Amino acid modified ionic liquid, its preparation method and application

Abstract

The application provides an amino acid modified ionic liquid and a preparation method and application thereof, the amino acid modified ionic liquid is an A-B structured compound comprising a cation A and an anion B; the cation A is a branched alkyl quaternary ammonium ion containing only one hydroxyl group; the anion B is a different amino acid modified geranic acid, and the different amino acid modified geranic acid is a monomer, a same and / or mixed amino acid dipeptide and / or polypeptide with a general formula B structure. The amino acid modified ionic liquid provided by the application not only has good oral safety, but also significantly enhances drug oral absorption, and can be used as a drug carrier, a dissolving agent, a penetration enhancer, a diluent and / or a dispersant, a surfactant in the drug field, is used for dispersing a drug active ingredient, enhances the solubility and / or permeability of the drug active ingredient, improves the stability of the drug in the gastrointestinal tract, and improves the transdermal absorption capacity of the active molecule.

Description

Technical Field

[0001] This invention relates to the field of drug delivery, and more particularly to an amino acid-modified ionic liquid, its preparation method, and its application. Background Technology

[0002] Oral administration is the preferred route of drug delivery in clinical practice, especially for long-term use. Over the past decade, oral medications have continued to dominate the market, accounting for more than 50% of FDA-approved drugs. After oral administration, drugs must be dissolved and absorbed through the gastrointestinal tract, enter the bloodstream, and distribute to the site of action to exert their therapeutic effect. However, oral formulations often face several problems, particularly for peptides and proteins: (i) poor solubility and / or permeability, (ii) poor stability in the gastrointestinal environment, and (iii) poor penetration of mucus and intestinal epithelial barriers, ultimately leading to low oral bioavailability and suboptimal therapeutic efficacy. This is especially true for large molecule drugs, whose oral bioavailability is often less than 1%, making it difficult to achieve effective therapeutic concentrations.

[0003] Oral drug delivery systems must overcome multiple barriers to achieve successful drug delivery. ① Poor drug solubility: Oral formulations must address the dissolution of poorly soluble drugs. Poor solubility is a major obstacle to the clinical application of BCS Class II and BCS Class IV drugs. Statistics show that 40% of marketed drugs and up to 70% of potential candidates exhibit extremely poor oral bioavailability due to their insolubility in water. ② pH and enzyme barriers: The acidic / alkaline environment of the digestive tract and proteases are major factors leading to the denaturation and degradation of protein and peptide drugs. Oral formulations must withstand the acidic environment of the stomach and the degrading enzymes in the intestine. ③ Mucus barrier: Oral drug delivery systems must penetrate the mucus barrier secreted by the epithelium. The surface of intestinal epithelial cells is covered with a mucus layer up to 100 μm thick, composed of hydrophobic and strongly negatively charged mucus glycoproteins intertwined. Ionic and hydrophobic interactions limit drug diffusion within the mucus layer. The continuous secretion and turnover of mucus makes it extremely difficult for drugs to cross the mucus layer and reach the intestinal epithelium. ④ Intestinal epithelial barrier: Oral drug delivery systems also need to overcome the intestinal epithelial barrier beneath the mucus layer. The intestinal epithelium is mainly composed of epithelial cells, M cells, and goblet cells. These cells are interconnected through tight junctions, forming a relatively impermeable barrier that severely restricts drug absorption.

[0004] To overcome various barriers to drug absorption and improve oral bioavailability, materials with diverse properties are used to enhance drug solubility and permeability, as well as improve drug stability in the gastrointestinal tract and its ability to penetrate mucus and intestinal epithelial cells. For example: ① Surfactants and polymers can be used to enhance the solubility and permeability of poorly soluble drugs; ② pH adjusters, protease inhibitors, and enteric coating materials can be used to improve drug stability; ③ Mucus-dissolving agents and surface-hydrophilic and electroneutrally neutral delivery carriers can enhance the ability of drugs to penetrate the mucus layer; ④ Absorption enhancers enhance transcellular and bypass transport of drugs by increasing the fluidity and permeability of the intestinal epithelium.

[0005] Furthermore, successful transdermal drug delivery requires overcoming the skin and mucous membrane barriers, while drugs for treating brain diseases need to overcome the blood-brain barrier. Drugs exert their effects at different sites by passing through various biological membranes, presenting challenges related to absorption and bioavailability. The unsatisfactory delivery performance of existing materials has prompted researchers to continuously explore safer, more effective, and clinically promising novel materials to improve drug absorption and bioavailability.

[0006] Ionic liquids (ILs) are organic salts that are liquid at room temperature, composed of organic cations and inorganic / organic anions. The main cations that make up ILs include imidazole, pyridine, quaternary ammonium, quaternary phosphate, guanidine, morpholinium, pyrazole, and dipyridine ions. The most common anions include halides, tetrafluoroborate and hexafluorophosphate, and organic acids. As a material with unique properties, high cost-effectiveness, tunability, and both solubilizing and permeation-enhancing capabilities, ionic liquids are gaining attention in the field of drug delivery. Currently, 50% of readily biodegradable ionic liquids are choline-based, belonging to the third generation of ionic liquids. Their safety is significantly improved compared to the previous two generations, and they are increasingly used in basic research on oral and transdermal drug delivery. However, the safety of most of these ionic liquids remains unsatisfactory, and their absorption-enhancing effectiveness needs further improvement; there are currently no successful examples of their commercialization. Currently, most of the ionic liquids used for drug delivery in international patent applications (CN113939273A, CN114980864A, US20220144914A1) are choline-based ionic liquids, such as CAGE composed of choline and geranilic acid. Although the safety of CAGE has been improved, it is still not ideal. It can kill bacteria, E. coli and other microorganisms without selectivity. Long-term use in oral delivery will inevitably affect the intestinal flora. In addition, CAGE has a significant impact on the vitality of cells such as epithelial cells and endothelial cells, and there are still safety issues in its application.

[0007] In ionic liquids, anions are key players in regulating their physicochemical properties, stabilizing proteins, inhibiting intestinal enzyme activity, opening tight junctions in intestinal epithelial cells, and promoting transdermal drug absorption. The cytotoxic mechanism of ionic liquids is also due to increased intracellular transport of toxic anions. There is an urgent need to discover new anion pairings with choline based on structure-activity relationships, design novel ionic liquids with better biocompatibility, improve biosafety and absorption-enhancing effectiveness, increase drug bioavailability, and facilitate the clinical translation of ionic liquids as drug delivery carriers. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, this invention provides an amino acid-modified ionic liquid. A novel ionic liquid is prepared by using a series of natural amino acids or amino acid repeating segments modified with geranium acid as an anionic molecule, paired with an alkyl quaternary ammonium cation containing one hydroxyl group. The structural differences in the side chain branching, number of hydroxyl and amide groups, presence of single and double anions, benzene rings, and amino acid repeating segments of the new compound affect the physicochemical properties, solubilizing ability, biosafety, and intestinal mucosal permeability of the ionic liquid. This influences the permeability of intestinal mucus, epithelium, and drugs in mucus, epithelial monolayers, and isolated intestinal segments, resulting in an ionic liquid with optimal permeability and safety, thus improving its effectiveness and safety in promoting drug absorption. This novel ionic liquid can further enhance drug delivery efficiency, effectively overcome drug absorption barriers, and greatly improve the in vivo bioavailability of drugs, benefiting a wide range of patients.

[0009] According to one aspect of the present invention, an amino acid-modified ionic liquid is provided, wherein the amino acid-modified ionic liquid is an AB structure compound containing a cation A and an anion B; wherein: the cation is an alkyl quaternary ammonium ion with only one hydroxyl group in its branched chain; and the anion B is geranilic acid modified with different amino acids, wherein the different amino acid-modified geranilic acid is a monomer, and / or a mixture of amino acid dipeptides and / or polypeptides with the following general formula B structure.

[0010]

[0011] Wherein, R is selected from the following groups:

[0012]

[0013] In this invention, the introduction of natural amino acids or repeating amino acid segments into the geraniol structure increases the intracellular transport of ionic liquids (ILs) into intestinal epithelial cells. The introduction of side chains and branches through amino acid modification increases the steric hindrance during the interaction between ILs and their anions, weakening the interaction between cations and anions and thus enhancing the interaction with drug molecules, thereby improving delivery efficacy. Simultaneously, the presence of long unsubstituted alkyl chains, oxygen atoms (hydroxyl, aldehyde, or carboxyl groups), enzymatic hydrolysis sites (ester or amide bonds), and aromatic rings in the aforementioned ionic liquid structure promotes biodegradability. Studies have shown that the introduction of oxygen-containing groups such as hydroxyl and amide groups into the anionic structure of ILs through modification with natural amino acids or repeating amino acid segments reduces the antibacterial activity of ILs, thus reducing the impact of novel ILs on the intestinal flora. The introduction of these groups, especially hydroxyl-containing side chains, improves the biodegradability of ILs, enhancing safety. Furthermore, the asymmetric insertion of IL cations into the lipid bilayer causes morphological changes, while the presence of oxygen in the side chains hinders cation insertion, resulting in lower toxicity for such ILs. Therefore, the amino acid-modified ionic liquid provided by this invention has stronger delivery efficiency, better biodegradability, less impact on intestinal flora, lower toxicity, and better safety.

[0014] In a preferred embodiment of the amino acid-modified ionic liquid of the present invention, preferably, in the AB structure compound, the molar equivalence ratio of the cation A to the anion B is 0.1-10. More preferably, in the AB structure compound, the molar equivalence ratio of the cation A to the anion B is 0.25-4.

[0015] In a preferred embodiment of the amino acid-modified ionic liquid of the present invention, the anion is preferably selected from: (3,7-dimethyl-2,6-octadienoyl)glycine, and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)alanine, and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)valine, and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)leucine. , and its dipeptides and / or polypeptides; 2-(3,7-dimethyl-2,6-octadienoyl)-3-methylvaleric acid, and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)methionine, and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)phenylalanine, and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)proline, and its dipeptides and / or polypeptides; 2-(3, (3,7-Dimethyl-2,6-octadienoyl)-3-hydroxybutyric acid and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)cysteine ​​and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)tyrosine and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)aspartic acid and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)silyl Amino acids and their dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)glutamic acid and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)tryptophan and its dipeptides and / or polypeptides; 4-amino-2-(3,7-dimethyl-2,6-octadienoamide)butyric acid and its dipeptides and / or polypeptides; (3,7-dimethyl-2,6-octadienoyl)histidine and its dipeptides and / or polypeptides. More preferably, the anion is (3,7-dimethyl-2,6-octadienoyl)serine; (3,7-dimethyl-2,6-octadienoyl)alanine; 2-(3,7-dimethyl-2,6-octadienoamide)-3-hydroxybutyric acid; (3,7-dimethyl-2,6-octadienoyl)glutamic acid; or (3,7-dimethyl-2,6-octadienoyl)aspartic acid.

[0016] This invention utilizes natural amino acids or amino acid repeating segments to modify geranium anions to construct novel immunosorbent assays (ILs). The IL structures incorporate different side chain branches, varying numbers of hydroxyl and amide groups, single and double anions, benzene rings, and amino acid repeating segments. Most of the geranium derivatives and novel ILs involved have not been reported in the literature. The inventors have conducted research on the appearance, solubility, FTIR, mass spectrometry, and other properties of each IL. 1The ionic liquids were characterized by H-NMR, DSC, viscosity, zeta potential, conductivity, and storage stability. The relationship between these indicators and the structure of the IL was analyzed, and the novel amino acid-modified ionic liquids with optimized properties were obtained, all of which have excellent pharmaceutical potential.

[0017] In a preferred embodiment of the amino acid-modified ionic liquid of the present invention, the cation is preferably selected from one or more of the following: 2-hydroxy-N,N,N-trimethylethylammonium; N,N,N-triethyl-2-hydroxyethylammonium; N-(2-hydroxyethyl)-N,N-dipropylpropylammonium; 4-hydroxy-N,N,N-tripropylbutylammonium; N,N,N-tributyl-4-hydroxybutylammonium; N,N-dibutyl-N-(2-hydroxyethyl)butylammonium; N-(2-hydroxyethyl)-N,N-dipentylpentanammonium; and 5-hydroxy-N,N,N-tripropylpentanammonium. More preferably, the cation is 2-hydroxy-N,N,N-trimethylethylammonium.

[0018] In existing technologies, the hydroxyl group of choline and the carboxyl group of geraniol have strong hydrogen bonding, and the stable supramolecular structure formed by the ion pair may be the source of safety concerns. However, modification with natural amino acids, such as serine or threonine, introduces hydroxyl-containing side chains into the geraniol structure, increasing steric hindrance and reducing interionic interactions. This results in ILs with enhanced delivery efficacy and improved safety.

[0019] The inventors have discovered that, compared to CAGE, the novel IL not only exhibits unprecedented safety but also significantly improves the transmembrane transport of the model molecule FITC-glucan on the Caco2 cell monolayer and the oral absorption of the model drug in rats. For example, the safe concentration of the ionic liquid modified with threonine and serine on cells is 6-8 times higher than that of choline-geraniol ILs (CAGE), and it has almost no effect on E. coli, demonstrating significantly improved safety in the gut microbiota compared to CAGE at the same molar concentration. More importantly, the serine-modified ionic liquid significantly improves the oral bioavailability of the model drug compared to CAGE (P = 0.0056). Furthermore, in animal experiments involving drug delivery of sorafenib mesylate using the aforementioned ionic liquids as carriers, the results showed that the AUC of the choline-germicolic acid ILs (CAGE), choline-threonine-modified germicolic acid ILs (CATG), and choline-alanine-modified germicolic acid ILs (CAAG) groups was 3 times that of the suspension group. The AUC of the choline-serine-modified germicolic acid ILs (CASG) group was 1.6 times that of the CAGE group and 4 times that of the suspension group. The AUC of the choline-glutamate-modified germicolic acid ILs (CAEG) group was significantly higher than that of the CAGE group (p<0.02), and the AUC of the choline-aspartic acid-modified germicolic acid ILs (CADG 4:1) group was also higher than that of the CAGE (1:2) group, being 1.72 times higher. Compared with CAGE (1:2), CATG, CAAG, CASG, CAEG (1:1), and CADG (4:1) were all found to improve the oral efficacy of SRF, indicating that ILs can significantly improve the oral absorption and bioavailability of the model drug sorafenib (SRF).

[0020] Studies have shown that CAGE involves the attraction of choline cations to negatively charged cell membranes, thereby inserting geraniol anions into the lipid bilayer and disrupting the cell membrane. In this invention, by modifying the geraniol anion with amino acids, the ability of the novel ILs to insert anions into the cell membrane may be affected, thus weakening cytotoxicity and antibacterial activity. The in vitro safety experiments demonstrated that the novel ILs have good oral safety. The optimized amino acid-modified ionic liquids, after in vitro evaluations including intestinal mucus and intestinal epithelial permeability enhancement, exhibit significant technical advantages and represent a major advancement compared to existing studies in terms of absorption-enhancing efficacy and safety at the whole-animal level.

[0021] According to another aspect of the present invention, the present invention provides a method for preparing the amino acid-modified ionic liquid, characterized in that the method comprises the following steps:

[0022] 1) Using amino acid benzyl ester as raw material, it is mixed with geranilic acid and a condensing agent, dissolved in an organic solvent, and the pH is adjusted to 7.5-11. The reaction is carried out at 5-55℃ for at least 12 hours. After removing the organic solvent, it is extracted, washed, and purified to obtain amino acid-modified geranilic acid benzyl ester. The condensing agent is selected from carbodiimide condensing agents, phosphocation condensing agents, and urea cation condensing agents.

[0023] 2) The benzyl geraniol ester obtained in step 1) is subjected to ester hydrolysis, acidified, and further extracted, washed, and purified to obtain amino acid-modified geraniol as an anion B; and

[0024] 3) Mix the anion B obtained in step 2) with the bicarbonate of the cation A to obtain an amino acid-modified ionic liquid.

[0025] In a preferred embodiment of the preparation method of the present invention, preferably, in step 1), the carbodiimide condensing agent is 1-hydroxybenzotriazole (HOBT), the phosphocation condensing agent is benzotriazole-N,N,N',N'-tetramethylurea hexafluorophosphate (HBTU), and the urea cation condensing agent is O-benzotriazole-N,N,N',N'-tetramethylurea tetrafluoroboric acid (TBTU); the organic solvent is dichloromethane or trichloromethane; the pH value is 8.5-10; and the reaction is carried out at a reaction temperature of 10-40°C for 18-36 hours.

[0026] In a preferred embodiment of the preparation method of the present invention, preferably, in step 1), the purification includes column chromatography and HPLC preparation. More preferably, in the column chromatography, a gradient elution of petroleum ether:ethyl acetate at a ratio of 10 to 1:1 is used.

[0027] In the preferred embodiment of the preparation method of the present invention, preferably, in step 2), the pH of the solution is adjusted to 8-12 with NaOH or KOH, and the ester hydrolysis reaction is carried out at room temperature for at least 4 hours, followed by post-treatment after the reaction is completed.

[0028] In a preferred embodiment of the preparation method of the present invention, preferably, in step 3), the molar equivalent ratio of the cation A to the anion B is 0.1 to 10. More preferably, the molar equivalent ratio of the cation A to the anion B is 0.25 to 4.

[0029] In a preferred embodiment of the preparation method of the present invention, preferably, in step 3), the amino acid-modified geranium acid is mixed with the cationic bicarbonate, stirred and reacted at 40°C for 24 h, water is removed by rotary evaporation, and then vacuum dried for 48 h to obtain the amino acid-modified ionic liquid.

[0030] In this invention, the purity of the anionic and cationic compounds plays a crucial role in the subsequent preparation of high-purity novel ionic liquids. Therefore, in this study, by controlling the pH, reaction temperature, and reaction time of the reaction solution, as well as the purification process of geranium modified with natural amino acids / repeating segments, high-purity geranium derivatives were ensured for subsequent preparation of the corresponding ILs. Most of the geranium derivatives and novel ILs involved in this project have not been reported in the literature, making their synthesis and characterization critical. Controlling the purity of intermediates and products is beneficial for ensuring the safety and efficacy of subsequent studies.

[0031] In a preferred embodiment of the preparation method of the present invention, the amino acid-modified geranilic acid is preferably: (3,7-dimethyl-2,6-octadienoyl)glycine; (3,7-dimethyl-2,6-octadienoyl)alanine; (3,7-dimethyl-2,6-octadienoyl)valine; (3,7-dimethyl-2,6-octadienoyl)leucine; 2-(3,7-dimethyl-2,6-octadienoamide)-3-methylvaleric acid; (3,7-dimethyl-2,6-octadienoyl)methionine; (3,7-dimethyl-2,6-octadienoyl)phenylalanine; (3,7-dimethyl-2,6-octadienoyl)proline; 2-( ...leucine; 2-(3,7-dimethyl-2,6-octadienoyl)proline; 2-(3,7-dimethyl-2,6-octadienoyl)leucine; 2-(3,7-dimethyl-2,6-octadienoyl)proline; 2-(3,7-dimethyl-2,6-octadienoyl)leucine; 2-(3,7-dimethyl-2,6-octadienoyl)leucine; 2-(3,7-dimethyl-2,6-octadienoyl)leucine; 2-(3,7-dimethyl-2,6-octadienoyl)leucine; 2-(3,7-dimethyl-2,6-octadienoyl)leucine; 2-(3,7- (3,7-Dimethyl-2,6-octadienoyl)-3-hydroxybutyric acid; (3,7-dimethyl-2,6-octadienoyl)cysteine; (3,7-dimethyl-2,6-octadienoyl)tyrosine; (3,7-dimethyl-2,6-octadienoyl)aspartic acid; (3,7-dimethyl-2,6-octadienoyl)serine; (3,7-dimethyl-2,6-octadienoyl)glutamic acid; (3,7-dimethyl-2,6-octadienoyl)tryptophan; 4-amino-2-(3,7-dimethyl-2,6-octadienoyl)butyric acid; (3,7-dimethyl-2,6-octadienoyl)histidine; and dipeptides and / or polypeptides of geranilic acid modified with the aforementioned amino acids.

[0032] In a preferred embodiment of the preparation method of the present invention, the cation is preferably: 2-hydroxy-N,N,N-trimethylethylammonium; N,N,N-triethyl-2-hydroxyethylammonium; N-(2-hydroxyethyl)-N,N-dipropylpropylammonium; 4-hydroxy-N,N,N-tripropylbutylammonium; N,N,N-tributyl-4-hydroxybutylammonium; N,N-dibutyl-N-(2-hydroxyethyl)butylammonium; N-(2-hydroxyethyl)-N,N-dipentylpentanammonium; or 5-hydroxy-N,N,N-tripropylpentanammonium.

[0033] The inventors have discovered that ionic liquids prepared with different ratios of cations and anions can affect the viability of Caco-2 cells; therefore, the ratio of cations to anions must be within a reasonable range. Their research shows that because the anion portion is an amino acid-modified geranium acid structure, it readily interacts with the cell membrane, altering the structure of the lipid bilayer within the cell membrane, thus significantly impacting the cells. Simultaneously, the presence of anions significantly affects the pH of the solution, changing the cell culture environment; if the concentration is too high, it will affect the cell state, leading to a decrease in cell viability.

[0034] According to another aspect of the present invention, the present invention provides the use of the amino acid-modified ionic liquid in the preparation of formulations for improving drug absorption and / or bioavailability. The amino acid-modified ionic liquid provided by the present invention not only has good oral safety but also significantly enhances the oral bioavailability of drugs.

[0035] In a preferred embodiment of the preparation method of the present invention, preferably, the amino acid-modified ionic liquid provided by the present invention is used as a drug carrier, solubilizer, penetration enhancer, diluent and / or dispersant, surfactant, for dispersing active pharmaceutical ingredients, overcoming in vivo barriers, improving drug bioavailability, enhancing the solubility and / or permeability of active pharmaceutical ingredients, improving the stability of drugs in the gastrointestinal tract, improving the ability of active molecules to penetrate mucus and intestinal epithelial cells, and enhancing the ability of active molecules to pass through skin, nasal mucosa, oral mucosa, and digestive tract mucosa, etc., in one or more of these ways.

[0036] In a preferred embodiment of the preparation method of the present invention, the amino acid-modified ionic liquid provided by the present invention contains a pharmaceutical component comprising one or more of hydrophobic small molecule drugs, hydrophilic small molecule drugs, gene drugs, and protein polypeptide drugs; the pharmaceutical component is preferably an antitumor drug, a diabetes drug, an antipreterm birth drug, an antipyretic analgesic and anti-inflammatory drug, and / or a nutritional supplement, including sorafenib, insulin, exenatide, atosiban, ketoprofen, fentanyl, and natural amino acids.

[0037] In a preferred embodiment of the preparation method of the present invention, preferably, the ionic liquid provided by the present invention is combined with a drug component to prepare one or more of the following: liquid preparations, solid preparations, semi-solid preparations, and gaseous preparations; wherein the liquid preparations include solutions, injections, lotions, and liniments; the solid preparations include powders, pills, tablets, and films; the semi-solid preparations include ointments, gels, suppositories, and pastes; and the gaseous preparations include aerosols and sprays.

[0038] In a preferred embodiment of the preparation method of the present invention, the amino acid-modified ionic liquid provided by the present invention is preferably used in one or more of the following fields: anti-tumor field, anti-rheumatism treatment field, antiviral treatment field, diabetes treatment field, respiratory disease medication, vaccine field, hypertension treatment field, sensory organ medication, anticoagulant, immunosuppressant, and antipyretic analgesic and anti-inflammatory field; preferably in the fields of anti-tumor field, diabetes treatment field, and antipyretic analgesic and anti-inflammatory field.

[0039] This invention utilizes a series of natural amino acids or amino acid repeating segments to modify geranium acid into novel anionic molecules. These anionic molecules are then paired with alkyl quaternary ammonium cations containing a single hydroxyl group to prepare novel ionic liquids. Not only are these novel ionic liquids and their anionic compounds almost entirely unreported in the literature, but their application in drug carriers is also completely unexplored. The anionic structure incorporates different side chain branches, varying numbers of hydroxyl and amide groups, single and double anions, benzene rings, and amino acid repeating segments. Unlike known compounds, this anionic structure significantly improves the safety of ILs, as well as their permeability-enhancing and intestinal epithelial absorption-enhancing effects, thereby positively impacting the safety and efficacy of drug delivery. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1a and Figure 1b Geranilic acid (Gly-GA) modified with glycine 1 H NMR and mass spectrum;

[0042] Figure 2a , Figure 2b and Figure 2c The ionic liquid (CAGG) formed by glycine-modified geranilic acid and choline. 1 HNMR, mass spectrum and infrared spectrum (including infrared spectrum of Gly-GA);

[0043] Figure 3a and Figure 3b Geranilic acid (Ala-GA) modified with alanine 1 H NMR and mass spectrum;

[0044] Figure 4a and Figure 4b Valine-modified geraniol (Val-GA) 1 H NMR and mass spectrum;

[0045] Figure 5a and Figure 5b Serine-modified geraniol (Ser-GA) 1 H NMR and mass spectrum;

[0046] Figure 6a and Figure 6b Threonine-modified geraniol (Thr-GA) 1 H NMR and mass spectrum;

[0047] Figure 7a and Figure 7b Geranilic acid (Thr2-GA) modified with threonine dipeptide 1 H NMR and mass spectrum;

[0048] Figure 8a and Figure 8b Geranilic acid (Asp-GA) modified with aspartic acid 1 H NMR and mass spectrum;

[0049] Figure 9a and Figure 9b Geranilic acid (Glu-GA) modified with glutamic acid 1 H NMR and mass spectrum;

[0050] Figure 10a and Figure 10b The ionic liquid (CAEG) formed by glutamic acid-modified geranilic acid and choline. 1 H NMR, mass spectrum;

[0051] Figure 11a , Figure 11b and Figure 11c The ionic liquid (CAAG) formed by alanine-modified geraniol and choline. 1 HNMR, mass spectrum and infrared spectrum (including infrared spectrum of Ala-GA);

[0052] Figure 12a , Figure 12b and Figure 12c The ionic liquid (CAVG) formed by valine-modified geraniol and choline. 1 HNMR, mass spectrum and infrared spectrum (including infrared spectrum of Val-GA);

[0053] Figure 13a , Figure 13b and Figure 13c The ionic liquid (CASG) formed by serine-modified geraniol and choline. 1 HNMR, mass spectrum and infrared spectrum (including infrared spectrum of Ser-GA);

[0054] Figure 14a , Figure 14b and Figure 14c The ionic liquid (CATG) formed by threonine-modified geranilic acid and choline. 1 HNMR, mass spectrum and infrared spectrum (including infrared spectrum of Thr-GA);

[0055] Figure 15a , Figure 15b and Figure 15c The ionic liquid (CAT2G) formed by geraniol modified with threonine dipeptide and choline. 1 H NMR, mass spectrum and infrared spectrum (including infrared spectrum of Thr2-GA);

[0056] Figure 16a and Figure 16b The ionic liquid (CADG) formed by aspartic acid-modified geraniol and choline. 1 H NMR, mass spectrum;

[0057] Figure 17a , Figure 17b and Figure 17c The effects of ionic liquids with different structures on the viability of Cao-2 cells (including different subtypes);

[0058] Figure 18a , Figure 18b and Figure 18c The effect of ionic liquids with different structures on the survival rate of Escherichia coli; Figure 18a The effect of ionic liquids at a concentration of 16 mM on Escherichia coli. Figure 18b The effect of ionic liquids at a concentration of 32 mM on Escherichia coli. Figure 18c The effect of ionic liquids at concentrations of 0–16 mM on Escherichia coli;

[0059] Figure 19a and Figure 19b Biodistribution of sorafenib under different structural ionic liquid carriers combined with drug delivery;

[0060] Figure 20a , Figure 20b , Figure 20c and Figure 20d Comparison of pharmacokinetic curves and AUC of SRF@ILs and SRF suspension in rats (including different subtypes). Detailed Implementation

[0061] To further illustrate the present invention, embodiments are given below. It should be noted that these embodiments are entirely illustrative. The purpose of providing these embodiments is to fully demonstrate the meaning and content of the present invention, but they do not limit the invention to the scope of the described embodiments.

[0062] Example 1: Synthesis of glycine-modified ionic liquids

[0063] (1) Synthesis of (3,7-dimethyl-2,6-octadienoyl)glycine (Gly-GA) with anion

[0064] One equivalent of glycine benzyl ester, 1.1 equivalents of geranilic acid, and 1.1 equivalents of HBTU were added to a round-bottom flask and dissolved in dichloromethane. A stir bar was added, and the pH was adjusted to 7.5 with triethylamine. The flask was sealed with sealing film, and the reaction was carried out at 5°C for 20 hours. The reaction was monitored by TLC (petroleum ether:ethyl acetate = 2:1 as the developing solvent). After 20 hours, no geranilic acid was present in the reaction solution, indicating that the reaction was complete.

[0065] Post-processing: The solvent dichloromethane was evaporated to dryness, and the product was reconstituted with ethyl acetate. The mixture was then elute successively with saturated sodium bicarbonate (NaHCO3) solution, saturated NaCl solution, and 5% KHSO4 solution. The ethyl acetate organic phase was collected and dried over anhydrous Na2SO4 for 2 hours. After 2 hours, the mixture was filtered to remove anhydrous Na2SO4. The filtrate was evaporated to dryness and purified by column chromatography. A column packed with petroleum ether was used for compaction and column chromatography. The resulting product was dissolved in ethyl acetate, mixed, and packed into the column. An appropriate elution solvent ratio was selected. The product was spotted using a UV-Vis thin-layer chromatography plate, and the RF value was adjusted to 0.2-0.3 to separate it from other impurities. Finally, a petroleum ether:ethyl acetate ratio of 8:1 was used for column chromatography to collect the product. The products were combined and evaporated to dryness to obtain glycine-modified geraniol benzyl ester Glyobzl-GA.

[0066] Glyobzl-GA was dissolved in an appropriate amount of methanol. The pH of the solution was adjusted to 8 with NaOH under ice bath conditions, and the ester hydrolysis reaction was carried out at room temperature for 4 hours. Post-processing followed by extraction. The obtained product was evaporated to dryness using a rotary evaporator. An appropriate amount of deionized water was added, and the pH was adjusted to 2 using 5% KHSO4 solution. The product was extracted with ethyl acetate, and the organic phase was collected and dried over anhydrous Na2SO4 for two hours. After 2 hours, the mixture was filtered to remove anhydrous Na2SO4, and the filtrate was evaporated to dryness. Column chromatography was then used for purification. A suitable elution solvent ratio was selected, and the product was spotted at an RF value of 0.2-0.3 using UV detection on a thin-layer chromatography plate to separate it from other impurities. The final elution solvent was petroleum ether:ethyl acetate = 2:1. The products were combined and evaporated to dryness to obtain the product (3,7-dimethyl-2,6-octadienoyl)glycine Gly-GA.

[0067] The resulting product [(3,7-dimethyl-2,6-octadienoyl)glycine Gly-GA] was subjected to... 1 The compound was characterized by 1H-NMR, mass spectrometry, and infrared spectroscopy. The anionic compound Gly-GA, obtained by modifying geraniol with glycine, was a yellow solid, with a total yield of 1.045 g (23.08%).

[0068] Gly-GA 1 Characterization by 1H NMR (400MHz, DMSO-d6) as follows Figure 1a As shown: δ 5.71 (q, J = 1.3 Hz, 1H), 5.13–5.04 (m, 1H), 3.75 (s, 2H), 2.14–2.02 (m, 7H), 1.66 (d, J = 1.4 Hz, 3H), 1.58 (d, J = 1.3 Hz, 3H).

[0069] Mass spectrometry analysis of Gly-GA showed a molecular weight of 225.12, which matches the molecular weight of the designed anionic compound. Figure 1b It can be seen that the prepared compound has high purity.

[0070] Infrared spectrum as shown Figure 2c As shown: Analysis shows that Gly-GA has a sharp and strong absorption at 3300, indicating a strong NH stretching vibration. Combined with the C=O bond at 1680, it is identified as the characteristic absorption peak of the amide bond. These data indicate that Gly-GA was successfully synthesized.

[0071] (2) Synthesis of glycine-modified geranilic acid-choline paired ionic liquid (CAGG)

[0072] One equivalent of choline bicarbonate and one equivalent of Gly-GA were accurately weighed using a balance with a ratio of 1 / 100,000. Gly-GA was first placed in a 100 mL round-bottom flask, and a 1.0 cm stir bar was placed in the flask. One equivalent of choline bicarbonate was slowly added dropwise to the round-bottom flask. The mixture was stirred and reacted at 40 °C for 24 h. The water was removed by rotary evaporation, and then vacuum dried for 48 h to obtain CAGG (1:1).

[0073] The obtained ILs were then subjected to... 1 The ionic liquid CAGG, synthesized by pairing Gly-GA with choline, was characterized by 1H-NMR, mass spectrometry, and infrared spectroscopy. It was a pale yellow liquid with good fluidity.

[0074] CAGG 1 H NMR (400MHz, DMSO-d6) Figure 2a ): δ7.32(d,J=4.9Hz,1H),5.74(q,J=

[0075] 1.3Hz,1H),5.08(tt,J=7.0,1.5Hz,1H),3.89–3.80(m,2H),3.43–3.40(m,2H),3.32(d,J= 4.7Hz, 2H), 3.12 (s, 9H), 2.15–1.99 (m, 7H), 1.65 (d, J = 1.5Hz, 3H), 1.58 (d, J = 1.4Hz, 3H).

[0076] The mass spectrum of CAGG and the assignment of each peak are as follows: Figure 2b As shown, M represents the choline cation group, and N represents the Gly-GA anion group. The mass spectrum peak with a molecular weight of 432.0 is assigned to the ion cluster [M2N]+; the mass spectrum peak with a molecular weight of 760.6 is assigned to the ion cluster [M3N2]+. The ion clusters or ion forms corresponding to other peaks in the mass spectrum are analyzed as follows: Figure 2b As shown.

[0077] Infrared spectral analysis of CAGG ( Figure 2c It can be seen that the C=O and OH groups of carboxylic acids in ionic liquids exhibit absorption peaks at 1690 and 2968 cm⁻¹, respectively, which further confirms the successful synthesis of CAGG.

[0078] Example 2: Synthesis of alanine-modified ionic liquids

[0079] In a round-bottom flask, 1 equivalent of benzyl alanine ester, 1.1 equivalents of geranilic acid, and 1.1 equivalents of HOBT were added and dissolved in dichloromethane. The anionic synthesis steps were performed as in Example 1, except that the pH was adjusted to 11 with triethylamine, and the reaction was carried out at 55°C for 12 h to prepare alanine-modified benzyl geranilic acid ester Ala-obzl-GA. The pH of the solution was adjusted to 9 with KOH under ice bath conditions, and the ester hydrolysis reaction was carried out at room temperature for 8 h. Post-treatment was then performed to obtain (3,7-dimethyl-2,6-octadienoyl)alanine Ala-GA. The obtained product was then... 1 Characterized by H-NMR, mass spectrometry and infrared spectroscopy.

[0080] The anionic compound Ala-GA, obtained by modifying geranium with alanine, was a pale yellow liquid, with a total yield of 3.254 g and a yield of 54.32%.

[0081] Ala-GA 1 H NMR (400MHz, DMSO-d6) Figure 3a ): δ7.39–7.28(m,1H),5.71(q,J=1.3

[0082] Hz,1H),5.13–5.05(m,1H),4.21(qd,J=7.3,5.0Hz,1H),2.16–2.01(m,7H),1.66(d,J=1.5Hz,3H),1.58(d,J=1.4Hz,3H),1.25(d,J=7.4Hz,3H).

[0083] Mass spectrometry analysis of Ala-GA showed that its molecular weight was 239.15 ( Figure 3b The molecular weight of the anionic compound is consistent with that of the designed compound.

[0084] Infrared spectrum as shown Figure 11c As shown in the figure, analysis reveals that, similar to Ala-GA, it has a diameter of 3300 cm. -1 The absorption band at the α region, compared to GA, exhibits an NH stretching vibration band, and surface amide bonds are present. These data indicate that Ala-GA was successfully synthesized.

[0085] Using a 1 / 100,000 balance, 0.1 equivalents of N,N,N-triethyl-2-hydroxyethylammonium bicarbonate and 1 equivalent of Ala-GA were precisely weighed. Following the ionic liquid synthesis steps in Example 1, an alanine-modified ionic liquid (0.1:1) was obtained.

[0086] Example 3: Synthesis of valine-modified ionic liquids

[0087] In a round-bottom flask, 1 equivalent of valine benzyl ester, 1.1 equivalent of geranilic acid, and 1.1 equivalent of TBTU were added and dissolved in dichloromethane. The anionic synthesis steps were performed as in Example 1, except that the pH was adjusted to 8.5 with triethylamine, and the reaction was carried out at 10°C for 36 h to prepare valine-modified geranilic acid benzyl ester Val-obzl-GA. The pH of the solution was adjusted to 10 with NaOH under ice bath conditions, and the ester hydrolysis reaction was carried out at room temperature for 12 h. Post-treatment was then performed to obtain (3,7-dimethyl-2,6-octadienoyl)valine Val-GA. The obtained product was then... 1 Characterized by H-NMR, mass spectrometry and infrared spectroscopy.

[0088] Val-GA, an anionic compound obtained by modifying geranilic acid with valine, is a pale yellow liquid, with a total yield of 2.356 g and a yield of 35.28%.

[0089] Val-GA 1 The characterization results of H NMR (400MHz, DMSO-d6) are as follows: Figure 4aAs shown: δ7.32(d,J=5.1Hz,1H),5.85(d,J=1.7Hz,1H),5.14–5.05(m,1H),4.17(dd,J=7.0,4.3Hz,1H),2.17–1.95(m,8H),1.66(d,J=1.5Hz,3H),1.59(s,3H),0.92–0.84(m,6H).

[0090] Mass spectrometry analysis of Val-GA showed that its molecular weight was 267.18 ( Figure 4b The molecular weight of the prepared compound is consistent with that of the designed anionic compound, and the figure shows that the purity of the prepared compound is high.

[0091] The infrared spectrum of Val-GA is as follows: Figure 12c As shown in the figure, the analysis reveals a similarity to the previous results, with Val-GA exhibiting a characteristic absorption band at 3300 cm⁻¹. -1 The presence of an NH vibrational absorption band indicates the synthesis of the amide bond. These data demonstrate the successful synthesis of Val-GA.

[0092] Using a 1 / 100,000 balance, 10 equivalents of N-(2-hydroxyethyl)-N,N-dipropylpropylammonium bicarbonate and 1 equivalent of Val-GA were precisely weighed. Following the ionic liquid synthesis steps in Example 1, a valine-modified ionic liquid (10:1) was obtained.

[0093] Example 4: Synthesis of serine-modified ionic liquids

[0094] In a round-bottom flask, 1 equivalent of serine benzyl ester, 1.1 equivalent of geranilic acid, and 1.1 equivalent of HBTU were added and dissolved in chloroform. The anionic synthesis steps were performed as in Example 1, except that the pH was adjusted to 10 with triethylamine, and the reaction was carried out at 40°C for 18 h to prepare serine-modified geranilic acid benzyl ester Ser-obzl-GA. The pH of the solution was adjusted to 11 with NaOH under ice bath conditions, and the ester hydrolysis reaction was carried out at room temperature for 24 h. After post-treatment, serine-modified geranilic acid Ser-GA was obtained. The obtained product was then processed using… 1 Characterized by H-NMR, mass spectrometry and infrared spectroscopy.

[0095] The anionic compound Ser-GA obtained by modifying geranium acid with serine is a pale yellow liquid with a yield of 48.35%.

[0096] Ser-GA 1 The H NMR (400MHz, DMSO-d6) results are as follows Figure 5aAs shown: δ 5.82 (q, J = 1.3 Hz, 1H), 5.13–5.05 (m, 1H), 4.30 (dd, J = 5.4, 4.4 Hz, 1H), 3.72–3.57 (m, 2H), 2.21–1.93 (m, 7H), 1.66 (d, J = 1.4 Hz, 3H), 1.59 (d, J = 1.4 Hz, 3H).

[0097] Mass spectrometry analysis of Ser-GA showed that its molecular weight was 255.15 ( Figure 5b This matches the molecular weight of the designed anionic compound. Figure 5b It can be seen that the prepared compound has high purity.

[0098] The infrared spectrum of Ser-GA is as follows: Figure 13c As shown, analysis reveals two characteristic peaks in the characteristic absorption band: one is the NH vibration absorption band at 3353.10 cm⁻¹, and the other is at 3510.61 cm⁻¹. -1 The OH vibrational absorption band indicates that the compound contains grafted amide bonds and hydroxyl groups. These data demonstrate the successful synthesis of Ser-GA.

[0099] Using a 1 / 100,000 balance, 0.25 equivalents of 4-hydroxy-N,N,N-tripropylbutylammonium bicarbonate and 1 equivalent of Ser-GA were precisely weighed. The ionic liquid was synthesized using the same steps as in Example 1 to obtain a serine-modified ionic liquid (0.25:1).

[0100] Example 5: Synthesis of Threonine-Modified Ionic Liquids

[0101] In a round-bottom flask, 1 equivalent of threonine benzyl ester, 1.1 equivalent of geranilic acid, and 1.1 equivalent of HBTU were added and dissolved in chloroform. The anionic synthesis steps were performed as in Example 1, except that the pH was adjusted to 9.0 with triethylamine, and the reaction was carried out at room temperature for 24 h to prepare threonine-modified geranilic acid benzyl ester Thr-obzl-GA. The pH of the solution was adjusted to 12 with NaOH under ice bath conditions, and the ester hydrolysis reaction was carried out at room temperature for 36 h. Post-treatment was then performed to obtain 2-(3,7-dimethyl-2,6-octadienamido)-3-hydroxybutyric acid Thr-GA. The obtained product was then... 1 Characterized by H-NMR, mass spectrometry and infrared spectroscopy.

[0102] Threonine-modified geraniol yielded the anionic compound Thr-GA, a pale yellow liquid with a yield of 42.39%.

[0103] Thr-GA 1 The characterization results of H NMR (400MHz, DMSO-d6) are as follows: Figure 6a As shown:1 H NMR (400MHz, DMSO-d6) δ7.62(d,J=8.6Hz,1H),5.90(q,J=1.3Hz,1H),5.10(tq,J=5.2,1.6Hz,1H),4.24(dd,J=8.7,3.4Hz,1H),4.12( qd,J=6.3,3.4Hz,1H),4.03(q,J=7.1Hz,1H),2.17–2.01(m,7H),1.66(d,J=1.4Hz,3H),1.59(d,J=1.4Hz,3H),1.06(d,J=6.4Hz,3H).

[0104] Mass spectrometry analysis of Thr-GA showed that its molecular weight was 269.15 ( Figure 6b This matches the molecular weight of the designed anionic compound. Figure 6b It can be seen that the prepared compound has high purity.

[0105] The infrared spectrum of Thr-GA is as follows Figure 14c As shown in the figure, analysis reveals that Thr-GA has a characteristic peak band at 3300 cm⁻¹. -1 -3650cm -1 The broad absorption band is likely due to the stretching bands of the NH and OH vibrations. These data indicate that Thr-GA was successfully synthesized.

[0106] Four equivalents of N,N,N-tributyl-4-hydroxybutammonium bicarbonate and one equivalent of Thr-GA were precisely weighed using a 1 / 100,000 balance. The ion liquid was synthesized using the same steps as in Example 1 to obtain a threonine-modified ion liquid (4:1).

[0107] Example 6: Synthesis of Threonine Dipeptide-Modified Ionic Liquids

[0108] In a round-bottom flask, 1 equivalent of threonine dipeptide benzyl ester, 1.1 equivalent of geranilic acid, and 1.1 equivalent of HBTU were added and dissolved in chloroform. The anionic synthesis steps were performed as in Example 1, except that the pH was adjusted to 9.0 with triethylamine, and the reaction was carried out at room temperature for 24 hours to prepare threonine dipeptide-modified geranilic acid benzyl ester Thr2-obzl-GA. The pH of the solution was adjusted to 12 with NaOH under ice bath conditions, and the ester hydrolysis reaction was carried out at room temperature for 18 hours. Post-treatment was then performed to obtain threonine dipeptide-modified geranilic acid Thr2-GA. The obtained product was then... 1 Characterized by H-NMR, mass spectrometry and infrared spectroscopy.

[0109] Thr2-GA, an anionic compound obtained by modifying geraniol with threonine dipeptide, is a pale yellow liquid with a yield of 15.69%.

[0110] Thr2-GA 1 H NMR (400MHz, DMSO-d6) Figure 7a As shown: 1 H NMR (400MHz, DMSO-d6) δ7.69(dd,J=24.7,8.6Hz,1H),5.89(q,J=1.3Hz,1H),5.13–5.07(m,1H),4.37(d,J=4.4Hz,1H),4.22(dt,J=6.1,3.0Hz,1H),4 .13(dd,J=6.5,3.0Hz,1H),3.95(dd,J=6.4,4.4Hz,1H),2.16–1.99(m,7H) ,1.66(d,J=1.4Hz,3H),1.59(d,J=1.4Hz,3H),1.07(dd,J=6.4,5.1Hz,6H).

[0111] Mass spectrometry analysis of Thr2-GA showed that its molecular weight was 370.21 ( Figure 7b The molecular weight of the prepared compound is consistent with that of the designed anionic compound, and the figure shows that the purity of the prepared compound is high.

[0112] The infrared spectrum of Thr2-GA is as follows: Figure 15c As shown in the figure, analysis reveals that Thr2-GA has a characteristic peak at 3200 cm⁻¹. -1 -3600cm -1 The broad absorption band is likely due to the stretching bands of the NH and OH vibrations. These data indicate that Thr2-GA was successfully synthesized.

[0113] Using a 1 / 100,000 balance, 0.5 equivalents of N,N-dibutyl-N-(2-hydroxyethyl)butanol bicarbonate and 1 equivalent of Thr2-GA were precisely weighed. The ion liquid was synthesized using the same steps as in Example 1 to obtain a threonine-modified ion liquid (0.5:1).

[0114] Example 7: Synthesis of Aspartic Acid-Modified Ionic Liquids

[0115] In a round-bottom flask, 1 equivalent of benzyl aspartate, 1.1 equivalent of geranilic acid, and 1.1 equivalent of HBTU were added and dissolved in chloroform. The anionic synthesis steps were performed as in Example 1, except that the pH was adjusted to 9.0 with triethylamine, and the reaction was carried out at room temperature for 24 hours to prepare aspartate-modified benzyl geranilic acid ester Asp-obzl-GA. The pH of the solution was adjusted to 12 with NaOH under ice bath conditions, and the ester hydrolysis reaction was carried out at room temperature for 24 hours. Post-treatment was then performed to obtain (3,7-dimethyl-2,6-octadienoyl)aspartic acid Asp-GA. The obtained product was then...1 Characterized by H-NMR, mass spectrometry and infrared spectroscopy.

[0116] Asp-GA 1 Characterization by 1H NMR (400MHz, DMSO-d6) as follows Figure 8a Shown: δ8.05(d,J=7.9Hz,1H),5.78–5.67(m,1H),5.09(td,J=7.1,6.7,3.0Hz,1H),4.57(d,J =25.4Hz,1H),2.80–2.54(m,2H),2.16–1.97(m,7H),1.71–1.62(m,3H),1.61–1.56(m,3H).

[0117] Mass spectrometry analysis of Asp-GA showed a molecular weight of 283, which matches the molecular weight of the designed anionic compound. Figure 8b It can be seen that the obtained compound has high purity. These data indicate that Asp-GA was successfully synthesized.

[0118] Two equivalents of N-(2-hydroxyethyl)-N,N-dipentylpentanium bicarbonate and one equivalent of Asp-GA were accurately weighed using a 1 / 100,000 balance. Following the ionic liquid synthesis steps described in Example 1, the product was eluted using a gradient of petroleum ether:ethyl acetate = 10 to 1:1, yielding the aspartic acid-modified ionic liquid (2:1).

[0119] Example 8: Synthesis of glutamate-modified ionic liquids

[0120] In a round-bottom flask, 1 equivalent of benzyl glutamate, 1.1 equivalent of geranilic acid, and 1.1 equivalent of HBTU were added and dissolved in chloroform. The anionic synthesis steps were performed as in Example 1, except that the pH was adjusted to 9.0 with triethylamine, and the reaction was carried out at room temperature for 24 hours to prepare glutamate-modified benzyl geraniate Glu-obzl-GA. The pH of the solution was adjusted to 12 with NaOH under ice bath conditions, and the ester hydrolysis reaction was carried out at room temperature for 24 hours. Post-treatment was then performed to obtain (3,7-dimethyl-2,6-octadienoyl)glutamate Glu-GA. The obtained product was then... 1 Characterized by H-NMR, mass spectrometry and infrared spectroscopy.

[0121] Glu-GA 1 Characterization by 1H NMR (400MHz, DMSO-d6) as follows Figure 9aShown: δ8.01(d,J=7.7Hz,1H),5.73(s,1H),5.10(t,J=6.7Hz,1H),4.22(td,J=8.4,5.0Hz,1H),2.37–2.19(m ,2H),2.16–2.01(m,7H),2.01–1.89(m,2H),1.76(dq,J=24.5,10.0,8.7Hz,1H),1.66(s,3H),1.59(s,3H).

[0122] Mass spectrometry analysis of Glu-GA showed a molecular weight of 297.15, which matches the molecular weight of the designed anionic compound. Figure 9b It can be seen that the prepared compound has high purity. These data indicate that Glu-GA was successfully synthesized.

[0123] One equivalent of choline bicarbonate and one equivalent of Glu-GA were precisely weighed using a 1 / 100,000 balance. Following the ionic liquid synthesis steps described in Example 1, the product was eluted using a gradient of petroleum ether:ethyl acetate = 10–4:1, yielding the glutamic acid-modified ionic liquid (1:1). The ionic liquid CAEG (1:1), synthesized by pairing Glu-GA with choline, is a yellow liquid with poorer fluidity than CAGE (1:2), but better solubility.

[0124] CAEG(1:1) 1 H NMR (400MHz, DMSO-d6) Figure 10a ): δ7.44(d,J=7.4Hz,1H),5.76(d,

[0125] J=1.4Hz,1H),5.09(tt,J=5.5,2.6Hz,1H),4.12(dt,J=9.6,6.3Hz,1H),3.84(d,J=5.8Hz,2H),3.41(t, J=5.3Hz,2H),3.12(s,9H),2.31–2.19(m,1H),2.16–1.99(m,7H),1.89–1.76(m,1H),1.71–1.52(m,6H).

[0126] The mass spectrum of CAEG (1:1) and the assignment of each peak are as follows: Figure 10b As shown, Ch represents the choline cation group, EG represents the Glu-GA anion group, and the mass spectrum peak with a molecular weight of 504 corresponds to the ion cluster [Ch2EG]+; the mass spectrum peak with a molecular weight of 607 corresponds to the ion cluster [Cho3EG]+. The ion clusters or ion forms corresponding to other peaks in the mass spectrum are analyzed as follows. Figure 10b As shown, this information confirms the successful synthesis of CAEG (1:1).

[0127] Example 9

[0128] 9.1 Using the method of Example 8, the following anion B and its ionic liquids, respectively bound to choline, were prepared sequentially.

[0129]

[0130]

[0131] 9.2 Prepare the following cations

[0132]

[0133]

[0134] 9.3 Explanation:

[0135] Choline-glycine modified geraniol ILs (CAGG) (see...) Figure 2a , Figure 2b and Figure 2c );

[0136] Choline-glutamate modified geraniol ILs (CAEG) (see) Figure 10a and Figure 10b );

[0137] Choline-alanine modified geraniol ILs (CAAG) (see...) Figure 11a , Figure 11b and Figure 11c );

[0138] Choline-valine modified geraniol ILs (CAVG) (see) Figure 12a , Figure 12b and Figure 12c );

[0139] Choline-serine modified geraniol ILs (CASG) (see) Figure 13a , Figure 13b and Figure 13c );

[0140] Choline-threonine modified geraniol ILs (CATG) (see...) Figure 14a , Figure 14b and Figure 14c );

[0141] Choline-threonine dipeptide-modified geraniol ILs (CAT2G) (see...) Figure 15a , Figure 15b and Figure 15c );

[0142] Choline-aspartic acid modified geraniol ILs (CADG) (see) Figure 16a and Figure 16b );

[0143] Choline-lysine modified geraniol ILs (CAKG).

[0144] Example 10: In vitro safety evaluation of amino acid-modified ionic liquids

[0145] 1. Experimental Method:

[0146] (1) Detection of Caco-2 cell proliferation activity using the CCK-8 assay

[0147] Caco-2 cells were cultured at a density of 8000 cells per well in 96-well plates and incubated at 37°C with 5% CO2 for 24 hours before drug administration. The original culture medium was aspirated, and MEM medium diluted with different ionic liquids was added to final concentrations of 64, 32, 16, 8, 4, 2, 1, 0.5, and 0.25 mM. Blank cell control and blank solvent control were also included. After 48 hours of incubation, the cell culture medium was removed from the culture plate, and the cells were washed twice with pre-warmed PBS (37°C). 100 μL of 10% CCK-8 / MEM medium was added to each well. The entire process was performed in the dark. After incubation at 37°C for 1.5 hours, the absorbance was measured at 450 nm using a microplate reader. Blank cells were used as a control to investigate the effects of different ILs on Caco-2 cell viability.

[0148] (2) Determination of Escherichia coli proliferation activity by absorbance method

[0149] Escherichia coli count: Dilute LB agar solution containing Escherichia coli in the logarithmic growth phase by 10... 8 10 10 10 12 Dilute 100 μl of the liquid medium and spread it evenly on LB solid medium (pre-solidified on Petri dishes). Incubate overnight at 37°C. The next day, count the number of colonies on the solid medium; this is the number of bacteria in 100 μl. Select an appropriate colony count for the plate (100-200 colonies is optimal) and calculate the concentration of *E. coli* in the liquid medium using the dilution factor.

[0150] E. coli concentration = colony count / coating volume * dilution factor

[0151] Bacterial administration: Dilute the ionic liquid to 32mM and 64mM concentrations with LB liquid medium, and administer with 100μl of each medium for 10 weeks. 5 LB liquid culture of the bacteria was performed using 96-well plates with six replicates, a blank control, and a solvent control. The concentrations of the ionic liquid were 16 mM and 32 mM. After incubation at 37°C for 48 h, the OD values ​​were measured. 600Value, calculate the relative survival percentage of E. coli:

[0152] The relative survival percentage of E. coli = (blank control OD) 600 - Solvent control OD 600 ) / (sample OD 600 - Solvent control OD 600 ).

[0153] 2. Experimental Results

[0154] The effects of ionic liquids modified with different amino acids at different concentrations on the viability of Caco-2 cells are shown in Tables 1 and 2. Figure 17a , Figure 17b and Figure 17c Compared to CAGE, CAGG's EC50 after modification with the amino acid Gly increased. 50 The effect was increased by 1.38 times. The effects of ILs prepared by hydrophilic amino acid modifications (Ser, Thr, Thr2) on Caco-2 cell viability were significantly reduced, and EC50 was also decreased. 50 Increased safety. Specifically, CASG has a lower impact on Caco-2 cell viability and EC2 levels. 50 The value is approximately 1.65 times that of CAGE and 1.19 times that of CAGG. Meanwhile, the EC value of CAEG... 50 7.54 times that of CAGE (1:2), EC of CADG 50 The concentration was 7.18 times that of CAGE (1:2); CAEG (2:1) and CAEG (4:1), which had higher choline ratios, showed better safety, with cell viability greater than 70% at the highest concentration studied (32 mM). This indicates that the novel ILs synthesized in this study had less impact on Caco-2 cell viability and exhibited better cell safety.

[0155] The gut microbiota can influence many physiological processes in the human body, and maintaining its stability helps maintain immune and metabolic homeostasis. CAGE has been reported to effectively inhibit various bacteria and fungi; CAGE (1:2) has shown significant antibacterial activity against *Escherichia coli*, but long-term oral administration may have adverse effects. Figure 18a , Figure 18b and Figure 18c As shown, modifying CAGE with hydrophobic amino acids had a relatively small effect on improving the ionic liquid's growth, and only a slight increase in bacterial proliferation compared to CAGE. However, after modification with hydrophilic amino acids with hydroxyl side chains, CASG, CATG, and CAT2G all exhibited low toxicity to Escherichia coli, showing a significant difference compared to CAGE (1:1) (p<0.0001).

[0156] like Figure 18a , Figure 18b and Figure 18c As shown, within the IL concentration range of 0–16 mM, CAEG (1:1) and CATG (1:1) exhibited weak inhibitory effects on Escherichia coli, showing a significant difference compared to CAGE (1:2) (p<0.0001). This result is consistent with the findings on Caco-2 cells, indicating that the safety of ionic liquids CASG, CATG, CATG2G, CAEG, and CATG is significantly improved at the cellular and bacterial levels. This further verifies that modifying the anionic structure of ionic liquids with hydrophilic hydroxyl groups can significantly enhance the safety of ionic liquids.

[0157] The results of the *E. coli* bacterial inhibition assay showed that, compared with CAGE, all amino acid-modified ILs had significantly reduced effects on bacterial activity and improved safety. CASG, CATG, CAT2G, CAEG, and CADG, obtained from hydrophilic amino acid modifications, had almost no effect on bacterial activity and exhibited the best safety. Studies have shown that CAGE causes cell membrane damage by attracting choline cations to negatively charged cell membranes, thereby inserting geraniol anions into the lipid bilayer. In this invention, by modifying geraniol anions with amino acids, the ability of the novel ILs to insert anions into the cell membrane may be affected, thus weakening cytotoxicity and antibacterial activity. The above in vitro safety experiments indicate that the novel ILs have good oral safety.

[0158] Table 1. EC50 of ionic liquids with different structures on Caco-2 cells (n=6) (Control Experiment 1)

[0159]

[0160] Table 2 EC50 of ionic liquids in Caco-2 cells (n=6) (Control Experiment 2)

[0161] ILs CAGE(1:2) CAEG(1:1) CADG(1:1) CADG(4:1) EC50 1.294 9.764 9.29 18.41

[0162] Example 11: Drug delivery system combining amino acid-modified ionic liquids with drug components

[0163] 1. Preparation of amino acid-modified ionic liquid drug delivery systems

[0164] Accurately weigh appropriate amounts of sorafenib tosylate powder, or insulin, exenatide, natural amino acids, atosiban, ketoprofen, fentanyl, etc., and add them to various ILs (CAGE, CAGG, CAAG, CAVG, CASG, CATG, CAT2G, CAEG, CADG) to achieve a drug concentration of 100 mg / mL. Centrifuge for 30 seconds using a handheld centrifuge to settle the drug and ionic liquid to the bottom of the EP tube. Sonicate in a water bath (100W) for 1 hour to dissolve the drug, obtaining a clear and homogeneous yellow or orange-yellow liquid. The formulation can be in liquid form, facilitating dosage and oral administration. Furthermore, the preparation of the formulation does not require special equipment, offering advantages such as simple operation and easy scale-up.

[0165] 2. Biodistribution study in rats

[0166] Twelve male SD rats were fasted overnight before the experimental drug administration and randomly divided into groups of three. Each group was administered SRF@ILs (sorafenib-amino acid-modified ionic liquid drug delivery system) and sorafenib suspension (prepared with 1% CMC-Na before use) by gavage at a dose of 8 mg / kg. The CAGE (1:2) dosage was 100 mg (0.227 mmol), and the dosages of the other different ionic liquids were the same as the CAGE dosage. The corresponding administration volume was calculated, and SRF@ILs were administered according to the calculated volume using a syringe and gavage needle. Nine hours after gavage administration, the rats were anesthetized with 10% chloral hydrate (0.3 ml / 100 g), and sterile PBS solution was perfused into the heart and subhepatic veins, totaling 200 ml, to remove all blood from the system. Heart, liver, spleen, lung, kidney, stomach, duodenum, jejunum, mesenteric lymphatic vessels, and brain of rats were collected. The contents were washed with PBS solution and wiped clean with filter paper before use. The drug content in the tissues was detected using LC-MS / MS.

[0167] 3. Pharmacokinetic studies in rats

[0168] Male SD rats were used and fasted overnight before experimental drug administration. They were then randomly divided into groups of six. Each group was administered SRF@ILs and sorafenib suspension (prepared with 1% CMC-Na before use) by gavage at a dose of 8 mg / kg. Blood samples of 0.3 mL were collected from the retro-orbital venous plexus at 1, 2, 4, 6, 8, 10, 12, 16, 24, 36, and 48 hours after administration. The samples were placed in heparin sodium anticoagulant tubes and centrifuged at 5000 rpm for 10 minutes at 4°C. The supernatant plasma was separated and stored at -80°C until the samples were analyzed for drug content using LC-MS / MS. The main pharmacokinetic parameters AUC, MRT, T1 / 2, Tmax, and Cmax were calculated using DAS 2.0 software. A two-tailed t-test was used to test the significance of the pharmacokinetic parameters, and statistical comparisons were performed on each parameter.

[0169] 4. Experimental Results

[0170] like Figure 19a and Figure 19b As shown, in terms of distribution in major organs, compared with SRF suspension, the drug concentration of SRF in major organs was increased in all ionic liquid groups, because ionic liquids significantly enhanced the oral absorption of SRF.

[0171] For example, compared to CAGE, CASG showed decreased distribution in organs such as the heart and liver, but increased distribution in the kidneys (p = 0.0559). SRF is FDA-approved for chemotherapy in liver and kidney cancer. The difference in drug distribution in the liver and kidneys after oral administration between CAGE and CASG delivery systems may be chosen based on clinical needs. The distribution trend of SRF in different organs in the CAAG group was basically consistent with that in the CAGE group, indicating that CAAG ionic liquid and CAGE (1:2) showed similar oral delivery efficacy. Biodistribution studies of SRF@ILs in rats showed that, 9 hours after administration, compared to the CAGE group, SRF@CASG showed decreased distribution in the heart and liver, increased distribution in the kidneys, and significantly increased distribution in the duodenum. This may reveal that the main route of increased absorption of CASG compared to CAGE is through absorption in the intestinal region.

[0172] At the same time, such as Figure 20a , Figure 20b , Figure 20c and Figure 20dAs shown in Table 3, the pharmacokinetic study of SRF@ILs in rats after oral administration revealed that the AUC of the CAGE, CATG, and CAAG groups was 3 times that of the suspension group, the AUC of the CASG group was 1.6 times that of the CAGE group and 4 times that of the suspension group. The AUC of the CAEG (1:1) group was significantly higher than that of the CAGE group (p<0.02), and the AUC of the CATG (4:1) group was also higher than that of the CAGE (1:2) group, being 1.72 times higher (Table 4). This verifies that compared with CAGE (1:2), CATG, CAAG, CASG, CAEG (1:1), and CATG (4:1) can all improve the oral efficacy of SRF, indicating that ILs can significantly improve the oral absorption and bioavailability of SRF.

[0173] Table 3: Calculation of oral pharmacokinetic parameters of sorafenib formulations with different ionic liquid carriers in rats (n=6)

[0174] Control Experiment 3 AUC(mg / L*h) MRT(h) <![CDATA[T 1 / 2 (h)]]> <![CDATA[T max (h)]]> <![CDATA[C max (mg / L)]]> SRF Suspension 22.93±12.28 14.15±2.92 14.29±8.22 8.02±3.10 1.45±0.58 SRF@CAGE(1:2) 59.86±18.60 15.56±2.51 11.41±3.41 7.33±3.01 3.16±1.01 SRF@CAAG(1:1) 64.08±14.76 17.95±3.67 17.18±8.86 6.00±3.10 3.16±1.01 SRF@CATG(1:1) 58.66±14.80 15.25±1.03 15.68±4.61 5.17±3.92 3.23±0.82 SRF@CASG(2:1) 80.05±5.97 12.61±2.02 7.28±2.86 5.83±3.12 5.27±0.96

[0175] Table 4: Calculation of oral pharmacokinetic parameters of sorafenib formulations with different ionic liquids as carriers in rats (n=3)

[0176] Control Experiment 4 AUC(mg / L*h) MRT(h) <![CDATA[T 1 / 2 (h)]]> <![CDATA[T max (h)]]> <![CDATA[C max (mg / L)]]> SRF@CAGE(1:2) 25.89±7.13 9.94±0.69 4.90±2.88 6.67±2.31 2.12±0.57 SRF@CAEG(1:1) 80.60±19.39 44.43±43.33 17.93±8.21 10.67±2.31 4.10±0.70 SRF@CADG(4:1) 44.62±32.59 8.97±2.21 4.91±3.23 6.00±0.00 3.56±1.32

[0177] Similar results have been observed in dosing regimens using ionic liquid carriers that combine insulin, exenatide, natural amino acids, atosiban, ketoprofen, fentanyl, etc., with amino acid modifications.

[0178] Example 12: Applications of amino acid-modified ionic liquids

[0179] The applications of ionic liquids include one or more of the following: anti-tumor drugs, antirheumatic drugs, antiviral drugs, diabetes drugs, respiratory disease medications, vaccines, hypertension treatment, sensory organ medications, anticoagulants, immunosuppressants, and antipyretic, analgesic, and anti-inflammatory drugs. The preferred drug components are anti-tumor drugs, diabetes drugs, anti-premature birth drugs, antipyretic, analgesic, and anti-inflammatory drugs, and / or nutritional supplements, including sorafenib, insulin, exenatide, atosiban, ketoprofen, fentanyl, and natural amino acids.

[0180] In the aforementioned application areas, the amino acid-modified ionic liquid is used as a drug carrier, solvent, penetration enhancer, diluent and / or dispersant, and surfactant. It is used for dispersing active pharmaceutical ingredients, overcoming in vivo barriers, improving oral absorption, enhancing the solubility and / or permeability of active pharmaceutical ingredients, improving drug stability in the gastrointestinal tract, enhancing the penetration ability of active molecules through mucus and intestinal epithelial cells, and enhancing the ability of active molecules to pass through skin, nasal mucosa, oral mucosa, and digestive tract mucosa, among other things. By combining the amino acid-modified ionic liquid with drug components and adding other appropriate excipients, one or more of the following formulations can be prepared: liquid formulations, solid formulations, semi-solid formulations, and gaseous formulations. Liquid formulations include solutions, injections, lotions, and liniments; solid formulations include powders, pills, tablets, and films; semi-solid formulations include ointments, gels, suppositories, and pastes; and gaseous formulations include aerosols and sprays.

[0181] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An amino acid-modified ionic liquid that enhances drug absorption and / or bioavailability, characterized in that, The amino acid-modified ionic liquid comprises an AB-structured compound containing cation A and anion B; wherein: The cation A is 2-hydroxy-N,N,N-trimethylethylammonium; The anion B is geranilic acid modified with different amino acids, and the different amino acid-modified geranilic acids are selected from... (3,7-Dimethyl-2,6-octadienoyl)alanine; 2-(3,7-Dimethyl-2,6-octadienamido)-3-hydroxybutyric acid; (3,7-Dimethyl-2,6-octadienoyl)aspartic acid; (3,7-Dimethyl-2,6-octadienoyl)serine; or (3,7-Dimethyl-2,6-octadienoyl)glutamic acid; The molar equivalent ratio of the cation A to the anion B is 1:1 to 4:

1.

2. A method for preparing the amino acid-modified ionic liquid as described in claim 1, characterized in that, The method includes the following steps: 1) Using amino acid benzyl ester as raw material, it is mixed with geranilic acid and a condensing agent, dissolved in an organic solvent, and the pH is adjusted to 7.5~11. The reaction is carried out at 5~55ºC for at least 12 hours. After removing the organic solvent, it is extracted, washed, and purified to obtain amino acid modified geranilic acid benzyl ester; wherein, the condensing agent is selected from carbodiimide type condensing agent, phosphocation type condensing agent, and urea cation type condensing agent; 2) The benzyl geraniol ester obtained in step 1) is subjected to ester hydrolysis, acidified, and further extracted, washed, and purified to obtain amino acid-modified geraniol as an anion B; and 3) Mix the anion B obtained in step 2) with the bicarbonate of the cation A to obtain an amino acid-modified ionic liquid; The anion B is: (3,7-Dimethyl-2,6-octadienoyl)alanine; 2-(3,7-Dimethyl-2,6-octadienamido)-3-hydroxybutyric acid; (3,7-Dimethyl-2,6-octadienoyl)aspartic acid; (3,7-Dimethyl-2,6-octadienoyl)serine; or (3,7-Dimethyl-2,6-octadienoyl)glutamic acid; The cation A is: 2-hydroxy-N,N,N-trimethylethylammonium; The molar equivalent ratio of the cation A to the anion B is 1:1 to 4:

1.

3. The method as described in claim 2, characterized in that, In step 1), the carbodiimide condensing agent is 1-hydroxybenzotriazole, the phosphocation condensing agent is benzotriazole-N,N,N',N'-tetramethylurea hexafluorophosphate, and the urea cation condensing agent is O-benzotriazole-N,N,N',N'-tetramethylurea tetrafluoroboric acid; the organic solvent is dichloromethane or chloroform; the pH value is 8.5~10; and the reaction is carried out at a reaction temperature of 10~40ºC for 18~36 hours.

4. The method as described in claim 2, characterized in that, In step 2), the pH of the solution is adjusted to 8-12 with NaOH or KOH, and the ester hydrolysis reaction is carried out at room temperature for at least 4 hours. After the reaction is completed, post-treatment is performed.

5. The use of an amino acid-modified ionic liquid as described in claim 1 in the preparation of a drug delivery carrier for improving the bioavailability of oral drugs.

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