Nicotine slow-release aerogel based on bacterial cellulose as well as preparation method and application of nicotine slow-release aerogel

Abstract

The invention belongs to the technical field of tobacco products, and particularly relates to nicotine slow-release aerogel based on bacterial cellulose as well as a preparation method and application of the nicotine slow-release aerogel. The nicotine slow-release aerogel comprises a graft-modified / ion-crosslinked bacterial cellulose network and a tobacco extract dispersed in the graft-modified / ion-crosslinked bacterial cellulose network, wherein the graft modified / ionic cross-linked bacterial cellulose network is used as an aerogel skeleton; the tobacco extract contains a target component nicotine which can be dissolved out and released from the target component nicotine after the aerogel swells in a saliva-like environment. Compared with a traditional buccal nicotine sustained-release product, the nicotine sustained-release aerogel is large in specific surface area, nicotine is derived from natural tobacco plants, and use of chemically synthesized nicotine is avoided. In addition, the nicotine slow-release aerogel is high in strength, good in biocompatibility, non-toxic, harmless, degradable and environment-friendly, and has important application value in the fields of buccal cigarettes, smokeless tobacco products, drug release and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of tobacco products, and in particular relates to a nicotine sustained-release aerogel based on bacterial cellulose and a preparation method and application thereof. Background Art

[0002] Nicotine in buccal tobacco products is mainly absorbed through the oral or nasal mucosa, and its release rate is very important for the eating experience. However, the existing buccal tobacco products are of a single type, which limits the expansion of the market and the growth of categories. Aerogel is a type of three-dimensional open network with a large number of air-filled pores assembled from polymer molecules as the main skeleton. Due to its unique advantages such as extremely low density, adjustable pores, and large specific surface area, it has been widely used in the fields of tissue engineering and drug delivery. Cellulose, as the most abundant natural polysaccharide in the world, has unparalleled biocompatibility, biodegradability and hydrophilicity, and is an excellent material for constructing aerogels. The raw materials of bacterial cellulose fermented from tobacco are natural biomass such as tobacco stems, tobacco foam, tobacco rods or scrapped cigarettes. It not only utilizes the non-toxic and harmless advantages of natural tobacco biomass, but also realizes the recycling of waste.

[0003] The nicotine sustained-release aerogel based on bacterial cellulose not only takes advantage of the non-toxicity of bacterial cellulose, but also achieves the sustained release of nicotine by controlling the release pathway. It is a new preparation method that combines multiple advantages such as low cost, natural source, and strong controllability. However, the existing technology lacks biocompatible aerogels with adjustable and controllable nicotine release rate. Summary of the invention

[0004] The purpose of the present invention is to provide a nicotine sustained-release aerogel based on bacterial cellulose, a preparation method and an application thereof, wherein grafted modified / ionically cross-linked bacterial cellulose and tobacco extract are blended to obtain an aerogel capable of slowing down the nicotine release rate, thereby avoiding the use of chemically synthesized nicotine salts and solving the problem of a single type of oral tobacco in smokeless new tobacco products.

[0005] To achieve the above objectives, this application is implemented through the following technical solutions:

[0006] A nicotine sustained-release aerogel based on bacterial cellulose, comprising a graft-modified / ion-crosslinked bacterial cellulose network and a tobacco extract, wherein:

[0007] The bacterial cellulose network forms a large number of interconnected pores through assembly; the tobacco extract is evenly dispersed in the bacterial cellulose network; and the tobacco extract contains natural nicotine.

[0008] Preferably, the tobacco extract in the nicotine sustained-release aerogel accounts for 30%-60% of the weight of the bacterial cellulose; and the nicotine in the nicotine sustained-release aerogel accounts for 0.3%-1.5% of the weight of the bacterial cellulose.

[0009] Preferably, the bacterial cellulose is obtained by fermenting a sugar- and nitrogen-containing culture medium followed by washing and drying; the tobacco extract is obtained from tobacco extract; and the graft-modified / ion-crosslinked bacterial cellulose is obtained by citric acid grafting, epichlorohydrin grafting or sodium alginate ion crosslinking.

[0010] The method for preparing the bacterial cellulose-based nicotine sustained-release aerogel described in any one of the above items comprises the following specific steps:

[0011] (1) Preparation of graft-modified / ion-crosslinked bacterial cellulose aqueous dispersion: Disperse citric acid-grafted bacterial cellulose or epichlorohydrin-grafted bacterial cellulose or sodium alginate-ion-crosslinked bacterial cellulose in deionized water at room temperature with a solid content of 0.5%-5%, and mix uniformly by ultrasonic mixing to obtain dispersion A;

[0012] (2) placing the dispersion A obtained in step (1) in a centrifuge tube, adding an appropriate amount of tobacco extract thereto, and oscillating and mixing to obtain a dispersion B;

[0013] (3) The dispersion B is placed in liquid nitrogen / refrigerator and frozen and solidified, then taken out and placed at room temperature to melt. The operation is repeated for multiple times. Thereafter, the frozen dispersion B is placed in a freeze dryer and dried to obtain nicotine sustained-release aerogel.

[0014] Preferably, when the bacterial cellulose undergoes grafting reaction or ion crosslinking reaction in step (1), the citric acid / epichlorohydrin in the reaction raw materials accounts for 0.05-1.00% of the mass of the bacterial cellulose, and the sodium alginate accounts for 0.20-1.50% of the mass of the bacterial cellulose.

[0015] Preferably, the nicotine content of the tobacco extract in step (2) is 0.05 mg / mL-5 mg / mL.

[0016] An application, namely, application of any of the above-mentioned bacterial cellulose-based nicotine sustained-release aerogels in the tobacco field.

[0017] Preferably, the bacterial cellulose-based nicotine sustained-release aerogel is used in the field of oral cigarettes, smokeless tobacco products or drug release.

[0018] Preferably, the simulated dissolution and sustained-release environment is an in vitro simulated saliva environment, and the dissolution-release law is analyzed using the Gallagher-Corrigan model;

[0019] The Gallagher-Corrigan model equation is: ,in,

[0020] F maxIndicates the final dissolution rate of nicotine released in the total time, F B Indicates the proportion of nicotine released in the first stage, t max represents the time of the maximum nicotine release rate in the second stage, k1 and k2 are the kinetic constants of the first and second stages, respectively (s -1 ).

[0021] The beneficial effects of the present invention are:

[0022] The present invention uses grafted modified / ion-crosslinked bacterial cellulose and tobacco extract to prepare nicotine slow-release aerogel, which can be used to construct an interconnected network structure to achieve slow release of nicotine, meeting the needs of biocompatible, environmentally friendly, and degradable oral tobacco products, but no relevant reports have been seen. The preparation of the above-mentioned bacterial cellulose-based nicotine slow-release aerogel has the following technical difficulties: 1. The uniform dispersion of tobacco extract in the aerogel; 2. The mechanical strength of the aerogel material; 3. The grafting rate / crosslinking density of the grafted modified / ion-crosslinked bacterial cellulose to ensure an appropriate nicotine release rate.

[0023] The present invention provides a nicotine slow-release aerogel based on bacterial cellulose, comprising graft-modified / ion-crosslinked bacterial cellulose and tobacco extract dispersed therein. The present invention utilizes the network pores formed by the graft-modified / ion-crosslinked bacterial cellulose in the freeze-thaw cycle as a nicotine release pathway, and the tortuous pathway limits the direct dissolution and release of nicotine, slowing down the release rate of nicotine, that is, achieving nicotine slow release.

[0024] The present invention enhances the mechanical strength of aerogel through freeze-thaw cycles. During the melting process, water molecules dissociate and hydrogen bonds are formed between bacterial cellulose. Multiple freeze-thaw cycles enhance the hydrogen bond force, thereby improving the mechanical strength of aerogel.

[0025] The present invention regulates the grafting rate and cross-linking density of the graft-modified / ion-cross-linked bacterial cellulose to ensure that the size of the pores formed in the aerogel is appropriate and the density is moderate to ensure the improvement of the sustained release effect.

[0026] The bacterial cellulose-based nicotine sustained-release aerogel of the present invention ensures the biocompatibility, safety and non-toxicity of the product throughout the entire preparation and application process, uses natural nicotine, overcomes the health risks brought by chemically synthesized nicotine, and is suitable for oral cigarettes, smokeless tobacco products, drug release and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a microstructure diagram of the nicotine sustained-release aerogel of Example 1;

[0028] Figure 2 This is a digital photo of the nicotine sustained-release aerogel of Example 1;

[0029] Figure 3 This is the nicotine release curve of the nicotine sustained-release aerogel in Example 2 in a simulated saliva environment in vitro;

[0030] Figure 4 This is a simulation curve established using the Gallagher-Corrigan model for the nicotine sustained-release aerogel in Example 2. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] The present invention provides a nicotine sustained-release aerogel based on bacterial cellulose, which comprises graft-modified / chemically cross-linked bacterial cellulose, in which tobacco extract containing nicotine is dispersed, wherein:

[0033] The bacterial cellulose network can form a large number of interconnected pores through assembly; the tobacco extract is evenly dispersed in the bacterial cellulose network; the tobacco extract contains natural nicotine;

[0034] In the present application, the tobacco extract in the nicotine sustained-release aerogel accounts for 30%-60% of the weight of the bacterial cellulose; the nicotine in the nicotine sustained-release aerogel accounts for 0.3%-1.5% of the weight of the bacterial cellulose.

[0035] In the present application, bacterial cellulose is obtained by fermenting a culture medium containing sugar and nitrogen, followed by washing and drying; and tobacco extract is obtained from tobacco extract.

[0036] In the present application, the graft-modified / ion-crosslinked bacterial cellulose is obtained by citric acid grafting, epichlorohydrin grafting or sodium alginate ion crosslinking.

[0037] In the present application, the bacterial cellulose grafted with citric acid can be prepared according to the following method:

[0038] (1) placing the bacterial cellulose obtained after fermentation and washing and 5%-100% of citric acid by weight in 500 mL of a uniform aqueous solution containing sodium dihydrogen phosphate and sodium bicarbonate (molar ratio of 1:1);

[0039] (2) The mixture was shaken in a shaker at 40°C for 24 hours for full activation. After activation, the mixture was refluxed and condensed at 150°C for 75 minutes to carry out a cross-linking reaction. After the cross-linking was completed, the mixture was filtered, the solid was washed three times with deionized water, and dried to obtain citric acid-modified bacterial cellulose.

[0040] In the present application, epichlorohydrin-modified bacterial cellulose can be prepared according to the following method:

[0041] (1) A bacterial cellulose aqueous dispersion containing different amounts of epichlorohydrin (5%-100% by weight relative to bacterial cellulose) was prepared by magnetic stirring at room temperature and heated to 60 o The mixture was cross-linked under reflux at 40 °C for 120 min, and the pH value of the dispersion was adjusted to 9 with 0.1 M NaOH solution.

[0042] (2) washing the reaction product with deionized water for at least three times, each time for 30 minutes, to remove residual NaOH and unreacted epichlorohydrin, and drying to obtain epichlorohydrin-grafted modified bacterial cellulose.

[0043] In the present application, the bacterial cellulose cross-linked with sodium alginate ions can be prepared according to the following method:

[0044] (1) Dissolve an appropriate amount of sodium alginate in deionized water and o C for 1 hour, add bacterial cellulose, wherein the mass of sodium alginate is 20%-150% of the mass of bacterial cellulose, disperse evenly by ultrasonication, and mix for 2 hours.

[0045] (2) Pour the above mixed solution into a dialysis bag, and place the dialysis bag in a 0.15 M calcium chloride dihydrate aqueous solution to promote the formation of an ion-crosslinked network. After 5 hours, dry the mixed solution in the dialysis bag to obtain ion-crosslinked bacterial cellulose.

[0046] The present invention also provides a method for preparing the bacterial cellulose-based nicotine slow-release aerogel, comprising the following steps:

[0047] (1) Preparation of grafted modified / ion-crosslinked bacterial cellulose aqueous dispersion: citric acid grafted bacterial cellulose or epichlorohydrin grafted bacterial cellulose or sodium alginate ion-crosslinked bacterial cellulose was dispersed in deionized water at room temperature with a solid content of 0.5%-5%, and ultrasonically mixed to obtain dispersion A.

[0048] (2) The dispersion obtained in step (1) is placed in a centrifuge tube, an appropriate amount of tobacco extract is added thereto, and the mixture is shaken and mixed to obtain dispersion B.

[0049] (3) The dispersion B is placed in liquid nitrogen for freezing and solidification, then taken out and placed at room temperature for thawing. The operation is repeated for multiple times. Thereafter, the frozen dispersion B is placed in a freeze dryer for drying to obtain a nicotine sustained-release aerogel.

[0050] In the present application, when the bacterial cellulose undergoes a grafting reaction or an ion crosslinking reaction in step (1), the citric acid / epichlorohydrin in the reaction raw materials accounts for 0.05-1.00% of the mass of the bacterial cellulose, and the sodium alginate accounts for 0.20-1.50% of the mass of the bacterial cellulose.

[0051] The present application also provides applications of the bacterial cellulose-based nicotine sustained-release aerogel, which can be used in the fields of oral cigarettes, smokeless tobacco products, drug release, etc.

[0052] The present application also provides a simulated release analysis method for the bacterial cellulose-based nicotine sustained-release aerogel, wherein the simulated dissolution release environment is an in vitro simulated saliva environment, and the dissolution release law can be analyzed using the Gallagher-Corrigan model.

[0053] The Gallagher-Corrigan model equation is: ,in,

[0054] F max Indicates the final dissolution rate of nicotine released in the total time, F B represents the proportion of nicotine released in the first stage, t max represents the time of the maximum nicotine release rate in the second stage, k1 and k2 are the kinetic constants of the first and second stages, respectively (s -1 ).

[0055] Example 1

[0056] A nicotine sustained-release aerogel based on bacterial cellulose includes 0.5 g of bacterial cellulose grafted with citric acid and 0.1 g of tobacco extract, which contains 1.5 mg of nicotine. This aerogel capable of achieving sustained-release of nicotine can swell first and then release nicotine in a simulated saliva environment in vitro. After the release curve is fitted with the Gallagher-Corrigan model, the kinetic parameters of the first and second stages of dissolution release are 0.0399 and 0.3524, respectively.

[0057] The preparation of this bacterial cellulose-based nicotine sustained-release aerogel is as follows:

[0058] (1) Preparation of grafted bacterial cellulose aqueous dispersion: 0.5 g of citric acid grafted bacterial cellulose was dispersed in deionized water at room temperature and ultrasonically mixed to obtain dispersion A.

[0059] (2) The dispersion A obtained in step (1) was placed in a 50 mL centrifuge tube, 2 mL of tobacco extract having a nicotine concentration of 0.75 mg / mL was added thereto, and the mixture was shaken and mixed to obtain a dispersion B.

[0060] (3) The dispersion B was placed in liquid nitrogen and frozen for 3 min, taken out, and thawed at room temperature. The operation was repeated 3 times. After that, the frozen dispersion B was placed in a freeze dryer to obtain a nicotine sustained-release aerogel. Its internal structure is interconnected and porous, such as Figure 1 As shown, the appearance is cylindrical, such as Figure 2 shown.

[0061] Among them, the citric acid-modified bacterial cellulose is prepared from citric acid and bacterial cellulose as precursors, and the preparation method thereof is as follows:

[0062] (1) 5 g of bacterial cellulose obtained after fermentation and washing and 0.15 g of citric acid were placed in 500 mL of a uniform aqueous solution containing 1.19 g of sodium dihydrogen phosphate and 0.84 g of sodium bicarbonate.

[0063] (2) The mixture was shaken in a shaker at 40°C for 24 hours for full activation. After activation, the mixture was refluxed and condensed at 150°C for 75 minutes to carry out a cross-linking reaction. After the cross-linking was completed, the mixture was filtered, the solid was washed three times with deionized water, and dried to obtain citric acid-modified bacterial cellulose.

[0064] The aerogel is placed in a simulated saliva environment in vitro to obtain a nicotine sustained release effect.

[0065] Example 2

[0066] A nicotine sustained-release aerogel based on bacterial cellulose includes 0.3 g of citric acid-grafted bacterial cellulose and 0.015 g of tobacco extract, which contains 4.5 mg of nicotine. This aerogel capable of sustained-release nicotine can swell first and then release nicotine in a simulated saliva environment in vitro. After the release curve is fitted with the Gallagher-Corrigan model, the kinetic parameters of the first and second stages of dissolution release are 0.00424 and 0.06507, respectively.

[0067] The preparation of this bacterial cellulose-based nicotine sustained-release aerogel is as follows:

[0068] (1) Preparation of grafted bacterial cellulose aqueous dispersion: 0.3 g of citric acid grafted bacterial cellulose was dispersed in deionized water at room temperature and ultrasonically mixed to obtain dispersion A.

[0069] (2) Place 20 mL of dispersion A obtained in step (1) in a 50 mL centrifuge tube, add 2 mL of tobacco extract having a nicotine concentration of 2.25 mg / mL, and shake to mix evenly to obtain dispersion B.

[0070] (3) Freeze the dispersion B in liquid nitrogen for 2 min, take it out, and thaw it at room temperature. Repeat the operation three times. Then, dry the frozen dispersion B in a freeze dryer to obtain a nicotine sustained-release aerogel. Its internal structure is interconnected and porous, such as Figure 1 As shown, the appearance is cylindrical, such as Figure 2 shown.

[0071] Among them, the citric acid-modified bacterial cellulose is prepared from citric acid and bacterial cellulose as precursors, and the preparation method thereof is as follows:

[0072] (1) 3 g of bacterial cellulose obtained after fermentation and washing and 1.5 g of citric acid were placed in 500 mL of a uniform aqueous solution containing 2.38 g of sodium dihydrogen phosphate and 1.68 g of sodium bicarbonate.

[0073] (2) The mixture was shaken in a shaker at 40°C for 24 hours for full activation. After activation, the mixture was refluxed and condensed at 150°C for 75 minutes to carry out a cross-linking reaction. After the cross-linking was completed, the mixture was filtered, the solid was washed three times with deionized water, and dried to obtain citric acid-modified bacterial cellulose.

[0074] The above aerogel was placed in an in vitro simulated saliva environment to obtain a nicotine sustained release effect. The nicotine release curve in the in vitro simulated saliva environment is as follows: Figure 3 shown.

[0075] Example 3

[0076] A nicotine sustained-release aerogel based on bacterial cellulose includes 0.5 g of epichlorohydrin grafted modified bacterial cellulose and 0.0125 g of tobacco extract, which contains 7.5 mg of nicotine. The aerogel capable of achieving sustained-release of nicotine can swell first and then release nicotine in a simulated saliva environment in vitro. After the release curve is fitted with the Gallagher-Corrigan model, the kinetic parameters of the first and second stages of dissolution release are 0.05126 and 0.3002, respectively. The dissolution release curve and the model fitting curve are shown in FIG. Figure 4 shown.

[0077] The preparation of this bacterial cellulose-based nicotine sustained-release aerogel is as follows:

[0078] (1) Preparation of grafted bacterial cellulose aqueous dispersion: 0.5 g of epichlorohydrin-grafted bacterial cellulose was dispersed in deionized water at room temperature and ultrasonically mixed to obtain dispersion A.

[0079] (2) The dispersion A obtained in step (1) was placed in a 50-mL centrifuge tube, 2 mL of tobacco extract having a nicotine concentration of 3.75 mg / mL was added thereto, and the mixture was shaken and mixed to obtain a dispersion B.

[0080] (3) The dispersion B was frozen in liquid nitrogen for 3 min, taken out, and thawed at room temperature. The operation was repeated 3 times. After that, the frozen dispersion B was dried in a freeze dryer to obtain nicotine sustained-release aerogel.

[0081] Among them, epichlorohydrin-modified bacterial cellulose is prepared from epichlorohydrin and bacterial cellulose as precursors, and its preparation method is as follows:

[0082] (1) A 0.15 g epichlorohydrin and 3 g bacterial cellulose aqueous dispersion was prepared by magnetic stirring at room temperature and refluxed at 60°C for 120 min. The pH of the dispersion was adjusted to 9 with 0.1 M NaOH solution.

[0083] (2) Wash the reaction product with deionized water for at least 3 times, each time for 30 minutes, to remove residual NaOH and unreacted epichlorohydrin. Dry to obtain epichlorohydrin-grafted modified bacterial cellulose.

[0084] The aerogel is placed in a simulated saliva environment in vitro to obtain a nicotine sustained release effect.

[0085] Example 4

[0086] A nicotine sustained-release aerogel based on bacterial cellulose includes 0.6 g of epichlorohydrin-grafted bacterial cellulose and 6 mg of tobacco extract, which contains 3 mg of nicotine. This aerogel capable of achieving sustained-release of nicotine can swell first and then release nicotine in a simulated saliva environment in vitro. After the release curve is fitted with the Gallagher-Corrigan model, the kinetic parameters of the first and second stages of dissolution release are 0.14473 and 0.4869, respectively.

[0087] The preparation of this bacterial cellulose-based nicotine sustained-release aerogel is as follows:

[0088] (1) Preparation of grafted bacterial cellulose aqueous dispersion: 0.6 g of epichlorohydrin-grafted bacterial cellulose was dispersed in deionized water at room temperature and ultrasonically mixed to obtain dispersion A.

[0089] (2) The dispersion A obtained in step (1) was placed in a 50 mL centrifuge tube, 5 mL of tobacco extract having a nicotine concentration of 0.6 mg / mL was added thereto, and the mixture was shaken and mixed to obtain a dispersion B.

[0090] (3) Freeze the dispersion B in liquid nitrogen for 1 min, take it out, and thaw it at room temperature. Repeat the operation three times. Then, dry the frozen dispersion B in a freeze dryer to obtain nicotine sustained-release aerogel.

[0091] Among them, epichlorohydrin-modified bacterial cellulose is prepared from epichlorohydrin and bacterial cellulose as precursors, and its preparation method is as follows:

[0092] (1) A 3 g epichlorohydrin and 3 g bacterial cellulose aqueous dispersion was prepared by magnetic stirring at room temperature and refluxed at 60 °C for 120 min. The pH of the dispersion was adjusted to 9 with 0.1 M NaOH solution.

[0093] (2) Wash the reaction product with deionized water for at least 3 times, each time for 30 minutes, to remove residual NaOH and unreacted epichlorohydrin. Dry to obtain epichlorohydrin-grafted modified bacterial cellulose.

[0094] The aerogel is placed in a simulated saliva environment in vitro to obtain a nicotine sustained release effect.

[0095] Example 5

[0096] A nicotine sustained-release aerogel based on bacterial cellulose includes 0.6 g of bacterial cellulose cross-linked with sodium alginate and 12 mg of tobacco extract, which contains 6 mg of nicotine. This aerogel capable of achieving sustained-release of nicotine can swell first and then release nicotine in a simulated saliva environment in vitro. After the release curve is fitted with the Gallagher-Corrigan model, the kinetic parameters of the first and second stages of dissolution release are 0.1396 and 0.5620, respectively.

[0097] The preparation of this bacterial cellulose-based nicotine sustained-release aerogel is as follows:

[0098] (1) Preparation of ion-crosslinked bacterial cellulose aqueous dispersion: 0.6 g of sodium alginate ion-crosslinked bacterial cellulose was dispersed in deionized water at room temperature and ultrasonically mixed to obtain dispersion A.

[0099] (2) The dispersion A obtained in step (1) was placed in a 50 mL centrifuge tube, 3 mL of tobacco extract with a nicotine concentration of 2 mg / mL was added thereto, and the mixture was shaken and mixed to obtain a dispersion B.

[0100] (3) The dispersion B was frozen and solidified in liquid nitrogen for 3 min, then taken out and thawed at room temperature. The operation was repeated several times. After that, the frozen dispersion B was dried in a freeze dryer to obtain nicotine sustained-release aerogel.

[0101] Among them, the sodium alginate ion-crosslinked bacterial cellulose is prepared from sodium alginate and bacterial cellulose as precursors, and the preparation method thereof is as follows:

[0102] (1) Dissolve 0.6 g of sodium alginate in deionized water and stir at 45 °C for 1 hour. Add 0.6 g of bacterial cellulose, disperse evenly by ultrasonication, and mix for 2 hours.

[0103] (2) Pour the above mixed solution into a dialysis bag, and place the dialysis bag in a 0.15 M calcium chloride dihydrate aqueous solution to promote the formation of an ion-crosslinked network. After 5 hours, dry the mixed solution in the dialysis bag to obtain ion-crosslinked bacterial cellulose.

[0104] The aerogel is placed in a simulated saliva environment in vitro to obtain a nicotine sustained release effect.

[0105] Comparative Example 1

[0106] 0.5 g of bacterial cellulose and 2 mL of tobacco extract with a nicotine content of 2.5 mg / mL were dispersed in deionized water, stirred or ultrasonically mixed, placed in liquid nitrogen / refrigerator for freezing and solidification, taken out, placed at room temperature for thawing, and the operation was repeated several times. After that, the frozen dispersion B was placed in a freeze dryer for drying to obtain nicotine sustained-release aerogel. That is, the material cannot show nicotine sustained-release performance and cannot be used in the field of oral cigarettes.

[0107] Comparative Example 2

[0108] 0.5 g of citric acid and 2 mL of tobacco extract with a nicotine content of 2.5 mg / mL were dispersed in deionized water, stirred or ultrasonically mixed evenly, placed in liquid nitrogen / refrigerator for freezing and solidification, taken out, placed at room temperature for thawing, the operation was repeated several times, and placed in a freeze dryer for treatment to obtain a powder sample, which could not form an aerogel.

[0109] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A nicotine sustained-release aerogel based on bacterial cellulose, characterized in that: Comprising a graft-modified / ionically cross-linked bacterial cellulose network and a tobacco extract, wherein: The bacterial cellulose network forms a large number of interconnected pores through assembly; the tobacco extract is evenly dispersed in the bacterial cellulose network; and the tobacco extract contains natural nicotine.

2. The bacterial cellulose-based nicotine sustained-release aerogel according to claim 1, characterized in that: The tobacco extract in the nicotine slow-release aerogel accounts for 30%-60% of the weight of the bacterial cellulose; the nicotine in the nicotine slow-release aerogel accounts for 0.3%-1.5% of the weight of the bacterial cellulose.

3. The bacterial cellulose-based nicotine sustained-release aerogel according to claim 1, characterized in that: The bacterial cellulose is obtained by fermenting a sugar- and nitrogen-containing culture medium, washing the fermented medium, and drying the fermented medium; the tobacco extract is obtained by tobacco extract; and the grafted modified / ion-crosslinked bacterial cellulose is obtained by citric acid grafting, epichlorohydrin grafting, or sodium alginate ion crosslinking.

4. A method for preparing a nicotine sustained-release aerogel based on bacterial cellulose according to any one of claims 1 to 3, characterized in that: The specific steps are: (1) Preparation of graft-modified / ion-crosslinked bacterial cellulose aqueous dispersion: Disperse citric acid-grafted bacterial cellulose or epichlorohydrin-grafted bacterial cellulose or sodium alginate-ion-crosslinked bacterial cellulose in deionized water at room temperature with a solid content of 0.5%-5%, and mix uniformly by ultrasonic mixing to obtain dispersion A; (2) placing the dispersion A obtained in step (1) in a centrifuge tube, adding an appropriate amount of tobacco extract thereto, and oscillating and mixing to obtain a dispersion B; (3) The dispersion B is placed in liquid nitrogen / refrigerator and frozen and solidified, then taken out and placed at room temperature to melt. The operation is repeated for multiple times. Thereafter, the frozen dispersion B is placed in a freeze dryer and dried to obtain nicotine sustained-release aerogel.

5. The method for preparing the bacterial cellulose-based nicotine sustained-release aerogel according to claim 4, characterized in that: When the bacterial cellulose undergoes a grafting reaction or an ion crosslinking reaction in step (1), the citric acid / epichlorohydrin in the reaction raw materials accounts for 0.05-1.00% of the mass of the bacterial cellulose, and the sodium alginate accounts for 0.20-1.50% of the mass of the bacterial cellulose.

6. The method for preparing the bacterial cellulose-based nicotine sustained-release aerogel according to claim 4, characterized in that: The nicotine content of the tobacco extract in step (2) is 0.05 mg / mL-5 mg / mL.

7. An application, characterized in that: Application of the bacterial cellulose-based nicotine sustained-release aerogel according to any one of claims 1 to 6 in the tobacco field.

8. The use according to claim 7, characterized in that: The bacterial cellulose-based nicotine sustained-release aerogel is used in the field of oral cigarettes, smokeless tobacco products or drug release.

9. The use according to claim 8, characterized in that: The simulated dissolution and sustained release environment is a simulated saliva environment in vitro, and the dissolution and release law is analyzed using the Gallagher-Corrigan model. The Gallagher-Corrigan model equation is: ,in, F max Indicates the final dissolution rate of nicotine released in the total time, F B Indicates the proportion of nicotine released in the first stage, t max represents the time of the maximum nicotine release rate in the second stage, k1 and k2 are the kinetic constants of the first and second stages, respectively (s -1 ).

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