Two-component in-situ-curing heat-insulating hydrogel containing gas microspheres, and preparation method therefor

Abstract

Disclosed in the present invention is a two-component in-situ-curing heat-insulating hydrogel containing gas microspheres. The heat-insulating hydrogel comprises gas microspheres, and the gas microspheres have a volume concentration of 5-20% in the cured heat-insulating hydrogel. The hydrogel of the present invention has excellent injectability, formability, biocompatibility and postoperative degradability. The gas microspheres greatly improve the heat insulation performance of the hydrogel. The hydrogel is convenient to operate, and has great industrialization value and clinical use value in the protection of endangered organs during tumor ablation treatment. In addition, the hydrogel can be implanted via minimally invasive injection so as to achieve cross-linking curing and forming in the body cavity, and all components of the hydrogel can be degraded, absorbed, and discharged from the body, greatly reducing the injury to patients caused by surgery and accelerating the postoperative recovery of patients.

Description

Two-component in-situ curing insulating water gel containing gas microspheres and preparation method thereof Technical Field

[0001] The present invention relates to a two-component in-situ solidified insulating water gel containing gas microspheres and a preparation method thereof, and relates to A61L, in particular to the field of pharmaceutical preparations. Background Art

[0002] With the deterioration of the living environment, the increase in life pressure, and the increase in unhealthy lifestyles, the incidence of human tumors and cancers has increased year by year. Existing treatment methods include surgical treatment, endocrine therapy, radionuclide therapy, and external beam radiation therapy. Surgical treatment is the main means of first-line treatment, but it will leave scars that affect the appearance. In the early stages of tumor diseases, interventional thermal ablation treatment technology is used to briefly increase the temperature in the target tissue to achieve tumor inactivation. The heat energy generated causes coagulative necrosis of the nodule. The coagulated necrotic tissue cells are dissolved and liquefied by hydrolytic enzymes and then absorbed by lymphocytes and blood vessels. The ablation area will gradually shrink until it disappears. Although thermal ablation treatment technology can achieve precise control of the target tissue, it will cause a certain degree of fibrosis or even necrosis of the surrounding tissue. The existing treatment method is to inject normal saline around the ablation area to reduce damage to the surrounding tissue, but the effect is not obvious. Therefore, it is crucial to develop a material with good thermal insulation effect to reduce the impact of thermal ablation treatment on the surrounding tissue.

[0003] Chinese invention patent CN202210068753.0 discloses a self-healing hydrogel with heat insulation function and its application. At room temperature, a water-soluble chitosan solution is mixed with a PEG derivative cross-linker solution with an aldehyde group at the end to undergo a chemical covalent cross-linking reaction to produce a self-healing hydrogel. The hydrogel is suitable for irregular tissue gaps and has a heat insulation effect. However, the formed hydrogel is a colloid, and heat will be conducted, resulting in poor heat insulation effect. Chinese invention patent CN202210603625.1 discloses a preparation method and application of an injectable hyaluronic acid hydrogel. By preparing L-cystine dimethyl ester grafted hyaluronic acid hydrogel HA-Dc, it is in a colloidal state under the conditions of the ablation temperature range. After injecting an equal volume of vitamin C solution into the colloid for 12 hours, it turns into a liquid state. Compared with water, it has better heat insulation and tissue protection effects. However, the pure gel has poor heat insulation effect and still has a certain impact on surrounding tissues.

[0004] Summary of the Invention

[0005] In order to improve the thermal insulation effect of the gel system and shorten the degradation time of the gel to achieve complete degradation without residue, the first aspect of the present invention provides a two-component in-situ cured insulating water gel containing gas microspheres. The insulating water gel contains gas microspheres, and the volume concentration of the gas microspheres in the cured insulating water gel is 5-20%.

[0006] As a preferred embodiment, the heat-insulating water gel is a gel system composed of a polyethylene glycol derivative solution and a polyamino cross-linking agent solution.

[0007] As a preferred embodiment, the polyethylene glycol derivative solution is a blocked multi-arm polyethylene glycol derivative solution, and the number of arms of the multi-arm polyethylene glycol derivative is 4-8.

[0008] As a preferred embodiment, the end-capping group of the multi-arm polyethylene glycol derivative solution is an active ester group or an aldehyde group of N-hydroxysuccinimide.

[0009] As a preferred embodiment, the weight average molecular weight of the multi-arm polyethylene glycol derivative is 1-10 kDa.

[0010] As a preferred embodiment, the polyamino crosslinker solution is selected from a combination of one or more of trilysine, polyethyleneimine and polylysine solutions.

[0011] As a preferred embodiment, the polyamino crosslinker solution is a combination of polyethyleneimine and polylysine solutions.

[0012] As a preferred embodiment, the molar ratio of the amino group in the polyethyleneimine to the amino group in the polylysine is (0.8-1.2):1.

[0013] As a preferred embodiment, the gas microspheres are prepared by introducing gas into an emulsification system, wherein the emulsification system includes an aqueous phase, an emulsifier, an oil phase and an aldehyde crosslinking agent, and the volume ratio of the oil phase to the aqueous phase is 1:(5-10).

[0014] As a preferred embodiment, the aqueous phase is an aqueous solution containing gelatin, and the mass ratio of the aldehyde cross-linking agent to gelatin is 1:(10-50).

[0015] As a preferred embodiment, the mass concentration of gelatin in the aqueous phase is 20-50%.

[0016] As a preferred embodiment, the emulsifier is an oil-soluble nonionic surfactant. Preferably, the oil-soluble nonionic surfactant is a fatty acid ester, and the fatty acid ester is sorbitan fatty acid ester.

[0017] As a preferred embodiment, the emulsifier is selected from one or a combination of Span-40, Span-80, and Span-85. Preferably, the emulsifier is Span-80.

[0018] As a preferred embodiment, the mass concentration of Span-80 in the oil phase is 1-5%.

[0019] As a preferred embodiment, the mass concentration of Span-80 in the oil phase is 1-3%.

[0020] As a preferred embodiment, the mass concentration of Span-80 in the oil phase is 2%.

[0021] As a preferred embodiment, the gas is selected from one or a combination of nitrogen, carbon dioxide, argon, helium, and air.

[0022] As a preferred embodiment, the oil phase is a non-polar organic solvent, and the non-polar organic solvent is selected from one or a combination of soybean oil, sesame oil, liquid paraffin, and silicone oil.

[0023] As a preferred embodiment, the aldehyde cross-linking agent is selected from one or a combination of formaldehyde, glutaraldehyde, dialdehyde starch, and dextran aldehyde.

[0024] During their experiments, the applicant discovered that by adding an aqueous phase to an oil phase containing an emulsifier, introducing an inert gas, and mechanically stirring the mixture to form an oil-in-water-in-gas emulsion system, adding the emulsion system to a gel system resulted in a hydrogel containing gas microspheres. This hydrogel exhibited thermal insulation after intracavitary injection, reducing the impact of thermal ablation on surrounding tissues. The applicant speculated that this may be due to a 1:5-10 mass ratio of the oil phase to the aqueous phase, which maintained the stability of the resulting emulsion. Prior to mixing with the gel system, the emulsion system retained a large number of bubbles, providing a gas reservoir for subsequent gelation. The applicant further discovered that a 1:10-50 mass ratio of an aldehyde crosslinker to gelatin increased the stability of the gel system containing gas microspheres. The applicant speculated that this may be due to the fact that gelatin at the optimal weight ratio formed a layered network structure around the outer periphery of the gas microsphere wall, supporting the gas microspheres and allowing the inert gas to completely fill the interstices of the crosslinked structure. Exceeding the optimal weight ratio would make the subsequent gel system less susceptible to degradation and absorption, adversely affecting subsequent treatment.

[0025] A second aspect of the present invention provides a method for preparing a two-component in-situ curing insulating water gel containing gas microspheres, comprising the following steps:

[0026] (1) preparing a polyethylene glycol derivative solution as component 1;

[0027] (2) preparing a polyamino crosslinker solution as a crosslinker solution;

[0028] (3) adding the aqueous phase to the oil phase containing the emulsifier, introducing gas, stirring, adding an aldehyde crosslinking agent, stirring for reaction, washing the air microspheres, removing the oil phase, and collecting the upper suspended microspheres to obtain gas microspheres;

[0029] (4) dispersing the gas microspheres into a crosslinker solution to prepare component 2;

[0030] (5) Component 1 and component 2 are drawn into a syringe, and then injected into equal volumes through a double syringe to mix and solidify to obtain a two-component in-situ solidified insulating water gel containing gas microspheres.

[0031] As a preferred embodiment, the method for preparing the two-component in-situ curing insulating water gel containing gas microspheres comprises the following steps:

[0032] (1) preparing a polyethylene glycol derivative solution, dissolving the polyethylene glycol derivative in a phosphate buffer solution, wherein the mass fraction of the polyethylene glycol derivative is 15-25%, as component 1;

[0033] (2) preparing a polyamino crosslinker solution, dissolving the polyamino crosslinker in a boric acid buffer solution, and preparing the crosslinker solution according to a molar ratio of aldehyde group of the polyethylene glycol derivative to amino group in the polyamino crosslinker = 1:(1.8-2.2);

[0034] (3) preparing the aqueous phase and heating it to 35-45°C, adding the emulsifier to the oil phase and heating it to 35-45°C, adding the aqueous phase to the oil phase containing the emulsifier, introducing filtered compressed gas, stirring continuously for 20-40 minutes, cooling to 5-10°C and continuing to stir for 1-1.5 hours, adding an aldehyde crosslinking agent, stirring and reacting for 2-4 hours, washing the air microspheres with an aqueous solution containing Tween-20, removing the oil phase, and collecting the upper suspended microspheres to obtain gas microspheres;

[0035] (4) dispersing the gas microspheres into a polyamino crosslinker solution to prepare component 2;

[0036] (5) Component 1 and component 2 are drawn into a syringe, and then injected into equal volumes through a double syringe to mix and solidify to obtain a two-component in-situ solidified insulating water gel containing gas microspheres.

[0037] As a preferred embodiment, the mass concentration of the aqueous solution containing Tween-20 is 0.1-1 wt%.

[0038] As a preferred embodiment, the pH of the phosphate buffer solution is 4-10; the pH of the borate buffer solution is 4-10. Preferably, the phosphate buffer solution is a buffer of disodium hydrogen phosphate and sodium dihydrogen phosphate, and the borate buffer solution is a buffer of boric acid and sodium borate.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The two-component in-situ cured insulating water gel containing gas microspheres of the present invention has a mass ratio of oil phase to water phase of 1: (5-10), which can maintain the stability of the formed emulsion system. Before being mixed with the gel system, a large number of bubbles can be stored in the emulsion system to provide gas storage capacity for the subsequent gel.

[0041] (2) The two-component in-situ cured insulating water gel containing gas microspheres of the present invention has an aldehyde crosslinker and gelatin with a mass ratio of 1: (10-50), which can increase the stability of the gel system containing gas microspheres, provide good mechanical support and physical morphological stability, and better provide support and stable isolation for tumors.

[0042] (3) The two-component in situ solidified insulating hydrogel containing gas microspheres described in the present invention has excellent injectability, formability, biocompatibility and postoperative degradability. The gas microspheres greatly improve the thermal insulation performance of the hydrogel and are easy to operate. It has great industrial value and clinical use value in protecting endangered organs in tumor ablation treatment.

[0043] (4) The two-component in-situ solidified insulating water gel containing gas microspheres described in the present invention can be implanted through minimally invasive injection to achieve cross-linking and solidification in the body cavity, and all components can be degraded, absorbed and excreted from the body, greatly reducing the damage caused by surgery to the patient and accelerating the patient's postoperative recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is a light microscopic image of gas hydrogel microspheres;

[0045] FIG2 is a comparison chart of the thermal insulation performance of Examples 1-4 after curing into glue and that of Comparative Example 1. DETAILED DESCRIPTION

[0046] Example 1

[0047] A two-component in-situ solidified insulating water gel containing gas microspheres. The insulating water gel contains gas microspheres, and the volume concentration of the gas microspheres in the solidified insulating water gel is 5%.

[0048] The heat-insulating water gel is a gel system composed of a polyethylene glycol derivative solution and a polyamino cross-linking agent solution.

[0049] The polyethylene glycol derivative solution is an 8-arm polyethylene glycol derivative solution terminated with ester-linked benzaldehyde groups and has a weight-average molecular weight of 10 kDa and was purchased from Beijing Jiankai Technology Co., Ltd.

[0050] The polyamino crosslinker solution is a combination of polyethyleneimine and polylysine solutions. The molar ratio of the amino groups in the polyethyleneimine to the amino groups in the polylysine is 0.9:1. The polyethyleneimine was purchased from Shanghai Maclean Biochemical Co., Ltd. The polylysine was purchased from Shanghai Maclean Biochemical Co., Ltd.

[0051] The gas microspheres are prepared by introducing gas into an emulsification system, wherein the emulsification system includes a water phase, an emulsifier, an oil phase and an aldehyde crosslinking agent, and the volume ratio of the oil phase to the water phase is 1:8.

[0052] The aqueous phase is an aqueous solution containing gelatin, and the mass ratio of the aldehyde cross-linking agent to gelatin is 1:30.

[0053] The mass concentration of gelatin in the aqueous phase is 30%.

[0054] The emulsifier is Span-80, and the mass concentration of Span-80 in the oil phase is 2%.

[0055] The gas is air.

[0056] The oil phase is liquid paraffin, and the aldehyde cross-linking agent is glutaraldehyde.

[0057] The pH of the phosphate buffer solution is 5.6, and the pH of the borate buffer solution is 9.2.

[0058] A method for preparing a two-component in-situ curing insulating water gel containing gas microspheres comprises the following steps:

[0059] (1) preparing a polyethylene glycol derivative solution by dissolving the polyethylene glycol derivative in a phosphate buffer solution, wherein the mass fraction of the polyethylene glycol derivative is 20%, as component 1;

[0060] (2) preparing a polyamino crosslinker solution, dissolving the polyamino crosslinker in a boric acid buffer solution, and preparing the crosslinker solution according to a molar ratio of aldehyde group of the polyethylene glycol derivative to amino group in the polyamino crosslinker of 1:1.9;

[0061] (3) The aqueous phase was heated to 40°C, the emulsifier was added to the oil phase and heated to 40°C, the aqueous phase was added to the oil phase containing the emulsifier, filtered compressed gas was introduced, and the mixture was stirred for 30 minutes, then cooled to 8°C and stirred for 1 hour, 1 mL of a 25 wt% aqueous solution of an aldehyde crosslinker was added, and the mixture was stirred for 3 hours. The air microspheres were washed with a 0.5% mass fraction of Tween-20 aqueous solution, the oil phase was removed, and the upper suspended microspheres were collected to obtain gas microspheres;

[0062] (4) dispersing the gas microspheres into a polyamino crosslinker solution to prepare component 2;

[0063] (5) Component 1 and component 2 were drawn into a syringe, and then injected with equal volumes (3 ml + 3 ml) through a double syringe to mix and solidify to obtain a two-component in-situ solidified insulating water gel containing gas microspheres.

[0064] The pH of the phosphate buffer solution is 5.6, and the pH of the borate buffer solution is 9.2.

[0065] Example 2

[0066] A two-component in-situ curing insulating water gel containing gas microspheres, the specific steps of which are the same as those of Example 1, except that the volume concentration of the gas microspheres in the cured insulating water gel is 10%.

[0067] Example 3

[0068] A two-component in-situ curing insulating water gel containing gas microspheres, the specific steps of which are the same as those of Example 1, except that the volume concentration of the gas microspheres in the cured insulating water gel is 20%.

[0069] Example 4

[0070] A two-component in-situ curing insulating water gel containing gas microspheres, wherein the specific steps are the same as those in Example 1, except that step 2 and step 3 are not included.

[0071] Performance Testing

[0072] 1. Curing time: Take 0.6mL each of component 1 and component 2 in Examples 1-4, and place a 2.5mL vial in a 37°C water bath. After standing for 5 minutes, use a pipette to take 200μL of component 1 solution into a 2.5mL vial. Then, use a different pipette tip to take 200μL of component 2 solution and add it to the vial containing component 1 solution. Vibrate the vial with your wrist at a frequency of 3 times / s for 3s, then repeatedly tilt the vial at a frequency of 1 time / s for observation until the liquid stops flowing. Start timing while adding component 2 solution, and end timing when the liquid stops flowing. The timing duration is the curing time. Three sets of samples were measured in parallel, and the average value was taken. The test results are shown in Table 1.

[0073] 2. Accelerated aging in vitro degradation test: Take 0.5 mL of each solution of component 1 and component 2 in Examples 1-4, use a disposable double mixed drug package (purchased from Mishawa), and inject equal volumes into a 0.5 cm × 0.5 cm × 0.5 cm cube mold. After solidification to form a hydrogel, the gel is taken out and placed in a 60°C oven for accelerated degradation test. The degradation of the gel is observed every day. The test results are shown in Table 1.

[0074] 3. Thermal insulation performance test: Take 0.5 mL of each solution of component 1 and component 2 in Examples 1-4, use a disposable double mixed drug bag (purchased from Mishawa), and inject equal volume into a 0.5 cm × 0.5 cm × 0.5 cm cube mold. After solidification to form a hydrogel, take out the gel, use a constant temperature water bath to heat to 99 ° C, put the material into the water bath, place a metal iron block on top of the material, use a double thermocouple to measure the temperature of the material contacting the water bath and the material contacting the iron block, and measure the temperature difference between the two temperatures. Among them, Comparative Example 1 is polyethylene propylene foam with a thermal conductivity of 0.045 W (MK), which is a high-efficiency thermal insulation material. The results are shown in Figure 2.

[0075] Table 1

[0076] Table 1 shows that the concentration of the hydrogel microspheres in Examples 1-4 has no significant effect on the curing time of the hydrogel. In the accelerated aging experiment, under the accelerated aging condition of 60°C, the complete degradation time is between 7 and 11 days (60°C, 7 days is approximately equal to 37°C, 34 days; 60°C, 9 days is approximately equal to 37°C, 44 days; 60°C, 11 days is approximately equal to 37°C, 54 days; 60°C, 14 days is approximately equal to 37°C, 69 days), which is suitable for the clinical needs of organ protection at different tumor treatment cycles.

[0077] Thermal insulation performance tests show that the addition of gas-containing hydrogel microspheres significantly improves the thermal insulation performance of the cured hydrogel. When the volume concentration of gas-containing hydrogel microspheres is 10%, the thermal insulation performance is optimal.

Claims

1. A two-component in-situ curing insulating water gel containing gas microspheres, characterized in that: The insulating water gel contains gas microspheres, and the volume concentration of the gas microspheres in the solidified insulating water gel is 5-20%.

2. The two-component in-situ curing insulating water gel containing gas microspheres according to claim 1, characterized in that: The insulating water gel is a gel system composed of a polyethylene glycol derivative solution and a polyamino cross-linking agent solution.

3. The two-component in-situ curing insulating water gel containing gas microspheres according to claim 2, characterized in that: The polyethylene glycol derivative solution is a blocked multi-arm polyethylene glycol derivative solution, and the number of arms of the polyethylene glycol derivative in the polyethylene glycol derivative solution is 4-8.

4. The two-component in-situ curing insulating water gel containing gas microspheres according to claim 3, characterized in that: The end-capping group of the multi-arm polyethylene glycol derivative solution is an active ester group or an aldehyde group of N-hydroxysuccinimide.

5. The two-component in-situ curing insulating water gel containing gas microspheres according to claim 2, characterized in that: The gas microspheres are prepared by introducing gas into an emulsification system, wherein the emulsification system comprises a water phase, an emulsifier, an oil phase and an aldehyde crosslinking agent, and the volume ratio of the oil phase to the water phase is 1:(5-10).

6. The two-component in-situ curing insulating water gel containing gas microspheres according to claim 5, characterized in that: The aqueous phase is an aqueous solution containing gelatin, and the mass ratio of the aldehyde cross-linking agent to gelatin is 1:(10-50).

7. The two-component in-situ curing insulating water gel containing gas microspheres according to claim 6, characterized in that: The mass concentration of gelatin in the water phase is 20-50%.

8. The two-component in-situ curing insulating water gel containing gas microspheres according to claim 5, characterized in that: The gas is selected from nitrogen, carbon dioxide, argon, helium, air or a combination thereof.

9. The two-component in-situ curing insulating water gel containing gas microspheres according to claim 5, characterized in that: The oil phase is a non-polar organic solvent, and the non-polar organic solvent is selected from soybean oil, sesame oil, liquid paraffin, silicone oil, or a combination of several thereof.

10. A method for preparing a two-component in-situ curing insulating water gel containing gas microspheres according to any one of claims 5 to 9, characterized in that: The following steps are involved: (1) preparing a polyethylene glycol derivative solution as component 1; (2) preparing a polyamino crosslinking agent solution as a crosslinking agent solution; (3) adding the aqueous phase to the oil phase containing the emulsifier, introducing gas, stirring, adding an aldehyde crosslinking agent, stirring for reaction, washing the air microspheres, removing the oil phase, and collecting the upper suspended microspheres to obtain gas microspheres; (4) dispersing the gas microspheres into a crosslinker solution to prepare component 2; (5) Component 1 and component 2 are drawn into a syringe, and then mixed by equal volume push injection through a double syringe, and solidified to obtain a two-component in-situ solidified insulating water gel containing gas microspheres.

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