A self-developing hydrogel

Abstract

The application discloses a self-developing hydrogel. The self-developing hydrogel is an iodine hydrogel formed by reaction of an iodine star-shaped multi-arm polyethylene glycol derivative and a polyamino compound. The self-developing hydrogel has high CT developing capacity, has a longer developing effect in vivo compared to a traditional hydrogel physically wrapping an iodine contrast agent, and is beneficial to long-term observation of the position and state of the hydrogel in vivo through X-ray.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of biomedical materials, and particularly relates to a self-developable injectable hydrogel and application thereof. BACKGROUND

[0002] Injectable hydrogels are widely used in tumor radiotherapy protection, vascular embolization, wound sealing and drug delivery. In use, the hydrogel usually needs to exist at the target site for a considerable period of time to complete its function, and in some cases the hydrogel is also gradually degraded and absorbed by the body. How to observe the position, shape and other changes of the hydrogel in the body by non-invasive means is an important clinical problem. X-ray or CT imaging is a commonly used detection means for observing implanted devices, which can observe the position and shape changes of the visible implant in a non-invasive manner. However, the hydrogel is usually composed of light elements such as carbon, nitrogen, oxygen and hydrogen, and has weak X-ray absorption ability, which cannot be observed by these devices. Chinese patent document CN 109646723 discloses an injectable two-component polyethylene glycol hydrogel, which has the characteristics of fast gelation time and controllable degradation. The polyethylene glycol-based hydrogel has good biological safety and has been used in wound sealing, tumor radiotherapy protection and other fields. However, this hydrogel does not have X-ray developing ability and can only be observed by nuclear magnetic resonance imaging, which is not conducive to non-invasive observation and monitoring during clinical use. Under the prior art, the X-ray developing fluid is directly wrapped in the hydrogel, so that the hydrogel can develop under X-ray. However, this visible gel will lose its developing effect due to the rapid diffusion of the developing fluid. Chinese patent document CN103417387A proposes to use hydrogel to wrap developing powder particles to achieve long-term developing purpose. However, for degradable hydrogel, the degradation of the hydrogel will release the developing powder, and the free developing powder is a serious safety hazard to the human body. SUMMARY

[0003] The present application discloses an injectable polyethylene glycol hydrogel that can be long-term self-developed, which is constructed by covalently binding iodine reagents to polyethylene glycol polymers to form a new type of iodinated polyethylene glycol aldehyde derivative, and forming a gel when the derivative is mixed with a crosslinking agent. The formed gel can maintain long-term developing effect in the body.

[0004] The specific technical scheme of the present application is as follows:

[0005] An iodinated star-shaped multi-arm polyethylene glycol derivative, at least one arm of the star-shaped multi-arm polyethylene glycol is terminated by an aldehyde group, and at least one arm is terminated by an iodine-substituted phenyl group.

[0006] The iodine-substituted phenyl group can be substituted with one or more iodine. Further, the phenyl group can also be substituted with one or more other groups, such as C1-C10 alkyl, C1-C10 alkoxy, hydroxyl, amino, one or more of I, and at least one of the groups is I.

[0007] The aldehyde group or the iodine-substituted phenyl group is connected to the star-shaped multi-armed polyethylene glycol via an ester bond, an amide bond, an ether bond, an urethane bond, an imine bond or a urea bond. A specific example of the present application is an ester bond.

[0008] The aldehyde group is selected from one or more of an aromatic aldehyde and an alkyl aldehyde. Preferably, the aldehyde group is a phenyl aldehyde group.

[0009] Preferably, the star-shaped multi-armed polyethylene glycol has between 4 and 8 arms.

[0010] Preferably, at least one of the arms of the star-shaped multi-armed polyethylene glycol is terminated with -(X)-(Y)-CHO and at least one of the arms is terminated with X and X' are the same or different and are selected from -O-, -O-CO-, -NHCO-, -CONH-, =N- or -NH-CO-NH-, Y represents -(CH2)m- or a substituted or unsubstituted phenyl group, m represents a positive integer from 1 to 6, and Ra-Re are the same or different and are selected from H, C1-C10 alkyl (more preferably C1-C6 alkyl), C1-C10 alkoxy (more preferably C1-C6 alkoxy), hydroxyl, amino, one or more of I, and at least one of the groups is I.

[0011] Further preferably, the iodinated star-shaped multi-armed polyethylene glycol derivative has the following structure:

[0012]

[0013] wherein one or more of R1-R3 in Formula I, one or more of R1-R5 in Formula II, or one or more of R1-R7 in Formula III is and the remaining substituents in Formula I, Formula II or Formula III are -(X)-(Y)-CHO, X and X' are the same or different and are selected from -O-, -O-CO-, -NHCO-, -CONH-, =N- or -NH-CO-NH-, Y represents -(CH2)m- or a substituted or unsubstituted phenyl group, m represents a positive integer from 1 to 6, and Ra-Re are the same or different and are selected from H, C1-C10 alkyl (more preferably C1-C6 alkyl), C1-C10 alkoxy (more preferably C1-C6 alkoxy), hydroxyl, amino, one or more of I, and at least one of the groups is I.

[0014] The iodinated star-shaped multi-armed polyethylene glycol derivative of the present application has two or more of when there are two or more -(X)-(Y)-CHO groups in Formula I, Formula II or Formula III, these groups are the same or different.

[0015] In one embodiment of the present application, the -(X)-(Y)-CHO group is selected from The -(X)-(Y)-CHO group is preferably selected from The -(X)-(Y)-CHO group is preferably selected from

[0016] Preferably, the molar ratio of aldehyde groups to iodine-substituted phenyl groups in the iodinated star-micelle polyethylene glycol derivative is from 1:7 to 5:3, more preferably from 2:6 to 4:4.

[0017] The development intensity of the star-micelle polyethylene glycol can be adjusted by adjusting the molar ratio of aldehyde groups to iodine-substituted phenyl groups.

[0018] The iodinated star-micelle polyethylene glycol derivative of the present application can be prepared by the following method:

[0019] (1) reacting a hydroxyl-terminated multi-armed polyethylene glycol with a benzene substituted with a carboxyl group and an iodine group (the benzene can also be substituted with other substituent groups) by esterification to obtain an iodine-terminated polyethylene glycol derivative;

[0020] In one embodiment, the multi-armed polyethylene glycol and the benzene substituted with a carboxyl group and an iodine group are dissolved in dichloromethane, an excess amount of DCC and DMAP is added to promote the esterification, and after the reaction is completed, the next step is performed directly without any treatment.

[0021] (2) reacting the product of step (1) with a benzene substituted with a carboxyl group and an aldehyde group (the benzene can also be substituted with other substituent groups) by formaldehyde to further obtain an aldehyde-terminated polyethylene glycol derivative.

[0022] In one embodiment, an excess amount of the benzene substituted with a carboxyl group and an aldehyde group is added to the solution of step (1), and an excess amount of DCC and DMAP is added at the same time, and after the reaction is completed, the product is obtained by precipitation with diethyl ether.

[0023] The reaction order (end-capping order) of steps (1) and (2) in the above method can be reversed.

[0024] Another object of the present application is to provide an iodinated hydrogel crosslinked from one or more of the iodinated star-micelle polyethylene glycol derivative of the present application, a polyamino compound and / or a polyhydrazine compound.

[0025] The aldehyde group of the iodinated star-micelle polyethylene glycol derivative is reacted with the amino group of the polyamino compound to form a Schiff base. Preferably, the polyamino compound is polylysine or a mixture of polylysine and polyethyleneimine.

[0026] The technical solutions disclosed in CN109939065A, CN109646723A, CN112225912A and CN113461973A can be referred to, and the degradation time of the hydrogel is adjusted by adjusting the ratio of polylysine to polyethyleneimine in the polyamino compound, the molar ratio of amino groups in the polyamino compound to aldehyde groups capped by the star-shaped multi-arm polyethylene glycol, and the connection between the aldehyde groups and the star-shaped multi-arm polyethylene glycol, so as to meet different needs in clinical application.

[0027] In one specific example, the concentration of the star-shaped multi-arm polyethylene glycol in the hydrogel is 2-40% (w / v), preferably 10-30%, and the concentration of the polyamino compound is 0.5-20%, preferably 1-5% (w / v).

[0028] The preparation method of the hydrogel according to the present application is as follows:

[0029] The iodinated star-shaped multi-arm polyethylene glycol derivative and the polyamino compound are dissolved in a pH 4-10 buffer (preferably a pH 4-10 phosphate or borate buffer), and then the two components are mixed to obtain the hydrogel. The two components of the hydrogel can be stored in a double-barreled syringe, and when used, the two components are sprayed or injected into the designated site through a mixing head to form a gel.

[0030] Another object of the present application is to provide the use of the iodinated star-shaped multi-arm polyethylene glycol derivative or the hydrogel in the preparation of a tissue filler, a tissue anti-adhesion agent, a tissue engineering scaffold, a sealing agent or an embolization agent. It can be used for vascular embolization, radiotherapy isolation protection, drug delivery, wound sealing, tissue anti-adhesion, tissue engineering and medical plastic surgery.

[0031] Advantages of the present application:

[0032] The present application provides a long-term self-developing injectable polyethylene glycol hydrogel, in which iodine reagents are covalently partially substituted on the end groups of polyethylene glycol, and the remaining aldehyde groups are reacted with polyamino compounds to form a gel. The gel has a fast gelation time and good stability. Compared with the traditional method of physically wrapping iodine contrast agents in hydrogels, since the iodine reagents are covalently connected to the hydrogel, the developed gel can maintain the developing effect for a long time in the body, which is convenient for long-term observation of the position and state of the hydrogel in the body by X-ray. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The nuclear magnetic resonance spectrum of the iodinated star-shaped multi-arm polyethylene glycol derivative product 6 is as follows: 1 H, CDCl3).

[0034] Figure 2CT imaging results of the iodinated hydrogel at different time points after subcutaneous implantation in rats.

[0035] Figure 3 CT imaging intensity of the iodinated hydrogel at different time points after subcutaneous implantation in rats. DETAILED DESCRIPTION

[0036] The present application will be further described in detail by specific examples and with reference to the data, it should be understood that these examples are only for the purpose of illustrating the present application, and are not intended to limit the scope of the present application in any way.

[0037] The terms used in the present application have the meanings generally understood by those of ordinary skill in the art, unless otherwise specified. In the following examples, various processes and methods not described in detail are conventional methods known in the art.

[0038] Example 1 Preparation of iodinated star-shaped multi-arm polyethylene glycol derivative

[0039] (1) 10 g of hydroxyl-terminated multi-arm polyethylene glycol was dissolved in 100 ml of dichloromethane with a certain amount of iodinating agent 2,3,5-triiodobenzoic acid (see Table 1 for specific dosage), DCC (2 times the molar amount of iodinating agent) and DMAP (the same molar amount as the iodinating agent) were added to promote esterification, the reaction was carried out at room temperature for 48 hours, and after the reaction was completed, the next step was directly carried out without treatment;

[0040] (2) Excess p-carboxybenzaldehyde was added to the solution obtained in step (1), and excess DCC and DMAP were also added, and the reaction was carried out at room temperature for 48 hours. After the reaction was completed, the product was obtained by precipitation with ether 6 times.

[0041] Table 1 Types of polyethylene glycol used in the reaction and the ratio of iodinating agent to polyethylene glycol

[0042] Polyethylene glycol species 2,3,5-Triiodobenzoic acid to polyethylene glycol hydroxyl feed molar ratio Derivative 1 8 arms, 10 kDa 2:1 Derivative 2 8 arms, 10 kDa 3:1 Derivative 3 8 arms, 15 kDa 2:1 Derivative 4 8 arms, 15 kDa 3:1 Derivative 5 8 arms, 15 kDa 4:1 Derivative 6 8 arms, 20 kDa 1.5:1 Derivative 7 8 arms, 20 kDa 2:1 Derivative 8 8 arms, 20 kDa 3:1

[0043] The NMR data of the derivative are as follows:

[0044] Derivative 1: 1 H NMR, CDC13, δ ppm 3.26-3.90 (2H, -CH2-CH2-O in PEG chain), 4.47-4.52 (2H, -CH2-COO- end group), 7.76 (1H, benzene ring on triiodobenzene), 7.95-7.98 (2H, benzene ring on benzaldehyde group), 8.21-8.23 (2H, benzene ring on benzaldehyde group), 8.30 (1H, benzene ring on triiodobenzene), 10.11 (1H, -CHO).

[0045] Derivative 2: 1H NMR, CDC13, δ ppm 3.26-3.89 (2H, PEG chain methyl-CH2-CH2-0), 4.47-4.53 (2H, -CH2-COO- end group), 7.76 (1H, benzene ring on triiodobenzene) 7.95-7.97 (2H, benzene ring on benzaldehyde group), 8.21-8.23 (2H, benzene ring on benzaldehyde group), 8.30 (1H, benzene ring on triiodobenzene), 10.11 (1H, -CHO).

[0046] Derivative 3: 1 H NMR, CDC13, δ ppm 3.26-3.89 (2H, PEG chain methyl-CH2-CH2-0), 4.47-4.53 (2H, -CH2-COO- end group), 7.76 (1H, benzene ring on triiodobenzene) 7.95-7.97 (2H, benzene ring on benzaldehyde group), 8.21-8.23 (2H, benzene ring on benzaldehyde group), 8.30 (1H, benzene ring on triiodobenzene), 10.11 (1H, -CHO).

[0047] Derivative 4: 1 H NMR, CDC13, δ ppm 3.26-3.89 (2H, PEG chain methyl-CH2-CH2-0), 4.47-4.53 (2H, -CH2-COO- end group), 7.76 (1H, benzene ring on triiodobenzene) 7.95-7.97 (2H, benzene ring on benzaldehyde group), 8.21-8.23 (2H, benzene ring on benzaldehyde group), 8.30 (1H, benzene ring on triiodobenzene), 10.11 (1H, -CHO).

[0048] Derivative 5: 1 H NMR, CDC13, δ ppm 3.26-3.89 (2H, PEG chain methyl-CH2-CH2-0), 4.47-4.53 (2H, -CH2-COO- end group), 7.76 (1H, benzene ring on triiodobenzene) 7.95-7.97 (2H, benzene ring on benzaldehyde group), 8.21-8.23 (2H, benzene ring on benzaldehyde group), 8.30 (1H, benzene ring on triiodobenzene), 10.11 (1H, -CHO).

[0049] Derivative 6: 1 H NMR, CDC13, δ ppm 3.26-3.89 (2H, PEG chain methyl-CH2-CH2-0), 4.47-4.53 (2H, -CH2-COO- end group), 7.76 (1H, benzene ring on triiodobenzene) 7.95-7.97 (2H, benzene ring on benzaldehyde group), 8.21-8.23 (2H, benzene ring on benzaldehyde group), 8.30 (1H, benzene ring on triiodobenzene), 10.11 (1H, -CHO).

[0050] Derivative 7: 1 H NMR, CDC13, δ ppm 3.27-3.88 (2H, PEG chain methyl-CH2-CH2-O), 4.47-4.52 (2H, -CH2-COO- end group), 7.76 (1H, benzene ring on 2,3,5-triiodobenzoyl) 7.95-7.97 (2H, benzene ring on benzaldehyde group), 8.21-8.23 (2H, benzene ring on benzaldehyde group), 8.30 (1H, benzene ring on 2,3,5-triiodobenzoyl), 10.11 (1H, -CHO).

[0051] Derivative 8: 1 H NMR, CDC13, δ ppm 3.27-3.88 (2H, PEG chain methyl-CH2-CH2-O), 4.47-4.52 (2H, -CH2-COO- end group), 7.76 (1H, benzene ring on 2,3,5-triiodobenzoyl) 7.95-7.97 (2H, benzene ring on benzaldehyde group), 8.21-8.23 (2H, benzene ring on benzaldehyde group), 8.30 (1H, benzene ring on 2,3,5-triiodobenzoyl), 10.11 (1H, -CHO).

[0052] The molar ratio of 2,3,5-triiodobenzoyl and benzaldehyde groups in the derivative is calculated by taking the NMR spectrum of derivative 6 as an example. A typical NMR spectrum (H) is shown in FIG. 1, where peak a represents the aldehyde hydrogen (-CHO) on the benzaldehyde group, peak b represents the methylene peak (-CH2) on the polyethylene glycol chain, and peak c represents the hydrogen on the benzene ring within the 2,3,5-triiodobenzoyl substituent. 1 H) as shown in FIG. 1, where peak a represents the aldehyde hydrogen (-CHO) on the benzaldehyde group, peak b represents the methylene peak (-CH2) on the polyethylene glycol chain, and peak c represents the hydrogen on the benzene ring within the 2,3,5-triiodobenzoyl substituent. Figure 1

[0053] By calculating the areas of peaks a, b, and c and their ratios, the number of 2,3,5-triiodobenzoyl and benzaldehyde substituents in individual polyethylene glycol molecules in different products can be obtained.

[0054] Derivative 1: about 1.7 2,3,5-triiodobenzoyl groups and about 5.6 benzaldehyde groups.

[0055] Derivative 2: about 2.5 2,3,5-triiodobenzoyl groups and about 4.9 benzaldehyde groups.

[0056] Derivative 3: about 1.6 2,3,5-triiodobenzoyl groups and about 5.8 benzaldehyde groups.

[0057] Derivative 4: about 2.4 2,3,5-triiodobenzoyl groups and about 4.8 benzaldehyde groups.

[0058] Derivative 5: about 3.3 2,3,5-triiodobenzoyl groups and about 4.1 benzaldehyde groups.

[0059] ​Derivative 6: 2,3,5-triiodobenzoyl about 1.2, benzaldehyde group about 6.4.

[0060] Derivative 7: 2,3,5-triiodobenzoyl about 1.6, benzaldehyde group about 5.5.

[0061] Derivative 8: 2,3,5-triiodobenzoyl about 2.5, benzaldehyde group about 4.8.

[0062] By changing the type of polyethylene glycol, the type of iodinating agent and the relative mass, different iodine-substituted polyethylene glycol aldehyde derivatives can be obtained. Experimental results show that by controlling the feeding ratio of the iodinating agent, the number of substitutions of the iodinating agent can be accurately controlled.

[0063] Example 2 Gelation performance test of iodinated polyethylene glycol derivatives

[0064] The different iodinated polyethylene glycol derivatives prepared in Example 1 were dissolved in phosphate buffer with a pH of 5.6 to prepare a solution with a concentration of 20% (w / v) as solution A. A borate buffer (pH 9.2) solution containing polylysine and polyethyleneimine (M.W. 1.8K) was prepared as solution B, in which the molar ratio of the amino groups in polylysine and polyethyleneimine to the aldehyde groups in polyethylene glycol was 1.5:1:1. Solution A and solution B were mixed by equal volume through a double syringe injector and injected to obtain iodinated hydrogels 1-8, and the time required for the solution to be converted into a gel was recorded as the gelation time of the gel.

[0065] Table 2 Gelation time of iodinated polyethylene glycol derivatives

[0066] Number of iodine reagent in individual polyethylene glycol molecules in derivatives Gelation time (seconds) Iodinated hydrogel 1 1.7 5 Iodinated hydrogel 2 2.5 7 Iodinated hydrogel 3 1.6 8 Iodinated hydrogel 4 2.4 14 Iodinated hydrogel 5 3.3 20 Iodinated hydrogel 6 1.2 10 Iodinated hydrogel 7 1.6 13 Iodinated hydrogel 8 2.5 25

[0067] Experimental results show that iodinated polyethylene glycol aldehyde derivatives can form a gel with a polyamino compound, and the gelation time is prolonged as the number of iodinating agents increases; under the same number of iodinating agents, the smaller the molecular weight of polyethylene glycol, the faster the gelation speed of the derivative.

[0068] Example 3 In vitro X-ray imaging effect of iodinated polyethylene glycol gel

[0069] Referring to step (2) of Example 1 and Example 2, a blank polyethylene glycol gel (8 arms, 20 kDa, no iodination, all benzaldehyde group substitution, gel 9) was prepared, and the gel 9 was physically wrapped with iohexyl, and the iodine concentration of the iohexyl developer in the gel was 0.6% (W / V) to prepare the developed gel 10. The developed intensity of the above gel after formation and the gel soaked in PBS at 37 degrees for one week was tested under CT respectively.

[0070] Table 3 Developed intensity of different gels after formation and the gel soaked in PBS at 37 degrees for one week

[0071]

[0072] The experimental results show that the iodine-substituted polyethylene glycol gel has higher CT developing intensity than the blank gel, and the developing intensity increases with the increase of the number of iodine substitutions; compared with the developing gel wrapped with iohexol, the iodine-substituted gel does not have obvious attenuation of developing intensity after being soaked in vitro for one week, while the developing intensity of the iohexol hydrogel attenuates to the developing level of the blank gel after one week.

[0073] Example 4 In-vivo X-ray developing effect of iodine-substituted polyethylene glycol gel

[0074] The iodine-substituted hydrogel 4 was implanted into the back of a rat subcutaneously, and CT developing test was performed immediately after the implantation, and then CT developing test was performed after 9 days and 15 days of implantation. The results are shown in Figure 2 The developing results show that obvious CT developing can still be observed after 9 days and 15 days of implantation.

[0075] The CT developing of the iodine-substituted hydrogel 4 was quantitatively tested, and the in-vivo developing value of the gel was obtained. The long-term developing intensity change in the body is shown in Figure 3 The results show that the iodine-substituted hydrogel has long-term stable developing intensity in the body.

Claims

1. An iodinated star-shaped multi-arm polyethylene glycol derivative, characterized in that... at least one arm of said star-shaped multi-armed polyethylene glycol is capped with an aldehyde group -(X)-(Y)-CHO and at least one arm is capped with an iodine-substituted phenyl group -(X)-(Y)-CHO is selected from , or -(X)-(Y)-CHO is selected from , , , , , , , the molar ratio of aldehyde group to iodine-substituted phenyl group is 1:7 to 5:3, and the molecular weight of said star-shaped multi-armed polyethylene glycol is 10 kDa, 15 kDa or 20 kDa.

2. The iodinated starburst polyethylene glycol derivative of claim 1, wherein The starburst polyethylene glycol has 4-8 arms.

3. The iodinated starburst polyethylene glycol derivative of claim 1, wherein has the following structure: ， ； wherein one or more of R1to R3in Formula I, one or more of R1to R5in Formula II, one or more of R1to R7in Formula III is and the remaining substituents in Formula I, Formula II, or Formula III are -(X)-(Y)-CHO.

4. The iodinated starburst polyethylene glycol derivative of claim 3, wherein two or more of the groups -(X)-(Y)-CHO in Formula I, Formula II, or Formula III are the same or different. two or more of the groups -(X)-(Y)-CHO in Formula I, Formula II, or Formula III are the same or different.

5. The iodinated starburst PEG derivative of claim 1, wherein The molar ratio of aldehyde groups to iodine-substituted phenyl groups is 2:6-4:

4.

6. An iodinated hydrogel, characterized in that The iodinated starburst polyethylene glycol derivative of any one of claims 1-5 is crosslinked with one or more of a polyamino compound and / or a polyhydrazide compound.

7. Use of the iodinated starburst polyethylene glycol derivative of any one of claims 1-5 or the hydrogel of claim 6 for the preparation of a tissue filler, a tissue anti-adhesion agent, a tissue engineering scaffold, a sealant, or an embolization agent.

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