Degradable drug-loaded hydrogel and preparation method thereof

Abstract

The invention belongs to the field of biological material preparation, and particularly relates to degradable drug-loading hydrogel and a preparation method thereof.Acrylate groups are introduced into 6s-PLA, 6s-PLA-HA is synthesized, a hydrogel material is synthesized through a photopolymerization method, then cefprozil serves as a model drug, and drug loading is conducted on the hydrogel through the supercritical impregnation technology. The composite material is self-prepared six-arm star-shaped polylactic acid (6s-PLA), the 6s-PLA is terminated by using acryloyl chloride to synthesize 6s-PLA-HA, PLA-PEG hydrogel is prepared by using a photopolymerization method, and a hydrogel material loaded with cefprozil is prepared by using a supercritical carbon dioxide impregnation technology. The material has the advantages of being excellent in mechanical property, non-toxic, good in biological safety, non-irritant, easy to process and form, degradable, anti-inflammatory and the like, and is expected to be widely applied to the field of biomedical materials.

Description

Technical Field

[0001] This invention belongs to the technical field of biomaterials, specifically relating to biodegradable drug-loaded hydrogels. Background Technology

[0002] In recent years, the preparation and application of biomaterials, especially biodegradable drug-loaded biomaterials, have attracted great attention.

[0003] Hydrogels are cross-linked polymer networks with water-retaining capabilities. Due to their unique properties, such as their ability to absorb large amounts of water or biological fluids, hydrogels have a wide range of biomedical applications in areas such as drug delivery, wound management, and tissue engineering.

[0004] CN101280094A discloses a "bioactive hydrogel-conductive polymer nanocomposite material and its synthesis method, comprising: dissolving purified ethylene glycol-hydroxy acid block copolymer in dichloromethane, cooling it to 0-5°C in an ice bath at a mass percentage of 10%-14%, adding 0.5-0.83 mol of acryloyl chloride and 0.33-0.67 mol of triethylamine at a molar ratio under anhydrous and oxygen-free conditions, stirring the reaction at 0-5°C for 10-18 h, then stirring the reaction at room temperature for 12-18 h, filtering to remove triethylamine hydrochloride, adding excess dry diethyl ether to the filtrate to obtain acrylate-terminated ethylene glycol-hydroxy acid block copolymer, dissolving the acrylate-terminated ethylene glycol-hydroxy acid block copolymer in dichloromethane, purifying it by hexane precipitation, and drying it; dissolving the above acrylate-terminated ethylene glycol-hydroxy acid block copolymer in water, and obtaining a gel by photo-initiated crosslinking or free radical crosslinking methods."

[0005] Photopolymerization is used to prepare hydrogels. For example, CN101311197B discloses "a copolymer prepared by the following method: using 2,2-dimethoxy-2-phenylacetophenone as an initiator, methylenebisacrylamide as a crosslinking agent, and HEMA-PCL, MAA, PEGDMA, or MPEG-MA as raw materials, a free radical polymerization reaction is initiated by irradiation with a 500W ultraviolet lamp at a wavelength of 365nm for 10-60 minutes to synthesize a hydrogel with the structure shown in P(CL-MAA-EG)." Impregnation method for loading drugs, such as CN115300455A which discloses "the application of a hydrogel carrier in drug sustained release, including the following steps: (1) impregnating an organic gel in a solution containing a drug to load the drug, and then obtaining a drug-loaded organic gel; (2) impregnating the drug-loaded organic gel in step (1) in water or an aqueous solution for solvent exchange, and then obtaining a drug-loaded hydrogel." Polylactic acid with a multi-arm structure exhibits better rheological properties and more end groups, allowing for the loading of more drugs. Acryloyl chloride is an extremely reactive compound that readily polymerizes in water to form acrylates.

[0006] Supercritical technology has the advantages of high diffusion, non-flammability, green and non-toxic properties, and low cost, and is widely used in the synthesis of medical polymer materials, pharmaceuticals, and the medical industry.

[0007] However, not all drug-loaded gels retain their original porous structure. The impact of drug loading on the material's structure, as well as the drug loading capacity and safety, still need improvement. Summary of the Invention

[0008] The purpose of this invention is to address the issues of structural limitations, drug safety, and efficacy in current drug-loaded hydrogels, and to provide a biodegradable drug-loaded hydrogel with excellent drug loading performance, no organic solvent residue, superior mechanical properties, and good biocompatibility. Another objective of this invention is to solve the problem of preparing a biodegradable drug-loaded hydrogel by providing a scientifically sound, easy-to-operate method for preparing such a hydrogel, resulting in a product with excellent performance.

[0009] To address the aforementioned problems, the present invention employs the following technical solution: a biodegradable drug-loaded hydrogel, wherein acrylate groups are introduced into 6S-PLA to synthesize 6S-PLA-HA, and the hydrogel material is synthesized using photopolymerization. Subsequently, using cefprozil as a model drug, the hydrogel is loaded with the drug using supercritical fluid impregnation technology.

[0010] Preferably, the biodegradable drug-loaded hydrogel is prepared by end-capping 6S-PLA with acrylic acid to synthesize acrylate, using photoinitiator 2959 as an initiator, reacting with polyethylene glycol and polyethylene glycol diacrylate under ultraviolet irradiation to synthesize hydrogel material, and then using cefprozil as a model drug to load the hydrogel with drug using supercritical impregnation technology to prepare a biodegradable drug-loaded hydrogel.

[0011] To solve the above problems, the technical problem addressed by this invention is: a method for preparing a biodegradable drug-loaded hydrogel, comprising the following steps: (1) Prepare a solution of acryloyl chloride tetrahydrofuran. Add 6s-PLA to a dry round-bottom flask and dissolve it in a certain amount of dried tetrahydrofuran under nitrogen protection. Place the flask in an ice bath, add six times the amount of triethylamine of the polymer, stir magnetically, add the solution of acryloyl chloride tetrahydrofuran dropwise, filter and dry to obtain 6s-PLA-HA. (2) Dissolve 6s-PLA-HA in dimethyl sulfoxide (DMSO) and heat to 40°C, stirring until completely dissolved; (3) Add polyethylene glycol (20000) and polyethylene glycol diacrylate (400) and continue stirring. Finally, add 5 wt% of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone (Irgacure 2959) to obtain a colorless and transparent solution. (4) After stirring, pour the mixture into a mold and irradiate it with a 365nm ultraviolet lamp for 240s to obtain a solid gel; (5) Rinse the gel three times with 75% alcohol, soak the gel in deionized water, change the deionized water every 2 hours, and repeat 10 times. (6) Add an excess of cefprozil to the upper layer of the high-pressure reactor and add gel material to the lower layer. Adjust the temperature and pressure to the supercritical impregnation temperature of 35-50℃ and the impregnation pressure of 10-16MPa to carry out supercritical drug impregnation. After depressurization, the drug-loaded gel material is obtained.

[0012] Preferably, in step (1), the acryloyl chloride tetrahydrofuran solution is prepared at a volume ratio of acryloyl chloride to tetrahydrofuran of 1:10.

[0013] Preferably, in step (1), the tetrahydrofuran solution of acryloyl chloride is added dropwise using a constant pressure dropping funnel at a rate of 3 s / d.

[0014] Preferably, in step (1), after the addition of the tetrahydrofuran solution of acryloyl chloride is completed, the reaction temperature is maintained at 0°C for 6 hours, and then the reaction is carried out at room temperature for 12 hours.

[0015] Preferably, in step (3), the mass ratio of 6s-PLA-HA: polyethylene glycol: polyethylene glycol diacrylate is 0.2-0.8:0.2-0.8:1.

[0016] Preferably, in step (6), the supercritical fluid used for supercritical drug impregnation in the high-pressure reactor is supercritical carbon dioxide.

[0017] Preferably, in step (6), the temperature of the high-pressure reactor is raised to 50°C, and the pressure is slowly raised to 14 MPa and maintained for 2 hours.

[0018] Compared with the prior art, the present invention has the following advantages: Polylactic acid with a multi-arm structure possesses better rheological properties and more terminal groups, allowing for the loading of more drugs. Acryloyl chloride is an extremely reactive compound that readily polymerizes in water to form acrylates. The 6S-PLA-HA / PEG / PEG-DA hydrogel prepared by photopolymerization offers a superior drug loading capacity due to its porous structure, high drug loading, absence of organic solvent residue, and a green and non-toxic preparation process. It allows for flexible replacement of target drugs as needed and is a biomaterial with excellent mechanical properties and biocompatibility. Cefprozil is a semi-synthetic oral cephalosporin, belonging to the second-generation cephalosporin antibiotics, and can be used to treat bronchitis or other bacterial infections.

[0019] This invention utilizes supercritical impregnation technology to load drugs onto materials and controls the penetration and expansion of the polymer matrix through temperature and pressure, allowing the drug to fully enter the material. Compared with traditional impregnation methods, it has advantages such as high drug loading capacity and no organic solvent residue. Attached Figure Description

[0020] Figure 1 The infrared spectrum of 6s-PLA-HA prepared in Example 1; Figure 2 The 1H-NMR spectrum of 6s-PLA-HA prepared in Example 1; Figure 3 XRD pattern of the hydrogel prepared in Example 2; Figure 4 The stress-strain curve of the hydrogel prepared in Example 2; Figure 5 is a SEM image of the drug-loaded hydrogel prepared in Example 3; Figure 6 This is a diagram illustrating the effect of using this invention. Detailed Implementation

[0021] The present invention will be further illustrated below with specific examples, but these are not intended to limit the invention. Unless otherwise specified, all materials, equipment, and reagents used in the following embodiments are commercially available.

[0022] Example 1

[0023] Preparation of 6s-PLA-HA: (1) The tetrahydrofuran and triethylamine used in the experiment were treated with calcium hydride to remove moisture. Acryloyl chloride tetrahydrofuran solution with a volume ratio of 1:10 to tetrahydrofuran was prepared in advance and used immediately. 6s-PLA was added to a dry round-bottom flask and dissolved in a certain amount of dried tetrahydrofuran under nitrogen protection. The mixture was placed in an ice bath and six times the amount of triethylamine was added. The magnetic stirring was turned on and the tetrahydrofuran solution of acryloyl chloride was added dropwise at a rate of 3s / d using a constant pressure dropping funnel. After the addition was completed, the reaction temperature was maintained at 0℃ for 6h and then the reaction was carried out at room temperature for 12h. The product was then collected.

[0024] (2) Centrifuge the product (4000r / min) for 40min, transfer the supernatant to a beaker, add excess n-hexane at 0℃ for back dissolution, stir continuously, place in a refrigerator to precipitate for 2h, filter using a Buchner funnel, repeat the back dissolution process 3 times, collect the filter residue and dry it in a vacuum drying oven at 30℃ for 48h to obtain 6s-PLA-HA.

[0025] Figure 1 The 6s-PLA-HA infrared spectrum (FTIR image) prepared for this example. From Figure 1 As can be seen from the data, the stretching vibration peaks of methyl CH3 and methine CH appear at 3002 cm⁻¹, respectively. -1 and 2952 cm -1 The stretching vibration peak of the ester group C=O is at 1760 cm⁻¹. -1 Location, 1461 cm -1 This corresponds to the bending vibration peak of CH, at 1180 cm⁻¹. -1 and 1046 cm -1 The characteristic peaks correspond to the stretching vibration peak of CO and the bending vibration peak of OH, respectively. The absorption peak around 3500 nm in the FTIR spectrum of 6s-PLA-HA is significantly reduced. This is because after acryloyl chloride capping, the terminal hydroxyl group of 6s-PLA is replaced by an acrylate group. Simultaneously, it can be seen that the absorption peak at 1642 cm⁻¹... -1 With 811cm -1 A new absorption peak appeared, which is attributed to the terminal C=C vibration absorption peak in 6s-PLA-HA. Compared with other groups, the proportion of C=C in the polymer is relatively small, so the absorption is weak. Based on this, it can be determined that the terminal hydroxyl group in 6s-PLA has been converted into an acrylate group.

[0026] Figure 2The 1H-NMR spectrum of the 6s-PLA-HA prepared for this example shows that the methyl hydrogen (c) on the polymer chain is at 1.53 ppm, the chemical shift of the methine (b) is at 5.12 ppm, and the characteristic hydrogen of inositol (a) is at around 3.67 ppm. An octet appears near 6.20 ppm in the 1H-NMR spectrum of the 6s-PLA-HA. This is attributed to the proton peaks of the ABX olefin, namely the hydrogen (d), hydrogen (e), and hydrogen (f) at the end of the polymer chain. Due to the overlap of the three characteristic hydrogen peaks, a typical dodecet does not appear. The ratio of the four peaks to hydrogen (a) is approximately 1:3:3:3. Therefore, it can be determined that the terminal hydroxyl group of 6s-PLA is replaced by an acrylate group.

[0027] Example 2

[0028] Preparation of solid hydrogels: (1) The 6s-PLA-HA prepared in Example 1 was mixed with polyethylene glycol (PEG) and polyethylene glycol diacrylate in a mass ratio of 0.8:0.2:1.

[0029] (2) Dissolve 6s-PLA-HA in dimethyl sulfoxide (DMSO) and heat to 40°C, stirring until completely dissolved.

[0030] (3) Add polyethylene glycol (20000) and polyethylene glycol diacrylate (400) and continue stirring. Finally, add 5 wt% of photoinitiator 2959 to obtain a colorless and transparent solution.

[0031] (4) After stirring, pour the mixture into a mold and irradiate it with a 365nm ultraviolet lamp for 240s to obtain a solid gel.

[0032] (5) Rinse the solid gel three times with 75% alcohol, soak the solid gel in deionized water, change the deionized water every 2 hours, and repeat 10 times.

[0033] Figure 3 The XRD pattern of the hydrogel prepared in this example is shown. As can be seen from the figure, there is a small sharp diffraction peak at 2θ=16.1° and a relatively broad diffraction peak at 2θ=20.75°, indicating that the gel has a crystalline state.

[0034] Example 3

[0035] Preparation of solid hydrogels: (1) The 6s-PLA-HA prepared in Example 1 was mixed with polyethylene glycol (PEG) and polyethylene glycol diacrylate in a mass ratio of 0.2:0.8:1.

[0036] The preparation of solid hydrogels was the same as in Example 2.

[0037] Example 4

[0038] Preparation of solid hydrogels: (1) The 6s-PLA-HA prepared in Example 1 was mixed with polyethylene glycol (PEG) and polyethylene glycol diacrylate in a mass ratio of 0.4:0.6:1.

[0039] The preparation of solid hydrogels was the same as in Example 2.

[0040] Example 5

[0041] Preparation of solid hydrogels: (1) The 6s-PLA-HA prepared in Example 1 was mixed with polyethylene glycol (PEG) and polyethylene glycol diacrylate in a mass ratio of 0.6:0.4:1.

[0042] The preparation of solid hydrogels was the same as in Example 2.

[0043] Figure 4 The figures show the stress-strain curves of the hydrogels prepared in Examples 2 to 5. As the content of 6s-PLA-HA gradually increases and the content of PEG gradually decreases, the elastic moduli are 36, 219, 518 and 1275 kPa, respectively. The stress of the gel material gradually increases, the deformation of the material gradually decreases, and the elastic modulus increases.

[0044] Example 6

[0045] Supercritical impregnation drug loading: (1) In the supercritical device, the upper layer of the high-pressure reactor is loaded with excess cefprozil and the lower layer is loaded with gel material, and the reactor is connected to the pipeline. (2) Turn on the temperature control system to heat the reactor to 40°C. During this process, turn on the condenser to cool it down. Then turn on the carbon dioxide cylinder to slowly increase the pressure to 16 MPa. Check the airtightness of the device every time the pressure increases by 1 MPa. (3) Turn on the plunger pump and slowly inject CO2 into the reactor to raise the pressure to the required experimental pressure of 16 MPa, and maintain it at the required temperature and pressure for 2 hours.

[0046] (4) Close the gas cylinder, completely release the CO2 in the system, turn off the power, and collect the drug-loaded gel material.

[0047] Figure 5 shows the surface morphology of the drug-loaded gel after supercritical impregnation. Figure 5(a) reveals obvious white particulate matter on the gel surface. A small amount of white particulate matter is also observed in the cross-sectional view of Figure 5(b), indicating successful drug loading. Furthermore, the drug-loaded material retains its original porous structure because the temperature and pressure conditions of supercritical carbon dioxide impregnation are mild and do not affect the material's structure.

[0048] In clinical use, the biodegradable drug-loaded hydrogel prepared above is inserted into the patient's nasal cavity using forceps or a sterile material delivery device. In animal experiments, mice were anesthetized with tribromoethanol and fixed in a supine position. The novel biodegradable material was cut to a suitable size (0.5mm*0.5mm*10mm) according to the size of the mouse's nasal cavity, and then gently packed into both nasal cavities of the mouse with forceps to ensure close contact with the nasal mucosa.

[0049] The product has demonstrated significant safety and therapeutic efficacy. Safety: In this study, the safety assessment results of the novel biodegradable material applied topically in mice were satisfactory. Figure 6 The safety verification experiment shown (a) consisted of normal mice as the control group and mice implanted with the material as the experimental group (b). During the experiment, the mice in the experimental group showed good general condition after local application of the novel biodegradable material. Their appetite and activity were not significantly affected, and no adverse reactions such as respiratory abnormalities, nasal bleeding, or sneezing were observed. This preliminarily indicates that the novel biodegradable material has minimal irritation to the respiratory tract and nasal mucosa of mice, does not cause acute local adverse reactions, and is well tolerated by the mouse body.

[0050] Histopathological examination of the nasal mucosa provided strong evidence for the safety of the novel biodegradable material. On day 7 after material application, the nasal mucosal epithelial structure of the control group mice remained intact, with neatly arranged cilia and no obvious inflammatory cell infiltration in the lamina propria. There was no significant difference between the experimental group and the control group. This result indicates that the novel biodegradable material does not damage the nasal mucosa and does not induce inflammatory or allergic reactions in mice.

[0051] HE pathological section results: Statistical analysis: Table 1. Comparison of HE staining percentage of inflammatory cells in mouse tissues from the blank control group and the safety verification group. P > 0.05, indicating no statistically significant difference in the number of inflammatory factors stained by HE between the control group and the experimental group.

[0052] ELISA results for serum IgE: Table 2 Comparison of IgE concentrations in mice between the blank control group and the safety verification group P > 0.05, indicating no statistically significant difference in serum IgE levels between the control group and the experimental group.

[0053] Therapeutic efficacy: A novel material loaded with dexamethasone and clarithromycin was placed into the nasal cavity of a mouse model of chronic sinusitis. The mice were sacrificed after 7 days, and the content of the inflammatory factor IL-5 in the nasal lavage fluid was examined. Figure 6 The experiment on the therapeutic effect of the drug-loaded material shown in Figure c is a control group of mice with chronic sinusitis, and the experimental group d is a group of mice filled with drug-loaded material.

[0054] Table 3. IL-5 concentrations in mice with chronic sinusitis before and after treatment. The IL-5 levels in the control group and the treatment group showed a highly significant difference (P<0.001), providing statistical support for the effectiveness of this treatment regimen.

[0055] In summary, the novel biodegradable material exhibits good safety in local application in mice, does not cause significant local or systemic toxicity, and can play a good role in the local treatment of chronic sinusitis.

[0056] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible implementations of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A biodegradable drug-loaded hydrogel, characterized in that, Acrylate groups were introduced into 6s-PLA to synthesize 6s-PLA-HA. Hydrogel materials were synthesized by photopolymerization. Subsequently, using cefprozil as a model drug, the hydrogel was loaded with the drug using supercritical impregnation technology.

2. The biodegradable drug-loaded hydrogel according to claim 1, characterized in that, The biodegradable drug-loaded hydrogel is prepared by end-capping 6S-PLA with acrylic acid to synthesize acrylate, using 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone as a photoinitiator, reacting with polyethylene glycol and polyethylene glycol diacrylate under ultraviolet irradiation to synthesize hydrogel material, and then using cefprozil as a model drug, loading the hydrogel with drug using supercritical impregnation technology to prepare a biodegradable drug-loaded hydrogel.

3. The method for preparing a biodegradable drug-loaded hydrogel according to claim 1 or 2, characterized in that, The steps are as follows: (1) Prepare a solution of acryloyl chloride tetrahydrofuran. Add 6s-PLA to a dry round-bottom flask and dissolve it in a certain amount of dried tetrahydrofuran under nitrogen protection. Place the flask in an ice bath, add six times the amount of triethylamine of the polymer, stir magnetically, add the solution of acryloyl chloride tetrahydrofuran dropwise, filter and dry to obtain 6s-PLA-HA. (2) Dissolve 6s-PLA-HA in dimethyl sulfoxide and heat to 40°C, stirring until completely dissolved; (3) Add polyethylene glycol and polyethylene glycol diacrylate and continue stirring. Finally, add 5 wt% of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone to obtain a colorless and transparent solution. (4) After stirring, pour the mixture into a mold and irradiate it with a 365nm ultraviolet lamp for 240s to obtain a solid gel; (5) Rinse the gel three times with 75% alcohol, soak the gel in deionized water, change the deionized water every 2 hours, and repeat 10 times. (6) Add an excess of cefprozil to the upper layer of the high-pressure reactor and add gel material to the lower layer. Adjust the temperature and pressure to the supercritical impregnation temperature of 35-50℃ and the impregnation pressure of 10-16MPa to carry out supercritical drug impregnation. After depressurization, the drug-loaded gel material is obtained.

4. The method for preparing a biodegradable drug-loaded hydrogel according to claim 3, characterized in that, In step (1), the acryloyl chloride tetrahydrofuran solution is prepared at a volume ratio of acryloyl chloride to tetrahydrofuran of 1:

10.

5. The method for preparing a biodegradable drug-loaded hydrogel according to claim 3, characterized in that, In step (1), the tetrahydrofuran solution of acryloyl chloride is added dropwise using a constant pressure dropping funnel at a rate of 3 s / d.

6. The method for preparing a biodegradable drug-loaded hydrogel according to claim 3, characterized in that, In step (1), after adding the tetrahydrofuran solution of acryloyl chloride, the reaction temperature is kept at 0°C for 6 hours, and then the reaction is carried out at room temperature for 12 hours.

7. The method for preparing a biodegradable drug-loaded hydrogel according to claim 3, characterized in that, In step (3), the mass ratio of 6s-PLA-HA: polyethylene glycol: polyethylene glycol diacrylate is 0.2-0.8:0.2-0.8:

1.

8. The method for preparing a biodegradable drug-loaded hydrogel according to claim 3, characterized in that, In step (6), the supercritical fluid used for supercritical drug impregnation in the high-pressure reactor is supercritical carbon dioxide.

9. The method for preparing a biodegradable drug-loaded hydrogel according to claim 3, characterized in that, In step (6), the temperature of the high-pressure reactor is raised to 50°C, and the pressure is slowly raised to 14 MPa and maintained for 2 hours.

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