CN112225912A

CN112225912A - Degradable medical hydrogel

Info

Publication number: CN112225912A
Application number: CN202011119562.XA
Authority: CN
Inventors: 潘震; 陈亮; 候森
Original assignee: Shanghai Ruining Biotechnology Co ltd
Current assignee: Shanghai Ruining Biotechnology Co ltd
Priority date: 2020-10-19
Filing date: 2020-10-19
Publication date: 2021-01-15
Anticipated expiration: 2040-10-19
Also published as: CN112225912B

Abstract

The invention discloses a medical hydrogel which is formed by in-situ crosslinking of aldehyde-terminated star-shaped multi-arm polyethylene glycol and a polyamino compound, wherein the aldehyde group is connected with the star-shaped multi-arm polyethylene glycol through ester bonds, the number of arms of the aldehyde-terminated star-shaped multi-arm polyethylene glycol is 2-8, and the single-arm molecular weight is 1000-5000 Da. The hydrogel with short-term degradability is obtained by selecting the aldehyde-terminated star-shaped multi-arm polyethylene glycol connected by ester bonds between aldehyde groups and the star-shaped multi-arm polyethylene glycol, wherein the star-shaped multi-arm polyethylene glycol has a specific arm number and a molecular weight range.

Description

Degradable medical hydrogel

Technical Field

The invention belongs to the technical field of biomedicine, and particularly relates to medical hydrogel which can be used as a radiation protection material for fields such as radiotherapy gaskets, postoperative tissue sealing and leakage prevention, tissue adhesion prevention, tissue filling agents, tissue repair, skin dressing, drug release and the like.

Background

The hydrogel is a soft material containing a large amount of moisture, which is obtained by crosslinking a hydrophilic polymer. The hydrogel has excellent physical and chemical properties and biological characteristics, such as high water content, high elasticity, softness, biocompatibility and the like, and has important application value in the biomedical research fields of drug delivery, tissue engineering and the like. Injectable hydrogels are hydrogels having a certain fluidity, which can be applied by an injection method, exhibit phase transition between sol and gel for external stimuli (changes in temperature, temperature/pH, etc.), are in a liquid state or a semi-solid state having shear thinning properties before being injected into a human body, and can form gel in situ after being injected into the human body, thereby eliminating the need for invasive surgery, effectively avoiding the risk of infection, and reducing the pain of patients. Various injectable PEG hydrogels that have been developed so far include amphiphilic polyester/polypeptide hydrogels in which PEG is a hydrophilic segment, PEG hydrogels prepared by supramolecular interaction, and PEG hydrogels prepared by mild chemical reactions.

Polyethylene glycol (PEG) is a class of nonionic polymers, and is a class of synthetic polymers approved by the U.S. Food and Drug Administration (FDA) for clinical applications in humans due to its good biocompatibility and safety. The PEG can be used as a pharmaceutic adjuvant, and can also be used for modifying (pegylating) the medicine by using the PEG containing the terminal active functional group. The pegylation technology has more advantages, and particularly has the characteristics of prolonging the in vivo circulation time, enhancing the biological activity, avoiding proteolysis and reducing the immune response in the aspect of modifying protein and polypeptide medicaments. Polyethylene glycol conjugates can be prepared by attaching reactive terminal functional groups such as amino, thiol, azide, alkynyl, and aldehyde groups to improve the performance of polyethylene glycol.

The PEG hydrogel is one of ideal materials for tumor radiotherapy gaskets and postoperative tissue sealing, leakage prevention and the like. After the treatment effect is completed for a certain time, the hydrogel needs to be degraded in vivo, otherwise, the long-term existence in vivo can cause unnecessary side effects. The cycles of different treatments usually differ widely, and therefore the degradation time of the hydrogel system needs to be adapted to the requirements of different applications.

CN105963792A discloses a medical hydrogel composition, comprising a first component and a second component, wherein the first component comprises polylysine and polyethyleneimine; the second component comprises one or more of four-arm-polyethylene glycol-succinimide glutarate, four-arm-polyethylene glycol-succinimide succinate and four-arm-polyethylene glycol-succinimide carbonate. When the gel is used, the nucleophilic reagent (polylysine and polyethyleneimine) of the first component and the electrophilic reagent (one or more of four-arm-polyethylene glycol-succinimide glutarate, four-arm-polyethylene glycol-succinimide succinate and four-arm-polyethylene glycol-succinimide carbonate) of the second component are subjected to Michael addition reaction, so that the gel can be rapidly formed and has the excellent property of low swelling. However, the succinimide organic acid ester-terminated polyethylene glycol material has a short half-life in water, is very easily hydrolyzed, requires a special technique to be stored in a powder form at room temperature for a long period of time, and is used within a short time (generally 1 hour) after dissolution, and is low in convenience.

The inventor's early research (CN109939065A) disclosed a medical hydrogel, which was formed by in-situ crosslinking of aldehyde-terminated star-shaped multi-armed polyethylene glycol and a polyamino compound, wherein the aldehyde and the star-shaped multi-armed polyethylene glycol are connected by ether bond, amido bond, urethane bond, imine bond or urea bond. The invention utilizes the aldehyde group at the end of the multi-arm polyethylene glycol to react with the amino group of the multi-amino compound to generate schiff base so as to generate crosslinking and form the medical injectable gel. The prepared gel has short gelling time, ideal gel bursting strength and good stability in aqueous solution. The long-term stability of the benzaldehyde-terminated polyethylene glycol connected by ether bond, amide bond and ester bond in aqueous solution was studied in this patent application. 400mg of each of ether bond linkage, amide bond linkage and ester bond linkage benzaldehyde group-terminated 8-arm polyethylene glycol (M.W.10K) was dissolved in 2mL of 0.1M borate buffer solution (pH9.2) as solution A; preparing a phosphate buffer solution containing 1.48% (w/v) of polyethyleneimine (M.W.1.8K) as a solution B; equal volume mixing of A, B solution resulted in a viscous hydrogel with initial gel formation times of 25 seconds, 2 seconds, and 5 seconds, respectively. And (3) placing the three solutions A in an oven at 37 ℃ for 1, 2, 4, 16, 24 and 40 hours, and then respectively measuring the change of the gelling time after mixing with the solution B and the initial gelling time. The results show that the ester-linked polyethylene glycol loses the gelling ability after 40 hours, while the ether-linked and amide-linked benzoyl-terminated 8-arm polyethylene glycol gelling time remains essentially unchanged.

Further research (CN109646723A) of the inventor of the application discloses a medical hydrogel, and on the basis of the previous research, the molar ratio of amino groups in a polyamino compound to aldehyde groups in aldehyde-terminated star-shaped multi-arm polyethylene glycol is limited to be 0.4-4.4: 1, the polyamino compound is polylysine or a mixture of polylysine and polyethyleneimine, and the molar ratio of polylysine to polyethyleneimine is 2-30: 3. The hydrogel has the advantages of quick gelling, long-term stability in aqueous solution, and good swelling performance and stability after multiple irradiation.

However, the chemical bond (ether bond, amido bond, urethane bond, imine bond or urea bond) between the aldehyde group and the star-shaped multi-arm polyethylene glycol in the hydrogel is difficult to degrade, and the hydrogel has a long stabilization period (more than two years) in an aqueous solution, so that the requirement of different occasions on the degradation time of the hydrogel cannot be met. For example, in hydrogel sealants, the degradation time is typically several days to 6 months, and radiation protective hydrogels are typically 3 to 12 months. The hydrogel in the prior art cannot meet the requirement of short-term degradability.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a degradable medical hydrogel, and all components of the hydrogel have long-term stability in aqueous solution through the regulation of a specific aqueous solution system.

The specific technical scheme of the invention is as follows:

the medical hydrogel is formed by in-situ crosslinking of star-shaped multi-arm polyethylene glycol terminated by aldehyde groups and a polyamino compound, wherein the aldehyde groups are connected with the star-shaped multi-arm polyethylene glycol through ester bond chemical bonds, the number of arms of the aldehyde-terminated multi-arm polyethylene glycol is 2-8, and the single-arm molecular weight is 1000-5000 Da.

The number of arms of the aldehyde-terminated multi-arm polyethylene glycol is preferably 4 to 8.

The aldehyde group is selected from one or more of aromatic aldehyde and alkyl aldehyde, and is preferably a benzaldehyde group.

The molar ratio of amino groups in the polyamino compound to aldehyde groups in the aldehyde group-terminated star-shaped multi-arm polyethylene glycol is 0.4-4.4: 1, the polyamino compound is polylysine or a mixture of polylysine and polyethyleneimine, and the molar ratio of polylysine to polyethyleneimine is 2-30: 3.

The aldehyde-terminated star-shaped multi-arm polyethylene glycol is stored for a long time in a dry powder or solution form, and the pH of the solution is 4-6.

The invention also aims to provide the medical hydrogel which can be used for preparing radiotherapy gaskets, postoperative tissue sealing and leakage prevention, tissue adhesion prevention, tissue fillers, tissue repair, skin dressings and medicinal preparations.

The preparation method of the medical hydrogel comprises the steps of dissolving the aldehyde-terminated star-shaped multi-arm polyethylene glycol in a pH4-6 buffer solution to prepare an aldehyde-terminated star-shaped multi-arm polyethylene glycol solution; dissolving a polyamino compound in a buffer solution with the pH value of 4-10 to prepare a polyamino compound solution; mixing the two to obtain the medical hydrogel.

The above buffer solution of pH4-10 is preferably phosphate or borate buffer solution of pH 4-10.

The final concentration of the aldehyde-terminated star-shaped multi-arm polyethylene glycol solution is 2-30% (w/v), preferably 10-20% (w/v); the concentration of the polyamino compound solution is 0.5-20%, preferably 1-5% (w/v).

The two-component hydrogel is prepared in a specific application, and comprises a first component containing a nucleophilic functional group and a second component containing an electrophilic functional group, wherein the first component is an aldehyde-terminated hydrophilic compound, the number of arms is not less than two, the hydrophilic compound is aldehyde-terminated star-shaped multi-arm polyethylene glycol, preferably 8-arm, 6-arm and 4-arm polyethylene glycol (single-arm molecular weight is 1000-plus 5000Da), and the aldehyde group is one or more of aromatic aldehyde and alkyl aldehyde, preferably benzaldehyde. The aldehyde group and the polymer may be connected by a chemical bond capable of hydrolysis such as an ester bond.

The second component can be selected from compounds containing polyamino groups, including polylysine (including epsilon-polylysine and polylysine) and one or more of polyethyleneimine.

Both of the above components may be provided in the form of an aqueous solution or powder due to the stability of the aldehyde group and the amino group in the aqueous solution. When in use, the two components are respectively dissolved in the buffer solution, and then the components are mixed to obtain the hydrogel. The two components of the hydrogel can be stored in a double syringe respectively, and the two components are sprayed out through a mixing head or injected to a designated position to form gel when in use.

The invention utilizes the aldehyde group at the end of the multi-arm polyethylene glycol to react with the amino group of the multi-amino compound to generate schiff base so as to generate crosslinking and form the medical injectable gel.

The invention has the advantages that:

the invention provides medical hydrogel with good degradability compared with the prior art.

The invention obtains the hydrogel which can be degraded in a short time by selecting the star-shaped multi-arm polyethylene glycol with the end capped by aldehyde group connected with the star-shaped multi-arm polyethylene glycol through ester bond, wherein the star-shaped multi-arm polyethylene glycol has specific arm number and molecular weight range. In the prior art, the degradation time of aldehyde polyethylene glycol hydrogel connected by amide bonds and other bonds which are not easy to hydrolyze is more than 2 years, and the hydrogel can be degraded within several days to 1 year by adjusting the arm number and the molecular weight of the star-shaped multi-arm polyethylene glycol.

Drawings

FIG. 1 shows the degradation of the abdominal cavity of a rat with aldehyde-terminated polyethylene glycol hydrogel connected by ester bond. Wherein A and D are the forms of the hydrogel after being implanted for one week, B and E are the forms of the hydrogel after being implanted for 3 months, and C and F are the forms of the hydrogel after being implanted for 8 months.

Detailed Description

The following examples illustrate specific steps of the present invention, but are not intended to limit the invention.

Terms used in the present invention generally have meanings commonly understood by those of ordinary skill in the art, unless otherwise specified.

The invention is described in further detail below with reference to specific examples and data, it being understood that these examples are intended to illustrate the invention and are not intended to limit the scope of the invention in any way.

In the following examples, various procedures and methods not described in detail are conventional methods well known in the art.

The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto.

EXAMPLE 1 stability of differently formulated hydrogels in aqueous solution

1. Investigating the degradation time of different types of benzaldehyde-terminated multi-arm polyethylene glycol

400mg of various types of benzaldehyde-terminated multi-arm polyethylene glycol was dissolved in 2mL of phosphate buffer (ph5.6) as a solution a; preparing a borax buffer solution (pH9.2) containing polylysine (the molar ratio of amino to benzaldehyde is 1: 1) and polyethyleneimine (M.W.1.8K) (the molar ratio of amino to benzaldehyde is 0.4: 1) as a solution B; and mixing the A, B solution in equal volume to obtain the hydrogel with viscosity.

The result shows that the aldehyde connecting bond of the aldehyde-terminated polyethylene glycol obviously influences the stability of the hydrogel in the aqueous solution, when the connecting bond is a chemical bond which is not easy to hydrolyze, such as ether bond or amido bond, the stability of the hydrogel is more than 2 years, and when the ester bond is used as the connecting bond, the degradation time of the hydrogel is between 1 and 12 months; when ester bonds are connecting bonds, the hydrogel is degraded slowly when the number of the arms of the polyethylene glycol is larger, and the hydrogel is degraded slowly when the molecular weight of the single arm of the polyethylene glycol is lower.

2. Taking the aldehyde-terminated star-shaped multi-arm polyethylene glycol with 8 arms and a single-arm molecular weight of 1250 as an example, the influence of the molar ratio of the amino in the amino compound to the aldehyde in the aldehyde-terminated star-shaped multi-arm polyethylene glycol and the molar ratio of polylysine to polyethyleneimine on the degradation time of the hydrogel is examined

Dissolving 400mg of 8-arm, single-arm, 1250Da molecular weight aldehyde-terminated star-shaped multi-arm polyethylene glycol in 2mL of phosphate buffer (pH5.6) to obtain solution A; preparing borax buffer solution (pH9.2) solutions of polylysine and polyethyleneimine (M.W.1.8K) with different contents as a solution B; and mixing the A, B solution in equal volume to obtain the hydrogel with viscosity.

The result shows that the degradation time of the hydrogel is not greatly influenced by the molar ratio of the amino in the polyamino compound to the aldehyde group in the aldehyde-terminated star-shaped multi-arm polyethylene glycol of 0.4-4.4: 1 and the molar ratio of the polylysine to the polyethyleneimine of 2-30: 3.

Example 2

Referring to formulation 5 in example 1, 400mg of each of the carboxaldehyde group-terminated 8-arm polyethylene glycol 8-PEG-ester-BA (one-arm molecular weight of 1250Da) was dissolved in 2mL of a phosphate buffer (pH7.4), a phosphate buffer (pH6.0), a phosphate-phosphate buffer (pH5.0), a phosphate-phosphate buffer (pH4.0), a phosphate-phosphate buffer (pH3.0), and a phosphate-phosphate buffer (pH2.5) as solutions A; placing the solution A in a 60-DEG oven to test the stability of the solution in an accelerated aging mode, taking out the solution at different time points, and preparing a borax buffer solution (pH9.2) containing 2.75% (w/v) of polylysine (the molar ratio of amino to aldehyde is 1: 1) and 0.67% (w/v) of polyethyleneimine (M.W.1.8K) (the molar ratio of amino to aldehyde is 0.4: 1) as a solution B; the solution A, B was mixed in equal volume and tested for gelling properties (gelling time).

The experimental results show that when the pH of the solution A is between 4 and 6, the gelling time is kept unchanged after aging for 26 days (equivalent to one year of storage at room temperature), and the solution stability is higher. When the content is less than or equal to 3 or more than or equal to 7.4, the aging can obviously influence the gelling time, and the solution stability is poor.

Example 3

600mg of carbowax 8-PEG-ester-BA (single-arm molecular weight 1250Da) with an ester bond connected benzaldehyde end cap and 8 arms is dissolved in 2mL of phosphate buffer solution (pH5.6) to be used as solution A; preparing a 0.075M borax buffer solution (pH9.2) of polylysine 4.12% (w/v) (the molar ratio of amino to aldehyde is 1: 1) and polyethyleneimine (M.W.1.8K) 1% (w/v) (the molar ratio of amino to aldehyde is 0.4: 1) as a B solution; and mixing the A, B solution in equal volume to obtain the viscous hydrogel, wherein the gelling time is 13 seconds, and the in vitro degradation time is about 10 months.

Example 4

The hydrogel of formulation 5 of example 1 was implanted into the abdominal cavity of rats and the degradation of the hydrogel in the animals was observed. The hydrogel remained substantially unchanged in morphology at 1 week (FIG. 1A, D) and 3 months (FIG. 1B, E); at 8 months (fig. 1C, F) the volume decreased significantly, with significant degradation; complete absorption at 11 months, no hydrogel could be found in the animals. The experimental result shows that the hydrogel of the formula has the degradation in vivo equivalent to that under in vitro conditions and can be completely absorbed in vivo within 11 months.

Claims

1. The medical hydrogel is formed by in-situ crosslinking of aldehyde-terminated star-shaped multi-arm polyethylene glycol and a polyamino compound, and is characterized in that the aldehyde group is connected with the star-shaped multi-arm polyethylene glycol through ester bonds, the number of arms of the aldehyde-terminated star-shaped multi-arm polyethylene glycol is 2-8, and the single-arm molecular weight is 1000-5000 Da.

2. The medical hydrogel according to claim 1, wherein the number of arms of said aldehyde-terminated star-shaped multi-arm polyethylene glycol is 4 to 8.

3. The medical hydrogel according to claim 1, wherein the aldehyde group is selected from one or more of aromatic aldehyde and alkyl aldehyde.

4. The medical hydrogel according to claim 1, wherein the molar ratio of the amino groups in the polyamino compound to the aldehyde groups in the aldehyde-terminated star-shaped multi-arm polyethylene glycol is 0.4-4.4: 1, the polyamino compound is polylysine or a mixture of polylysine and polyethyleneimine, and the molar ratio of polylysine to polyethyleneimine is 2-30: 3.

5. Use of a medical hydrogel according to any one of claims 1 to 4 for the preparation of a radioprotective material.

6. The method for preparing the medical hydrogel according to any one of claims 1 to 4, wherein the aldehyde-terminated star-shaped multi-arm polyethylene glycol is dissolved in a pH4-6 buffer solution to prepare an aldehyde-terminated star-shaped multi-arm polyethylene glycol solution; dissolving a polyamino compound in a buffer solution with the pH value of 4-10 to prepare a polyamino compound solution; mixing the two to obtain the medical hydrogel.

7. The method for preparing medical hydrogel according to claim 6, wherein the final concentration of the aldehyde-terminated star-shaped multi-arm polyethylene glycol solution is 2-30%, w/v, and the concentration of the polyamino compound solution is 0.5-20%, w/v.

8. The preparation method of the medical hydrogel according to claim 7, wherein the final concentration of the aldehyde-terminated star-shaped multi-arm polyethylene glycol solution is 10-20% w/v, and the concentration of the polyamino compound solution is 1-5% w/v.