A high-toughness instant hydroxypropyl methyl cellulose hollow capsule, a preparation method and application thereof

Abstract

The application belongs to the technical field of medical packaging materials, and particularly relates to a high-toughness instant hydroxypropyl methyl cellulose hollow capsule as well as a preparation method and application thereof. The high-toughness instant hydroxypropyl methyl cellulose hollow capsule is composed of the following components in parts by weight: 18-25 parts of hydroxypropyl methyl cellulose, 0.4-1.2 parts of a composite gelling agent, 0.2-0.6 parts of a coagulant aid, 1-3 parts of a toughening anti-brittle agent, 0.05-0.2 parts of a surfactant and 70-80 parts of water. By introducing trehalose and optimizing the gelling system, the mechanical strength of the HPMC capsule in a low-humidity environment is significantly improved, the friability is reduced, the rapid disintegration performance of the capsule in gastric juice is ensured, and the application is particularly suitable for filling of drugs with high hygroscopicity or sensitivity to moisture.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical packaging materials technology, specifically relating to a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule, its preparation method, and its application. Background Technology

[0002] Hydroxypropyl methylcellulose (HPMC) empty capsules, as plant-derived capsules, have gained widespread use in the pharmaceutical and health product industries due to their outstanding advantages such as low water content, no risk of cross-linking reaction, and suitability for sensitive contents, and are gradually replacing traditional animal-derived gelatin capsules.

[0003] However, the mechanical properties of existing HPMC empty capsules are highly dependent on ambient humidity. Under low humidity conditions, the capsule shell becomes significantly more brittle due to water loss, making it difficult to withstand high-speed filling and polishing, resulting in a high breakage rate and the risk of microbial contamination. Simultaneously, HPMC capsules exhibit delayed disintegration in simulated gastric fluid, and the higher gel temperature leads to slower rupture and dissolution rates, potentially affecting the onset time of rapid-acting formulations. Currently, conventional improvement methods mainly involve adding carrageenan or gellan gum to enhance gel strength, or relying on glycerol plasticizers to improve toughness. However, gelling agents tend to form dense networks that delay disintegration, while glycerol easily causes capsules to soften and deform under high humidity and relapse into brittleness under low humidity. More importantly, these components lack a synergistic stabilizing mechanism, making it difficult for capsules to simultaneously meet the requirements of low-humidity toughness, high-humidity morphological stability, and rapid disintegration when dealing with different humidity and media environments. Summary of the Invention

[0004] The purpose of this invention is to provide a high-toughness, fast-dissolving hydroxypropyl methylcellulose (HPMC) empty capsule, its preparation method, and its application, thereby overcoming the shortcomings of the prior art. By introducing trehalose and optimizing the gelation system, the mechanical strength of HPMC capsules in low humidity environments is significantly improved, and the brittleness is reduced. At the same time, the rapid disintegration performance of the capsules in gastric juice is guaranteed, making it particularly suitable for filling drugs with high hygroscopicity or those sensitive to moisture.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule, which is composed of the following components by weight: 18-25 parts of hydroxypropyl methylcellulose, 0.4-1.2 parts of composite gelling agent, 0.2-0.6 parts of coagulant aid, 1-3 parts of toughening and anti-brittleness agent, 0.05-0.2 parts of surfactant and 70-80 parts of water.

[0006] HPMC serves as the structural framework, providing a continuous film-forming matrix and a hydrophilic dissolution basis. Under ionic and temperature-triggered conditions, composite gelling agents (carrageenan, gellan gum) dynamically cross-link with HPMC molecules through electrostatic and hydrogen bonding, rapidly constructing a stable three-dimensional network and achieving efficient and controllable curing from sol to gel. Acolytic agents enhance the order and stability of this network, ensuring uniform capsule formation and a dense structure. Toughening and anti-brittleness agents permeate the network, significantly improving the material's elongation at break and low-wet brittleness resistance through flexible bridging of molecular chains and stress, forming a mechanical synergy with the rigid network. Water, as the system's medium, not only regulates the entire gelation kinetics process but also adjusts the network's flexibility through dynamic equilibrium of hydrogen bonds, becoming a key carrier for the functional coupling of various components.

[0007] In a second aspect, the present invention provides a method for preparing the high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsules described in the first aspect, comprising the following steps: (1) Add hydroxypropyl methylcellulose to a portion of preheated water, stir and mix well, then cool to the set temperature and continue stirring and mixing to prepare a dispersion. (2) Add the composite gelling agent, coagulant aid, toughening and anti-brittleness agent and surfactant to the remaining preheated water in sequence and stir to mix well to make auxiliary liquid; (3) Add the excipient liquid to the dispersion and stir to mix well. Then, perform vacuum degassing to prepare the capsule liquid. (4) Dip the preheated die needle into the capsule liquid, and after drying, demolding, cutting and fitting, a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule is obtained.

[0008] HPMC is dispersed separately in hot water to allow for full hydration and swelling, forming a continuous and uniform dispersion, thus avoiding agglomeration caused by subsequent material addition interference. The composite gelling agent, toughening agent, and other excipients are pre-formulated into a homogeneous excipient solution, ensuring not only the complete dissolution and activation of each functional component (especially the ion-sensitive gelling agent) but also achieving the pre-assembly of the functional additive system. The excipient solution is gently mixed into the HPMC dispersion, inducing orderly cross-linking between HPMC and gelling agent molecules to form a uniform and stable three-dimensional network structure. This preparation method effectively avoids problems such as uneven dispersion and excessively rapid localized reactions that easily occur with single-component addition, ensuring the stability and spinnability of the capsule solution from the source, as well as the uniformity, high toughness, and rapid solubility of the final capsule product.

[0009] Thirdly, the present invention provides the application of the high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsules described in the first aspect in food, health products, cosmetics, and biopharmaceuticals.

[0010] Fourthly, the present invention provides a gastric disintegrating, fast-release capsule, which uses the high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule described in the first aspect. The beneficial effects of this invention are: (1) In the formulation of the hydroxypropyl methylcellulose (HPMC) empty capsules of this invention, trehalose is introduced into the capsule shell formulation. Utilizing the excellent water retention and biofilm protection properties of trehalose, it forms a hydrogen bond network with the HPMC molecular chain, inhibiting excessive shrinkage of polymer chain segments during drying and water loss, thereby significantly improving the stability of the capsule shell. Tamarind gum, through the steric hindrance effect of its molecular chain, embeds itself into the gaps in the double helix structure of gellan gum, forming a heterogeneous bonding region, thereby blocking the large-scale homogeneous aggregation of gellan gum molecules. This not only successfully eliminates the thermal hysteresis phenomenon of traditional gelling systems, reducing the difference between gelling temperature and melting temperature to within 5°C, making process control more precise; but also, the rapid and effective hydration characteristics exhibited by tamarind gum in the gastric juice environment can generate huge osmotic pressure and hydrostatic pressure inside the capsule shell, causing mechanical fragmentation and disintegration of the capsule shell from the inside, achieving instantaneous dissolution performance.

[0011] (2) The preparation method of the present invention effectively overcomes the problems of uneven dispersion and excessively fast local reaction that are easily caused by one-time feeding of multiple components, and ensures the stability of capsule liquid and the uniformity, high toughness and rapid reproducibility of the final capsule product from the source. Detailed Implementation

[0012] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Specific conditions not specified in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Components whose manufacturers are not specified are all commercially available conventional products.

[0013] The existing HPMC capsules are brittle and fragile in dry environments, affecting the yield of high-speed filling and causing slow disintegration and delayed drug release when exposed to water. Current improvement methods mainly involve adding carrageenan or simple plasticizing, but these methods can easily lead to the capsules softening or becoming unstable when wet, making it difficult to achieve an ideal balance between toughness and rapid dissolution.

[0014] This invention optimizes the composition of the toughening and anti-brittleness agent, utilizing the polyhydroxy structure of trehalose to form a dense hydrogen bond network with HPMC molecules. This locks in moisture while inhibiting excessive shrinkage of polymer chains under dry conditions, significantly improving the stability of the capsule shell and overcoming the problem of low-moisture brittleness while maintaining toughness. A low-acyl gellan gum-tamarind gum composite gelling system is also constructed. The steric hindrance effect of tamarind gum molecules embeds them into the gaps between the gellan gum double helices, forming heterogeneous bonding regions. This effectively blocks the homogeneous aggregation of gellan gum, eliminates the thermal hysteresis phenomenon of traditional systems, and controls the solidification-melting temperature difference within 5°C. Simultaneously, the rapid hydration of tamarind gum in gastric juice generates enormous hydrostatic pressure, causing the capsule shell to rapidly disintegrate mechanically. This fundamentally solves the technical contradiction of existing HPMC capsules, which struggle to simultaneously achieve high filling adaptability and rapid solubility.

[0015] The technical solution adopted in this invention is as follows: In a first aspect, the present invention provides a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule, which is composed of the following components by weight: 18-25 parts of hydroxypropyl methylcellulose, 0.4-1.2 parts of composite gelling agent, 0.2-0.6 parts of coagulant aid, 1-3 parts of toughening and anti-brittleness agent, 0.05-0.2 parts of surfactant and 70-80 parts of water.

[0016] As an example, the high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule is composed of the following components by weight: 20 parts hydroxypropyl methylcellulose, 0.8 parts composite gelling agent, 0.3 parts coagulant aid, 2 parts toughening and anti-brittleness agent, 0.1 parts surfactant and 76.8 parts water.

[0017] Alternatively, 18 parts hydroxypropyl methylcellulose, 0.5 parts composite gelling agent, 0.25 parts coagulant aid, 1.2 parts toughening and anti-brittleness agent, 0.05 parts surfactant and 80 parts water.

[0018] Alternatively, 25 parts hydroxypropyl methylcellulose, 1.2 parts composite gelling agent, 0.6 parts coagulant aid, 3 parts toughening and anti-brittleness agent, 0.2 parts surfactant and 70 parts water.

[0019] In some other embodiments, the viscosity of hydroxypropyl methylcellulose is 4-15 mPa·s; The composite gelling agent is composed of low-acyl gellan gum and tamarind gum in a mass ratio of 1:(0.5-1.5).

[0020] In some other embodiments, the toughening and anti-brittleness agent is composed of trehalose and glycerol in a mass ratio of (1-2):1.

[0021] In some other embodiments, the coagulant includes one or more of potassium citrate, calcium gluconate, or calcium lactate; The surfactant includes one or more of polysorbate 80 or sodium dodecyl sulfate.

[0022] In other embodiments, the high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsules have an extreme low-moisture friability of ≤2 / 50 capsules, a disintegration time of ≤5 min in gastric juice simulated medium, a deformation rate of ≤1.5% in high-humidity environments, and a drying loss of ≤6%.

[0023] In a second aspect, the present invention provides a method for preparing the high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsules described in the first aspect, comprising the following steps: (1) Add hydroxypropyl methylcellulose to a portion of preheated water, stir and mix well, then cool to the set temperature and continue stirring and mixing to prepare a dispersion. (2) Add the composite gelling agent, coagulant aid, toughening and anti-brittleness agent and surfactant to the remaining preheated water in sequence and stir to mix well to make auxiliary liquid; (3) Add the excipient liquid to the dispersion and stir to mix well. Then, perform vacuum degassing to prepare the capsule liquid. (4) Dip the preheated die needle into the capsule liquid, and after drying, demolding, cutting and fitting, a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule is obtained.

[0024] In some other embodiments, in step (1), the water is preheated to 80-90°C and then cooled to a set temperature of 50-60°C. In step (2), the water preheating temperature is 70-80℃; In step (3), the stirring temperature is 50-55℃, the time is 1-2 h, and the viscosity of the capsule solution is 500-1500 mPa·s.

[0025] In some other embodiments, the capsule preparation solution is heated at 50°C and a shear rate of 10 s. - The apparent viscosity at ¹ is 400-1000 mPa·s; and its rheological behavior conforms to the power-law equation τ= K·γn, where the non-Newtonian exponent n is between 0.6 and 0.8, exhibiting obvious shear-thinning characteristics.

[0026] In some other embodiments, the thermotropic gel temperature (Tgel) of the adhesive is between 48-54°C; during the process of the temperature dropping from 80°C to Tgel, the rate of increase of its storage modulus G' is 100-300 Pa / °C, ensuring instantaneous setting after dipping.

[0027] The raw materials and preparation method of this invention work together to form a gel with specific shear-thinning properties (n=0.6-0.8) and suitable viscosity (400-1000 mPa·s), thereby ensuring the uniformity and operability of mixing, degassing, and dipping during the production process. The synergistic effect of the composite gelling agent and other components in the formulation endows the gel with a defined thermotropic gelation temperature (48-54℃) and a rapid rate of increase in storage modulus (100-300 Pa / ℃). This allows the liquid film after dipping to gel and solidify instantly and precisely during the cooling process, laying a solid foundation for the subsequent drying to form a dense, uniformly thick capsule wall.

[0028] In some other embodiments, in step (4), the preheating temperature of the die needle is 20-25°C, the temperature of the capsule adhesive liquid is 45-50°C, and the dipping time is 5-10 s.

[0029] Thirdly, the present invention provides the application of the high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsules described in the first aspect in food, health products, cosmetics, and biopharmaceuticals.

[0030] Fourthly, the present invention provides a gastric disintegrating immediate-release capsule, which uses the high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule described in the first aspect.

[0031] The solution of the present invention will be further described below with reference to specific embodiments and comparative examples: Example 1 This embodiment provides a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule, which is composed of the following components by weight: 20 parts of hydroxypropyl methylcellulose (viscosity 10 mPa·s, 20℃, 2% aqueous solution, abbreviated as low viscosity HPMC), 0.8 parts of composite gelling agent (0.5 parts of low acyl gellan gum, 0.3 parts of tamarind gum), 0.3 parts of coagulant aid (potassium citrate), 2 parts of toughening and anti-brittleness agent (1.2 parts of trehalose, 0.8 parts of glycerin), 0.1 parts of surfactant (polysorbate 80), and 76.8 parts of water.

[0032] A method for preparing high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsules includes the following steps: (1) Sol: Heat part of purified water to 805°C, add hydroxypropyl methylcellulose, stir to disperse evenly, cool to 55°C and stir until completely dissolved to prepare a dispersion; (2) Preparation of auxiliary liquid: Take the remaining purified water and heat it to 75°C. Add the composite gelling agent, coagulant aid, toughening and anti-brittleness agent and surfactant in sequence. Stir until completely dissolved to prepare the auxiliary liquid. Use the entanglement of tamarind gum side chain and gellan gum helical structure to form a pregel micronucleus. Keep it warm for later use. (3) Mixing and homogenization: Add the excipient liquid from step (2) to the dispersion liquid from step (1), keep it warm and stir at 52°C for 1.5 hours, and perform vacuum degassing treatment for 45 minutes to adjust the viscosity of the glue to 1000 mPa·s to obtain the capsule preparation glue. (4) Dipping and molding: Preheat the stainless steel mold needle to 22°C, dip it into the capsule-forming adhesive liquid at 50°C, and dip it for 10 seconds. (5) Drying and demolding: After the mold needle is dipped in glue, it enters the drying channel and is dried at constant temperature and humidity (temperature is 30℃ and humidity is 40%) for 45 minutes. Then it is demolded, cut and assembled to obtain the finished capsule.

[0033] Example 2 This embodiment provides a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule, which is composed of the following components by weight: 18 parts hydroxypropyl methylcellulose, 0.5 parts composite gelling agent (0.3 parts low-acyl gellan gum, 0.2 parts tamarind gum), 0.25 parts coagulant (potassium citrate), 1.2 parts toughening and anti-brittleness agent (0.8 parts trehalose, 0.4 parts glycerin), 0.05 parts surfactant (polysorbate 80), and 80 parts water.

[0034] The preparation method is the same as in Example 1.

[0035] Example 3 This embodiment provides a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule, which is composed of the following components by weight: 25 parts hydroxypropyl methylcellulose, 1.2 parts composite gelling agent (0.48 parts low-acyl gellan gum and 0.72 parts tamarind gum), 0.6 parts coagulant (potassium citrate), 3 parts toughening and anti-brittleness agent (2 parts trehalose and 1 part glycerin), 0.2 parts surfactant (polysorbate 80), and 70 parts water.

[0036] The preparation method is the same as in Example 1.

[0037] Example 4 This embodiment provides a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule, which is composed of the following components by weight: 20 parts of hydroxypropyl methylcellulose (viscosity of 5 mPa·s, 20℃, 2% aqueous solution, abbreviated as low viscosity HPMC), 0.8 parts of composite gelling agent (0.5 parts of low acyl gellan gum, 0.3 parts of tamarind gum), 0.3 parts of coagulant aid (0.2 parts of calcium gluconate, 0.1 parts of calcium lactate), 2 parts of toughening and anti-brittleness agent (1.2 parts of trehalose, 0.8 parts of glycerol), 0.1 parts of surfactant (sodium dodecyl sulfate), and 76.8 parts of water.

[0038] Comparative Example 1 Unlike Example 1, the formulation of the hydroxypropyl methylcellulose empty capsule is shown in Table 1. The composite gelling agent is replaced with 0.8 parts of pure low-acyl gellan gum, and the remaining composition and preparation method are the same as in Example 1.

[0039] Comparative Example 2 Unlike Example 1, the formulation of the hydroxypropyl methylcellulose empty capsule is shown in Table 1. The toughening and anti-brittleness agent is replaced with 2.0 parts of pure glycerin, and trehalose is not used. The remaining composition and preparation method are the same as in Example 1.

[0040] Comparative Example 3 Unlike Example 1, the formulation of the hydroxypropyl methylcellulose empty capsule is shown in Table 1. The toughening and anti-brittleness agent is replaced with 2.0 parts of pure trehalose, and glycerol is not used. The remaining composition and preparation method are the same as in Example 1.

[0041] Comparative Example 4 Unlike Example 1, the formulation of hydroxypropyl methylcellulose empty capsules is shown in Table 1. In this case, the composite gelling agent is replaced with an equal amount of water, and there is no composite gelling agent. The remaining composition and preparation method are the same as in Example 1.

[0042] Comparative Example 5 Unlike Example 1, the formulation of hydroxypropyl methylcellulose empty capsules is shown in Table 1. In this case, the coagulant was replaced with an equal amount of water, and no coagulant was used. The remaining composition and preparation method are the same as in Example 1.

[0043] Comparative Example 6 Unlike Example 1, the formulation of the hydroxypropyl methylcellulose empty capsule is shown in Table 1. In this case, the toughening and anti-brittleness agent is replaced with an equal amount of water, and there is no toughening and anti-brittleness agent. The remaining composition and preparation method are the same as in Example 1.

[0044] Comparative Example 7 Unlike Example 1, the formulation of the hydroxypropyl methylcellulose empty capsules is shown in Table 1. In this case, the surfactant is replaced with an equal amount of water, and there is no surfactant. The remaining composition and preparation method are the same as in Example 1.

[0045] Table 1. Formulation composition of hydroxypropyl methylcellulose empty capsules

[0046] The performance of the hydroxypropyl methylcellulose empty capsules prepared in the examples and comparative examples was tested, and the results are shown in Table 2. Among them, extreme low-humidity brittleness: after being placed at 15% RH for 24 hours, the capsules were tested to determine whether they became brittle and fragile under extremely dry conditions, evaluating their mechanical strength in packaging in highly dry climates. Gastric juice simulated medium disintegration time: in simulated gastric juice at 37°C, the disintegration rate and performance of the capsules in gastric juice were tested; this is a key indicator for evaluating their in vivo release behavior. High humidity environment deformation rate: after being placed at 75% RH for 48 hours, the tendency of the capsules to absorb moisture, soften, stick together, or deform under high humidity conditions was tested, evaluating their storage stability and tolerance to humid climates. Drying weight loss: after drying to constant weight at 105°C, the moisture content of the capsules was measured; excessive moisture will affect stability, while insufficient moisture may lead to brittleness.

[0047] Table 2. Performance of Hydroxypropyl Methylcellulose Empty Capsules

[0048] As shown in Table 2, the use of gellan gum alone (Comparative Example 1) resulted in an extremely slow disintegration time (19.5 minutes), rendering it unusable for pharmaceutical applications. Furthermore, relying solely on glycerol plasticizer (Comparative Example 2) not only led to a high brittleness rate under extremely low humidity (8 / 50 breakage) but also caused severe deformation under high humidity conditions (8.9%). The data from Example 1 demonstrate that the specific proportion mixture claimed in this invention induces clear microstructural reorganization and synergistic effects, representing a significant technological advancement.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule, characterized in that, The product is composed of the following components by weight: 18-25 parts hydroxypropyl methylcellulose, 0.4-1.2 parts composite gelling agent, 0.2-0.6 parts coagulant aid, 1-3 parts toughening and anti-brittleness agent, 0.05-0.2 parts surfactant, and 70-80 parts water.

2. The high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule as described in claim 1, characterized in that, The viscosity of the hydroxypropyl methylcellulose is 4-15 mPa·s; The composite gelling agent is composed of low-acyl gellan gum and tamarind gum in a mass ratio of 1:(0.5-1.5).

3. The high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule as described in claim 1, characterized in that, The toughening and anti-brittleness agent is composed of trehalose and glycerol in a mass ratio of (1-2):

1.

4. The high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule as described in claim 1, characterized in that, The coagulant includes one or more of potassium citrate, calcium gluconate, or calcium lactate.

5. The high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule as described in claim 1, characterized in that, The surfactant includes one or more of polysorbate 80 or sodium dodecyl sulfate.

6. A method for preparing a high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsule according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Add hydroxypropyl methylcellulose to a portion of preheated water, stir and mix well, then cool to the set temperature and continue stirring and mixing to prepare a dispersion. (2) Add the composite gelling agent, coagulant aid, toughening and anti-brittleness agent and surfactant to the remaining preheated water in sequence and stir to mix well to make auxiliary liquid; (3) Add the excipient liquid to the dispersion and stir to mix well. Then, perform vacuum degassing to prepare the capsule liquid. (4) Dip the preheated die needle into the capsule liquid, and after drying, demolding, cutting and fitting, a high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule is obtained.

7. The method for preparing high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsules as described in claim 6, characterized in that, In step (1), the water is preheated to 80-90℃ and then cooled to the set temperature of 50-60℃. In step (2), the water preheating temperature is 70-80℃; In step (3), the stirring temperature is 50-55℃, the time is 1-2 h, and the viscosity of the capsule solution is 500-1500 mPa·s.

8. The method for preparing high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsules as described in claim 6, characterized in that, In step (4), the preheating temperature of the die needle is 20-25℃, the temperature of the gel is 45-50℃, and the dipping time is 5-10 s.

9. The use of the high-toughness, fast-dissolving hydroxypropyl methylcellulose hollow capsule according to any one of claims 1-5 in food, health products, cosmetics and biopharmaceuticals.

10. A gastric disintegrating immediate-release capsule, characterized in that, The high-toughness, fast-dissolving hydroxypropyl methylcellulose empty capsules as described in any one of claims 1-5 are used.

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