparative Example 2) is relatively low, approximately 8.63~14.54 KPa. After introducing 1% (Example 2) and 1.5% (Example 3) tannic acid, the wet adhesion of the membranes is significantly improved, reaching 33.78~44.57 KPa. Simultaneously, the elastic support, sealing performance, and anti-disintegration ability of the membranes are all improved. These results indicate that introducing an appropriate amount of tannic acid into the optimized PVA / HPMC composite matrix can effectively enhance the interfacial adhesion of the membrane under humid conditions and improve the structural stability of the membrane after hydration.

[0043] Furthermore, by Figure 4 As shown in CD, the introduction of NaHCO3 solution into the membrane-tissue interface enabled the membrane to be effectively detached from the adhesion interface, with a detachment force of 6.83–8.67 kPa. This may be because the NaHCO3 solution altered the local interfacial environment, weakening hydrogen bonds and other non-covalent interactions between tannins, the membrane matrix, and the tissue surface, thus gradually loosening the originally stable adhesion interface. This result indicates that the anthocyanin oral fiber membrane constructed in this invention not only forms a stable adhesion under moist conditions but also exhibits removable properties under assisted treatment, which helps reduce the discomfort that may result from excessive adhesion during detachment.

[0044] Figure 5 UV shielding performance of anthocyanin-loaded oral fiber membranes with different tannin additions. Figure 5 As can be seen, compared with the membrane without added tannic acid (Comparative Example 1) and the membrane with low tannic acid content (Comparative Example 2), the membranes containing tannic acid (Examples 2 and 3) exhibited stronger UV blocking capabilities for both UV-A and UV-B, with a more significant blocking effect on UV-B. This result indicates that the introduction of tannic acid can improve the membrane's ability to shield against ultraviolet light, thereby reducing the damage of ultraviolet light to the anthocyanin structure. This effect may be related to the ultraviolet absorption capacity of the polyphenolic structure of tannic acid itself, and the fact that tannic acid promotes the formation of a coarser fibrous structure in the membrane, extending the optical transmission path.

[0045] Figure 6 Anthocyanin-loaded anthocyanin oral fiber membranes with different tannin additions exhibit color stability and anthocyanin retention properties during light storage. Figure 6It can be seen that after 14 days of continuous light exposure, the H-PVA / ACN group membrane without added tannic acid (Comparative Example 1) showed significant color changes and anthocyanin loss, while the group containing tannic acid exhibited a smaller increase in overall color difference, higher anthocyanin retention, lower degradation rate, and longer half-life. These results indicate that tannic acid can improve the light-induced storage stability of anthocyanins in the membrane. This may be because, on the one hand, tannic acid can enhance the membrane's UV shielding ability, reducing light-induced anthocyanin degradation; on the other hand, tannic acid can act as a co-coloring agent, forming non-covalent interactions such as hydrogen bonds and hydrophobic interactions with anthocyanins, thereby slowing down the structural transformation and degradation process of anthocyanins and improving the stability of the product during storage and use.

[0046] Figure 7 Anthocyanin release curves of anthocyanin-loaded oral fiber membranes with different tannin additions in artificial saliva. Figure 7 It can be seen that all groups of membranes exhibited rapid anthocyanin release characteristics in artificial saliva, indicating that the membranes can meet the rapid response requirements in the oral environment. Compared with the group without added tannins (Comparative Example 1) and the group with low tannin content (Comparative Example 2), the initial burst release of anthocyanins was moderated after the addition of tannins, and the release process was more stable; among them, the group with appropriate tannin content showed better cumulative release under acidic conditions. These results indicate that the present invention can improve the stability and effective release performance of the anthocyanin release process without affecting the rapid response of the oral environment.

[0047] Figure 8 Evaluation of the transfer performance of anthocyanin-loaded oral fiber membranes with different tannin addition amounts in an artificial mucus layer. Figure 8 It can be seen that the membrane regulated by tannic acid can improve the overall transport capacity of anthocyanins in the mucus layer, as evidenced by an increase in anthocyanin concentration and transport height in the mucus layer. This result indicates that the introduction of tannic acid helps improve interfacial contact after membrane hydration and the diffusion and transport of anthocyanins in the mucus environment. However, when the tannic acid content is too high, the short-term transmembrane permeability does not improve further, which may be related to the enhanced membrane network structure, enhanced interaction between anthocyanins and tannic acid, or increased diffusion resistance. Therefore, the amount of tannic acid added is not necessarily better the higher it is, but should be controlled within an appropriate range to balance wet adhesion, structural stability, and active ingredient transport performance.

Claims

1. An anthocyanin oral fibrous film, characterized by: The anthocyanin oral fiber membrane is a nanofiber membrane prepared by electrospinning using a spinning solution comprising polyvinyl alcohol, hydroxypropyl methylcellulose, tannic acid and anthocyanins; in the spinning solution, the mass ratio of polyvinyl alcohol to hydroxypropyl methylcellulose is 4:1 to 1:4, the mass concentration of tannic acid is 0.5% to 1.5%, and the mass concentration of anthocyanins is 1.0% to 3.0%.

2. The anthocyanin oral fiber membrane according to claim 1, characterized in that: The wet adhesion of the anthocyanin oral fiber membrane is 33~45 kPa; the peel strength of the anthocyanin oral fiber membrane after treatment with NaHCO3 solution is 6~9 kPa.

3. The method for preparing the anthocyanin oral fiber membrane according to claim 1 or 2, characterized in that: Polyvinyl alcohol and hydroxypropyl methylcellulose were heated and dissolved separately, then mixed evenly to obtain an electrospinning precursor solution. Tannic acid solution was then added to the above electrospinning precursor solution, followed by anthocyanin solution. The mixture was stirred at room temperature to form a homogeneous spinning solution. The spinning solution was injected into the injection pump of the electrospinning equipment, the electrospinning equipment was turned on, the parameters were adjusted, and spinning began to obtain a nanofiber membrane. After drying, the anthocyanin oral fiber membrane was obtained.

4. The method for preparing anthocyanin oral fiber membrane according to claim 3, characterized in that: The parameters of the electrospinning equipment are set as follows: the injection pump flow rate is 0.6~1 mL / h, the spinning voltage is 12~20 kV, the distance between the needle tip and the collector is 10~20 cm, the ambient temperature is 20~30℃, and the relative humidity is 60%~85%.

5. The method for preparing anthocyanin oral fiber membrane according to claim 3, characterized in that: The stirring conditions are as follows: magnetic stirring at a rate of 500-800 rpm for 1-3 hours.

6. The method for preparing anthocyanin oral fiber membrane according to claim 3, characterized in that: The drying conditions are equilibrium drying at 20~30℃ for 12~48 h.

7. The method for preparing anthocyanin oral fiber membrane according to claim 3, characterized in that: The tannic acid solution uses a 70% (v / v) aqueous ethanol solution as the solvent.

8. The method for preparing anthocyanin oral fiber membrane according to claim 3, characterized in that: The anthocyanin solution uses a citrate-sodium citrate buffer solution with a pH of 3.0 as the solvent.

9. The use of the anthocyanin oral fiber membrane according to claim 1 or 2 in the preparation of oral topical active ingredient delivery carriers.

10. The use of the anthocyanin oral fiber membrane according to claim 1 or 2 in the preparation of oral care membranes.

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