Preparation method and application of cassava starch-beta-cyclodextrin nanoparticles embedding gamma-aminobutyric acid

Abstract

The application discloses a preparation method and application of cassava starch-beta-cyclodextrin nanoparticles embedding gamma-aminobutyric acid, and the preparation method comprises the following steps: step one, preparing nanoparticles by using a cassava starch suspension and beta-cyclodextrin, and then preparing a solution; step two, preparing a gamma-aminobutyric acid solution; and mixing the prepared gamma-aminobutyric acid solution with the nanoparticle solution in step one. The gamma-aminobutyric acid cassava starch-beta-cyclodextrin nanoparticles can improve the stability of gamma-aminobutyric acid, further improve the effect of gamma-aminobutyric acid on sleep quality, and has practical application value in medical production.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical technology, specifically relating to a method for preparing and applying cassava starch-β-cyclodextrin nanoparticles encapsulated with γ-aminobutyric acid. Background Technology

[0002] Gamma-aminobutyric acid (GABA) is a neurotransmitter and an important inhibitory neuroregulatory substance that is widely found in animals and microorganisms. It regulates nerve transmission and nerve electrical activity by binding to receptors and inhibiting the excitability of neurons. It is essential for maintaining the balance and normal function of the nervous system and has a variety of biological functions, including regulating nerve transmission, sleep, mood, and neural development.

[0003] However, the effects of adding γ-aminobutyric acid (GABA) to food in existing technologies are not ideal. This invention application has discovered through research that preparing GABA into cassava starch-β-cyclodextrin nanoparticles encapsulating GABA can improve its stability and medicinal efficacy. Summary of the Invention

[0004] To address the issue of unsatisfactory effects of γ-aminobutyric acid (GABA) in existing technologies, this invention provides a method for preparing and applying γ-aminobutyric acid-encapsulated cassava starch-β-cyclodextrin nanoparticles. Studies have shown that the γ-aminobutyric acid-encapsulated cassava starch-β-cyclodextrin nanoparticles prepared by this invention can improve the stability of GABA, and simultaneously exhibit good sleep-regulating and improving effects.

[0005] This invention first provides a method for preparing cassava starch-β-cyclodextrin nanoparticles encapsulated with γ-aminobutyric acid, which includes the following steps:

[0006] Step 1) Prepare nanoparticles (TS-β-CD-NPs) using cassava starch suspension and β-cyclodextrin, and then prepare a solution;

[0007] Step 2) Prepare a γ-aminobutyric acid solution. Mix the prepared γ-aminobutyric acid solution with the TS-β-CD-NPs solution from Step 1) to obtain γ-aminobutyric acid cassava starch-β-cyclodextrin nanoparticles (GABA-TS-β-CD-NPs).

[0008] The present invention also provides the application of cassava starch-β-cyclodextrin nanoparticles of γ-aminobutyric acid obtained according to the preparation method of the present invention in the preparation of drugs for protecting the nervous system.

[0009] The present invention also provides the application of cassava starch-β-cyclodextrin nanoparticles of γ-aminobutyric acid obtained according to the preparation method of the present invention in the preparation of sleep-improving drugs.

[0010] The present invention also provides a pharmaceutical composition containing cassava starch-β-cyclodextrin nanoparticles (GABA-TS-β-CD-NPs) containing γ-aminobutyric acid obtained by the preparation method of the present invention.

[0011] The present invention has the following beneficial effects:

[0012] 1) The method of this invention significantly improves the encapsulation rate of γ-aminobutyric acid in cassava starch-β-cyclodextrin nanoparticles and enhances the stability of γ-aminobutyric acid.

[0013] 2) The cassava starch-β-cyclodextrin nanoparticles of γ-aminobutyric acid prepared by the method of the present invention improve the medicinal effect of γ-aminobutyric acid in improving sleep, and have practical application value in pharmaceutical production. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprising of," etc., will be understood to include the stated components or steps, without excluding other substances or steps.

[0015] Furthermore, to better illustrate the present invention, numerous specific details are provided in the following detailed embodiments.

[0016] Those skilled in the art will understand that the present invention can be practiced even without certain specific details. In some embodiments, materials, methods, and means well known to those skilled in the art are not described in detail in order to highlight the spirit of the invention.

[0017] Unless otherwise defined, all scientific and technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art.

[0018] The structural formulas and Chinese names of the compounds used in this invention are shown below:

[0019] In this invention, the term "TS" refers to cassava starch;

[0020] The term "β-CD" refers to β-cyclodextrin.

[0021] The term "CS" stands for corn starch;

[0022] The term "NPs" refers to nanoparticles;

[0023] The term "GABA" stands for γ-aminobutyric acid.

[0024] The term “GABA-TS-β-CD-NPs” refers to cassava starch-β-cyclodextrin nanoparticles containing γ-aminobutyric acid.

[0025] In this invention, the term "room temperature" refers to the temperature of an article being close to or the same as the temperature of a space (e.g., the location of a fume hood in which the article is located). Typically, room temperature is about 20°C to about 30°C, or about 22°C to 27°C, or about 25°C.

[0026] This invention first provides a method for preparing cassava starch-β-cyclodextrin nanoparticles encapsulated with γ-aminobutyric acid, which includes the following steps:

[0027] Step 1) Prepare cassava starch and β-cyclodextrin nanoparticles using a cassava starch suspension and β-cyclodextrin, then prepare a cassava starch and β-cyclodextrin nanoparticle solution. The preparation of the cassava starch suspension includes the following steps: 1) Dissolve cassava starch in water, heat to gelatinize, and then cool to room temperature; 2) Sonicate the gelatinized product obtained in Step 1; the water used in Step 1) is preferably deionized water; the gelatinization temperature is 80-100℃, preferably 90℃; the gelatinization time is 0.5-5h, preferably 1h; cooling is done with running water. Step 2) The ultrasonication of the gelatinized product is divided into two stages: the first stage is ultrasonication at 600W for 30-60min, and the second stage is ultrasonication at 300W with the addition of an organic solvent, preferably ethanol, for another 10-40min. Further, the method includes a step of removing the organic solvent by rotation.

[0028] Step 2) Prepare a γ-aminobutyric acid solution. Mix the prepared γ-aminobutyric acid solution with the nanoparticle solution from Step 1) to obtain γ-aminobutyric acid cassava starch-β-cyclodextrin nanoparticles (GABA-TS-β-CD-NPs).

[0029] Preferably, in the above preparation method, the preparation of the cassava starch suspension in step one) further includes a step of removing the organic solvent by rotation.

[0030] Preferably, in step one of the above preparation method, the mass ratio of cassava starch to β-cyclodextrin is 1:5-5:1, more preferably 1:2-2:1, and particularly preferably 1:2, 1:1, or 2:1.

[0031] Preferably, in the above preparation method, step one) of preparing cassava starch and β-cyclodextrin nanoparticles further includes the following process: mixing cassava starch suspension and β-cyclodextrin, dissolving in deionized water, stirring at 40-60℃ for 4-8 hours, centrifuging after uniform stirring, and freeze-drying to obtain cassava starch and β-cyclodextrin nanoparticles. Preferably, stirring is performed at 50℃ at a stirring speed of 700 rpm.

[0032] Preferably, in the above preparation method, step one) of preparing nanoparticles with cassava starch and β-cyclodextrin and then making a solution further includes the following process: dissolving the cassava starch and β-cyclodextrin nanoparticles obtained by freeze-drying to obtain a nano suspension.

[0033] The above preparation method, step two) prepares a γ-aminobutyric acid solution and mixes it with the nanoparticle solution from step one) as follows: dissolve γ-aminobutyric acid in deionized water to obtain a γ-aminobutyric acid solution, then dissolve the γ-aminobutyric acid solution, potato starch and β-cyclodextrin nanoparticles to obtain a nano suspension, mix and stir evenly, and freeze-dry to obtain GABA-TS-β-CD-NPs.

[0034] The GABA-TS-β-CD-NPs prepared under the preferred preparation conditions of this invention have superior performance, for example, improving the encapsulation rate and pharmaceutical efficacy of γ-aminobutyric acid.

[0035] The present invention also provides the application of GABA-TS-β-CD-NPs obtained according to the preparation method of the present invention in the preparation of drugs for protecting the nervous system.

[0036] The present invention also provides the application of GABA-TS-β-CD-NPs obtained according to the preparation method of the present invention in the preparation of sleep-improving drugs.

[0037] The present invention also provides a pharmaceutical composition containing GABA-TS-β-CD-NPs obtained by the preparation method described above according to the present invention.

[0038] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0039] Example 1: Preparation of cassava starch-β-cyclodextrin nanoparticles encapsulated with γ-aminobutyric acid

[0040] 2g of cassava starch was dissolved in 100mL of deionized water and thoroughly mixed. The mixture was then heated in a 90℃ water bath for 1 hour until completely gelatinized. Subsequently, it was rapidly cooled to room temperature with running water and then sonicated at 600W for 30 minutes. Afterward, 50mL of anhydrous ethanol was added under 300W sonication, and sonication continued for 30 minutes. The ethanol was then removed by rotary evaporation to obtain a cassava starch suspension. The obtained cassava starch suspension was mixed with 2g of β-cyclodextrin and brought to a final volume of 100mL with deionized water. This mixture was magnetically stirred at 700rpm for 6 hours at 50℃ to ensure thorough mixing. After stirring, the mixture was centrifuged and freeze-dried to obtain TS-β-CD-NPs. 300mg of TS-β-CD-NPs was dissolved in 10mL of deionized water to prepare a nano-suspension. Simultaneously, 60mg of γ-aminobutyric acid (GABA) was dissolved in 5mL of deionized water to obtain a GABA solution. The obtained γ-aminobutyric acid solution was mixed with the above nano suspension and stirred uniformly at 600 rpm. Finally, cassava starch-β-cyclodextrin nanoparticles (GABA-TS-β-CD-NPs) encapsulating γ-aminobutyric acid were obtained by freeze drying.

[0041] Example 2 Preparation of cassava starch-β-cyclodextrin nanoparticles encapsulated with γ-aminobutyric acid

[0042] 2g of cassava starch was dissolved in 100mL of deionized water and thoroughly mixed. The mixture was then heated in a 90℃ water bath for 1 hour until completely gelatinized. Subsequently, it was rapidly cooled to room temperature with running water and then sonicated at 300W for 30 minutes. Afterward, 50mL of anhydrous ethanol was added under 300W sonication, and sonication continued for 30 minutes. The ethanol was then removed by rotary evaporation to obtain a cassava starch suspension. The obtained cassava starch suspension was mixed with 2g of β-cyclodextrin and brought to a final volume of 100mL with deionized water. This mixture was magnetically stirred at 700rpm for 6 hours at 50℃ to ensure thorough mixing. After stirring, the mixture was centrifuged and freeze-dried to obtain TS-β-CD-NPs. 300mg of TS-β-CD-NPs was dissolved in 10mL of deionized water to prepare a nano-suspension. Simultaneously, 60mg of γ-aminobutyric acid (GABA) was dissolved in 5mL of deionized water to obtain a GABA solution. A solution of γ-aminobutyric acid (GABA) was mixed with a nano-suspension and stirred uniformly at 600 rpm. Finally, cassava starch-β-cyclodextrin nanoparticles (GABA-TS-β-CD-NPs) encapsulating GABA were obtained by freeze drying.

[0043] Example 3 Preparation of corn starch-β-cyclodextrin nanoparticles encapsulating γ-aminobutyric acid

[0044] 2g of corn starch was dissolved in 100mL of deionized water and thoroughly mixed. The mixture was then heated in a 90℃ water bath for 1 hour until completely gelatinized. Subsequently, it was rapidly cooled to room temperature with running water and then sonicated at 600W for 30 minutes. Afterward, 50mL of anhydrous ethanol was added under 300W sonication, and sonication continued for 30 minutes. The ethanol was then removed by rotary evaporation to obtain a corn starch suspension. The obtained corn starch suspension was mixed with 2g of β-cyclodextrin and brought to a final volume of 100mL with deionized water. This mixture was magnetically stirred at 700rpm for 6 hours at 50℃ to ensure thorough mixing. After stirring, the mixture was centrifuged and freeze-dried to obtain TS-β-CD-NPs. 300mg of TS-β-CD-NPs was dissolved in 10mL of deionized water to prepare a nano-suspension. Simultaneously, 60mg of γ-aminobutyric acid (GABA) was dissolved in 5mL of deionized water to obtain a GABA solution. A solution of γ-aminobutyric acid (GABA) was mixed with a nano-suspension and stirred uniformly at 600 rpm. Finally, corn starch-β-cyclodextrin nanoparticles (GABA-TS-β-CD-NPs) encapsulating GABA were obtained by freeze drying.

[0045] Example 4 Preparation of cassava starch-β-cyclodextrin nanoparticles encapsulating γ-aminobutyric acid

[0046] 2g of cassava starch was dissolved in 100mL of deionized water and thoroughly mixed. The mixture was then heated in a 90℃ water bath for 1 hour until completely gelatinized. Subsequently, it was rapidly cooled to room temperature with running water and then sonicated at 600W for 30 minutes. Afterward, 50mL of anhydrous ethanol was added under 300W sonication, and sonication continued for 30 minutes. The ethanol was then removed by rotary evaporation to obtain a cassava starch suspension. The obtained cassava starch suspension was mixed with 4g of β-cyclodextrin and brought to a final volume of 100mL with deionized water. This mixture was magnetically stirred at 700rpm for 6 hours at 50℃ to ensure thorough mixing. After stirring, the mixture was centrifuged and freeze-dried to obtain TS-β-CD-NPs. 300mg of TS-β-CD-NPs was dissolved in 10mL of deionized water to prepare a nano-suspension. Simultaneously, 60mg of γ-aminobutyric acid (GABA) was dissolved in 5mL of deionized water to obtain a GABA solution. A solution of γ-aminobutyric acid (GABA) was mixed with a nano-suspension and stirred uniformly at 600 rpm. Finally, cassava starch-β-cyclodextrin nanoparticles (GABA-TS-β-CD-NPs) encapsulating GABA were obtained by freeze drying.

[0047] Example 5 Preparation of cassava starch-β-cyclodextrin nanoparticles encapsulated with γ-aminobutyric acid

[0048] 2g of cassava starch was dissolved in 100mL of deionized water and thoroughly mixed. The mixture was then heated in a 90℃ water bath for 1 hour until completely gelatinized. Subsequently, it was rapidly cooled to room temperature with running water and then sonicated at 600W for 30 minutes. Afterward, 50mL of anhydrous ethanol was added under 300W sonication, and sonication continued for 30 minutes. The ethanol was then removed by rotary evaporation to obtain a cassava starch suspension. The obtained cassava starch suspension was mixed with 1g of β-cyclodextrin and brought to a final volume of 100mL with deionized water. This mixture was magnetically stirred at 700rpm for 6 hours at 50℃ to ensure thorough mixing. After stirring, the mixture was centrifuged and freeze-dried to obtain TS-β-CD-NPs. 300mg of TS-β-CD-NPs was dissolved in 10mL of deionized water to prepare a nano-suspension. Simultaneously, 60mg of γ-aminobutyric acid (GABA) was dissolved in 5mL of deionized water to obtain a GABA solution. A solution of γ-aminobutyric acid (GABA) was mixed with a nano-suspension and stirred uniformly at 600 rpm. Finally, cassava starch-β-cyclodextrin nanoparticles (GABA-TS-β-CD-NPs) encapsulating GABA were obtained by freeze drying.

[0049] Example 6 Determination of γ-aminobutyric acid encapsulation rate

[0050] The free GABA content in the supernatant of GABA-TS-β-CD-NPs and GABA-CS-β-CD-NPs was determined by HPLC. A 1 ml suspension of GABA-TS-β-CD-NPs and GABA-CS-β-CD-NPs nanoparticles was prepared, centrifuged at 30°C using a high-speed refrigerated centrifuge, and the precipitate was washed three times with an equal volume of ultrapure water. All supernatants were collected, filtered through a 0.22 μm filter membrane, added to an inner-lined tube, and then placed in a HPLC vial for analysis. The encapsulation efficiency was calculated as follows:

[0051]

[0052] In the formula: M1 represents the total amount of added GABA (mg), and M2 represents the amount of free (unencapsulated) GABA (mg).

[0053] Table 1. Encapsulation efficiency test results of GABA-TS-β-CD-NPs and GABA-CS-β-CD-NPs

[0054]

[0055] Example 7: In vitro simulated digestion experiment

[0056] 1. Preparation of artificial gastric juice and artificial intestinal juice

[0057] Artificial gastric juice: Pepsin was added to an appropriate amount of 0.1 mol / L HCl solution, and the final concentration was controlled to be 4 mg / mL. Artificial intestinal juice: Trypsin was added to an appropriate amount of 0.1 mol / L sodium bicarbonate solution, and the final concentration was controlled to be 2 mg / mL, then mixed with an equal volume of 12 mg / mL sodium cholate.

[0058] 2. In vitro simulated digestion experiment

[0059] Prepare four 100mL stoppered conical flasks. Add 25mL of physiological saline and 4mL of artificial gastric juice to each flask, mix thoroughly, and adjust the pH to 2.0-2.5 using hydrochloric acid standard solution. Add 15mg of GABA standard to two flasks and an equal amount of GABA-TS-β-CD-NPs prepared in Example 1 to the other two flasks. After mixing, extract the solution once in each flask, then add NaHCO3 and place in a constant temperature water bath at 37℃ with shaking (100r / min) for 2h. Take the artificial gastric juice from two flasks and digest for 1h, then add artificial intestinal juice for further digestion.

[0060] Add 4 ml of physiological saline to the above solution after 1 hour of digestion with artificial gastric juice, adjust the pH of the solution to 6.5-7.0 using 0.5 mol / L NaHCO3 solution, and shake in a constant temperature water bath (37℃, 100 r / min). Then add 18 mL of artificial intestinal juice, adjust the pH to 7.0-7.5, and shake in a constant temperature water bath for 3 hours (37℃, 100 r / min).

[0061] All the above sample solutions were filtered through a 0.22 μm filter membrane after being placed in an ice bath, sonicated for 20 min, and analyzed by HPLC.

[0062] Based on the HPLC analysis of GABA and GABA-TS-β-CD-NPs after simulated in vitro digestion, the degradation rates of GABA and GABA-TS-β-CD-NPs were as follows: after 2 hours of simulated gastric digestion, the degradation rate of GABA was 25.3%, and that of GABA-TS-β-CD-NPs was 14.5%; after 3 hours of simulated intestinal digestion, the degradation rate of GABA was 37.9%, and that of GABA-TS-β-CD-NPs was 21.2%. GABA-TS-β-CD-NPs can effectively reduce the degradation rate of GABA in the gastric environment and are targeted to the intestines to exert their effects, thus improving the utilization rate of GABA to some extent.

[0063] Example 8: Evaluation of the sleep-inducing effects of GABA-CS-CNC-NPs

[0064] Eighty qualified male ICR mice (SPF grade) were randomly divided into eight groups (n = 10) according to body weight: a normal control group, a diazepam group (1.3 mg / kg), low-, medium-, and high-dose GABA groups (50, 100, and 150 mg / kg), and low-, medium-, and high-dose GABA-TS-β-CD-NPs groups (50, 100, and 150 mg / kg). After a week of acclimatization, the mice were administered the drugs by gavage for seven consecutive days, once daily. All mice underwent sample management and behavioral testing between 9:00 AM and 11:00 AM.

[0065] Experiment on the use of sodium pentobarbital to prolong sleep time

[0066] Thirty minutes after the last gavage, all mice were intraperitoneally injected with an above-threshold dose of sodium pentobarbital (50 mg / kg) and placed on a warm mat (37 °C) with their abdomens facing upwards. Sleep latency (the time from the start of sodium pentobarbital injection to the disappearance of the rectifier reflex) and sleep duration (the time from the disappearance of the rectifier reflex to its recovery) were recorded. Mice that did not fall asleep within 15 minutes were excluded from the experiment.

[0067] Subthreshold dose hypnosis experiment with sodium pentobarbital

[0068] Thirty minutes after the last gavage, all mice were intraperitoneally injected with a subthreshold dose of sodium pentobarbital (40 mg / kg) and placed on a warm mat (37 °C) with their abdomens facing upwards. The number of mice falling asleep in each group was recorded as the criterion for falling asleep being the loss of righting reflex for more than 1 minute.

[0069] Table 2. Experiment on sodium pentobarbital prolonging sleep time (n=10)

[0070]

[0071] Note: The GABA-TS-β-CD-NPs in Table 2 were prepared according to the method in Example 1. * indicates P < 0.05 compared to the control group, ** indicates P < 0.001 compared to the control group; # indicates P < 0.05 compared to the high-dose GABA group.

[0072] Table 3. Hypnotic Experiments with Subthreshold Doses of Sodium Pentobarbital (n=10)

[0073]

[0074] Note: GABA-TS-β-CD-NPs in Table 3 were prepared according to the method in Example 1.

[0075] Tables 2 and 3 show that the results of the pentobarbital sodium sleep prolongation experiment and the pentobarbital sodium subthreshold dose hypnosis experiment were positive, proving that GABA-TS-β-CD-NPs have a sleep-improving effect, and the high-dose group of GABA-TS-β-CD-NPs significantly improved the sleep prolongation time of mice compared with the high-dose group of GABA.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a cassava starch-β-cyclodextrin nanoparticle embedding γ-aminobutyric acid, characterized by, Includes the following steps: Step 1) Prepare nanoparticles using cassava starch suspension and β-cyclodextrin, then prepare a cassava starch and β-cyclodextrin nanoparticle solution; the preparation of the cassava starch suspension includes the following steps: 1) Dissolve cassava starch in water, heat to gelatinize, and then cool to room temperature; the water is deionized water; the gelatinization temperature is 80-100℃; the gelatinization time is 0.5-5h; cooling is done with running water; 2) Ultrasound the gelatinized product obtained in step 1; the mass ratio of cassava starch to β-cyclodextrin is 1:2-2:1; Step 2) Prepare a γ-aminobutyric acid solution. Mix the prepared γ-aminobutyric acid solution with the cassava starch and β-cyclodextrin nanoparticle solution obtained in Step 1) to obtain cassava starch-β-cyclodextrin nanoparticles encapsulating γ-aminobutyric acid.

2. The production method according to claim 1, characterized by, The gelatinization temperature is 90°C.

3. The production method according to claim 2, characterized by, The sonication of the gelatinized material is divided into two stages. In the first stage, the material is sonicated at 600W for 30-60 minutes. In the second stage, an organic solvent, namely ethanol, is added at 300W, and the material is sonicated again for 10-40 minutes.

4. The production method according to claim 3, characterized by, The ultrasonication of the paste also includes the step of removing the organic solvent by rotary evaporation.

5. The preparation method according to claim 1, characterized in that, Step 1) involves the following process for preparing cassava starch and β-cyclodextrin nanoparticles: cassava starch suspension and β-cyclodextrin are mixed and dissolved in deionized water, stirred at 40-60℃ for 4-8 hours, and after stirring until homogeneous, centrifuged and freeze-dried to obtain cassava starch and β-cyclodextrin nanoparticles.

6. The production method according to claim 5, wherein Step 1) involves preparing nanoparticles using cassava starch suspension and β-cyclodextrin, and then making a solution. This process also includes the following steps: dissolving freeze-dried cassava starch and β-cyclodextrin nanoparticles in deionized water to obtain a cassava starch and β-cyclodextrin nanoparticle suspension.

7. The preparation method according to claim 1, characterized in that, Step 2) Preparation of γ-aminobutyric acid solution. The γ-aminobutyric acid solution prepared is mixed with the cassava starch and β-cyclodextrin nanoparticle solution from Step 1) including the following steps: dissolving γ-aminobutyric acid in deionized water to obtain γ-aminobutyric acid solution, then mixing and stirring the γ-aminobutyric acid solution with the cassava starch and β-cyclodextrin nanoparticles to obtain a nanoparticle suspension, and then freeze-drying to obtain cassava starch-β-cyclodextrin nanoparticles encapsulated with γ-aminobutyric acid.

8. The application of cassava starch-β-cyclodextrin nanoparticles encapsulated with γ-aminobutyric acid obtained by the preparation method according to claim 1 in the preparation of sleep-improving drugs.

9. A pharmaceutical composition, characterized by, Tapioca starch-β-cyclodextrin nanoparticles containing γ-aminobutyric acid obtained by the preparation method according to claim 1.

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