Preparation method of composite soft capsule shell containing plant starch

Abstract

The invention provides a preparation method of a composite soft capsule shell containing plant starch, and belongs to the technical field of soft capsules. The composite soft capsule shell is prepared from the following components in percentage by mass: 15 to 30 percent of gelatin, 5 to 20 percent of modified plant starch, 1 to 15 percent of composite plant gum, 1 to 10 percent of dopamine grafted pulullan, 10 to 30 percent of plasticizer and 25 to 45 percent of solvent; compared with the existing soft capsule skin, the soft capsule skin prepared by the invention has better mechanical strength and toughness, overcomes the problem of disintegration and delayed release caused by a capsule shell crosslinking aging reaction, is beneficial to the preservation of the soft capsule and reduces the storage cost.

Description

Technical Field

[0001] The invention relates to the technical field of soft capsules, and in particular to a method for preparing a composite soft capsule skin containing plant starch. Background Art

[0002] Capsule-type skin care products are a new type of skin care products that encapsulate skin care ingredients in a capsule-shaped container. They are favored by the market due to their portability and precise dosage control, especially in the market with strong demand for single-use and portable products. According to the shape of the capsule skin, they can be divided into soft capsules or hard capsules. The capsule material of soft capsules is mainly composed of animal gelatin, glycerin and other raw materials, which can be used to encapsulate various active ingredients, such as essential oils, vitamins and antioxidants, and can maintain the stability and effectiveness of active substances. However, animal gelatin has a strong odor, which can easily affect product acceptance and is easy to deteriorate during storage. At the same time, during the use of soft capsules, its collagen is prone to cross-linking reactions, deterioration, leakage, odor, and slow disintegration. It is also easy to absorb containers, stick, rupture, and capsule shell aging, and has disadvantages such as limited application range.

[0003] With the deepening of research, plant starch capsules have become a hot topic in the fields of cosmetics and other fields. This is a plant capsule skin made of starch, glycerin, and purified water. Its ingredients are relatively natural and safe, but it has poor flexibility and is easy to break, delayed disintegration, low stability, and difficult processing, which affects its quality and safety.

[0004] Therefore, if a soft capsule can be prepared that can reduce the capsule odor without affecting the flexibility, it will be beneficial to the application of soft capsule technology. Summary of the invention

[0005] In view of the defects of the prior art, the present invention prepares a composite soft capsule skin containing plant starch, which has good mechanical strength, flexibility and stability and a rapid disintegration time.

[0006] In order to achieve the above purpose, the present invention solves the technical problem by adopting the following technical solutions:

[0007] In a first aspect, the present invention provides a composite soft capsule skin containing plant starch, which comprises, by mass percentage, 15-30% gelatin, 5-20% modified plant starch, 1-15% composite plant gum, 1-10% dopamine grafted pullulan, 10-30% plasticizer, and 25-45% water.

[0008] Preferably, by mass percentage, the composition comprises 20-25% gelatin, 10-15% modified plant starch, 5-10% composite plant gum, 2-7% dopamine-grafted pullulan, 13-23% plasticizer, and 30-40% water.

[0009] More preferably, the composition comprises, by mass percentage, 23% gelatin, 12% modified plant starch, 8% composite plant gum, 4% dopamine-grafted pullulan, 18% plasticizer, and 35% water.

[0010] Preferably, the preparation of the modified plant starch comprises the following steps:

[0011] 10 mol / L sodium hydroxide solution, potato starch and water are mixed and stirred at a solid-liquid ratio of 1:6:70 for 4-6 hours, and then the homogenate is neutralized, filtered, washed and dried to obtain modified starch.

[0012] Preferably, the composite plant gum is prepared from cationic guar gum, tamarind gum and gum arabic in a mass ratio of (1-3):3:1.

[0013] The cationic guar gum has a positive charge, and can electrostatically interact with negatively charged groups in components such as gelatin, thereby enhancing the cohesive force of the entire colloid system; the tamarind gum is a polysaccharide gum, and its long chain structure can be entangled with the molecular chains of components such as gelatin and modified plant starch to increase the strength of the system; the gum arabic is a gum with good emulsification and thickening properties, which can make the various components better dispersed in the system, and its molecular chain will also interact with other gum molecules to form a denser network structure, thereby improving the mechanical strength and toughness of the soft capsule.

[0014] Further preferably, the composite plant gum is prepared from cationic guar gum, tamarind gum and gum arabic in a mass ratio of 2:3:1.

[0015] Preferably, the preparation of the dopamine-grafted pullulan comprises:

[0016] S1. Add pullulan to water at a solid-liquid ratio of 1: (70-90) and let stand at room temperature for 24 hours, then adjust the pH to 9-11, then add chloroacetic acid solution and stir at 45°C for 1.5-2.5 hours. After the reaction, neutralize the reaction solution, dialyze, precipitate with alcohol, wash and dry to obtain carboxymethylated pullulan;

[0017] S2. Carboxymethylated pullulan and 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride are added to water at room temperature to activate the carboxyl group, and then 3-methacryloyl dopamine is added. The mixture is reacted at 40-50°C for 7-9 hours under nitrogen protection. After the reaction, the dopamine-grafted pullulan is obtained after alcohol precipitation, washing and drying.

[0018] Preferably, the plasticizer is one or more of glycerol, sorbitol, mannitol, maltitol, and polyethylene glycol.

[0019] The plasticizer can increase the flexibility of the soft capsule to prevent it from being easily broken when subjected to external force, and can also make the various components of the soft capsule better mixed and compatible, making the entire system more uniform and stable.

[0020] Preferably, the plant starch is one or more of potato starch, tapioca starch, corn starch, waxy corn starch, pea starch, and wheat starch.

[0021] In a second aspect, the present invention provides a method for preparing a composite soft capsule skin containing plant starch, comprising the following steps:

[0022] Mix water, modified plant starch, composite plant gum, dopamine-grafted pullulan and plasticizer, stir at 200 r / min and heat to 85-90°C, keep stirring for about 30 minutes, then add gelatin and keep stirring at 80°C until the gelatin is completely dissolved, evacuate for 40 minutes, vacuum degree -0.06 MPa, then let the gelatin solution stand at 60-65°C, and then press to obtain capsules.

[0023] In a third aspect, the present invention further provides a soft capsule, comprising the composite soft capsule skin containing plant starch.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention grafts the active groups of 3-methacryloyl dopamine with carboxymethylated pullulan, and the active groups in the dopamine structure interact with the carboxymethylated pullulan, which is helpful to stabilize the molecular structure of pullulan and reduce the cross-linking reaction during storage, thereby improving the disintegration and delayed release caused by the cross-linking aging reaction of the capsule shell, which is beneficial to the storage of the soft capsule and reduces the storage cost.

[0026] At the same time, the grafted carboxymethyl pullulan cooperates with gelatin, modified plant starch, composite plant gum, plasticizer and deionized water within a certain range, and the prepared soft capsules have good mechanical strength, toughness and stability; and compared with pure gelatin soft capsules, the modified plant starch is added to reduce the amount of gelatin added, and the prepared soft capsules not only maintain good mechanical strength and toughness, but also avoid the problem of excessive odor of existing soft capsules affecting sensory experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 1 is a table showing the tensile strength test results of different soft capsule skins in the embodiments of the present invention.

[0029] Figure 2 1 is a table showing the elongation at break test results of different soft capsule skins in the embodiments of the present invention. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the present invention, there is no particular limitation on the specific dispersion and stirring treatment methods.

[0032] In the present invention, the test methods used are conventional methods unless otherwise specified; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0033] In the present invention, the term "gelatin" used is a hydrolyzed protein extracted from animal collagen, usually derived from the skin, bones and connective tissue of cattle, pigs or fish. In the present invention, gelatin can be food grade animal gelatin with a freezing strength range of 100-300g Bloom.

[0034] Cationic guar gum powder: nitrogen content is 1.3-1.6%, viscosity of 1% aqueous solution is 2000mPa.s, pH value is 8.0, 25°C.

[0035] Example 1

[0036] 1. A composite soft capsule skin containing plant starch, comprising, by mass percentage, 23% gelatin, 12% modified plant starch, 8% composite plant gum, 4% dopamine-grafted pullulan, 18% plasticizer (glycerol), and 35% deionized water.

[0037] Wherein, the preparation of the modified plant starch comprises the following steps:

[0038] 10 mol / L sodium hydroxide solution, potato starch and deionized water were mixed and stirred at a mass volume ratio of 1:6:70 (g / mL) for 5 h at a stirring speed of 80 r / min. The slurry was neutralized with 5 mol / L hydrochloric acid to a pH of 7.2, filtered, and the filter cake was washed three times with deionized water and dried at 45°C to obtain modified starch.

[0039] The composite plant gum is prepared from cationic guar gum, tamarind gum and gum arabic in a mass ratio of 2:3:1.

[0040] The preparation of the dopamine-grafted pullulan comprises the following steps:

[0041] (1) At room temperature, 10 g of pullulan was added to deionized water at a ratio of 1:80 (g / mL) and allowed to stand for 24 h. The pH was then adjusted to 10 with 20% sodium hydroxide. 0.4 g of chloroacetic acid was then weighed and dissolved in 100 mL of deionized water. The solution was slowly added to the pullulan solution within 25 min and stirred at 45 °C for 2 h at a stirring speed of 80 rpm.

[0042] (2) After the reaction, the pH of the reaction solution was neutralized to 7.0 with dilute hydrochloric acid, and then dialyzed with deionized water for 72 hours to remove small molecular impurities and then filtered. The filter cake was added to three times the volume of 95% ethanol and allowed to stand overnight. The precipitate was washed three times with 75% ethanol and freeze-dried to obtain carboxymethylated pullulan.

[0043] (3) 12 g of carboxymethylated pullulan and 10 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) were added to 150 mL of deionized water, stirred at 100 r / min at room temperature for 1 h, and then 3-methacryloyl dopamine solution (8.5 g of 3-methacryloyl dopamine dissolved in 50 mL of deionized water) was added dropwise within 10 min. The mixture was reacted at 50° C. for 8 h under nitrogen protection. After the reaction was completed, the filter cake was added to three times the volume of 95% ethanol and allowed to stand overnight. The precipitate was washed three times with 75% ethanol and freeze-dried to obtain dopamine-grafted pullulan.

[0044] 2. A method for preparing a composite soft capsule skin containing plant starch, comprising the following steps:

[0045] Weigh all the raw materials according to the above formula, add deionized water, modified plant starch, composite plant gum, dopamine-grafted pullulan and plasticizer into the gelatinization pot, stir at 200r / min and heat to 85-90℃, keep stirring for about 30min, then add gelatin to keep the material temperature at 80℃, stir until the gelatin is completely dissolved and evenly dissolved, evacuate for about 40min, vacuum degree -0.06mpa. After evacuation, transfer the glue solution to an insulation bucket and let it stand at 60-65℃ to remove bubbles in the glue solution to obtain capsule skin glue solution, which can be pressed into capsules by a capsule forming machine.

[0046] Example 2

[0047] 1. A composite soft capsule skin containing plant starch, comprising, by mass percentage, 20% gelatin, 15% modified plant starch, 10% composite plant gum, 2% dopamine-grafted pullulan, 13% plasticizer (sorbitol), and 40% deionized water.

[0048] Wherein, the preparation of the modified plant starch comprises the following steps:

[0049] 10 mol / L sodium hydroxide solution, potato starch and deionized water were mixed and stirred at a mass volume ratio of 1:6:70 (g / mL) for 4 hours at a stirring speed of 80 r / min. The slurry was neutralized with 5 mol / L hydrochloric acid to a pH of 7.2, filtered, and the filter cake was washed three times with deionized water and dried at 45°C to obtain modified starch.

[0050] The composite plant gum is prepared from cationic guar gum, tamarind gum and gum arabic in a mass ratio of 1:3:1.

[0051] The preparation of the dopamine-grafted pullulan comprises:

[0052] (1) At room temperature, 10 g of pullulan was added to deionized water at a ratio of 1:70 (g / mL) and allowed to stand for 24 h. The pH was then adjusted to 11 with 20% sodium hydroxide. 0.5 g of chloroacetic acid was then weighed and dissolved in 100 mL of deionized water. The solution was slowly added to the pullulan solution within 25 min and stirred at 45 °C for 1.5 h at a stirring speed of 80 rpm.

[0053] (2) After the reaction, the pH of the reaction solution was neutralized to 7.0 with dilute hydrochloric acid, and then dialyzed with deionized water for 72 hours to remove small molecular impurities and then filtered. The filter cake was added to three times the volume of 95% ethanol and allowed to stand overnight. The precipitate was washed three times with 75% ethanol and freeze-dried to obtain carboxymethylated pullulan.

[0054] (3) 12 g of carboxymethylated pullulan and 10 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) were added to 150 mL of deionized water, stirred at 100 r / min at room temperature for 1 h, and then 3-methacryloyl dopamine solution (8.5 g of 3-methacryloyl dopamine dissolved in 50 mL of deionized water) was added dropwise within 10 min. The mixture was reacted at 50 ° C for 9 h under nitrogen protection. After the reaction was completed, the filter cake was added to three times the volume of 95% ethanol and allowed to stand overnight. The precipitate was washed three times with 75% ethanol and freeze-dried to obtain dopamine-grafted pullulan.

[0055] 2. A method for preparing a composite soft capsule skin containing plant starch is the same as that in Example 1.

[0056] Example 3

[0057] 1. A composite soft capsule skin containing plant starch, comprising, by mass percentage, 25% gelatin, 10% modified plant starch, 5% composite plant gum, 7% dopamine-grafted pullulan, 23% plasticizer (mannitol), and 30% deionized water.

[0058] Wherein, the preparation of the dopamine grafted modified plant starch comprises the following steps:

[0059] 10 mol / L sodium hydroxide solution, potato starch and deionized water were mixed and stirred at a mass volume ratio of 1:6:70 (g / mL) for 6 hours at a stirring speed of 80 r / min. The slurry was neutralized with 5 mol / L hydrochloric acid to a pH of 7.2, filtered, and the filter cake was washed three times with deionized water and dried at 45°C to obtain modified starch.

[0060] The composite plant gum is prepared from cationic guar gum, tamarind gum and gum arabic in a mass ratio of 3:3:1.

[0061] The preparation of the dopamine-grafted pullulan comprises:

[0062] (1) At room temperature, 10 g of pullulan was added to deionized water at a ratio of 1:90 (g / mL) and allowed to stand for 24 h. The pH was then adjusted to 9 with 20% sodium hydroxide. 0.3 g of chloroacetic acid was then weighed and dissolved in 100 mL of deionized water. The solution was slowly added to the pullulan solution within 25 min and stirred at 45 °C for 2.5 h at a stirring speed of 80 rpm.

[0063] (2) After the reaction, the pH of the reaction solution was neutralized to 7.0 with dilute hydrochloric acid, and then dialyzed with deionized water for 72 hours to remove small molecular impurities and then filtered. The filter cake was added to three times the volume of 95% ethanol and allowed to stand overnight. The precipitate was washed three times with 75% ethanol and freeze-dried to obtain carboxymethylated pullulan.

[0064] (3) 12 g of carboxymethylated pullulan and 10 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) were added to 150 mL of deionized water, stirred at 100 r / min at room temperature for 1 h, and then 3-methacryloyl dopamine solution (8.5 g of 3-methacryloyl dopamine dissolved in 50 mL of deionized water) was added dropwise within 10 min. The mixture was reacted at 40° C. for 7 h under nitrogen protection. After the reaction was completed, the filter cake was added to three times the volume of 95% ethanol and allowed to stand overnight. The precipitate was washed three times with 75% ethanol and freeze-dried to obtain dopamine-grafted pullulan.

[0065] 2. A method for preparing a composite soft capsule skin containing plant starch is the same as that in Example 1.

[0066] Example 4

[0067] The difference between Example 4 and Example 1 is that Example 4 uses an equal amount of tapioca starch to replace potato starch, and all other aspects are the same.

[0068] Example 5

[0069] The difference between Example 5 and Example 1 is that Example 5 uses an equal amount of corn starch to replace potato starch, and the other aspects are the same.

[0070] Example 6

[0071] The difference between Example 6 and Example 1 is that Example 6 uses an equal amount of waxy corn starch to replace potato starch, and all other aspects are the same.

[0072] Example 7

[0073] The difference between Example 7 and Example 1 is that Example 7 uses an equal amount of wheat starch to replace potato starch, and all other aspects are the same.

[0074] Example 8

[0075] The difference between Example 8 and Example 1 is that Example 8 replaces potato starch with an equal amount of pea starch, and the other aspects are the same.

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 1 is that the composite soft capsule skin formula of Comparative Example 1 is different, and the others are the same.

[0078] A composite soft capsule skin containing plant starch comprises, by mass percentage, 15% gelatin, 20% modified plant starch, 1% composite plant gum, 1% dopamine-grafted pullulan, 18% plasticizer (glycerol), and 45% deionized water.

[0079] Comparative Example 2

[0080] The difference between Comparative Example 2 and Example 1 is that the composite soft capsule skin formula of Comparative Example 2 is different, and the others are the same.

[0081] A composite soft capsule skin containing plant starch comprises, by mass percentage, 30% gelatin, 5% modified plant starch, 15% composite plant gum, 10% dopamine-grafted pullulan, 15% plasticizer (glycerol) and 25% deionized water.

[0082] Comparative Example 3

[0083] The difference between Comparative Example 3 and Example 1 is that, in Comparative Example 3, an equal amount of plant starch (potato starch) is used to replace the modified plant starch, and the other aspects are the same.

[0084] Comparative Example 4

[0085] The difference between Comparative Example 4 and Example 1 is that no modified plant starch is added to Comparative Example 4, and the balance is supplemented with gelatin, and the other contents are the same.

[0086] A composite soft capsule skin containing plant starch comprises, by mass percentage, 35% gelatin, 8% composite plant gum, 4% dopamine-grafted pullulan, 18% plasticizer (glycerol) and 35% deionized water.

[0087] Comparative Example 5

[0088] The difference between Comparative Example 5 and Example 1 is that the dopamine-grafted pullulan is replaced by an equal amount of pullulan in Comparative Example 5, and the other contents are the same.

[0089] Comparative Example 6

[0090] The difference between Comparative Example 6 and Example 1 is that dopamine-grafted pullulan is not added in Comparative Example 6, and the balance is supplemented with gelatin, and the other contents are the same.

[0091] A composite soft capsule skin containing plant starch comprises, by mass percentage, 31% gelatin, 12% modified plant starch, 8% composite plant gum, 18% plasticizer (glycerol) and 35% deionized water.

[0092] Test Example 1

[0093] 1. Capsule skin performance test

[0094] The capsule skin glue prepared in Examples 1-3 and Comparative Examples 1-6 was poured onto a glass plate and dried at 50° C. for 12 hours to obtain capsule skin samples. Before testing, all capsule skin samples were balanced at a humidity below 25% for 15 days before capsule skin performance testing was performed.

[0095] 1. Mechanical properties test

[0096] At room temperature, the capsule skin was cut into strips of 10 mm × 60 mm in size, and the mechanical properties of the capsule skin were tested using a tensile tester. The tensile strength (MPa) and elongation at break (%) were measured at a tensile speed of 100 mm / min. The calculation formula is as follows:

[0097]

[0098] In formula (1), Ts is the tensile strength, MPa; F is the maximum tension that the sample withstands when it breaks, N; S is the initial cross-sectional area of ​​the sample, mm 2 .

[0099]

[0100] In formula (2), EB is the elongation at break, %; L is the maximum tension the sample withstands when it breaks, N; L is the elongation at break, mm; L0 is the initial spacing, 40 mm.

[0101] 2. Disintegration time test

[0102] Soft capsules are prone to aging during their shelf life, resulting in slow disintegration, which in turn affects the absorption of drugs in the body. This is because gelatin, the shell material of soft capsules, is easily oxidized by itself or cross-linked with aldehydes to form a water-insoluble film, which in turn affects the disintegration and dissolution of the soft capsules. Therefore, the anti-oxidative properties of soft capsules are analyzed through disintegration time tests.

[0103] According to the disintegration time limit test method for capsules in Part 4 of the 2020 edition of the Chinese Pharmacopoeia, the soft capsule skins are placed in the disintegration instrument and the time required for the capsule skin to completely disintegrate is observed in a water bath at a temperature of 37°C ± 1°C, that is, the time required for the disintegration residue to completely pass through the sieve. Check 6 capsules at a time. If 1 capsule cannot be completely disintegrated, another 6 capsules should be taken for retesting, and all should meet the requirements.

[0104] Table 1 Soft capsule skin disintegration time test results

[0105] Group Disintegration time (min) Example 1 5 Example 2 6 Example 3 5 Comparative Example 1 8 Comparative Example 2 7 Comparative Example 3 10 Comparative Example 4 9 Comparative Example 5 12 Comparative Example 6 11

[0106] Result analysis:

[0107] The lower the tensile strength, the capsule skin is easy to split during the production of soft capsules and is difficult to form; the greater the elongation at break, the better the flexibility, that is, it can withstand greater deformation before breaking without damage. On the contrary, when the flexibility is poor, the capsule skin is easy to break. Figure 1 and Figure 2 As shown, the tensile strength and elongation at break of Examples 1-3 are significantly greater than those of Comparative Examples 1-6. Although the tensile strength of the soft capsules prepared using gelatin in Comparative Example 4 is higher than that of Comparative Example 3, the soft capsules made of pure gelatin have a strong odor, which affects product acceptance and is not conducive to product preservation. Moreover, the tensile strength and elongation at break of Example 1 are the largest, indicating that the capsules prepared by the present invention have good tensile strength and flexibility, and can effectively prevent the soft capsules from being difficult to shape, leaking, or rupturing.

[0108] As shown in Table 1, compared with Comparative Examples 1-6, the disintegration time of the soft capsule skins prepared in Examples 1-3 is basically within 6 minutes, while the disintegration time of the control group needs to be more than 7 minutes, indicating that the capsule skin prepared in the present invention disintegrates rapidly and improves the disintegration and delayed release caused by the cross-linking aging reaction of the capsule shell. The soft capsule skins prepared in Examples 4-8 are the same as those prepared in Example 1, and are not described here.

[0109] 2. Soft Capsule Stability Test

[0110] According to the content material liquid (vitamin E oil, provided by Guangzhou Kewan Biotechnology Co., Ltd.) 0.3g / grain and the capsule skin glue liquid 0.2g / grain, the content material liquid and the capsule skin glue liquid prepared in Examples 1-3 and Comparative Examples 1-6 were placed on a capsule machine to be pressed into soft capsules. The rotation speed was 20r / min, the indoor temperature was 25°C, and the relative humidity was 30%±5%.

[0111] The prepared capsules were placed in a constant temperature incubator for temperature testing. The heat resistance and cold resistance temperature test cycles were 2 months, heat resistance (37±2℃), cold resistance (-15±2℃); cycle test (first 37℃ high temperature for 24h, -15℃ low temperature for 24h), cycle 10 times, after the test, the room temperature was restored to observe whether there was no obvious difference from before the test, and there was no damage or deformation, then it was judged as qualified, otherwise it was unqualified. On the 0th day, the capsule skin was intact and elastic without cracks. Commercially available vitamin E oil soft capsules (net content of 0.3g, pure gelatin soft capsules) were set as the control group.

[0112] Table 2 Soft capsule stability test results

[0113]

[0114] It can be seen from Table 2 that, compared with the control group, the soft capsules made of the soft capsule skins of Examples 1-3 are still intact, elastic and leak-free after high and low temperature tests, while the commercially available soft capsules are prone to brittle skins; at the same time, compared with Comparative Examples 1-6, the soft capsules made of the soft capsule skins of Examples 1-3 have better stability, indicating that the components of the present invention cooperate with each other, and the lack or replacement of components such as gelatin, modified plant starch, composite plant gum, dopamine-grafted pullulan, etc., easily lead to insufficient stability of the soft capsule skin, thereby affecting the quality and efficacy of the soft capsule.

[0115] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A composite soft capsule skin containing plant starch, characterized in that: According to mass percentage, it includes 15-30% gelatin, 5-20% modified plant starch, 1-15% composite plant gum, 1-10% dopamine grafted pullulan, 10-30% plasticizer and 25-45% water.

2. The composite soft capsule skin containing plant starch according to claim 1, characterized in that: According to mass percentage, it includes 20-25% gelatin, 10-15% modified plant starch, 5-10% composite plant gum, 2-7% dopamine grafted pullulan, 13-23% plasticizer and 30-40% water.

3. The composite soft capsule skin containing plant starch according to claim 1, characterized in that: In terms of mass percentage, it includes 23% gelatin, 12% modified plant starch, 8% composite plant gum, 4% dopamine-grafted pullulan, 18% plasticizer, and 35% dissolved water.

4. The composite soft capsule skin containing plant starch according to any one of claims 1 to 3, characterized in that: The preparation of the modified plant starch comprises the following steps: 10 mol / L sodium hydroxide solution, potato starch and water are mixed and stirred at a solid-liquid ratio of 1:6:70 for 4-6 hours, and then the homogenate is neutralized, filtered, washed and dried to obtain modified starch.

5. The composite soft capsule skin containing plant starch according to any one of claims 1 to 3, characterized in that: The composite plant gum is prepared from cationic guar gum, tamarind gum and gum arabic in a mass ratio of (1-3):3:

1.

6. The composite soft capsule skin containing plant starch according to any one of claims 1 to 3, characterized in that: The preparation of the dopamine-grafted pullulan comprises: S1. Add pullulan to water at a solid-liquid ratio of 1: (70-90) and let stand at room temperature for 24 hours, then adjust the pH to 9-11, then add chloroacetic acid solution and stir at 45°C for 1.5-2.5 hours. After the reaction, neutralize the reaction solution, dialyze, precipitate with alcohol, wash and dry to obtain carboxymethylated pullulan; S2. Carboxymethylated pullulan and 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride are added to water at room temperature to activate the carboxyl group, and then 3-methacryloyl dopamine is added. The mixture is reacted at 40-50°C for 7-9 hours under nitrogen protection. After the reaction, the dopamine-grafted pullulan is obtained after alcohol precipitation, washing and drying.

7. The composite soft capsule skin containing plant starch according to any one of claims 1 to 3, characterized in that: The plasticizer is one or more of glycerol, sorbitol, mannitol, maltitol and polyethylene glycol.

8. The composite soft capsule skin containing plant starch according to any one of claims 1 to 3, characterized in that: The plant starch is one or more of potato starch, cassava starch, corn starch, waxy corn starch, pea starch and wheat starch.

9. A method for preparing a composite soft capsule skin containing plant starch according to any one of claims 1 to 8, characterized in that: The following steps are involved: Mix water, modified plant starch, composite plant gum, dopamine-grafted pullulan and plasticizer, stir at 200 r / min and heat to 85-90°C, keep stirring for about 30 minutes, then add gelatin and keep stirring at 80°C until the gelatin is completely dissolved, evacuate for 40 minutes, vacuum degree -0.06 MPa, then let the gelatin solution stand at 60-65°C, and then press to obtain capsules.

10. A soft capsule, characterized in that: The invention comprises a composite soft capsule skin containing plant starch as described in any one of claims 1 to 8.

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