A multi-layered, alternating structure oral nicotine gel product and a method of making the same

Abstract

The application discloses a multi-layer alternative structure oral nicotine gel product and a preparation method thereof. The product comprises n nicotine gel layers and n+1 flavoring auxiliary layers, wherein n is a positive integer greater than or equal to 1; the nicotine gel layers and the flavoring auxiliary layers are arranged alternately in sequence, and the flavoring auxiliary layers are located at the outermost layers. By arranging the flavoring auxiliary layers without nicotine at the outermost layers of the product, direct contact between the nicotine gel layers and the oral mucosa is avoided, and the safety risk of consumers who are not tolerant to nicotine is reduced. In addition, the nicotine content of each nicotine gel layer can be independently set, avoiding the stimulation caused by the one-time large release of nicotine in traditional products. In addition, by introducing a concave-convex interlocking structure and a built-in support framework between the layers, the structural integrity and the anti-layering ability of the multi-layer product in the oral environment are significantly enhanced, and by embedding flavor burst beads, an optional sensory enhancement experience is provided.

Description

Technical Field

[0001] This invention belongs to the technical field of smokeless tobacco products and nicotine substitutes, specifically relating to a multi-layered alternating structure oral nicotine gel product and its preparation method. Background Technology

[0002] Oral cigarettes, as a new type of smokeless tobacco product, have advantages such as ease of use, no combustion required, and no secondhand smoke pollution, and have gradually become a research hotspot in the tobacco industry in recent years. Currently, commercially available oral cigarette products are mainly in pouch form, which involves mixing tobacco powder, nicotine salts, flavorings, fillers, and other ingredients and sealing them in a non-woven fabric pouch. Consumers place the pouch between their upper lip and gums, and the nicotine and flavor substances are gradually released through saliva.

[0003] With the continuous development of technology, multi-layered oral products have begun to emerge in the industry to accommodate nicotine release. For example, patent application CN120240696A discloses a multi-layered nicotine oral dissolution membrane, including a first membrane layer and a second membrane layer. The gradient release of nicotine is achieved through the difference in dissolution rates of the different membrane layers. However, the core of this solution is a thin-film structure with only two layers, which limits its product form, number of layers, and structural properties.

[0004] Patent application CN120391717A discloses a slow-release oral tobacco with a layered structure, consisting of a nicotine salt layer, a tobacco extract layer, and a tobacco powder layer from the inside out. Membranes with different permeability are provided between the layers to achieve precise controlled release. However, this product system contains tobacco raw materials and has only a three-layer fixed structure.

[0005] Patent application CN122397957A discloses a modular multi-layer composite nicotine bag, which includes a base module layer, a conditioning module layer, a flavoring module layer and a flavor module layer, etc., as a multi-layer non-woven composite sheet. However, its core substrate is a non-woven composite material, which is completely different from the product form of gel solid. The drug release principle and product structural characteristics are fundamentally different.

[0006] In addition, there are related technologies for nicotine controlled-release particles, which construct "core-shell" multi-layer structure particles by multi-layering and functionalizing the nicotine core particles to achieve layered release, but this type of technology is a granular dosage form.

[0007] While the aforementioned existing technologies all employ multi-layered structural designs to optimize nicotine release and have improved to some extent the problems of instantaneous nicotine release and poor user experience associated with traditional pouch-packaged cigarettes, the overall technical solutions still have the following issues:

[0008] First, there are safety concerns. Existing bagged cigarettes and some multi-layered oral products typically mix nicotine directly with flavorings or place it within adjacent layers. When a consumer puts the product in their mouth, the nicotine-containing layer comes into direct contact with the oral mucosa, where the nicotine is rapidly released and absorbed. For consumers with nicotine intolerance, this direct contact poses a significant safety risk, potentially leading to dizziness, nausea, and other discomfort. Once discomfort is felt, it is difficult to immediately stop consuming the product because the nicotine has already been absorbed through the mucosa.

[0009] Secondly, there are limitations in release time. Existing bagged cigarettes, because all components are mixed inside the bag, rely primarily on saliva to wet and dissolve the components, making precise control of the release rate difficult and resulting in a relatively short overall release time. While some multi-layered products achieve gradient release through membranes with different dissolution rates, their structural design is still primarily membrane-based, with a limited number of layers (usually 2-3), making it impossible to achieve a longer and more stable release curve.

[0010] Third, there is a lack of uniformity and customizability in nicotine release. In existing products, the distribution of nicotine is typically uniform or passively regulated only through interlayer permeation membranes. However, in actual use, due to gravity and the flow of saliva in the mouth, the dissolution and release of the product are directional—the part closest to the oral mucosa (i.e., the bottom) usually dissolves first. Existing technologies fail to fully utilize this physical law to design a gradient distribution of nicotine for a gentler release experience. Furthermore, existing products lack the flexibility to customize the nicotine content of each layer according to individual consumer needs.

[0011] Fourth, there is the issue of structural stability. Existing oral films or gels are mostly sheet-like or film-like, which are prone to deformation, melting, or adhesion to the oral mucosa in the oral environment. This not only affects the user experience but also makes removal inconvenient for consumers. Especially when consumers feel discomfort and need to remove the product immediately, melted or adhered products are difficult to remove intact. Furthermore, and more importantly, after prolonged use in the moist oral environment, the multi-layered stacked structure is prone to interfacial separation and delamination between layers, compromising product integrity. This not only affects the predictability of the release curve but may also cause the nicotine gel layer to be accidentally exposed to the oral mucosa, increasing safety risks.

[0012] Fifth, the problems caused by tobacco powder. Some existing oral tobacco products still contain tobacco powder, which may not only result in an unpleasant taste, but also leave residue in the mouth, affecting oral hygiene.

[0013] In summary, current multi-layered oral lozenges generally suffer from low safety profiles, insufficient nicotine release duration and stability, poor personalization, and weak structural stability, failing to simultaneously meet multiple usage requirements such as safe use, long-lasting and stable drug release, superior taste, and structural stability. Therefore, developing a tobacco-free, structurally stable, long-lasting, and stable gradient nicotine release product with high safety profile has become an urgent technical challenge in this field.

[0014] To address the above problems, this invention is proposed. Summary of the Invention

[0015] To address the shortcomings of existing technologies, this invention provides a multi-layered, alternating structure oral nicotine gel product and its preparation method. The product employs a multi-layered (odd-numbered layers) alternating stacked design similar to a "hamburger," for example, a 7-layer oral nicotine gel product consists of 3 layers of nicotine gel and 4 layers of flavoring and excipients arranged alternately, with the outermost layers (i.e., the 1st and 7th layers) being flavoring and excipient layers. This structural design ensures that during use, the oral cavity first comes into contact with the nicotine-free flavoring and excipient layers, rather than directly with the nicotine gel layer, thus greatly improving safety. Simultaneously, through the alternating stacking of layers and the independent customization of the nicotine content in each layer, a long-lasting, uniform, and gentle release of nicotine is achieved. Furthermore, this invention significantly enhances the structural integrity and anti-delamination ability of the multi-layered product in the oral environment by introducing interlocking structures and an internal support framework between the layers, while also providing optional sensory enhancement experiences through the embedding of flavor burst beads.

[0016] The technical solution of this invention is as follows:

[0017] The first aspect of the present invention provides a multi-layered alternating structure oral nicotine gel product, comprising n layers of nicotine gel and n+1 layers of flavoring and fragrance excipients, where n is a positive integer ≥1; the nicotine gel layers and the flavoring and fragrance excipients layers are arranged alternately in sequence, and the flavoring and fragrance excipients layers are located on the outermost layer.

[0018] A multi-layered alternating structure oral nicotine gel product is characterized by being composed of an odd number of alternating layers of flavoring and excipients and nicotine gel layers, with the outermost two layers being flavoring and excipient layers. Taking a 7-layer structure as an example, from top to bottom, they are:

[0019] Layer 1: Fragrance and flavoring auxiliary material layer (outermost layer, nicotine-free)

[0020] Layer 2: Nicotine gel layer

[0021] Layer 3: Fragrance and flavoring additives layer (nicotine-free)

[0022] 4th layer: Nicotine gel layer

[0023] 5th layer: Fragrance and flavoring additives layer (nicotine-free)

[0024] Layer 6: Nicotine gel layer

[0025] 7th layer: Fragrance and flavoring auxiliary material layer (outermost layer, nicotine-free)

[0026] That is, the flavor and fragrance auxiliary material layer and the nicotine gel layer are arranged alternately, with a total number of odd-numbered layers (seven layers), of which 3 layers are nicotine gel layers, 4 layers are flavor and fragrance auxiliary material layers, and the outermost two layers of the product are flavor and fragrance auxiliary material layers.

[0027] The total number of layers in the product of this invention is not limited to seven layers. It can also be five layers (two nicotine gel layers + three alternating fragrance and flavoring layers), nine layers (four nicotine gel layers + five alternating fragrance and flavoring layers), or other odd-numbered layer combinations, as long as the outermost two layers are both fragrance and flavoring layers, and the nicotine gel layer and fragrance and flavoring layers are arranged alternately.

[0028] Preferably, the adjacent nicotine gel layers and the fragrance and flavoring auxiliary material layers are bonded together by an interlocking structure.

[0029] The interlocking structure is as follows: at the adjacent interface between the nicotine gel layer and the fragrance and flavoring auxiliary material layer, one layer is provided with a protrusion, and the other layer is provided with a groove of a matching shape at the corresponding position. The protrusion is embedded in the groove to form a mechanical lock.

[0030] Furthermore, the protrusion includes a positioning post or positioning strip. In production, the shape of the protrusion is selected according to the actual situation. It can be a regular cylinder, a frustum with unequal top and bottom areas, a cuboid, or a trapezoidal prism (similar to a mortise and tenon joint).

[0031] In other words, the groove can be located on either the nicotine gel layer or the flavor and fragrance auxiliary layer, as long as it is another protrusion that is compatible with the groove.

[0032] Preferably, the interlocking structure is formed by first forming a layer with the raised pattern in the mold during casting, and then casting another layer of material that matches the first layer so that the other layer flows into the gap between the raised parts, and then cooling and solidifying to form an interlocking structure.

[0033] or,

[0034] The interlocking structure is formed by first creating a layer with the groove pattern in the mold during casting, then casting another layer of material that matches this layer so that the other layer flows into the groove, and finally forming an interlock after cooling and solidification.

[0035] Preferably, the flavoring and fragrance excipient layer is a solid sheet layer, comprising the following raw materials:

[0036] Water-soluble polymeric film-forming material: 30-50 parts by weight;

[0037] Fragrance and flavoring: 5-15 parts by weight;

[0038] Sweetener: 1-3 parts by weight;

[0039] Plasticizer: 5-15 parts by weight;

[0040] Purified water, balance (i.e., purified water: make up to 100 parts by mass. The sum of the mass parts of all components is 100 parts by mass.).

[0041] The water-soluble polymeric film-forming material includes one or more of hydroxypropyl methylcellulose, polyvinyl alcohol, or pullulan.

[0042] The flavorings include one or more of menthol, fruit flavorings, or floral flavorings;

[0043] The sweetener includes one or more of sucralose or aspartame;

[0044] The plasticizer includes one or more of glycerol or propylene glycol.

[0045] The flavoring and fragrance auxiliary layer of the present invention is prepared from the above raw materials, wherein the types and amounts of flavorings and fragrances in the flavoring and fragrance auxiliary layer can be adjusted according to the target flavor.

[0046] Preferably, the flavoring and fragrance excipient layer does not contain nicotine. This layer has a certain dissolution rate in oral saliva, enabling it to quickly release its aroma after the product is placed in the mouth, providing a good initial taste experience, while also acting as a physical barrier to separate the nicotine gel layer from the oral mucosa.

[0047] Preferably, at least one of the flavoring and fragrance excipient layers contains an edible, saliva-insoluble mesh-like support framework. This mesh-like support framework is made of food-grade insoluble material (preferably ethyl cellulose, hydroxypropyl methylcellulose, or edible polyester fiber). The mesh-like support framework has regularly arranged mesh pores and maintains a solid state during product use, providing overall support for the multi-layered alternating structure and preventing the product from disintegrating too quickly in the oral cavity. The food-grade insoluble material includes ethyl cellulose, hydroxypropyl methylcellulose, or edible polyester fiber.

[0048] Preferably, flavor burst beads are embedded in the mesh holes of the mesh-like support skeleton. The outer shell of the flavor burst beads is an edible polymer material (preferably sodium alginate-chitosan composite wall material), and the inside is encapsulated with flavor oil. The burst beads break in the oral saliva environment or under external force biting, releasing flavor substances and providing additional sensory stimulation. The edible polymer material includes sodium alginate-chitosan composite wall material.

[0049] Preferably, the nicotine gel layer is a gel-like solid layer (similar to a jelly-like semi-solid layer), comprising the following raw materials:

[0050] Gel matrix: 8-15 parts by weight;

[0051] Nicotine salts: 1.5-4 parts by weight;

[0052] Moisturizer: 10-25 parts by weight;

[0053] pH adjuster: 0.5-2 parts by weight;

[0054] Purified water, balance (i.e., purified water: make up to 100 parts by mass. The sum of the mass parts of all components is 100 parts by mass.).

[0055] The gel matrix includes one or more of carrageenan, gelatin, gellan gum, or sodium alginate.

[0056] The nicotine salt includes one or more of nicotine tartrate or nicotine benzoate;

[0057] The moisturizer includes one or more of glycerin or sorbitol;

[0058] The pH adjuster includes one or more of sodium carbonate or disodium hydrogen phosphate.

[0059] The nicotine gel layer is a semi-solid gel-like layer, similar to jelly, which slowly dissolves in saliva and releases nicotine. The physical properties of the gel state give it excellent shape retention in the oral environment, making it resistant to deformation or melting.

[0060] The nicotine gel layer described in this invention is prepared from the above raw materials.

[0061] Preferably, the nicotine content in the multiple nicotine gel layers is uniformly distributed, or the layers are arranged sequentially from one side of the oral nicotine gel product to the other side along the thickness direction of the oral nicotine gel product, with the nicotine content increasing or decreasing in the nicotine gel layers.

[0062] In other words, the nicotine content in the multiple nicotine gel layers is distributed in a gradient from bottom to top. This gradient distribution from bottom to top includes either a decreasing gradient distribution of nicotine content in the nicotine gel layers from bottom to top, or an increasing gradient distribution of nicotine content in the nicotine gel layers from bottom to top.

[0063] A significant advantage of this invention is that the nicotine content in the multi-layered nicotine gel can be independently customized, thereby achieving gradient control of nicotine release. Taking a 7-layer structure as an example (3 nicotine gel layers and 4 flavoring and auxiliary material layers):

[0064] Option 1 (Uniform Distribution): When the target total nicotine amount is 1.5 mg, the nicotine can be evenly distributed among the three gel layers, with each layer containing 0.5 mg of nicotine. This uniform distribution method can achieve uniform overall release.

[0065] Option 2 (Decreased Gradient Distribution): Utilizing the physical principle of gravity when the product is placed in the mouth—due to the direction of gravity, the bottom layer (7th layer) of the product comes into full contact with and dissolves in saliva first. Therefore, the nicotine content can be set in descending order from bottom to top in the 3-layer nicotine gel. For example, when the target total nicotine amount is 1.5mg, the 6th layer (bottom gel) can be set to 0.7mg, the 4th layer (middle gel) to 0.5mg, and the 2nd layer (top gel) to 0.3mg. In this way, during product use, the lower high-content gel releases first to provide initial satisfaction, the middle layer releases subsequently to maintain nicotine levels, and the upper low-content gel releases last to achieve a smooth finish, resulting in a gentler and more stable overall release curve.

[0066] Option 3 (Incremental Gradient Distribution): The gradient is set in reverse, that is, the content is high in the upper layer and low in the lower layer. It is suitable for release needs that require rapid satisfaction in the first stage and gradual weakening in the second stage.

[0067] In other words, the gradient distribution direction of nicotine in this invention is not limited to decreasing from bottom to top, but can also be set to increasing from bottom to top or other distribution patterns according to actual needs.

[0068] Preferably, in the oral nicotine gel product, n=3; the nicotine content in the three nicotine gel layers is distributed in a decreasing gradient from bottom to top, and the nicotine content in the three nicotine gel layers is 0.7mg, 0.5mg, and 0.3mg respectively from bottom to top.

[0069] Preferably, the oral nicotine gel product is in sheet form, with a thickness of 2-8 mm, a length of 10-30 mm, and a width of 8-20 mm. The cross-sectional shape of the product can be rectangular, circular, or elliptical, and is not limited to the above shapes; it can also be other shapes suitable for oral administration.

[0070] The shape of the product of this invention is not limited to sheet (thickness less than the planar dimension), but can also be elongated cylindrical (thickness greater than the radial diameter), spherical, or other shapes suitable for oral administration.

[0071] Preferably, the oral nicotine gel product does not contain tobacco raw material powder.

[0072] A second aspect of the present invention provides a method for preparing the oral nicotine gel product described in the first aspect of the present invention, wherein the nicotine gel layer and the flavoring and excipient layer are bonded together through one of the following means:

[0073] Method 1, casting molding method: The raw materials are cast into the mold in order from bottom to top. After each layer is cast, it is cooled and solidified before the next layer is cast, and finally a complete multi-layer integrated structure is formed. The layers are connected by the physical bonding between adjacent layers, and the adhesion between the nicotine gel layer and the fragrance and flavoring auxiliary material layer is achieved.

[0074] Method 2, hot-pressing composite method: Each layer of sheet is prepared separately, and then the multiple layers of sheets are stacked in sequence. The layers are then composited by low-temperature hot pressing. Low-temperature hot pressing conditions: temperature is controlled at 40~60℃, and pressure is controlled at 0.5~2MPa.

[0075] Method 3, coating and drying method: each layer of raw material slurry is coated onto the substrate in sequence, and each layer is dried and cured after coating, and the layers are stacked one by one to form a multi-layer structure;

[0076] Preferably, when the adjacent nicotine gel layer and the flavoring and fragrance excipient layer are bonded together through an interlocking structure, the preparation method is selected from the casting molding method of method one. This specific case can be called the interlocking casting molding method. During the casting process, it is necessary to select a casting mold with a corresponding convex-concave design according to the concave-convex structure of the layer. The preparation method includes the following two cases:

[0077] Scenario 1: The preparation method includes the following steps:

[0078] (1) Casting the bottom layer, the protrusion is formed on the surface of the layer by the concave pattern on the surface of the mold, and a bottom layer with the protrusion on one side is obtained;

[0079] (2) Casting the intermediate layer: After the bottom layer cools and solidifies, the intermediate layer material that matches the bottom layer is cast so that the intermediate layer material wraps the protrusion of the bottom layer. After cooling and solidification, an interlocking structure is formed. The protrusion is formed on the side of the intermediate layer away from the bottom layer by the concave pattern on the mold surface, so that an intermediate layer with the groove on one side and the protrusion on the other side is obtained.

[0080] (3) Cast the top layer. After the middle layer cools and solidifies, cast the top layer material that matches the middle layer so that the top layer material wraps the protrusion of the middle layer. After cooling and solidification, an interlocking structure is formed to obtain a top layer with the groove on one side.

[0081] Scenario 2, the preparation method includes the following steps:

[0082] (a) Casting the bottom layer, using the convex pattern on the surface of the mold to form the groove on the surface of the bottom layer, to obtain the bottom layer with the groove on one side;

[0083] (b) Casting the intermediate layer: After the bottom layer cools and solidifies, casting the adjacent intermediate layer material that matches the bottom layer, so that the intermediate layer material flows into and fills the groove of the bottom layer, and after cooling, forming an interlocking structure of concave and convex, and forming the groove on the side of the intermediate layer away from the bottom layer by the convex pattern on the mold surface, so as to obtain an intermediate layer with the protrusion on one side and the groove on the other side.

[0084] (c) Cast the top layer. After the middle layer cools and solidifies, cast the top layer material that matches the middle layer. The top layer material flows into and fills the groove of the middle layer. After cooling and solidification, an interlocking structure is formed, resulting in a top layer with the protrusion on one side.

[0085] When the intermediate layer has multiple layers, repeat step (2) or step (b).

[0086] Preferably, method one is used to achieve interlayer bonding. The preparation method includes steps such as preparing a fragrance and flavoring auxiliary material slurry, preparing a nicotine gel layer slurry, casting and molding in sequence from bottom to top, and demolding and cutting.

[0087] The bottom-up order refers to the order from the bottom layer to the top layer.

[0088] Specifically, when method one (casting molding method) is used, the preparation method of the oral nicotine gel product with the multi-layered alternating structure includes the following steps:

[0089] Step 1: Preparation of the fragrance and flavor auxiliary material slurry. Add water-soluble polymeric film-forming material and sweetener to purified water, heat to 60~80℃ and stir to dissolve. After cooling to 40~50℃, add fragrance and flavor and plasticizer, stir evenly to obtain the fragrance and flavor auxiliary material slurry.

[0090] Step 2: Preparation of nicotine gel layer slurry. Add the gel matrix and humectant to purified water, heat to 70-90℃ and stir until completely dissolved. After cooling to 50-60℃, add nicotine salt and pH adjuster, stir evenly, and obtain nicotine gel layer slurry.

[0091] Step 3: Multi-layer casting. Following a bottom-up order, each layer of slurry is poured into the mold sequentially. Specifically:

[0092] First, pour the 7th layer (fragrance, flavoring and auxiliary material layer slurry) and let it cool and solidify.

[0093] The sixth layer (nicotine gel layer slurry) is poured on top of the seventh layer and allowed to cool and solidify.

[0094] The fifth layer (fragrance, flavoring and auxiliary material slurry) is poured on the sixth layer and cooled to solidify;

[0095] The fourth layer (nicotine gel layer slurry) is poured on the fifth layer and allowed to cool and solidify.

[0096] The third layer (fragrance, flavoring and auxiliary material slurry) is poured on the fourth layer and cooled to solidify;

[0097] The second layer (nicotine gel layer slurry) is poured on top of the third layer and allowed to cool and solidify.

[0098] The first layer (fragrance, flavoring and auxiliary material slurry) is poured on the second layer and cooled to solidify.

[0099] Preferably, when casting at least one layer of fragrance and flavoring additives, a pre-made mesh-like support skeleton is placed in the mold, and then the slurry is poured to embed the mesh-like support skeleton; or after casting is completed and before cooling and solidification, the pre-made mesh-like support skeleton is pressed into the surface of the layer so that the mesh-like support skeleton is embedded in the interior of the layer.

[0100] Preferably, after casting and before cooling and solidification, the flavor burst beads are embedded in the mesh holes of the mesh-like support skeleton.

[0101] Step 4: Demolding and Cutting. Remove the molded seven-layer structure from the mold, cut it to the required size, and package it to obtain the finished product.

[0102] When method two (hot-pressing composite method) is selected, the preparation method of the oral nicotine gel product with the multi-layered alternating structure includes the following steps:

[0103] (1) Prepare fragrance and flavor additive layer sheets and nicotine gel layer sheets respectively: Prepare slurry according to their respective formulas, cast them into sheets of corresponding thicknesses, and set them aside after cooling and solidification;

[0104] (2) Stack the sheets in order from bottom to top (7th layer → 6th layer → 5th layer → 4th layer → 3rd layer → 2nd layer → 1st layer).

[0105] (3) Place the stacked multilayer sheets in a hot press and hot press them at a temperature of 40~60℃ and a pressure of 0.5~2MPa for 1~5min. Preferably, before stacking, embossing is performed on the surface of at least one layer to form a raised or grooved pattern. During hot pressing, the raised parts of the adjacent layers are embedded in the grooves to form a tenon and mortise interlocking. Alternatively, at least one layer of fragrance and flavor auxiliary material sheet is pre-perforated to form a through-hole array. During hot pressing, the adjacent nicotine gel sheet partially melts and flows into the through-hole to form a pin anchor.

[0106] (4) After cooling, cut to the required size and package to obtain the finished product.

[0107] The specific steps of Method 3 (coating and drying method):

[0108] When method three (coating and drying method) is selected, the preparation method of the oral nicotine gel product with the multilayer alternating structure includes the following steps:

[0109] (1) Prepare the fragrance and flavor additive layer slurry and the nicotine gel layer slurry respectively;

[0110] (2) On a flat substrate (such as food-grade stainless steel strip or polytetrafluoroethylene film), apply each layer of slurry in the order from bottom to top: first apply the 7th layer (fragrance and flavor auxiliary material slurry), and after drying and curing, form a solid layer; then apply the 6th layer (nicotine gel layer slurry) on the 7th layer, and after drying and curing; and so on, until the 1st layer (fragrance and flavor auxiliary material slurry) is applied.

[0111] (3) The thickness of each coating layer is controlled by the gap of the scraper of the coater. The drying conditions after each coating layer are hot air drying at 40~60℃ and drying time is 10~30min.

[0112] (4) Peel the formed multi-layer structure from the substrate, cut it to the required size, and package it to obtain the finished product.

[0113] Specifically, when using the interlocking casting molding method (when adjacent nicotine gel layers and flavoring and excipient layers are bonded together through an interlocking structure), the preparation method of the multi-layered alternating structure oral nicotine gel product includes the following steps:

[0114] (1) Prepare the fragrance and flavor additive layer slurry and the nicotine gel layer slurry respectively;

[0115] (2) Interlocking casting:

[0116] First, pour the seventh (bottom) layer of flavoring and auxiliary material slurry to the set thickness and cool it to a semi-solid state. Use a template with raised or recessed patterns to imprint its surface, or directly use a mold with raised or recessed patterns to create grooves or raised areas on the surface of the seventh layer. Continue cooling until fully solidified. Then, pour the sixth layer of nicotine gel slurry, allowing the gel slurry to flow into the grooves of the seventh layer or wrap around the raised areas of the seventh layer, covering it to the set thickness. After cooling and solidification, a mechanical interlocking effect is formed between the sixth and seventh layers. Form grooves or raised areas on the upper surface of the sixth nicotine gel layer in the same way, then pour the fifth layer of flavoring and auxiliary material slurry, allowing it to flow into the grooves or wrap around the raised areas. After cooling and solidification, an interlocking effect is formed. Repeat the above operations to complete the pouring of the fourth, third, second, and first layers. Each layer is cooled and solidified before pouring the next layer.

[0117] (3) Optimized process parameters:

[0118] The preferred casting temperature for the flavoring and fragrance additive layer slurry is 40–50°C; the preferred casting temperature for the nicotine gel layer slurry is 50–60°C. Each layer is cooled to complete solidification after casting before casting the next layer. The preferred diameter of the through holes is 0.5–1.2 mm, and the preferred spacing between holes is 2–5 mm. The preferred height of the protrusions is 0.2–1.0 mm, and the preferred width of the protrusions is 0.5–3 mm.

[0119] If a grid-like support framework and flavor capsules are embedded in the flavor and fragrance auxiliary material layer, the framework and capsule positions should be avoided when forming the interlocking structure, or the grooves should be formed first and then the framework and capsules should be embedded to avoid the imprinting template damaging the framework and capsules.

[0120] (4) Demolding and cutting:

[0121] After all layers have been cast and cooled to solidify, the product is removed from the mold, cut to the required size, and packaged to obtain the finished product.

[0122] The advantages of this invention's multi-layered alternating structure oral nicotine gel product and its preparation method are as follows: 1. Enhanced safety: By placing the nicotine-free flavoring and excipient layer on the outermost layer of the product, direct contact between the nicotine gel layer and the oral mucosa is avoided, reducing the safety risks for consumers with nicotine intolerance; simultaneously, the solid and gel-state solid morphology design makes the product easy to remove intact. 2. Extended release time: The seven-layered alternating stacked "layer-by-layer progressive" release mode significantly extends the single use time of nicotine to 1 hour compared to the one-time immersion release of traditional pouch-packaged oral cigarettes. 3. Improved release gentleness: Through the independent content customization and gradient distribution design of the three nicotine gel layers (e.g., from bottom to top 0.7mg→0.5mg→0.3mg), a gentle release curve of "strong first, then weak" is achieved by utilizing the physical law of gravity. 4. Good structural stability: The combined structure of the solid excipient layer and the gel-state solid layer makes the product less prone to deformation, melting, or adhesion to the oral mucosa under oral temperature conditions. 5. High interlayer bonding strength: The interlocking structure significantly enhances the anti-peeling ability between layers. Even after partial dissolution of the flavoring and fragrance layers, the interlocking structure maintains the relative positions of each layer, preventing delamination in multi-layered products during later use and ensuring the predictability of the release curve and safety. 6. Strong anti-disintegration ability: The built-in edible mesh skeleton provides mechanical support for the entire product. As the flavoring and fragrance layers gradually dissolve, the skeleton maintains the overall shape of the product, preventing premature disintegration and extending the effective usage time. It also facilitates complete removal after use. 7. Customizable sensory experience: Flavor burst beads embedded in the mesh holes allow consumers to selectively obtain additional flavor bursts through active chewing, achieving a dual-mode release of "basic continuous release + on-demand pulsed release," enhancing the product's interactivity and personalized experience. 8. Tobacco powder-free: Nicotine salts are used instead of tobacco powder as the nicotine source, avoiding unpleasant taste and oral residue.

[0123] Compared with the prior art, the present invention has the following beneficial effects:

[0124] 1. The four flavoring and fragrance layers of the product of this invention are all solid sheet layers. Three layers (layers 1, 3, and 5) act as separators, separating the three nicotine gel layers from each other. The outermost two layers (layers 1 and 7) are nicotine-free flavoring and fragrance layers. When a consumer places the product in their mouth, the oral mucosa first comes into contact with the nicotine-free flavoring and fragrance layers. The nicotine gel layers are encapsulated and isolated by these layers, preventing direct contact with the oral mucosa. This significantly reduces the risk of nicotine burst release, making it especially safe for consumers with nicotine intolerance. Furthermore, because each layer is solid or gel-like, the product is less likely to melt or leak in the mouth, allowing for easy and complete removal if discomfort is experienced, further ensuring safety.

[0125] 2. Through a seven-layer alternating stacked structure, three nicotine gel layers are physically separated by four layers of flavoring and fragrance additives. In oral saliva, each layer needs to dissolve sequentially—the outer flavoring and fragrance additive layer dissolves first, exposing the inner nicotine gel layer; after the gel layer dissolves, the next flavoring and fragrance additive layer is exposed, and so on. This "layer-by-layer" release mode, compared to the "one-time complete immersion" mode of pouch-packaged cigarettes, greatly extends the overall nicotine release time.

[0126] 3. The nicotine content of each nicotine gel layer in this invention can be set independently. It can be either uniformly distributed to achieve stable release or gradient distributed (such as decreasing from bottom to top) to achieve a gentle release curve of "concentrated first and then diluted" by utilizing the physical law of gravity, thus avoiding the irritation caused by a large release of nicotine at once in traditional products.

[0127] 4. The interlocking structure of the interlayered concave and convex layers of the present invention effectively solves the technical problem of easy delamination and peeling of multilayer products during long-term use in the moist environment of the oral cavity. During use, the protrusions of the fragrance and flavoring excipient layer or nicotine gel layer always maintain an elastomeric state in the oral cavity. Even if the surrounding matrix dissolves, the protrusions and grooves can still "rivet" the adjacent layers together, maintaining the integrity of the product.

[0128] 5. This invention is the first to introduce an edible, insoluble mesh framework into oral nicotine products. This framework serves two purposes: firstly, as a "structural reinforcing bar" that imparts excellent anti-disintegration properties to the product; and secondly, as a "functional carrier" to contain the flavor burst beads. This "framework + burst bead" combination design achieves a synergistic unity of structural support and functional release. Consumers can actively trigger additional flavor pulses through chewing during the basic release process, according to their personal preferences.

[0129] 6. The nicotine of this invention is derived from nicotine salts and does not contain tobacco powder raw materials, thus avoiding the unpleasant taste and oral residue problems caused by tobacco powder in traditional oral cigarettes, while also circumventing some regulatory restrictions on tobacco products.

[0130] 7. The flavoring and fragrance auxiliary layer of this invention is a solid sheet layer, and the nicotine gel layer is a semi-solid gel similar to jelly. Both layers are solid or semi-solid, exhibiting excellent shape retention. At oral temperature (approximately 37°C), the product will not melt or deform, demonstrating good structural stability and maintaining its intact shape throughout consumer use, resulting in a positive user experience.

[0131] 8. In particular, the product of the present invention differs from the product in the patent application mentioned in the background art in that: (1) the present invention adopts an odd number of alternating stacked structure, specifically n layers of nicotine gel layer and n+1 layers of flavoring and fragrance auxiliary material layer are arranged alternately, and the outermost layer of the product is a nicotine-free flavoring and fragrance auxiliary material layer; (2) the present invention adopts a composite structure of alternating stacked gel solid layer and solid sheet layer, abandoning the traditional film layer and non-woven fabric layer structure; (3) the product system of the present invention does not add tobacco raw material powder at all. Attached Figure Description

[0132] Figure 1 This is a schematic diagram of the overall structure of the oral nicotine gel product with a 7-layer alternating structure in Embodiment 1 of the present invention.

[0133] Figure 2 This is a schematic diagram of the overall structure of the oral nicotine gel product with an interlocking structure between the flavor and fragrance auxiliary material layer and the nicotine gel layer in Embodiment 3 of the present invention.

[0134] Figure 3 This is a partial cross-sectional schematic diagram of an oral nicotine gel product with an interlocking structure between the fragrance and flavoring auxiliary material layer and the nicotine gel layer in Embodiment 3 of the present invention.

[0135] Figure 4 This is a top view of the fragrance and flavoring auxiliary material layer with embedded mesh-like support skeleton and popping beads in Embodiment 3 of the present invention.

[0136] The component names corresponding to the reference numerals in the attached diagram are as follows: 1-First flavor and fragrance auxiliary layer; 2-First nicotine gel layer; 3-Second flavor and fragrance auxiliary layer; 4-Second nicotine gel layer; 5-Third flavor and fragrance auxiliary layer; 6-Third nicotine gel layer; 7-Fourth flavor and fragrance auxiliary layer; 8-Protrusion; 9-Groove; 10-Grid-like support skeleton; 11-Grid holes; 12-Flavor burst beads;

[0137] Among them, the first flavoring and fragrance auxiliary material layer 1 is the outermost layer and also the top layer, which does not contain nicotine;

[0138] The second flavoring and fragrance auxiliary layer 3 is an intermediate layer and does not contain nicotine; the third flavoring and fragrance auxiliary layer 5 is an intermediate layer and does not contain nicotine.

[0139] The fourth layer of flavorings and fragrances, layer 7, is the outermost and bottom layer, and does not contain nicotine. Detailed Implementation

[0140] The present invention will be further described below through embodiments, but is not limited to these embodiments. Experimental methods not specifically described in the embodiments generally use conventional conditions and conditions described in manuals, or conditions recommended by the manufacturer. The general equipment, materials, reagents, etc., used are all commercially available unless otherwise specified.

[0141] Example 1:

[0142] Objective: To prepare a nicotine gel product with a total nicotine content of 1.5 mg and a seven-layer alternating structure (n=3), wherein the nicotine content in the multiple nicotine gel layers is uniformly distributed.

[0143] like Figure 1 The oral nicotine gel product includes a first flavoring and fragrance auxiliary layer 1 (the outermost and top layer, which does not contain nicotine), a first nicotine gel layer 2, a second flavoring and fragrance auxiliary layer 3 (which does not contain nicotine), a second nicotine gel layer 4, a third flavoring and fragrance auxiliary layer 5 (which does not contain nicotine), a third nicotine gel layer 6, and a fourth flavoring and fragrance auxiliary layer 7 (the outermost and bottom layer, which does not contain nicotine).

[0144] 1. Fragrance and flavor additive layer slurry formula (dosage per layer):

[0145]

[0146] 2. Nicotine gel layer slurry formulation (dosage per layer):

[0147]

[0148] 3. Preparation steps:

[0149] (1) Hydroxypropyl methylcellulose and sucralose are added to purified water, heated to 70°C and stirred to dissolve. After cooling to 45°C, menthol and glycerin are added and stirred evenly to obtain the flavor and fragrance auxiliary material slurry.

[0150] (2) Add carrageenan and glycerin to purified water, heat to 80°C and stir until completely dissolved, cool to 55°C and add nicotine tartrate and sodium carbonate, stir evenly to obtain nicotine gel layer slurry.

[0151] (3) Cast the following layers in the mold from bottom to top: 7th layer (fragrance and flavor auxiliary material slurry, about 0.5 mm thick) → cool and solidify → 6th layer (nicotine gel layer slurry, about 0.8 mm thick) → cool and solidify → 5th layer (fragrance and flavor auxiliary material slurry) → cool and solidify → 4th layer (nicotine gel layer slurry) → cool and solidify → 3rd layer (fragrance and flavor auxiliary material slurry) → cool and solidify → 2nd layer (nicotine gel layer slurry) → cool and solidify → 1st layer (fragrance and flavor auxiliary material slurry) → cool and solidify.

[0152] (4) Demold, cut into 20mm×12mm sheet products, and package.

[0153] 4. Effects: After the product is placed in the mouth, the outermost layer of flavoring and excipients first releases a minty aroma, followed by three layers of nicotine gel that release nicotine evenly in sequence (0.5mg per layer). The overall release is stable, and a single use lasts for about 1 hour.

[0154] Example 2:

[0155] Objective: To prepare a nicotine gel product with a total nicotine content of 1.5 mg and a seven-layer alternating structure (n=3), wherein the nicotine content in the multiple nicotine gel layers is distributed in a gradient manner (decreasing from bottom to top).

[0156] like Figure 1 The oral nicotine gel product includes a first flavoring and fragrance auxiliary layer 1 (the outermost and top layer, which does not contain nicotine), a first nicotine gel layer 2, a second flavoring and fragrance auxiliary layer 3 (which does not contain nicotine), a second nicotine gel layer 4, a third flavoring and fragrance auxiliary layer 5 (which does not contain nicotine), a third nicotine gel layer 6, and a fourth flavoring and fragrance auxiliary layer 7 (the outermost and bottom layer, which does not contain nicotine).

[0157] 1. Fragrance and flavor additive layer slurry formula (dosage per layer):

[0158]

[0159] 2. Nicotine gel layer slurry formulation:

[0160]

[0161] 3. Preparation steps:

[0162] The preparation steps are the same as in Example 1, except that the three nicotine gel layers use different slurry formulations (different nicotine contents), and are cast sequentially in the order of the 6th layer (0.7mg) → the 4th layer (0.5mg) → the 2nd layer (0.3mg).

[0163] 4. Effects: When placed in the mouth, due to gravity, the bottom layer (the 7th layer) of the product first comes into full contact with saliva. After the 7th layer of flavoring and excipients dissolves, the 6th layer of nicotine gel (0.7mg) is exposed, releasing a higher concentration of nicotine to provide initial satisfaction. Subsequently, the 5th layer of flavoring and excipients dissolves, exposing the 4th layer of nicotine gel (0.5mg), releasing a moderate concentration of nicotine to maintain satisfaction. Finally, the 3rd layer of flavoring and excipients dissolves, exposing the 2nd layer of nicotine gel (0.3mg), releasing a lower concentration of nicotine for a smooth finish. The entire release process presents a gentle curve of "strong at first, then weak," avoiding the irritation caused by a large release of nicotine at once.

[0164] Example 3:

[0165] Objective: To prepare a seven-layer alternating structure oral nicotine gel product (n=3) with an interlocking concave-convex structure and a mesh skeleton, wherein the nicotine content in the multiple nicotine gel layers is uniformly distributed.

[0166] like Figure 2-4 The oral nicotine gel product includes a first flavoring and fragrance auxiliary layer 1 (the outermost and top layer, which does not contain nicotine), a first nicotine gel layer 2, a second flavoring and fragrance auxiliary layer 3 (which does not contain nicotine), a second nicotine gel layer 4, a third flavoring and fragrance auxiliary layer 5 (which does not contain nicotine), a third nicotine gel layer 6, and a fourth flavoring and fragrance auxiliary layer 7 (the outermost and bottom layer, which does not contain nicotine).

[0167] The first flavor and fragrance auxiliary layer 1 facing the first nicotine gel layer 2, the first nicotine gel layer 2 facing the second flavor and fragrance auxiliary layer 3, the second flavor and fragrance auxiliary layer 3 facing the second nicotine gel layer 4, the second nicotine gel layer 4 facing the third flavor and fragrance auxiliary layer 5, the third flavor and fragrance auxiliary layer 5 facing the third nicotine gel layer 6, and the third nicotine gel layer 6 facing the fourth flavor and fragrance auxiliary layer 7 all have protrusions 8; correspondingly, the first nicotine gel layer 2 facing the first flavor and fragrance auxiliary layer 1, the second flavor and fragrance auxiliary layer 3 facing the first nicotine gel layer 2, the second nicotine gel layer 4 facing the second flavor and fragrance auxiliary layer 3, the third flavor and fragrance auxiliary layer 5 facing the second nicotine gel layer 4, the third nicotine gel layer 6 facing the third flavor and fragrance auxiliary layer 5, and the fourth flavor and fragrance auxiliary layer 7 facing the third nicotine gel layer 6 all have grooves 9.

[0168] The first flavor and fragrance auxiliary layer 1, the second flavor and fragrance auxiliary layer 3, the third flavor and fragrance auxiliary layer 5, and the fourth flavor and fragrance auxiliary layer 7 all have a grid-like support skeleton 10. The grid-like support skeleton 10 has regularly arranged grid holes 11, and flavor burst beads 12 are embedded in the grid holes.

[0169] 1. Fragrance and flavor additive layer slurry formulation (dosage per layer): Same as Example 1.

[0170] 2. Nicotine gel layer slurry formulation (dosage per layer): Same as in Example 1.

[0171] 3. Mesh-like support skeleton: food-grade ethyl cellulose is 3D printed into square mesh sheets with mesh hole size of 2mm×2mm and skeleton wire diameter of 0.5mm. The overall size is adapted to the product size (20mm×12mm).

[0172] 4. Flavored popping beads: Peppermint oil is encapsulated using sodium alginate-chitosan composite wall material. The popping beads have a diameter of 1.5mm and contain an average of 5μL of peppermint oil per bead.

[0173] 5. Preparation steps:

[0174] (1) Prepare the flavor and fragrance auxiliary material slurry and the nicotine gel slurry in the same way as in Example 1.

[0175] (2) Casting the 7th layer (bottom layer, flavoring and auxiliary material slurry): After casting and before cooling and solidification, lay the pre-made mesh support skeleton flat on the surface of the slurry, gently press it down so that the skeleton is partially embedded in the slurry, and then cool and solidify to integrate the mesh support skeleton with the 7th layer. Embed flavor popping beads (1 per hole) in the mesh holes of the mesh support skeleton, with the popping beads partially exposed on the surface of the 7th layer. When casting the 7th layer, the convex pattern on the surface of the mold is used to form grooves on the surface of the layer, resulting in the bottom layer with the grooves on one side (the side near the 6th layer is grooved, and the side away from the 6th layer is flat, serving as the outermost layer) (groove diameter 0.8mm, spacing between adjacent grooves 3mm);

[0176] (3) Cast the 6th layer (intermediate layer, nicotine gel layer slurry) on the 7th layer. After the 7th layer cools and solidifies, cast the 6th layer so that the material of the 6th layer flows into and fills the groove of the 7th layer. After cooling and solidification, an interlocking structure is formed. The convex pattern on the surface of the mold makes the side of the 6th layer away from the 7th layer form a groove, resulting in a 6th layer with a protrusion on one side and a groove on the other side (the side of the 6th layer facing the 7th layer is protruding, and the side of the 6th layer facing the 5th layer is grooved). Anchor the 6th layer to the 7th layer.

[0177] (4) Following the method in step (3), cast the 5th layer (intermediate layer, flavor and fragrance auxiliary material slurry), the 4th layer (intermediate layer, nicotine gel layer slurry), the 3rd layer (intermediate layer, flavor and fragrance auxiliary material slurry), and the 2nd layer (intermediate layer, nicotine gel layer slurry) in sequence.

[0178] (5) Cast the first layer (top layer, fragrance and flavor additive slurry) on the second layer. After the second layer cools and solidifies, cast the first layer so that the material of the first layer flows into and fills the groove of the second layer. After cooling and solidification, an interlocking structure is formed, resulting in a first layer with a protrusion on one side (the side of the first layer facing the second layer is protruding, and the side away from the second layer is flat, serving as the outermost layer). Anchor the first layer to the second layer; this first layer serves as the top layer.

[0179] The 5th, 3rd and 1st layers (all flavor and fragrance auxiliary material layers) are embedded with a grid-like support skeleton and flavor burst beads in the manner of step (2).

[0180] (6) Demold, cut into 20mm×12mm sheet products, and package.

[0181] 6. Effects: When used in the mouth, the interlocking structure significantly enhances the interlayer bonding. After one hour of continuous use, the layers remained intact and showed no delamination. The mesh framework maintained the overall shape of the product throughout use; even when the outer flavoring and fragrance layers partially dissolved, the product did not disintegrate or fragment. Consumers can actively press the product with their tongue or teeth to break the capsules, releasing additional mint flavor and providing an immediate cooling sensation, achieving a dual-mode sensory experience of "continuous release + on-demand pulse."

[0182] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A multi-layered alternating structure oral nicotine gel product, characterized in that, It comprises n layers of nicotine gel and n+1 layers of flavoring and fragrance additives, where n is a positive integer ≥1; the nicotine gel and flavoring and fragrance additives are arranged alternately in sequence, and the flavoring and fragrance additives are located on the outermost layer.

2. The oral nicotine gel product according to claim 1, characterized in that, The adjacent nicotine gel layer and the fragrance and flavoring auxiliary material layer are bonded together by an interlocking structure. The interlocking structure is as follows: at the adjacent interface between the nicotine gel layer and the fragrance and flavoring auxiliary material layer, one layer is provided with a protrusion, and the other layer is provided with a groove of a matching shape at the corresponding position. The protrusion is embedded in the groove to form a mechanical lock.

3. The oral nicotine gel product according to claim 2, characterized in that, The interlocking structure is formed by first creating a layer with the raised pattern in the mold during casting, then casting another layer of material that matches the first layer so that the other layer flows into the gap between the raised parts, and finally forming an interlock after cooling and solidification. or, The interlocking structure is formed by first creating a layer with the groove pattern in the mold during casting, then casting another layer of material that matches this layer so that the other layer flows into the groove, and finally forming an interlock after cooling and solidification.

4. The oral nicotine gel product according to claim 1, characterized in that, The flavoring and fragrance additive layer is a solid sheet layer, comprising the following raw materials: Water-soluble polymeric film-forming material: 30-50 parts by weight; Fragrance and flavoring: 5-15 parts by weight; Sweetener: 1-3 parts by weight; Plasticizer: 5-15 parts by weight; Purified water, balance; The water-soluble polymeric film-forming material includes one or more of hydroxypropyl methylcellulose, polyvinyl alcohol, or pullulan. The flavorings include one or more of menthol, fruit flavorings, or floral flavorings; The sweetener includes one or more of sucralose or aspartame; The plasticizer includes one or more of glycerol or propylene glycol; The flavoring and fragrance additive layer does not contain nicotine.

5. The oral nicotine gel product according to claim 1, characterized in that, At least one of the flavoring and fragrance excipient layers contains an edible, saliva-insoluble mesh-like support framework. This mesh-like support framework is made of food-grade insoluble material and has regularly arranged mesh pores. During use, the mesh-like support framework maintains a solid state, providing overall support for the multi-layered alternating structure and preventing the product from disintegrating too quickly in the mouth. The food-grade insoluble material includes ethyl cellulose, hydroxypropyl methylcellulose, or edible polyester fiber. Flavor burst beads are embedded in the mesh holes of the mesh-like support skeleton. The outer shell of the flavor burst beads is made of edible polymer material and the inside is encapsulated with flavor oil. The burst beads break in the oral saliva environment or under external force biting, releasing flavor substances and providing additional sensory stimulation. The edible polymer material includes sodium alginate-chitosan composite wall material.

6. The oral nicotine gel product according to claim 1, characterized in that, The nicotine gel layer is a gel-state solid layer comprising the following raw materials: Gel matrix: 8-15 parts by weight; Nicotine salts: 1.5-4 parts by weight; Moisturizer: 10-25 parts by weight; pH adjuster: 0.5-2 parts by weight; Purified water, balance; The gel matrix includes one or more of carrageenan, gelatin, gellan gum, or sodium alginate. The nicotine salt includes one or more of nicotine tartrate or nicotine benzoate; The moisturizer includes one or more of glycerin or sorbitol; The pH adjuster includes one or more of sodium carbonate or disodium hydrogen phosphate.

7. The oral nicotine gel product according to claim 1, characterized in that, The nicotine content in the multiple nicotine gel layers is uniformly distributed, or the layers are arranged sequentially from one side of the oral nicotine gel product to the other side along the thickness direction of the oral nicotine gel product, with the nicotine content increasing or decreasing in the nicotine gel layers.

8. The oral nicotine gel product according to claim 1, characterized in that, The oral nicotine gel product is in sheet form, with a thickness of 2-8 mm, a length of 10-30 mm, and a width of 8-20 mm; The shape of the product can be rectangular, circular, or oval; The oral nicotine gel product does not contain tobacco raw material powder.

9. A method for preparing an oral nicotine gel product according to any one of claims 1-8, characterized in that, The nicotine gel layer and the flavor and fragrance additive layer are bonded together through one of the following methods: Method 1, casting molding method: The raw materials are cast into the mold in order from bottom to top. After each layer is cast, it is cooled and solidified before the next layer is cast, and finally a complete multi-layer integrated structure is formed. The layers are connected by the physical bonding between adjacent layers, and the adhesion between the nicotine gel layer and the fragrance and flavoring auxiliary material layer is achieved. Method 2, hot-pressing composite method: Each layer of sheet is prepared separately, and then the multiple layers of sheets are stacked in sequence. The layers are then composited by low-temperature hot pressing. Low-temperature hot pressing conditions: temperature is controlled at 40~60℃, and pressure is controlled at 0.5~2MPa. Method 3, coating and drying method: each layer of raw material slurry is coated onto the substrate in sequence, and each layer is dried and cured after coating, and the layers are stacked one by one to form a multi-layer structure.

10. The preparation method according to claim 9, characterized in that, When the adjacent nicotine gel layer and the flavor and fragrance excipient layer are bonded together through an interlocking structure, the preparation method is selected from the casting molding method of method one. During the casting process, a casting mold with a corresponding convex-concave design needs to be selected according to the concave-convex structure of the layer. The preparation method includes the following two cases: Scenario 1: The preparation method includes the following steps: (1) Casting the bottom layer, the protrusion is formed on the surface of the layer by the concave pattern on the surface of the mold, and a bottom layer with the protrusion on one side is obtained; (2) Casting the intermediate layer: After the bottom layer cools and solidifies, the intermediate layer material that matches the bottom layer is cast so that the intermediate layer material wraps the protrusion of the bottom layer. After cooling and solidification, an interlocking structure is formed. The protrusion is formed on the side of the intermediate layer away from the bottom layer by the concave pattern on the mold surface, so that an intermediate layer with the groove on one side and the protrusion on the other side is obtained. (3) Cast the top layer. After the middle layer cools and solidifies, cast the top layer material that matches the middle layer so that the top layer material wraps the protrusion of the middle layer. After cooling and solidification, an interlocking structure is formed to obtain a top layer with the groove on one side. Scenario 2, the preparation method includes the following steps: (a) Casting the bottom layer, using the convex pattern on the surface of the mold to form the groove on the surface of the bottom layer, to obtain the bottom layer with the groove on one side; (b) Casting the intermediate layer: After the bottom layer cools and solidifies, casting the adjacent intermediate layer material that matches the bottom layer, so that the intermediate layer material flows into and fills the groove of the bottom layer, and after cooling, forming an interlocking structure of concave and convex, and forming the groove on the side of the intermediate layer away from the bottom layer by the convex pattern on the mold surface, so as to obtain an intermediate layer with the protrusion on one side and the groove on the other side. (c) Cast the top layer. After the middle layer cools and solidifies, cast the top layer material that matches the middle layer. The top layer material flows into and fills the groove of the middle layer. After cooling and solidification, an interlocking structure is formed, resulting in a top layer with the protrusion on one side. When the intermediate layer has multiple layers, repeat step (2) or step (b).

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