Thixotropic micromolecular gel, preparation method and application thereof

Abstract

The invention provides thixotropic small-molecule gel as well as a preparation method and application thereof, and belongs to the technical field of gel drug carriers. The micromolecular gel provided by the invention is formed by self-assembly of a gelator in a solvent. The used gelator is an amphiphilic small molecule composed of a dipeptide sequence with an aromatic ring structure and a hydrophobic alkyl chain. The micromolecular gel formed by the gelator has thixotropic property, the recovery rate of the micromolecular gel can reach 96% at most, and the minimum gelator concentration required for forming stable gel is not higher than 0.2%. Meanwhile, the gel can be used as an injectable gel carrier of an anti-cancer drug, and the pH stimulation response controllable slow release of the anti-cancer drug is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of gel drug carriers and relates to a thixotropic small molecule gel, a preparation method and application thereof. Background Art

[0002] Small molecule gels are a type of three-dimensional network structure formed by self-assembly through non-covalent interactions such as hydrogen bonds, π-π stacking, hydrophobic interactions, and van der Waals forces to capture solvent molecules. Compared with polymer gels, this type of gel has attracted the attention of more and more researchers in various fields due to its advantages such as easy-to-modify structure, sensitive stimulus response characteristics, and reversibility. Peptide-based small molecule gels have good biocompatibility and biodegradability, and have been widely used in biomedical fields such as cell culture, drug delivery, and tissue repair. Thixotropic gels are a very advantageous type of gel among small molecule gels, and their demand in many fields such as drug delivery is extremely urgent. The toxic and side effects of anticancer drugs have always been a major factor threatening the lives of anticancer patients. Injectable gel drug delivery carriers can directly inject drugs into the lesion site to achieve targeted release and reduce the toxic and side effects of drugs.

[0003] However, due to the complexity of the self-assembly process and its mechanism research, the thixotropy of small molecule gels is an advantageous property that is hard to come by. Designing thixotropic gels with target application scenarios is still a major challenge hindering the application of small molecule gels.

[0004] Therefore, a method for simply and conveniently synthesizing thixotropic small molecule gels is needed to solve the above technical problems. Summary of the invention

[0005] The thixotropic small molecule gel of the present invention is formed by self-assembly of a gel factor in a solvent. The gel factor structure used is composed of a hydrophobic alkyl chain and a hydrophilic dipeptide sequence. The gel factor can form a small molecule gel with thixotropy, providing a reference for the design of thixotropic small molecule gel from the perspective of molecular structure design. At the same time, as a thixotropic gel material, it realizes the loading of anticancer drugs to form an injectable drug-loaded gel, providing a reference for the research in the field of injectable gel drug delivery.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a thixotropic small molecule gel is formed by self-assembly of a small molecule gel factor in a solvent. The small molecule gel factor used has a structure shown in formula (I):

[0007]

[0008] In formula (I), x=8-18, y=1-5,

[0009] In formula (I), R includes:

[0010]

[0011] Preferably, the small molecule gel factor is synthesized by a liquid phase amide condensation method, and the synthesis method comprises the following steps:

[0012] Tryptophan or phenylalanine or tyrosine, glycine or alanine or aminobutyric acid or aminovaleric acid or aminocaproic acid, alkylamine, condensation reagent, additive and organic solvent are mixed to carry out amide condensation reaction, and the final product obtained is a small molecule gel factor.

[0013] The structural compound of the alkylamine has a structure shown in formula (V):

[0014] Wherein x=8-18.

[0015] Preferably, the condensation reagents in the step include: dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), onium salts, organophosphorus, s-triazine derivatives, carbonyldiimidazoles. The additives include: N-hydroxy-7-azabenzotriazole HOAt, 1-hydroxybenzotriazole HOBt, 4-dimethylaminopyridine DMAP, N-hydroxysuccinimide HOSu, 1H,1H-pentafluoropropanol PfpOH; the solvents include: N,N-dimethylformamide DMF, dichloromethane DCM, tetrahydrofuran THF, acetonitrile.

[0016] Preferably, in the step, amino acid (tryptophan or phenylalanine or tyrosine or glycine or alanine or aminobutyric acid or aminovaleric acid or aminocaproic acid): condensing agent or additive: amine (H 2 N-(CH 2 ) x-1 CH 3 ) is 1:0.8~1.2:1.5~2.5, where the value range of x is 8~18.

[0017] Preferably, in the step, the amide condensation reaction temperature is 0-60°C.

[0018] Preferably, when preparing the thixotropic small molecule gel, the final product gel factor is dissolved in a solvent to form a gel after self-assembly.

[0019] More preferably, the solvent includes: water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), methanol, ethanol, acetone, benzene, toluene, xylene and any two or more of the above solvents mixed in any proportion.

[0020] More preferably, the concentration of the gel factor used is greater than or equal to 0.2% w / v.

[0021] The present invention also discloses an application of a thixotropic small molecule gel, which uses the thixotropic small molecule gel as a carrier of active drugs, and can successfully load drugs for treating various diseases such as cardiovascular and cerebrovascular diseases, cancer, hypertension, diabetes, inflammation, neurological diseases, etc. The active drug preparation can be directly delivered to the lesion site by a syringe, and released in response to the pH stimulation of the cell microenvironment at the lesion site, thereby achieving targeted and controllable release of the drug and reducing the toxic and side effects of the drug. The thixotropic small molecule gel can also be used in the construction of a cell culture environment or the preparation of tissue engineering products.

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention synthesizes a series of gel factors through a simple and easy-to-operate liquid phase amide condensation method. The synthesized gel factors have a hydrophilic dipeptide end and a hydrophobic alkyl chain end, and have a wide range of application potentials as amphiphilic materials.

[0024] 2. The gel prepared by the method of the present invention is simple and easy to operate and has a shear thixotropic recovery rate as high as 96%.

[0025] 3. The present invention can be applied to the field of controlled-release drug preparations, achieving anticancer drug loading and pH-stimulation-responsive release of drugs; it has the combined characteristic performance of injectability and pH-stimulation-responsive release, greatly reducing the toxic and side effects of free drugs. At the same time, the present invention also has a wide range of application potentials in biomedical fields such as cell culture and tissue repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The invention discloses a thixotropic small molecule gel, a preparation method and a gel factor GTC for its application. 16 Images of gels prepared in different solvents;

[0027] Figure 2 The gel factor GTC of the present invention 16 In 50% DMSO / H 2 Electron micrograph of the gel prepared in O;

[0028] Figure 3 The gel factor GTC of the present invention 16 The prepared gel has a gel thixotropy characterization graph with a recovery rate of 96%;

[0029] Figure 4 The GTC of the present invention 16 Image of gel loaded with anticancer drug DOX;

[0030] Figure 5The GTC of the present invention 16 Characterization diagram of pH-responsive release behavior of the anticancer drug DOX by gel. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the relevant technologies in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] refer to Figures 1 to 5 The following is a thixotropic small molecule gel GTC of the present invention. 16 , its preparation method and its application implementation method.

[0033] Example

[0034] Gel factor GTC 16 Chemical structure

[0035]

[0036] Small molecule gel factor GTC 16 Preparation process:

[0037] This series of small molecule gel factors are synthesized by liquid phase peptide synthesis. The synthesis steps are:

[0038] (1) Preparation of Boc-Trp-C 16 . Dissolve 1.52g (5mmol, 1eq.) of BOC-L-tryptophan in 10mL of DMF and place in an ice bath at 0℃. Then add 0.76g (5mmol, 1eq.) of HOBT and 1.00g (5mmol, 1eq.) of DCC. After 1 to 2.5h (or immediately), add 2.41g (10mmol, 2eq.) of hexadecylamine H dissolved in 20mL of ethyl acetate. 2 N-(CH 2 ) 15 CH 3 The reaction was carried out in an ice bath for 2.5 h, and then the temperature was gradually lowered to room temperature for 3 days. After post-treatment, the white target intermediate Boc-Trp-C was obtained. 16 .

[0039] (2) Preparation of NH 2 -Trp-C 16 12.29 g (21.23 mmol) of Boc-Trp-C 16Dissolved in dry 45 mL DCM solvent (2 eq), followed by the addition of 45 mL (2 eq) of trifluoroacetic acid.

[0040] The reaction was continued for 40 to 50 minutes. After post-treatment, the target white intermediate product NH 2 -Trp-C 16 .

[0041] (3) Preparation of Boc-Gly-Trp-C 16 1.58 g (9 mmol) of Boc-glycine was dissolved in 10 mL of DMF and placed in an ice bath at 0°C. Then 1.22 g (9 mmol) of HOBt and 2.06 g (10 mmol) of DCC were added. Then 4.3 g (10 mmol) dissolved in 25 mL of ethyl acetate was added.

[0042] H 2 N-Trp-C 16 , reacted in an ice bath for 2.5 h, then gradually lowered the temperature to room temperature and reacted for 3 days. Post-treatment gave the white target intermediate Boc-Gly-Trp-C 16 .

[0043] (4) Preparation of H 2 N-Gly-Trp-C 16 (Abbreviated as: GTC 16 ). 1.64 g (2.96 mmol) of Boc-Gly-Trp-C 16 Add to a round-bottom flask, add 12 mL (4 eq) formic acid and react for 4 h.

[0044] After post-treatment, the final product H 2 N-Gly-Trp-C 16 .

[0045] Preparation method of gel:

[0046] 10 mg of the gel factor GTC synthesized by the above method was added 16 First, completely dissolve it in 0.5 mL of DMSO, and then add 0.5 mL of H 2 Make a mixed solvent of DMSO: HO 2 The volume ratio of O is 5:5. After standing for less than 1 minute, a translucent gel GTC is formed. 16 .

[0047] The gel GTC prepared by the above method 16 After being destroyed by external force, it becomes a fluid state. After standing for a while, it returns to its original solid gel state, indicating that the gel has good thixotropic properties.

[0048] In the gel factor synthesis method of this embodiment:

[0049] Boc-glycine can be replaced by Boc-alanine, Boc-aminobutyric acid, Boc-aminovaleric acid, Boc-aminocaproic acid.

[0050] Boc-tryptophan can be replaced by Boc-phenylalanine, Boc-tyrosine.

[0051] Hexadecylamine can be replaced by octylamine, nonylamine, decylamine, dodecylamine, tetradecylamine, or octadecylamine.

[0052] Amide condensation agent DCC can be replaced by DIC and EDCI

[0053] The catalyst HOBT can be replaced by DMAP.

[0054] Methods for preparing the gel include, but are not limited to, heating-cooling cycle method, solvent trigger method, pH trigger method, etc., which can be used to prepare the gel using the gel factor in this embodiment.

[0055] The various solutions in the gel preparation process mentioned in this embodiment are mixed in any order, as long as a gel with a self-assembled structure is finally formed.

[0056] The good solvent DMSO used in this embodiment can be replaced by DMF, methanol, ethanol, or acetone.

[0057] The ratio of the good solvent to the poor solvent in this embodiment may be in the range of 0-1.

[0058] The gel factor GTC used in this embodiment 16 The concentration can be selected in the range of ≥0.2% w / v.

[0059] The solvent used in this embodiment is DMSO / H 2 O ratio can be 1:9~8:2.

[0060] Example

[0061] Preparation method of drug-loaded gel carrier:

[0062] 10 mg Gel Factor GTC 16 First, completely dissolve it in 0.5 mL DMSO to form solution A, then add 0.5 mL aqueous solution B containing 1 mg of drug doxorubicin (DOX) to the mixed solution A to form mixed solution C. Let the solution C stand to form drug-loaded gel GTC. 16 / DOX.

[0063] Gel characterization and thixotropy test:

[0064] (1) Take a photo of the gel prepared in the example, and the obtained real picture is as follows Figure 1 As shown, attached Figure 1 Various ratios of DMSO / H 2 GTC formed in O solvent 16 Gel image.

[0065] (2) The gel prepared in the example was freeze-dried and then tested by SEM. The results are as follows Figure 2 As shown, the gel forms a dense three-dimensional network structure, which can be used to load active drugs and the like.

[0066] (3) The thixotropic properties of the fresh gel in the example were characterized. The results are as follows: Figure 3 As shown in the figure, the gel maintains good solid characteristics in the low shear rate mode, and becomes liquid after being damaged by a large stress. After the stress damage is removed, the gel recovers to 96% of its original state. This shows that the gel has very good shear thixotropic properties and has application potential in various application scenarios.

[0067] (4) Take a photo of the drug-loaded gel prepared in the above application example. The actual photo is as follows: Figure 4 As shown. Figure 4 It can be seen that a good gel is still formed after loading the drug DOX.

[0068] (5) The drug release in vitro of the drug-loaded gel prepared in the above application examples was characterized, such as Figure 5 As shown,

[0069] The drug-loaded gel achieved pH stimulus-responsive release behavior in PBS solutions of different pH values.

[0070] In this embodiment, the drug loading includes but is not limited to anticancer drugs such as DOX and CPT.

[0071] The key points of this embodiment are: 1. The molecular structure of a series of gel factors is composed of a dipeptide sequence and an alkyl chain. 2. The gel factors are dissolved in water or other solvents and formed by self-assembly. 3. The gel can be used in thixotropic gel material scenarios. 4. The gel is used in biomedical fields such as drug delivery, cell culture, and tissue engineering.

[0072] In summary, the present invention synthesizes a series of gel factors through a simple and easy-to-operate liquid phase condensation method. The synthesized gel factors have a hydrophilic peptide end and a hydrophobic alkyl chain end, and have a wide range of application potential as amphiphilic materials. The gel formed by the gel factor has thixotropic properties and can be used for the loading of anticancer drugs and pH stimulation response controlled release.

[0073] It should be emphasized that the above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A thixotropic small molecule gel, characterized in that: The small molecule gel is formed by self-assembly of a small molecule gel factor in a solvent, and the small molecule gel factor has a structure shown in formula (I): In formula (I), x=8-1888, y=1-5; Among them, R includes:

2. The method for preparing the thixotropic small molecule gel according to claim 1, characterized in that: The small molecule gel factor is synthesized by a liquid phase amide condensation method, and the synthesis method comprises the following steps: Tryptophan or phenylalanine or tyrosine, glycine or alanine or aminobutyric acid or aminovaleric acid or aminocaproic acid, alkylamine, condensation reagent, additive and organic solvent are mixed to carry out amide condensation reaction, and the final product obtained is a small molecule gel factor; The structural compound of the alkylamine has a structure shown in formula (V): In formula (V), x=8-18.

3. The method for preparing a thixotropic small molecule gel according to claim 2, characterized in that: The condensation reagents include: dicyclohexylcarbodiimide DCC, diisopropylcarbodiimide DIC, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide EDCI, onium salts, organic phosphorus, s-triazine derivatives, carbonyl diimidazoles; the additives include: N-hydroxy-7-azabenzotriazole HOAt, 1-hydroxybenzotriazole HOBt, 4-dimethylaminopyridine DMAP, N-hydroxysuccinimide HOSu, 1H,1H-pentafluoropropanol PfpOH; the solvents include: N,N-dimethylformamide DMF, dichloromethane DCM, tetrahydrofuran THF, acetonitrile.

4. The method for preparing a thixotropic small molecule gel according to claim 2, characterized in that: In the amide condensation reaction step, amino acid: condensing agent or additive: amine (H2N-(CH2) x-1 CH3) in a molar ratio of 1:0.8-1.2:1.5-2.5; The amino acids include: tryptophan, phenylalanine, tyrosine, glycine, alanine, aminobutyric acid, aminovaleric acid, and aminocaproic acid.

5. The method for preparing a thixotropic small molecule gel according to claim 2, characterized in that: The amide condensation reaction temperature is 0-60°C.

6. The method for preparing a thixotropic small molecule gel according to claim 2, characterized in that: When preparing the thixotropic small molecule gel, the final product gel factor is dissolved in a solvent to form a gel after self-assembly.

7. The method for preparing a thixotropic small molecule gel according to claim 6, characterized in that: The solvent includes: water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), methanol, ethanol, acetone, benzene, toluene, xylene and any two or more of the above solvents mixed in any proportion.

8. The use of the thixotropic small molecule gel according to any one of claims 1 to 7, characterized in that: The thixotropic small molecule gel is applied to the preparation of drug controlled release preparations in the field of biomedicine.

9. The use of the thixotropic small molecule gel according to claim 8, characterized in that: The thixotropic small molecule gel is applied to the construction of a cell culture environment.

10. The use of the thixotropic small molecule gel according to claim 8, characterized in that: The thixotropic small molecule gel is used in the preparation of tissue engineering products.

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