Injectable schizophyllan gel drug delivery system and method of preparation thereof

Abstract

The application relates to the field of biomaterials and drug delivery technology, and relates to an injectable schizophyllan gel drug delivery system and a preparation method thereof. An aqueous solution containing schizophyllan is concentrated to obtain a schizophyllan pre-gel; the schizophyllan pre-gel is soaked in an organic solvent to obtain an organic gel; wet annealing treatment is performed to obtain an annealed gel; the annealed gel is soaked in deionized water to obtain a schizophyllan hydrogel; the schizophyllan hydrogel is subjected to first freeze-drying to obtain a dry gel; the dry gel is loaded with drugs through physical soaking to obtain a drug-loaded gel; the drug-loaded gel is subjected to second freeze-drying and is allowed to absorb water. Freeze treatment is conducive to the migration and diffusion of drug molecules into the pores of the hydrogel, and the cumulative release amount of the drug is larger. The second freeze-drying treatment enhances the interaction between the network structure of the schizophyllan hydrogel and the drug molecules, reduces the diffusion rate of the drug, and achieves the effect of slow release.

Description

Technical Field

[0001] This application relates to the fields of biomaterials and drug delivery technology, and more specifically, to an injectable slit-fold polysaccharide gel drug delivery system and its preparation method. Background Technology

[0002] In the field of modern drug delivery, injectable hydrogels have attracted widespread attention due to their unique properties. With the increasing demand for cosmetic and tissue engineering applications, the development of controlled drug release carriers is particularly important. Injectable hydrogels exhibit rapid gelation, controllable structure, and low tissue damage, demonstrating enormous potential for drug delivery. An ideal drug delivery system must possess high drug loading efficiency, controlled release kinetics, mechanical stability, and biocompatibility, while also meeting the requirements of minimally invasive delivery.

[0003] However, existing drug-loaded hydrogel systems face challenges: while the introduction of chemical cross-linking agents improves mechanical strength, their residues may lead to reduced drug activity and toxic reactions such as apoptosis and inflammation. Furthermore, the rigid network topology makes it difficult to achieve targeted drug delivery via minimally invasive injection.

[0004] Common drug delivery methods include in-situ polymerization, surface modification, and drug mixing.

[0005] However, in-situ polymerization, which encapsulates the drug during hydrogel formation, can improve the encapsulation rate, but it requires more stringent reaction conditions.

[0006] Surface modification method: Drugs are fixed to the surface of hydrogels by chemical bonding or physical adsorption, which can achieve slow drug release, but the drug loading capacity is low.

[0007] Drug mixing method: The drug is diffused into the gel network, but this may lead to uneven drug distribution and burst release, making it difficult to control the release rate and not conducive to the sustained release effect of the drug. Summary of the Invention

[0008] The purpose of this application is to provide an injectable split-fold polysaccharide gel drug delivery system and its preparation method.

[0009] In a first aspect, this application provides a method for preparing an injectable slit-fold polysaccharide gel drug delivery system, comprising:

[0010] The aqueous solution containing schizophyllum polysaccharide was concentrated to obtain schizophyllum polysaccharide pregel;

[0011] The pregel of slit polysaccharide was soaked in an organic solvent to obtain an organic gel;

[0012] The organic gel was subjected to wet annealing to obtain an annealed gel;

[0013] The annealed gel was soaked in deionized water to obtain a slit polysaccharide hydrogel;

[0014] The slit polysaccharide hydrogel was subjected to a first freeze-drying process to obtain a dry gel.

[0015] Drug-loaded gels are obtained by loading the dry gel with drugs through physical soaking.

[0016] The drug-loaded gel is subjected to a second freeze-drying process and allowed to absorb water to obtain the final drug-loaded gel.

[0017] In the above technical solution, a dry gel is obtained by freeze-drying the slit-polysaccharide hydrogel. Firstly, the slit-polysaccharide hydrogel undergoes freeze-drying, which forms a more porous three-dimensional network structure, resulting in larger pores and better connectivity within the gel. This facilitates the migration and diffusion of drug molecules into the pores of the hydrogel, allowing the hydrogel to load more drug and resulting in a greater cumulative drug release. Then, physical soaking to load the drug into the dry gel, followed by freeze-drying, enhances the interaction between the slit-polysaccharide hydrogel network structure and the drug molecules, thereby reducing the drug diffusion rate and release amount, achieving a sustained-release effect.

[0018] In other embodiments of this application, the above-described method of loading drugs onto dry gels using physical immersion includes:

[0019] The dry gel is added to the drug solution for soaking;

[0020] Optionally, the soaking time is 3-24 hours.

[0021] In other embodiments of this application, adding the dry gel to the drug solution includes:

[0022] The dry gel is added to the drug solution at a mass ratio of (1-10):(1-8).

[0023] In other embodiments of this application, the concentration of the drug solution is 0.01-10 mg / ml.

[0024] In other embodiments of this application, the porosity of the dry gel is 10%-90%.

[0025] In other embodiments of this application, the specific surface area of ​​the dry gel is 10 m². 2 / g-270m 2 / g.

[0026] In other embodiments of this application, the first freeze-drying of the slit-glucan hydrogel includes:

[0027] Freeze-dry the slit polysaccharide hydrogel at -50℃ to 120℃ for 3 to 24 hours; alternatively, freeze at -50℃ to -10℃ for 5 to 20 hours; or dry at 25℃ to 120℃ for 5 to 10 hours.

[0028] Optionally, the drug-loaded gel undergoes a second freeze-drying process, comprising:

[0029] The slit polysaccharide hydrogel was freeze-dried at a temperature of -50℃ to 120℃ for 3-24 hours.

[0030] Secondly, this application provides an injectable slit-fold polysaccharide gel drug delivery system, which is prepared by the method for preparing the injectable slit-fold polysaccharide gel drug delivery system provided in any of the first aspects above.

[0031] In other embodiments of this application, the injectable slit polysaccharide gel drug delivery system includes: slit polysaccharide hydrogel and drug;

[0032] The drug is located in the pores of the slit-polysaccharide hydrogel; the slit-polysaccharide hydrogel encapsulates the drug; the drug and the slit-polysaccharide hydrogel are connected by physical bonds.

[0033] In other embodiments of this application, the drug includes at least one of taurine, tauroursodeoxycholic acid, vitamin C derivative, paclitaxel, amphotericin B liposomes, transglutaminase, or DNA plasmid.

[0034] In other embodiments of this application, the cumulative release rate of the injectable slit-glucan gel drug delivery system is 60.5%-98.17%.

[0035] In other embodiments of this application, the drug loading capacity of the injectable slit-glucosyl gel drug delivery system is 32.31%-58.64%. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 A schematic diagram of SPG hydrogel loading drugs, and the chemical structural formulas of SPG, taurine, and tauroursodeoxycholic acid drugs;

[0038] Figure 2 The absorption curves of the drug-loaded solution were calibrated using a UV spectrophotometer, and the standard absorption curves were obtained for taurine concentrations in the range of 0.01–0.3 mg / mL.

[0039] Figure 3 To calibrate the absorption curve of the gel-loaded tauroursodeoxycholic acid solution using a UV spectrophotometer, and to obtain the standard absorption curve of the tauroursodeoxycholic acid concentration in the range of 0.01–1.0 mg / mL;

[0040] Figure 4 In vitro drug release data graphs, drug loading, and cumulative release rate of the taurine gel systems used in the examples and comparative examples;

[0041] Figure 5 The in vitro drug release data, drug loading, and cumulative release rate of the tauroursodeoxycholic acid gel system are shown in the example diagram. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0043] Therefore, the following detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0044] Slit-glycan (SPG) is a hydrophilic polysaccharide molecule linked by β-glycosidic bonds. It has good biocompatibility, super moisturizing and lubricating properties. Its characteristics include: 1) Anti-enzyme stability: It lacks specific degrading enzymes, which allows it to exist stably for a long time; 2) Multifunctional bioactivity: It has synergistic therapeutic functions such as antibacterial, antioxidant and immunomodulatory functions.

[0045] Injectable hydrogels can slowly release drugs or active ingredients, such as vitamin C derivatives, through microsphere encapsulation or nanocarriers to enhance whitening effects.

[0046] The polyhydroxy structure of slit-glucan can bind to drug molecules, enabling slow release. However, previous studies have shown that injectable hydrogels based on slit-glucan have high water content and a loose network structure, resulting in insufficient drug-network interaction. Simple mixing may lead to rapid drug release.

[0047] Further research has revealed that freeze-drying technology can effectively preserve and process substances, removing moisture through rapid freezing and a vacuum environment, thereby maintaining the product's structure and function. Furthermore, the drying process can enhance the interaction between polymers and drugs, thus achieving a sustained-release effect.

[0048] Based on the above research, this application provides a method for preparing an injectable slit-fold polysaccharide gel drug delivery system, comprising:

[0049] The aqueous solution containing schizophyllum polysaccharide was concentrated to obtain schizophyllum polysaccharide pregel;

[0050] The pregel of slit polysaccharide was soaked in an organic solvent to obtain an organic gel;

[0051] The organic gel was subjected to wet annealing to obtain an annealed gel;

[0052] The annealed gel was soaked in deionized water to obtain a slit polysaccharide hydrogel;

[0053] The slit polysaccharide hydrogel was subjected to a first freeze-drying process to obtain a dry gel.

[0054] Drug-loaded gels are obtained by loading drugs onto dry gels through physical soaking.

[0055] The drug-loaded gel is subjected to a second freeze-drying process and allowed to absorb water to obtain the final drug-loaded gel.

[0056] In the above technical solution, a dry gel is obtained by freeze-drying the slit-polysaccharide hydrogel. Firstly, the slit-polysaccharide hydrogel undergoes freeze-drying, which forms a more porous three-dimensional network structure, resulting in larger pores and better connectivity within the gel. This facilitates the migration and diffusion of drug molecules into the pores of the hydrogel, allowing the hydrogel to load more drug and resulting in a greater cumulative drug release. Then, physical soaking to load the drug into the dry gel, followed by freeze-drying, enhances the interaction between the slit-polysaccharide hydrogel network structure and the drug molecules, thereby reducing the drug diffusion rate and release amount, achieving a sustained-release effect.

[0057] Furthermore, the aforementioned freeze-drying followed by physical soaking, and the subsequent freeze-drying after the addition of drug molecules to the sample, enhances the interaction between the network structure and the drug molecules, reducing the diffusion coefficient. This approach best preserves the structure and function of the slit-polysaccharide hydrogel while strengthening the interaction between the hydrogel polymer and the drug, achieving the dual effects of increased drug loading and sustained drug release. In other words, it effectively enhances the control and rate of drug release, realizing the sustained-release function. This better-controlled sustained-release function shows significant application potential in fields such as cosmetics and tissue engineering.

[0058] Furthermore, in some embodiments of this application, the preparation method of the injectable slit-glucan gel drug delivery system includes the following steps:

[0059] Step S1: Prepare the slit-fold polysaccharide hydrogel.

[0060] Furthermore, in some embodiments of this application, the step of preparing the slit-fold polysaccharide hydrogel includes:

[0061] The aqueous solution containing schizophyllum polysaccharide was concentrated to obtain schizophyllum polysaccharide pregel;

[0062] The pregel of slit polysaccharide was soaked in an organic solvent to obtain an organic gel;

[0063] The organic gel was subjected to wet annealing to obtain an annealed gel;

[0064] The gel was soaked in deionized water to obtain a slit polysaccharide hydrogel.

[0065] Further optionally, in some embodiments of this application, an aqueous solution containing schizophyllum polysaccharide is concentrated to obtain a schizophyllum polysaccharide pregel, wherein the schizophyllum polysaccharide content in the pregel is 5wt%-60wt%.

[0066] For example, in some embodiments of this application, an aqueous solution containing schizophyllum polysaccharide is concentrated to obtain a schizophyllum polysaccharide pregel. The content of schizophyllum polysaccharide in the pregel is 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt%, or any two of the aforementioned values.

[0067] Furthermore, in some embodiments of this application, the slit polysaccharide pregel is soaked in an organic solvent to obtain an organic gel.

[0068] Further optionally, the aforementioned organic solvent includes at least one of dimethylacetamide, dimethyl sulfoxide, dimethylformamide, or formamide.

[0069] For example, in some embodiments of this application, the organic solvent is selected from any one of dimethylacetamide, dimethyl sulfoxide, dimethylformamide, or formamide. Alternatively, in some embodiments of this application, the organic solvent is selected from a mixture of dimethylacetamide and dimethyl sulfoxide; or in some embodiments of this application, the organic solvent is selected from a mixture of dimethylacetamide, dimethyl sulfoxide, dimethylformamide, and formamide; the proportions of each raw material in each of the above mixtures can be arbitrarily selected.

[0070] Furthermore, in some embodiments of this application, the organic gel is subjected to wet annealing.

[0071] Further optionally, in some embodiments of this application, the above-mentioned wet annealing treatment of the organic gel includes: at 100℃-150℃ for 3h-72h.

[0072] For example, in some embodiments of this application, the above-mentioned wet annealing treatment of the organic gel includes: a temperature of 100°C, 110°C, 120°C, 130°C, 140°C, 145°C, 150°C or any two of the aforementioned values, and a treatment time of 3h, 4h, 5h, 6h, 8h, 10h, 15h, 20h, 30h, 40h, 50h, 60h, 72h or any two of the aforementioned values.

[0073] Furthermore, in some embodiments of this application, the annealed gel obtained above is soaked in deionized water to obtain a slit polysaccharide hydrogel.

[0074] Alternatively, the annealed gel obtained above can be soaked in deionized water for 3-24 hours.

[0075] The above-mentioned SPG hydrogel without chemical crosslinking was obtained through wet annealing. This design effectively avoids the risks of poor biocompatibility and drug activity damage caused by chemical crosslinking agents in traditional drug delivery systems while maintaining mechanical stability and shear thinning properties. It provides a new, safe and injectable material option for the medical field.

[0076] In some embodiments of this application, the hydrogel obtained by the above-described wet annealing process can refer to Chinese Patent CN118978716B - A method for preparing an injectable hydrogel based on slit polysaccharide, and its products and applications.

[0077] Step S2: Prepare dry gel.

[0078] Furthermore, in some embodiments of this application, the preparation of the dry gel described above includes:

[0079] The slit polysaccharide hydrogel was freeze-dried to obtain a dry gel.

[0080] Furthermore, in some embodiments of this application, the freeze-drying of the slit-glucan hydrogel includes:

[0081] The slit polysaccharide hydrogel was freeze-dried at -50℃ to 120℃ for 3h to 24h.

[0082] Exemplarily, freeze-drying a slit-polysaccharide hydrogel includes:

[0083] Freeze-dry at temperatures ranging from -50℃, -30℃, -15℃, 0℃, 25℃, 60℃, 80℃, 100℃, 120℃, or any two of the aforementioned values; and for drying times ranging from 3h, 5h, 7h, 10h, 12h, 15h, 20h, 24h, or any two of the aforementioned values.

[0084] Further optionally, the freeze-drying temperature is -50℃ to -40℃; further optionally, the freeze-drying temperature is -50℃ to -30℃; further optionally, the freeze-drying temperature is -50℃ to -20℃; further optionally, the freeze-drying temperature is -50℃ to -10℃.

[0085] Further optionally, the vacuum level during freezing is 5-50 Pa. For example, the vacuum level during freezing is 5 Pa, 10 Pa, 20 Pa, 30 Pa, 40 Pa, 50 Pa, or any two of the aforementioned values.

[0086] Further optionally, the vacuum degree during freezing is 5-10 Pa; further optionally, the vacuum degree during freezing is 5-20 Pa; further optionally, the vacuum degree during freezing is 5-30 Pa; further optionally, the vacuum degree during freezing is 5-40 Pa. Optionally, freezing is performed at -50℃ to -10℃ for 5-20 hours; drying is performed at 25℃ to 120℃ for 5-10 hours.

[0087] Step S3: Load the drug onto the dry gel by physical soaking.

[0088] Furthermore, in some embodiments of this application, loading the drug onto the dry gel by physical soaking includes:

[0089] The dry gel is added to the drug solution for soaking.

[0090] Furthermore, in some embodiments of this application, the soaking time is 3-24 hours.

[0091] For example, in some embodiments of this application, the soaking time is 3h, 5h, 7h, 10h, 12h, 15h, 18h, 20h, 24h or any range between the two aforementioned values.

[0092] Furthermore, in some embodiments of this application, adding the dry gel to the drug solution includes:

[0093] The dry gel is added to the drug solution at a mass ratio of (1-10):(1-80) to the volume ratio of the dry gel to the drug solution.

[0094] Exemplarily, in some embodiments of this application, adding the dry gel to the drug solution includes:

[0095] The dry gel is added to the drug solution at a mass ratio of (1, 1.5, 2, 3, 5, 7, 9, 10 or any two of the aforementioned values) to a volume ratio of (1, 5, 10, 20, 40, 60, 70, 80 or any two of the aforementioned values).

[0096] Furthermore, in some embodiments of this application, the concentration of the drug solution is 0.01-10 mg / ml.

[0097] For example, in some embodiments of this application, the concentration of the drug solution is 0.01 mg / ml, 0.1 mg / ml, 0.5 mg / ml, 1 mg / ml, 3 mg / ml, 5 mg / ml, 10 mg / ml, or a range between any two of the aforementioned values.

[0098] Furthermore, in some embodiments of this application, the porosity of the dry gel obtained by the above steps is 10%-90%.

[0099] For example, in some embodiments of this application, the porosity of the dry gel obtained by the above steps is 40%, 79%, 90%, or any two of the aforementioned values.

[0100] Further optionally, in some embodiments of this application, the porosity of the dry gel obtained in the above steps is 10%-80%. Further optionally, in some embodiments of this application, the porosity of the dry gel obtained in the above steps is 20%-70%. Further optionally, in some embodiments of this application, the porosity of the dry gel obtained in the above steps is 30%-80%. Further optionally, in some embodiments of this application, the porosity of the dry gel obtained in the above steps is 40%-80%. Further optionally, in some embodiments of this application, the specific surface area of ​​the dry gel obtained in the above steps is 10-270 m². 2 / g.

[0101] For example, in some embodiments of this application, the specific surface area of ​​the dry gel obtained by the above steps is 98 m². 2 / g、200m 2 / g、270m 2 / g or the range between any two of the aforementioned values.

[0102] Further, optionally, in some embodiments of this application, the specific surface area of ​​the dry gel obtained by the above steps is 20-200 m². 2 / g. Further optionally, in some embodiments of this application, the specific surface area of ​​the dry gel obtained by the above steps is 50-200 m² / g.2 / g. Further optionally, in some embodiments of this application, the specific surface area of ​​the dry gel obtained in the above steps is 100-200 m². 2 / g.

[0103] Step S4: Perform a second freeze-drying on the drug-loaded gel and allow it to absorb water to obtain the final drug-loaded gel.

[0104] Further, optionally, in some embodiments of this application, the drug-loaded gel is subjected to a second freeze-drying, including:

[0105] The slit polysaccharide hydrogel was freeze-dried at -50℃ to 120℃ for 3h-24h.

[0106] Optionally, freeze at -50℃ to -10℃ for 5 to 20 hours; or dry at 25℃ to 120℃ for 5 to 10 hours.

[0107] Alternatively, the vacuum level during freezing is 5-40 Pa.

[0108] Further, alternatively, in some embodiments of this application, the gel is allowed to absorb water, and an appropriate amount of water can be adsorbed according to the actual situation to obtain the final drug-loaded gel.

[0109] Further optionally, in some embodiments of this application, the final drug-loaded gel has a water content of 90 wt% or more.

[0110] Some embodiments of this application provide an injectable slit-fold polysaccharide gel drug delivery system, which is prepared using the preparation method of the injectable slit-fold polysaccharide gel drug delivery system provided in any of the foregoing embodiments.

[0111] Furthermore, in some embodiments of this application, the injectable slit-polysaccharide gel drug delivery system includes: slit-polysaccharide hydrogel and drug.

[0112] Further, in some embodiments of this application, the injectable slit-polysaccharide gel drug delivery system comprises, by weight percentage, (1-30 wt%) slit-polysaccharide hydrogel and (32.31%-59.9%) a drug. Exemplarily, the injectable slit-polysaccharide gel drug delivery system comprises, by weight percentage, 1%, 2%, 5%, 10%, 15%, 20%, 25%, 30% or any two of the aforementioned values ​​of slit-polysaccharide hydrogel; and 32.31%, 33%, 33.5%, 34%, 35%, 38%, 40%, 45%, 50%, 52%, 55%, 58%, 59.9% or any two of the aforementioned values ​​of a drug. Further, in some embodiments of this application, the drug is located in the pores of the slit-polysaccharide hydrogel; the slit-polysaccharide hydrogel encapsulates the drug; and the drug is physically bonded to the slit-polysaccharide hydrogel.

[0113] For example, in some embodiments of this application, the physical bonds described above are mainly hydrogen bonds.

[0114] Furthermore, in some embodiments of this application, the drug includes at least one of the following: taurine, tauroursodeoxycholic acid, vitamin C derivative, paclitaxel, amphotericin B liposome, transglutaminase, and DNA plasmid.

[0115] Furthermore, in some embodiments of this application, the cumulative release rate of the injectable slit-glucosyl gel drug delivery system is 60.5-98.17%.

[0116] For example, in some embodiments of this application, the cumulative release rate of the injectable slit-glucan gel drug delivery system is 74.38%, 79.63%, 72.10%, 60.5%, 68.30%, 70.5%, 98.17%, and 76.15%, or a range between any two of the aforementioned values.

[0117] Furthermore, in some embodiments of this application, the drug loading capacity of the injectable slit-glucosyl gel drug delivery system is 32.31%-58.64%.

[0118] For example, in some embodiments of this application, the drug loading of the injectable slit polysaccharide gel drug loading system is 58.64%, 47.4%, 46.32%, 42.21%, 50.31%, 48.18%, 32.31%, or any two of the aforementioned values.

[0119] Exemplarily, in some embodiments of this application, the injectable slit-fold polysaccharide gel drug delivery system includes: slit-fold polysaccharide and taurine; as per the appendix to the specification. Figure 1 As shown, Figure 1 A schematic diagram of a schizopolysaccharide (SPG) hydrogel loaded with taurine drug is shown, along with the chemical structural formulas of SPG and the taurine drug. The polyhydroxyl groups of schizopolysaccharide can interact with the hydroxyl groups of taurine, forming hydrogen bonds and enhancing the binding of schizopolysaccharide to the drug; drying further enhances this binding. During freeze-drying, water freezes, and the ice crystals act as a removable template to expand the gel network, forcing the schizopolysaccharide molecular chains and drug molecules to approach closely at the interface. Subsequently, the sublimation of the ice crystals momentarily "locks" this high specific surface area conformation, allowing the hydroxyl hydrogen bonds on the schizopolysaccharide molecular chains to act as acceptors for the amine groups on the drug molecules, forming more and stronger hydrogen bonds, thereby significantly enhancing the interaction between the drug and the gel network.

[0120] Exemplary, in some embodiments of this application, the injectable slit-fold polysaccharide gel drug delivery system comprises: slit-fold polysaccharide and tauroursodeoxycholic acid; as per the appendix to the specification. Figure 1 As shown, Figure 1 A schematic diagram of tauroursodeoxycholic acid (TAA) loaded onto a schizopolysaccharide (SPG) hydrogel is shown, along with the chemical structural formulas of SPG and TAA. The polyhydroxyl groups of schizopolysaccharide can interact with the hydroxyl groups of TAA, forming hydrogen bonds and enhancing the binding of schizopolysaccharide to the drug. Drying further enhances this binding. During freeze-drying, water freezes, and the ice crystals act as a removable template to expand the gel network, forcing the schizopolysaccharide molecular chains and drug molecules to approach closely at the interface. Subsequently, the sublimation of the ice crystals momentarily "locks" this high specific surface area conformation, allowing the hydroxyl hydrogen bond donors and acceptors on the schizopolysaccharide molecular chains to form more and stronger hydrogen bonds with the hydroxyl donors on the drug molecules, thereby significantly enhancing the interaction between the drug and the gel network.

[0121] The features and performance of this application will be further described in detail below with reference to embodiments:

[0122] Example 1

[0123] An injectable slit-fold polysaccharide gel drug delivery system is provided, prepared according to the following steps:

[0124] (1) Preparation of SPG hydrogel:

[0125] The aqueous solution containing schizophyllum polysaccharide was concentrated to obtain a schizophyllum polysaccharide pregel, the content of schizophyllum polysaccharide in the pregel being 10 wt%.

[0126] The pregel of the slit polysaccharide obtained above was soaked in the organic solvent dimethylacetamide to obtain an organic gel.

[0127] The organic gel was subjected to wet annealing at 100℃ for 24 hours to obtain the annealed gel.

[0128] The annealed gel was soaked in deionized water for 7 days and dialyzed to obtain a slit polysaccharide hydrogel.

[0129] (2) Preparation of dry gel:

[0130] The slit-fold polysaccharide hydrogel obtained in step (1) was subjected to a single freeze-drying process. The specific steps were as follows: after placing the gel in a freeze dryer, the temperature was first lowered to -30°C at a uniform rate of 5 min⁻¹ and maintained for 10 h to completely freeze the aqueous phase into an ice crystal template; then the vacuum pump was started to reduce the chamber pressure to 10-20 Pa, and the temperature was slowly increased to -10°C at a rate of 5°C h⁻¹ to allow the ice crystals to sublimate directly; finally, the temperature was increased to 25°C and the drying continued for 8 h to obtain a dry gel.

[0131] (3) Loading drugs by physical immersion:

[0132] The dry gel obtained in step (2) is physically soaked to obtain a drug-loaded gel. The specific steps are as follows: the SPG dry gel prepared in step (2) is transferred to a drug-containing solution and soaked for 20 hours at a ratio of dry gel mass / drug solution volume = 1g: 10mL. After taking it out, the free solution is filtered out and the surface residue is removed by gently washing with deionized water at the same temperature for 1 minute to obtain the drug-loaded gel.

[0133] (4) Preparation of drug-loaded dry gel:

[0134] The drug-loaded gel obtained in step (3) was subjected to a second freeze-drying process. The specific steps were as follows: after placing the drug-loaded gel in a freeze dryer, the temperature was first lowered to -30°C at a uniform rate of 5 min⁻¹ and maintained for 10 h to completely freeze the aqueous phase into an ice crystal template; then the vacuum pump was started to reduce the chamber pressure to 10-20 Pa, and the temperature was slowly increased to -10°C at a rate of 5°C h⁻¹ to allow the ice crystals to sublimate directly; finally, the temperature was increased to 25°C and dried for another 8 h to obtain a porosity of 79% and a specific surface area of ​​200 m². 2 The drug-loaded dry gel of g-1 is firmly anchored to the network by hydrogen bonds. After absorbing a certain amount of water (water content: 90wt%) into the drug-loaded dry gel, the drug-loaded gel (GFB) is obtained.

[0135] Example 2

[0136] The difference from Example 1 is that taurine is replaced with tauroursodeoxycholic acid, and the preparation steps are the same as in Example 1.

[0137] Example 3

[0138] The difference from Example 1 is that the porosity of the dry gel is different. The specific steps for preparing the dry gel are as follows: After placing the drug-loaded gel prepared in step (3) into a freeze dryer, it is first cooled to -50°C at a uniform rate of 5°C min-1 and kept for 10 hours to completely freeze the aqueous phase into an ice crystal template; then the vacuum pump is started to reduce the chamber pressure to 30 Pa, and the temperature is slowly increased to -10°C at a rate of 5°C h-1 to allow the ice crystals to sublimate directly; finally, the temperature is increased to 25°C and dried for another 8 hours to form a gel with a porosity of 90% and a specific surface area of ​​200 m². 2 g-1 yielded a dry gel. The drug was firmly anchored to the network via hydrogen bonds. After a second freeze-drying of the drug-loaded dry gel, a certain amount of water was absorbed (water content: 90 wt%) to obtain a drug-loaded gel.

[0139] Example 4

[0140] The difference from Example 1 is that the porosity of the dry gel is different. The specific steps for preparing the dry gel are as follows: After placing the drug-loaded gel prepared in step (3) into a freeze dryer, it is first cooled to 0°C at a uniform rate of 5°C min-1 and kept for 10 hours to completely freeze the aqueous phase into an ice crystal template; then the vacuum pump is started to reduce the chamber pressure to 30 Pa, and the temperature is slowly increased to -10°C at a rate of 5°C h-1 to allow the ice crystals to sublimate directly; finally, the temperature is increased to 25°C and dried for another 8 hours to form a gel with a porosity of 40% and a specific surface area of ​​200 m². 2 g-1 yielded a dry gel. The drug was firmly anchored to the network via hydrogen bonds. After a second freeze-drying of the drug-loaded dry gel, a certain amount of water was absorbed (water content: 90 wt%) to obtain a drug-loaded gel.

[0141] Example 5

[0142] The difference from Example 1 is that the specific surface area of ​​the dry gel is different. The specific steps for preparing the dry gel are as follows: After placing the drug-loaded gel prepared in step (3) into a freeze dryer, it is first cooled to -30°C at a uniform rate of 20°C min-1 and kept for 10 hours to rapidly freeze the aqueous phase into an ice crystal template; then the vacuum pump is started to reduce the chamber pressure to 30 Pa, and the temperature is slowly increased to -10°C at 5°C h-1 to allow the ice crystals to sublimate directly; finally, the temperature is increased to 25°C and dried for another 8 hours to form a gel with a porosity of 79% and a specific surface area of ​​270 m². 2 g-1 yielded a dry gel. The drug was firmly anchored to the network via hydrogen bonds. After a second freeze-drying of the drug-loaded dry gel, a certain amount of water was absorbed (water content: 90 wt%) to obtain a drug-loaded gel.

[0143] Example 6

[0144] The difference from Example 1 is that the specific surface area of ​​the dry gel is different. The specific steps for preparing the dry gel are as follows: After placing the drug-loaded gel prepared in step (3) into a freeze dryer, it is first cooled to -30°C at a uniform rate of 1°C min-1 and kept for 10 hours to rapidly freeze the aqueous phase into an ice crystal template; then the vacuum pump is started to reduce the chamber pressure to 30 Pa, and the temperature is slowly increased to -10°C at a rate of 5°C h-1 to allow the ice crystals to sublimate directly; finally, the temperature is increased to 25°C and dried for another 8 hours to form a gel with a porosity of 79% and a specific surface area of ​​98 m². 2 g-1 yielded a dry gel. The drug was firmly anchored to the network via hydrogen bonds. After a second freeze-drying of the drug-loaded dry gel, a certain amount of water was absorbed (water content: 90 wt%) to obtain a drug-loaded gel.

[0145] Comparative Example 1

[0146] An injectable slit-fold polysaccharide gel drug delivery system is provided, prepared according to the following steps:

[0147] (1) Preparation of SPG hydrogel:

[0148] The aqueous solution containing schizophyllum polysaccharide was concentrated to obtain a schizophyllum polysaccharide pregel, the content of schizophyllum polysaccharide in the pregel being 10 wt%.

[0149] The pregel of the slit polysaccharide obtained above was soaked in the organic solvent dimethylacetamide to obtain an organic gel.

[0150] The organic gel was subjected to wet annealing at 100℃ for 24 hours to obtain the annealed gel.

[0151] The annealed gel was soaked in deionized water for 7 days and dialyzed to obtain a slit polysaccharide hydrogel.

[0152] (2) Freeze-drying

[0153] After placing the SPG gel prepared in step (1) into a freeze dryer, it was first cooled to -40°C at a uniform rate of 1°C min⁻¹ and held for 10 h to completely freeze the aqueous phase into an ice crystal template. Then, the vacuum pump was started to reduce the chamber pressure to 10-20 Pa, and the temperature was slowly increased to -10°C at a rate of 5°C h⁻¹ to allow the ice crystals to sublimate directly. Finally, the temperature was increased to 25°C and dried for another 8 h to obtain a gel with a porosity of 95% and a specific surface area of ​​310 m². 2 dry gel of g-1.

[0154] (3) Physical immersion method for loading drugs:

[0155] The SPG dry gel was rapidly transferred to a drug-containing solution and soaked for 20 hours at a ratio of dry gel mass / drug solution volume = 1 g : 10 mL. After removal, the free solution was filtered off, and the gel was gently washed with deionized water for 1 min to remove surface residue, thus obtaining the drug-loaded control gel (GFA).

[0156] Comparative Example 2

[0157] A slit-fold polysaccharide drug delivery system is provided, prepared according to the following steps:

[0158] (1) Preparation of SPG hydrogel:

[0159] The aqueous solution containing schizophyllum polysaccharide was concentrated to obtain a schizophyllum polysaccharide pregel, the content of schizophyllum polysaccharide in the pregel being 10 wt%.

[0160] The pregel of the slit polysaccharide obtained above was soaked in the organic solvent dimethylacetamide to obtain an organic gel.

[0161] The organic gel was subjected to wet annealing at 100℃ for 24 hours to obtain the annealed gel.

[0162] The annealed gel was soaked in deionized water for 7 days and dialyzed to obtain a slit polysaccharide hydrogel.

[0163] (2) Physical immersion method for loading drugs:

[0164] The SPG gel prepared in step (1) was physically soaked to obtain a drug-loaded gel. The specific steps were as follows: the SPG gel was quickly transferred to a drug-containing solution and soaked for 20 hours at a ratio of dry gel mass / drug solution volume = 1g: 10mL. After taking it out, the free solution was filtered out and the surface residue was gently washed with deionized water at the same temperature for 1 minute to remove the surface residue and obtain the drug-loaded gel (Gel).

[0165] Experimental Example

[0166] The performance of the drug-loaded systems prepared in the aforementioned embodiments and comparative examples was tested.

[0167] 1. Determination of drug loading and release

[0168] (1) In this experiment, the drug concentration was determined by ultraviolet-visible spectroscopy (UV-Vis) using a Shimadzu UV-1800 spectrophotometer.

[0169] The specific operation is as follows: Place the solution in a 1 mm thick quartz cuvette and seal it. Select the absorption mode and use phosphate buffered saline (PBS) as the reference solvent to test the absorption rate in the wavelength range of 200 to 600 nm.

[0170] (2) Plotting the standard curve

[0171] Accurately weigh specific amounts of taurine and tauroursodeoxycholic acid (TUDCA) and place them in 5 mL volumetric flasks. Shake with PBS solution until completely dissolved, then dilute to the mark with PBS solution to obtain stock solutions. Measure 0.1 mL, 0.3 mL, 0.5 mL, 0.7 mL, 1 mL, 3 mL, 5 mL, and 7 mL of each stock solution into 10 mL volumetric flasks. Dilute to the mark with PBS solution and mix well to obtain a series of standard solutions. Since taurine itself has weak absorption of ultraviolet light, a colorimetric reagent (formaldehyde:acetylacetone = 1:2 v / v mixed solution) is added. The solution is heated in an oil bath at 100°C for 20 min, cooled to room temperature, and the absorbance is measured at 412 nm. Tauroursodeoxycholic acid (TUDCA) does not require colorimetric treatment; the absorbance is measured directly at 205 nm. A linear regression was performed on absorbance against concentration to plot standard curves for taurine and tauroursodeoxycholic acid, and their linear range and correlation were verified.

[0172] like Figure 2 The absorption curves of the drug-loaded solution were calibrated using a UV spectrophotometer, along with standard absorption curves for taurine concentrations in the range of 0.01–0.3 mg / mL. The results showed a linear relationship between taurine concentration and absorption intensity within this range.

[0173] like Figure 3 The absorption curves of the gel-loaded tauroursodeoxycholic acid solution were calibrated using a UV spectrophotometer, along with standard absorption curves for tauroursodeoxycholic acid concentrations ranging from 0.01 to 1.0 mg / mL. The results showed a linear relationship between tauroursodeoxycholic acid concentration and absorption intensity within this range.

[0174] (3) Determination of drug loading and release

[0175] The gels from each embodiment or comparative example were immersed in PBS solution, and the absorbance of the solution before and after drug loading was measured by UV spectrophotometer (taurine: 412 nm; tauroursodeoxycholic acid: 205 nm). The change in drug concentration in the solution was calculated by combining the standard curve, and the drug loading was calculated by measuring the concentration difference of the solution before and after drug loading (Formula 1). The in vitro drug release experiment was carried out in a forced-air drying oven at a set temperature of 37°C. The drug-loaded hydrogel was placed in PBS solution simulating the human body environment (37°C, pH 7.4), and samples were taken at preset time points to measure the absorbance of the drug in the release solution. The drug concentration was calculated according to the standard curve, and the cumulative release rate Q was calculated using Formula (2). n (%), plot the release curve, and analyze the drug release behavior at different time points.

[0176]

[0177] Where m1 and m2 are the total drug input and free drug input, respectively; V0 and V are the PBS volume of the target medium and the volume of each sample taken, respectively; c n Let M be the drug concentration in the solution at the nth sampling, and M be the drug loading. The release equilibrium time t0 is defined as the point at which drug release reaches saturation.

[0178] The test results of each embodiment and comparative example are shown in Table 1.

[0179] Table 1

[0180]

[0181]

[0182] Figure 4The in vitro release of taurine was demonstrated using unfreeze-dried gel (Comparative Example 2, denoted as Gel) and gels that underwent freeze-drying treatment before and after drug absorption (freeze-drying first method: Example 1, denoted as GFA; Comparative Example 1, denoted as GFB) as carriers.

[0183] From Table 1 above and the appendix to the instruction manual Figure 4 The results show that:

[0184] Example 1 utilizes a freeze-drying-first method to form a more porous three-dimensional network structure, resulting in larger pores and better connectivity within the gel. This facilitates the migration and diffusion of taurine molecules, allowing the hydrogel to load more drug. Simultaneously, secondary freeze-drying enhances the interaction between the gel network structure and drug molecules, reducing the drug diffusion rate. Therefore, Example 1 (GFB) exhibits a longer release period compared to Comparative Example 1 (GFA) and Comparative Example 2 (Gel).

[0185] Furthermore, taurine was rapidly released from the hydrogel within 48 hours, with the cumulative release rate gradually increasing, followed by a slow and continuous release over the next 4 days. This release effect further demonstrates that the drying process enhances the interaction between the polymer and the drug, thereby achieving a sustained-release effect.

[0186] Furthermore, Figure 5 The in vitro drug release data, drug loading, and cumulative release rate of the tauroursodeoxycholic acid gel system (Example 2) are shown in Table 1. As can be seen from Table 1, Example 2 utilizes a freeze-drying-first method to form a more porous three-dimensional network structure, resulting in larger pores and better connectivity within the gel. This facilitates the migration and diffusion of tauroursodeoxycholic acid molecules, allowing the hydrogel to load more drug and achieve a higher drug release rate. Simultaneously, the freeze-drying method enhances the interaction between the gel network structure and drug molecules, thereby achieving a sustained drug release effect.

[0187] 2. Drug release kinetics study

[0188] To study the release patterns and mechanisms of drugs from carriers, mathematical models are typically used to describe drug release behavior. In this experiment, we conducted an in-depth study of drug release kinetics on SPG hydrogels loaded with drugs. The following are three classic kinetic models:

[0189] (a) The Zero-Order model is commonly used in drug delivery systems. Compared to the limitations of traditional immediate-release formulations and first-order release kinetic drug delivery systems (such as large fluctuations in drug concentration and short effective duration of action), this model assumes that the drug is released at a constant rate, and the release amount is linearly positively correlated with time, as shown in formula (3). With its constant-rate drug release characteristic, this model can maintain the drug concentration within the therapeutic window for a longer period of time, thereby achieving a more ideal therapeutic effect.

[0190]

[0191] in, The amount of drug released into the solution at time t, k0: zero-order release rate constant, representing the amount of drug released per unit time, t: release time.

[0192] (b) The Higuchi model is an important model in the field of drug delivery. It was proposed by Takeru Higuchi in 1961 and is specifically used to describe the release rate of drugs from matrix devices. It plays a key role in the development of modern controlled-release drug technology. Although it has assumptions and approximations, it is widely used because of its simplicity and ability to accurately predict the release rate in most cases. It can also be extended as needed to adapt to more complex situations. The Higuchi model derives the correlation equation between the cumulative drug release and the square root of time using the pseudo-steady-state method under specific conditions. The model assumes that the drug release rate is proportional to the concentration difference of the drug in the solid. The mathematical expression is shown in Equation (4).

[0193]

[0194] in, The amount of drug released into the solution at time t, kH: Higuchi constant, which is related to the diffusion coefficient of the drug and the structural characteristics of the carrier, t: release time.

[0195] (c) The Ritger-Peppas model, proposed by Ritger and Peppas, primarily studies the release mechanism of porous hydrophilic polymers. This model is a more general drug release model that can simultaneously describe multiple drug release mechanisms such as diffusion control, dissolution control, and reaction control, and fully considers the time-dependent characteristics of drug release. Its core formula (5) shows that this model is applicable to moderately swollen drug-controlled release systems, where the diffusion index n is a key parameter for determining the release mechanism. It analyzes in detail the release of drugs under different geometries such as planar sheets, cylinders, and spheres, and considers the influence of particle size distribution on release kinetics. It is of great significance in the field of drug-controlled release research, providing a powerful tool for understanding drug release mechanisms and system design.

[0196]

[0197] where the amount of drug released into the solution at time t, kd: the release rate constant, n is the exponent of the release mechanism, t: the release time.

[0198] To gain a deeper understanding of the mechanism of drug release from Schizophyllan hydrogels in vitro, the Higuchi, Zero-order, and Rigter-Peppas kinetic equations were used to fit the release data respectively to explore the drug release mechanism in the gel. The fitting results are listed in Table 2. Table 2 Fitting parameters of taurine release by Higuchi, Zero-Order, and Ritger-Peppas models

[0199]

[0200] It can be seen from Table 2 that

[0201] The fitting of the Zero-order and Higuchi model shows that the diffusion coefficients (K0, k H and K d ) of GFA are the largest, and the diffusion coefficients (K0, k H and K d ) of GFB are the smallest, indicating that simply by the method of freeze-drying, the interaction between the network structure and the drug can be enhanced, making the drug diffusion rate slower.

[0202] Meanwhile, through fitting, it is found that the Rigter-Peppas model has the best fitting effect. The drug release mechanism can be determined according to the n value. For the bulk hydrogel sample, when 0.45 < n < 0.89, it is the random diffusion mechanism, between the two limiting processes of Fick diffusion and Case II diffusion. The n values of the three samples in this experiment are all in this range, indicating that the release behavior of taurine and tauroursodeoxycholic acid from SPG hydrogels follows the random diffusion mechanism, that is, the synergistic effect of Fickian diffusion and polymer chain relaxation.

[0203] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A method for preparing an injectable slit-glucan gel drug delivery system, characterized in that, include: The aqueous solution containing schizophyllum polysaccharide was concentrated to obtain schizophyllum polysaccharide pregel; The pregel of the slit polysaccharide was soaked in an organic solvent to obtain an organic gel; The organic gel was subjected to wet annealing to obtain an annealed gel. The annealed gel was soaked in deionized water to obtain a slit polysaccharide hydrogel; The slit polysaccharide hydrogel was subjected to a first freeze-drying process to obtain a dry gel. Drug-loaded gels are obtained by loading the dry gel with drugs through physical soaking. The drug-loaded gel is subjected to a second freeze-drying process and allowed to absorb water to obtain the final drug-loaded gel; the porosity of the dry gel is 40%-90%; the specific surface area of ​​the dry gel is 98 m² / g–270 m² / g; the drug includes at least one of taurine, tauroursodeoxycholic acid, paclitaxel, amphotericin B liposomes, and transglutaminase.

2. The method for preparing the injectable slit-fold polysaccharide gel drug delivery system according to claim 1, characterized in that, The loading of the drug onto the dry gel by physical soaking includes: The dry gel is added to the drug solution for soaking.

3. The method for preparing the injectable slit-fold polysaccharide gel drug delivery system according to claim 2, characterized in that, Soaking time is 3-24 hours.

4. The method for preparing the injectable slit-fold polysaccharide gel drug delivery system according to claim 2, characterized in that, The concentration of the drug solution is 0.01-10 mg / ml.

5. The method for preparing the injectable slit-fold polysaccharide gel drug delivery system according to claim 1, characterized in that, The first freeze-drying of the slit-fold polysaccharide hydrogel includes: Freeze at -50℃ to -10℃ for 5 to 20 hours; dry at 25℃ to -120℃ for 5 to 10 hours.

6. The method for preparing the injectable slit-fold polysaccharide gel drug delivery system according to claim 1, characterized in that, The second freeze-drying of the drug-loaded gel includes: Freeze at -50℃ to -10℃ for 5 to 20 hours; dry at 25℃ to 120℃ for 5 to 10 hours.

7. An injectable slit-glucan gel drug delivery system, characterized in that, The drug delivery system was prepared using the method described in any one of claims 1-6 for injectable slit-fold polysaccharide gel.

8. The injectable slit-fold polysaccharide gel drug delivery system according to claim 7, characterized in that, The injectable slit polysaccharide gel drug delivery system includes: slit polysaccharide hydrogel and drug; The drug is located in the pores of the slit-fold polysaccharide hydrogel; the slit-fold polysaccharide hydrogel encapsulates the drug; the drug is connected to the slit-fold polysaccharide hydrogel by physical bonds.

9. The injectable slit-fold polysaccharide gel drug delivery system according to claim 8, characterized in that, The physical bonds are mainly hydrogen bonds.

10. The injectable slit-fold polysaccharide gel drug delivery system according to claim 8, characterized in that, The injectable slit-polysaccharide gel drug delivery system comprises, by weight percentage: 1%-30% slit-polysaccharide hydrogel and 32.31%-59.9% drug.

11. The injectable slit-fold polysaccharide gel drug delivery system according to claim 7, characterized in that, The cumulative release rate of the injectable slit-glucan gel drug delivery system is 60.5%-98.17%.

12. The injectable slit-fold polysaccharide gel drug delivery system according to claim 7, characterized in that, The drug loading capacity of the injectable slit-glucan gel drug delivery system is 32.31%-58.64%.

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