ROS responsive carrier-free nano preparation for treating cerebral arterial thrombosis and ischemic myocardial infarction

Abstract

The invention relates to an ROS responsive carrier-free nano preparation for treating cerebral arterial thrombosis and ischemic myocardial infarction. The ROS responsive carrier-free nano preparation is formed by a host compound and a guest compound through self-assembly acting force, the host compound is a pterostilbene dimer, and the guest compound is arginine. According to the nano preparation, hydrophobic pterostilbene dimer is used as a host compound, hydrophilic arginine is used as a guest compound, and the hydrophobic pterostilbene dimer and the hydrophilic arginine are combined through intermolecular self-assembly acting force to form the nano preparation, so that the druggability of pterostilbene is improved, the toxicity of the medicine is reduced, and the uptake effect of the medicine in nerve cells and the brain targeting property are remarkably improved; the ROS-responsive carrier-free nano preparation has the advantages of good dispersibility, regular and uniform morphology, high drug loading rate and obvious neuroprotection effect, and is suitable for treating myocardial infarction and cerebral infarction (cerebral apoplexy).

Description

Technical Field

[0001] The present invention relates to the field of medical technology, and in particular to a ROS-responsive carrier-free nanoformulation for treating ischemic stroke and ischemic myocardial infarction. Background Art

[0002] Ischemic myocardial infarction and ischemic stroke are cardiovascular diseases that pose a serious threat to human health, characterized by high morbidity, disability, and mortality. Currently, clinical treatments for acute ischemic stroke primarily include reperfusion therapies such as intravenous thrombolysis and endovascular thrombectomy. However, these treatments have numerous limitations. Intravenous thrombolysis typically uses recombinant tissue plasminogen activator (rt-PA), the only thrombolytic agent currently approved by the US Food and Drug Administration (FDA) for the treatment of acute ischemic stroke. However, intravenous thrombolysis is subject to a strict time window, typically requiring patients to receive treatment within 4.5-6 hours of onset. This leaves a significant number of patients missing the optimal treatment window and thus failing to benefit. Furthermore, while endovascular thrombectomy broadens the therapeutic window to some extent, the procedure is complex, requiring high technical expertise in both medical equipment and personnel. Furthermore, it carries certain surgical risks, including complications such as reperfusion injury after vascular recanalization. These factors limit its widespread application and therapeutic efficacy.

[0003] Furthermore, after ischemic stroke, localized brain hypoxia and ischemia trigger a complex series of pathophysiological processes, among which oxidative stress plays a key role, leading to the generation of large amounts of reactive oxygen species (ROS). ROS further exacerbate neuronal damage and disrupt the integrity of the blood-brain barrier, thereby aggravating brain injury and neurological deficits. Although some existing treatments can alleviate some symptoms to a certain extent, there is a lack of specific targeted interventions for ROS-mediated damage. Therefore, the development of small molecule drug formulations with excellent antioxidant activity for the treatment of ischemic stroke is of great significance. Such drug formulations can specifically respond to elevated ROS levels in ischemic brain tissue and precisely release drugs at the lesion site, thereby more effectively clearing excess ROS, reducing oxidative stress damage, and protecting neurons and the blood-brain barrier. This provides a new and more effective strategy for the treatment of acute ischemic stroke, potentially overcoming the limitations of existing treatments and improving patient prognosis and quality of life.

[0004] Pterostilbene (Pte) is a natural organic compound extracted from plants with significant antioxidant, anti-inflammatory, anti-cancer, cardiovascular protection, and neuroprotective activities. Its chemical structure contains groups such as styryl, showing certain hydrophobic characteristics, and has potential application value in the fields of food preservation and health product development. However, pterostilbene has many characteristics that are not conducive to clinical application, such as its low solubility in water and poor solubility of its molecules under normal physiological conditions, which seriously hinders its absorption and distribution process in the body. At the same time, pterostilbene has poor metabolic stability in the body and a short half-life, making it difficult to maintain effective drug concentrations in the body. In addition, due to its physicochemical properties and in vivo pharmacokinetic characteristics, the bioavailability of pterostilbene is relatively low, and the effective amount of drug that enters the blood circulation and reaches the target site is limited. Summary of the Invention

[0005] The present invention aims to at least partially address one of the technical problems in the related art. To this end, one object of the present invention is to provide a ROS-responsive, carrier-free nanoformulation for the treatment of ischemic stroke and ischemic myocardial infarction. This nanoformulation is capable of responding to the excessive ROS produced after stroke and myocardial infarction, reducing cellular damage caused by oxidative stress by regulating ROS levels, thereby providing a new and more effective strategy for the treatment of ischemic stroke and ischemic myocardial infarction.

[0006] To this end, in one aspect of the present invention, a ROS-responsive carrier-free nanoformulation for the treatment of ischemic stroke and ischemic myocardial infarction is proposed, which is formed by a host compound and a guest compound through self-assembly forces;

[0007] The host compound is a pterostilbene dimer synthesized by us with a completely new chemical molecular structure, and the guest compound is arginine.

[0008] According to the present invention, a ROS-responsive carrier-free nanoformulation for the treatment of ischemic stroke and ischemic myocardial infarction utilizes a hydrophobic pterostilbene dimer as a host compound and a hydrophilic arginine as a guest compound. The two are combined through intermolecular self-assembly forces to form a nanoformulation, thereby improving the drugability of pterostilbene, reducing drug toxicity, and significantly improving the drug uptake effect in nerve cells and brain targeting. The ROS-responsive carrier-free nanoformulation has good dispersibility, regular and uniform morphology, high drug loading rate, and significant neuroprotective effect, and is suitable for the treatment of ischemic stroke and ischemic myocardial infarction.

[0009] In addition, according to the above embodiment of the present invention, a ROS-responsive carrier-free nanoformulation for the treatment of ischemic stroke and ischemic myocardial infarction is proposed, which may also have the following additional technical features:

[0010] Optionally, the chemical structural formula of the pterostilbene dimer having a novel chemical structure is as follows:

[0011]

[0012] Optionally, the pterostilbene dimer is obtained by esterification reaction between pterostilbene and a ROS-responsive bridging molecule.

[0013] Furthermore, the ROS-responsive bridging molecule is thioketal or polypropylene sulfide, borate ester, thioether ester, telluride (divalent tellurium), selenium (Se), ferrocene, etc.

[0014] Optionally, the synthesis method of the pterostilbene dimer is as follows:

[0015]

[0016] Furthermore, the synthesis method of the pterostilbene dimer is as follows:

[0017] Adding thioketal, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 1-hydroxybenzotriazole into a reaction kettle filled with an organic solvent for activation to obtain a first solution;

[0018] Pterostilbene and 4-dimethylaminopyridine are added into a reaction kettle filled with an organic solvent and dissolved to obtain a second solution;

[0019] The first solution was added dropwise to the second solution, and the mixture was reacted at room temperature for 12 hours to obtain a reaction solution;

[0020] The reaction solution was extracted with saturated NaHCO3, washed with saturated NaCl until neutral, dried with anhydrous Na2SO4, and concentrated by rotary evaporation to obtain a concentrate;

[0021] The concentrated solution is purified by silica gel column chromatography to obtain the pterostilbene dimer.

[0022] Optionally, the organic solvent is one or more of dichloromethane, tetrahydrofuran, dimethyl sulfoxide, and dimethylformamide.

[0023] Optionally, the self-assembly force includes hydrogen bonds or van der Waals forces.

[0024] Optionally, the molar mass ratio of the host compound to the guest compound is 1-4:4-1.

[0025] In the second aspect of the present invention, the present invention proposes the use of the above-mentioned ROS-responsive carrier-free nanoformulation in the preparation of drugs for ischemic stroke and ischemic myocardial infarction.

[0026] In summary, the ROS-responsive carrier-free nanoformulation provided by the present invention has the following advantages compared with related technologies:

[0027] The present invention synthesizes for the first time a pterostilbene dimer with a new chemical structure that has the ability to respond to ROS and release, which can release pterostilbene monomers in high ROS lesion areas in the brain, thereby achieving on-demand release of pterostilbene.

[0028] This invention self-assembles a hydrophobic drug, pterostilbene dimer, with a hydrophilic drug, arginine, to create a nanoformulation. Compared to traditional nanoformulations, this carrier-free self-assembled nanomedicine boasts a high drug loading capacity, effectively utilizing all drug components. By eliminating the use of inert carrier materials, the carrier-free nanomedicine reduces carrier-induced systemic toxicity and renal metabolic stress, resulting in improved biocompatibility and biodegradability.

[0029] The invention prepares the drug by co-adding a dimer prodrug and arginine into water and utilizing an anti-solvent precipitation method. The preparation method is simple and flexible, green and environmentally friendly, easy to scale up production, and conducive to industrial application.

[0030] The present invention uses a combination of a hydrophobic pterostilbene dimer prodrug and hydrophilic arginine. The introduction of hydrophilic arginine reduces the cytotoxicity of the hydrophobic drug pterostilbene. Compared with a single drug, the targeted uptake effect of the nanomedicine is improved, and the neuroprotective effect is stronger.

[0031] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The characterization of the pterostilbene dimer prodrug (PTP) according to Example 1 of the present invention, wherein A is the preparation process equation of the PTP dimer, B is the nuclear magnetic resonance hydrogen spectrum of the PTP dimer prodrug, C is the infrared spectrum of the PTP dimer prodrug, and D is the ultraviolet spectrum of the PTP dimer prodrug;

[0033] Figure 2 The hydrated particle size results, electron microscopy morphology, element distribution and molecular docking of the carrier-free nanoformulation PTP-Larg NPs according to Example 2 of the present invention are shown;

[0034] Figure 3 The toxicity and cell viability of neuronal N2a cells at different dosages according to Example 3 of the present invention;

[0035] Figure 4 The toxicity and cell viability of microglial BV2 cells at different administration concentrations according to Example 3 of the present invention;

[0036] Figure 5 The results of drug uptake by N2a according to Example 4 of the present invention are as follows;

[0037] Figure 6 The results of drug uptake by BV2 according to Example 4 of the present invention are as follows;

[0038] Figure 7 The toxicity of the carrier-free nanoformulation PTP-Larg NPs to red blood cells according to Example 5 of the present invention;

[0039] Figure 8 The protective effect of the carrier-free nanoformulation PTP-Larg NPs according to Example 6 of the present invention on the infarct area in cerebral ischemia model mice;

[0040] Figure 9 The figure shows the protective effect of the carrier-free nanoformulation PTP-Larg NPs according to Example 7 of the present invention on the integrity of cortical neurons in cerebral ischemia model mice. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the presence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships, without substantially changing the technical content, should also be regarded as the scope of the present invention.

[0042] In order to better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0043] The test materials used in the present invention are all common commercial products and can be purchased on the market; unless otherwise specified, the experiments involved are all conventional experimental methods.

[0044] The present invention is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present invention in any way.

[0045] Example 1 Preparation of Pterostilbene Dimer Prodrug (PTP)

[0046] Accurately weigh 25.2 mg of thioketal (TK), 61.4 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl), 40.5 mg of 1-hydroxybenzotriazole (HOBt), 64 mg of pterostilbene (Pte), and 12.3 mg of 4-dimethylaminopyridine (DMAP).

[0047] TK, EDC·HCl, and HOBt were added to a reactor containing 5 mL of dichloromethane and activated for 30 minutes. Pterostilbene and DMAP were added to a separate reactor and dissolved in 3 mL of dichloromethane until fully dissolved. The TK, EDC·HCl, and HOBt solutions were then slowly added dropwise to the pterostilbene and DMAP solution. The reaction mixture was allowed to react at room temperature for 12 hours. The reaction solution was extracted with saturated NaHCO₃, washed with saturated NaCl until neutral, dried over anhydrous Na₂SO₄, and concentrated by rotary evaporation. The column was wet-packed and wet-loaded. The reaction solution was concentrated to 3-5 mL and then slowly loaded. Using dichloromethane as the eluent, the solution was rapidly eluted, with the purified pterostilbene dimer prodrug (PTP) eluting first.

[0048] like Figure 1 As shown, the obtained pterostilbene dimer prodrug (PTP) was detected by infrared spectroscopy, ultraviolet spectroscopy, mass spectrometry and nuclear magnetic resonance hydrogen spectrum to detect the ester peak of PTP (1747.4 cm -1 ) and the disappearance of the TK carboxyl hydrogen atom signal (12.2 ppm) confirmed the completion of the synthesis of PTP.

[0049] Example 2 Synthesis of carrier-free nanoformulation PTP-Larg NPs

[0050] The PTP prepared in Example 1 was dissolved in acetonitrile to prepare a 1 mg / mL PTP solution; at the same time, arginine was dissolved in deionized water to prepare a 1 mg / mL arginine solution; 1 mL of the PTP solution was slowly dripped into 4 mL of the arginine solution and kept stirring for 12 hours; the reaction solution was rotary evaporated at 45°C for 15 minutes to remove the organic solvent; the reaction solution was completely transferred to a dialysis bag (MWCO = 1000Da) and dialyzed for 12 hours, during which the deionized water buffer was replaced at least three times; the dialyzed solution was mixed and centrifuged at 500 rpm to obtain the supernatant, which was freeze-dried for later use to obtain the carrier-free nanoformulation PTP-Larg NPs.

[0051] like Figure 2As shown in the figure, the prepared nanoparticles (NPs) were morphologically characterized by transmission electron microscopy (TEM), and the resulting images clearly showed that the particles had a uniformly dispersed spherical structure. The particle size of the nanoparticles was further accurately measured using dynamic light scattering (DLS), and the results showed that their average particle size was approximately 130nm. This result is consistent with the morphological characteristics observed by TEM, confirming the uniformity and size consistency of the nanoparticles.

[0052] Example 3

[0053] The cell suspension was transferred to a 96-well plate, 3000 cells were seeded per well, and the cells were transferred to a cell culture incubator. A gradient drug concentration solution of 0, 3.125, 6.25, 12.5, 25, 50, and 100 μg / mL was prepared in DMEM high-glucose medium and added to the 96-well plate at an accurate volume of 100 μL per well. The cells were then cultured for 12 hours. In order to prevent the gradual evaporation of the culture medium during the experiment and affect the experimental results, an appropriate amount of sterile PBS buffer solution was added to each well around the experimental group wells. After reaching the experimental time point, the CCK-8 proliferation and toxicity detection reagent was diluted to 10% with DMEM high-glucose medium, 100 μL CCK-8 reagent was added to each well, and then placed on a shaker for 30 seconds and incubated in a 37°C incubator for 30-40 minutes. After incubation, the absorbance (OD) of each well at a wavelength of 450 nm was measured using a microplate reader. Cell viability = (drug group absorbance - baseline absorbance) / (control group absorbance - baseline absorbance) × 100%. The glucose-oxygen deprivation / reperfusion (OGD / R) model is a classic in vitro model of cerebral ischemia. First, cells were cultured normally until their optimal state. The complete medium (containing 10% FBS and 1% penicillin-streptomycin) in the culture dish was removed and washed twice with PBS. Subsequently, serum-free and antibiotic-free sugar-free DMEM medium was added. The cells were glucose-deprived and oxygen-deprived for 8 hours in an incubator at 37°C, 5% CO2, and 95% N2. At the end of the incubation, the cells were switched to high-glucose medium containing serum and antibiotics and cultured under normal conditions for 24 hours. Using the hypoxia / reoxygenation (OGD / R) model, control, OGD / R model, and drug groups were set up, and cell viability changes were measured using the CCK8 assay.

[0054] The results are as follows Figure 3 and Figure 4 As shown, 12 hours after administration, the PTP-Larg nanoformulation and PTP prodrug exhibited significantly reduced cytotoxicity compared to Pte monomer. Furthermore, after OGD / R modeling, both Pte monotherapy and the PTP-Larg nanoformulation demonstrated protective effects on cells, with the nanoformulation group showing a more pronounced protective effect. In the OGD / R model, both the Pte monotherapy group and the nanoformulation group demonstrated protective effects on cells, with the nanoformulation group exhibiting a more pronounced protective effect than the Pte monotherapy group.

[0055] Example 4

[0056] Cells were plated and adjusted to exponential growth state. After digestion, 1×10 4 Cells were seeded / well in a 24-well plate with a cell slide and incubated for 12 hours until fully adhered. The cells were then treated with drugs for 8 hours. At each time point, the 24-well plates were removed and the cells were washed twice with PBS. The cells were fixed with pre-cooled 4% PFA at 4°C for 30 minutes. After washing, the cells were stained with DAPI for 5 minutes.

[0057] Carefully pick up the cell slide with tweezers and transfer it to a glass slide. Add anti-quenching mounting medium, cover with a coverslip, and secure with nail polish. Place the 24-well plate on the confocal fluorescence microscope stage, find the appropriate field of view, ensure consistent 488nm (FITC) fluorescence excitation channel parameters, and photograph samples at all time points.

[0058] The results are as follows Figure 5 and Figure 6 As shown in the figure, at the same time, the cell fluorescence intensity of PTP-Larg nanomedicine after uptake was stronger than that of Larg single drug, and there was a significant difference, indicating that the uptake effect of nanomedicine was better than that of single drug.

[0059] Example 5

[0060] Blood samples were collected using a precise orbital blood sampling method. Using a disposable infusion needle pretreated with EDTA-2Na, the needle was carefully inserted into the epicanthal venous plexus of a C57 mouse to draw blood. Blood was then rapidly drained into a vacutainer tube pre-filled with sodium heparin, ensuring that the collected blood was well anticoagulated and paving the way for subsequent experimental steps. A centrifuge was pre-cooled to 4°C and the previously collected and anticoagulated whole blood was placed in the centrifuge at 2000 rpm for 5 minutes. After centrifugation, the supernatant was discarded, and 2 mL of 0.9% NaCl solution was added to the remaining pellet. The pellet was then centrifuged three times to obtain a pure, impurity-free red blood cell suspension. Furthermore, 50 μL of the red blood cell pellet was precisely measured and carefully transferred to a container containing 2 mL of 0.9% NaCl solution. Gently and evenly agitated, the red blood cells were thoroughly mixed with the solution to prepare a red blood cell suspension that met experimental requirements. The experimental groups were set up, specifically divided into: positive control group (using ddH2O), negative control group (using 0.9% NaCl), Pte (concentration precisely set to 0.5 mg / mL) group, Larg group (concentration also set to 0.5 mg / mL) and PTP-Larg nanoformulation group (concentration 0.5 mg / mL). Subsequently, the corresponding drugs of each group were added to the prepared red blood cell suspension according to the precise dosage and placed in a 37°C incubator for 2 hours of incubation. After the incubation process, the state of the sample was clearly photographed and recorded, and then the sample was placed in an environment with a temperature of 4°C again, centrifuged at 2500rpm for 5 minutes, and the supernatant was carefully transferred to a 96-well plate. To ensure the accuracy and reliability of the experimental data, 3 replicates were set up for each group, and the absorbance values of the supernatant at 540nm and 577nm were accurately measured using an enzyme marker.

[0061] The results are as follows Figure 7 As shown in the data, at the same dosage concentration, the PTP-Larg NPs nanoformulation exhibited safer biocompatibility. In comparison, pterostilbene showed obvious characteristic absorption peaks at 540 nm and 577 nm, and the blood sample showed a uniform light red color, suggesting that it had obvious blood toxicity at this concentration.

[0062] Example 6

[0063] The MCAO (middle cerebral artery occlusion) model was used to perform transient cerebral blood flow obstruction on mice. While performing thrombus removal and reperfusion, the mice were given drug intervention and a 30 mg / kg dose of the drug preparation was given by intraperitoneal injection. After 24 hours of treatment, the mice were killed, and then the intact brain tissue samples were peeled off and collected for TTC staining to assess the volume of cerebral infarction. TTC (2,3,5-triphenyltetrazolium chloride) staining is a conventional and effective method. The principle of TTC staining is based on the dysfunction of succinate dehydrogenase in the infarcted brain tissue, which cannot metabolize TTC into red formazan. Therefore, the undamaged brain tissue will appear red, while the infarcted area will appear white.

[0064] The results are as follows Figure 8 As shown, after corresponding drug treatment, different groups exhibited varying degrees of neuroprotection. In particular, significant neuroprotection was observed in the groups treated with Pte and PTP-Larg during the reperfusion phase, as evidenced by a significant reduction in infarct volume. Notably, the protective effect of the nanodrug group was even more pronounced than in the single-drug treatment group, likely attributable to the unique physicochemical properties of nanodrugs, such as improved drug penetration, enhanced targeting, and reduced systemic side effects.

[0065] Example 7

[0066] Nissl bodies, as structures rich in rough endoplasmic reticulum and free ribosomes in neurons, have obvious differences in morphology and distribution due to different neuronal functions. Toluidine blue is a basic dye whose cations can bind to acidic substances (such as nucleic acids, polysaccharides, proteins, etc.) in tissue cells to form a stable staining complex. In neurons, Nissl bodies (composed of rough endoplasmic reticulum and free ribosomes) are rich in RNA and can be stained dark blue by toluidine blue, while the cell nucleus is light blue. In this embodiment, the protective efficacy of the drug preparation on neurons was investigated by evaluating the integrity of the Nissl bodies of cortical neurons.

[0067] Remove the embedded brain tissue sample from -80℃ and transfer it to a -25℃ environment in a freezing microtome for 30 minutes to equilibrate the tissue to an appropriate hardness. Squeeze an appropriate amount of OCT on the slice carrier, remove the brain tissue and place it on it, and quickly freeze it for 20 minutes to freeze and solidify the OCT between the carrier and the tissue to prevent the tissue from loosening during the slicing process. Adjust the blade position and first set the slice thickness to 50μm for coarse cutting until the hippocampal structure appears; then reset the slice thickness to 20μm for fine cutting. Place the preheated slide close to the brain slice and use the temperature difference to automatically adhere the brain tissue to the slide. Then use a brush to dip a small amount of PBS to spread the slice and ensure that the slice is flat. After the brain slice is dried, put it into a slice box and store it at -20℃. When using, take out the frozen slice and place it in a fume hood or oven to air dry for 20 minutes.

[0068] Staining and mounting: Wash three times with 0.1M PBS for 5 minutes each; then degrease with 75%, 95%, 100%, 95%, and 75% ethanol, each for 3 minutes; wash twice with 0.1M PBS for 5 minutes each; stain with 1% toluidine blue (prepared in deionized water) for 20 minutes; rinse with deionized water and differentiate with 70% ethanol for 10-20 seconds; rinse sections with deionized water and dehydrate with 75%, 95%, and 100% ethanol for 3 minutes each; then clear with xylene twice for 5 minutes each. Mount sections with neutral resin and allow to dry before storage at room temperature or direct microscopic examination.

[0069] The results are as follows Figure 9 As shown, in the normal control group, the edges of neuronal cells were neat and compactly arranged, showing a healthy cell morphology. In contrast, the number of neuronal cells in the ischemic stroke model group was significantly reduced and sparsely arranged, revealing the severe damage suffered by the cells. In the group treated with Pte and Larg alone, cell loosening was only observed in local areas. In the group treated with the PTP-Larg nanoformulation, the neuronal cell morphology was regular, tightly arranged, and the cell body was large and round, which was more similar to the cell morphology of the normal group, indicating that the nanoformulation has a significant protective effect on neurons.

[0070] In summary, according to an embodiment of the present invention, a hydrophobic drug pterostilbene dimer with ROS responsiveness and another hydrophilic drug arginine are assembled based on self-assembly technology into a carrier-free nanoformulation with good dispersibility, regular and uniform morphology, high drug loading rate, and significant neuroprotective effect, which is suitable for the efficient treatment of acute ischemic stroke.

[0071] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0072] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A ROS-responsive carrier-free nanoformulation for the treatment of ischemic stroke and ischemic myocardial infarction, characterized in that: It is formed by the host compound and the guest compound through self-assembly force; The host compound is pterostilbene dimer, and the guest compound is arginine.

2. The ROS-responsive carrier-free nanoformulation according to claim 1, wherein The chemical structural formula of the pterostilbene dimer is as follows:

3. The ROS-responsive carrier-free nanoformulation according to claim 1, wherein The pterostilbene dimer is obtained by esterification reaction between pterostilbene and ROS-responsive bridging molecules.

4. The ROS-responsive carrier-free nanoformulation according to claim 3, wherein The ROS-responsive bridging molecule is thioketal, polypropylene sulfide, borate ester, thioether ester, telluride, selenium or ferrocene.

5. The ROS-responsive carrier-free nanoformulation according to claim 2, wherein The synthesis method of the pterostilbene dimer is as follows:

6. The ROS-responsive carrier-free nanoformulation according to claim 5, wherein The synthesis method of the pterostilbene dimer is as follows: Adding thioketal, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 1-hydroxybenzotriazole into a reaction kettle filled with an organic solvent for activation to obtain a first solution; Pterostilbene and 4-dimethylaminopyridine are added into a reaction kettle filled with an organic solvent and dissolved to obtain a second solution; The first solution was added dropwise to the second solution, and the mixture was reacted at room temperature for 12 hours to obtain a reaction solution; The reaction solution was extracted with saturated NaHCO3, washed with saturated NaCl until neutral, dried with anhydrous Na2SO4, and concentrated by rotary evaporation to obtain a concentrate; The concentrated solution is purified by silica gel column chromatography to obtain the pterostilbene dimer.

7. The ROS-responsive carrier-free nanoformulation according to claim 6, wherein The organic solvent is one or more of dichloromethane, tetrahydrofuran, dimethyl sulfoxide, and dimethylformamide.

8. The ROS-responsive carrier-free nanoformulation according to claim 1, wherein The self-assembly forces include hydrogen bonds or van der Waals forces.

9. The ROS-responsive carrier-free nanoformulation according to claim 1, wherein The molar mass ratio of the host compound to the guest compound is 1-4:4-1.

10. Use of the ROS-responsive carrier-free nanoformulation according to any one of claims 1 to 9 in the preparation of a drug for acute ischemic stroke.

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