Targeted drug and preparation method therefor and use thereof

Abstract

Provided are a targeted drug and a preparation method therefor and the use thereof. The targeted drug comprises a tissue-type plasminogen activator and a targeting peptide. Thrombus-targeting modification is directly performed on thrombolytic drug rtPA, which has the widest clinical application, by means of a chemical method. The defects of rtPA in terms of a narrow therapeutic time window, a high medication dosage and a high hemorrhage risk are significantly improved. The preparation process is simple and controllable, and the materials required for the preparation are readily available and cost-effective. The toxic effects and degradation problems of materials such as compounds are eliminated. In addition, the treatment process does not require other instruments and devices, which makes the clinical transformation and use of the thrombus-targeting rtPA possible.

Description

Targeted drug and its preparation method and application

[0001] Related cross-references

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on June 27, 2023, with application number "202310764776.X" and public name "Targeted Drugs, Preparation Methods and Applications Thereof", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of nanomedicine technology, and in particular to targeted drugs and their preparation methods and applications. Background Art

[0004] Thrombotic diseases, including myocardial infarction, pulmonary embolism, and ischemic stroke, are the leading causes of death and disability worldwide. Ischemic stroke, in particular, has become the second leading cause of death in humans. Acute vascular occlusion at the site of a thrombus can cause severe tissue damage and even organ failure, ultimately threatening life. Timely thrombolysis to recanalize occluded blood vessels is the most effective treatment strategy for thrombotic diseases. The thrombolytic drug recombinant human tissue plasminogen activator (rtPA) is the only thrombolytic drug approved by the US Food and Drug Administration for the treatment of ischemic stroke and is currently the most mature, commonly used, and most effective treatment in clinical practice. Due to its excellent ability to dissolve fibrin, the main component of thrombi, it has been used by intravenous injection to treat thrombotic diseases such as ischemic stroke, pulmonary embolism, and myocardial infarction. However, due to the short half-life of rtPA (approximately 4-8 minutes), its dredging efficiency is low, and high-dose intravenous infusion is required to maintain effective drug concentrations. Repeated administration and systemic application can easily lead to hemorrhagic transformation, and serious bleeding complications have limited the application of rtPA. Clinical guidelines generally recommend thrombolytic therapy within 3-12 hours after the onset of symptoms. Beyond this treatment time window, the benefits of thrombolysis will no longer outweigh the risk of bleeding, resulting in less than 5% of patients receiving rtPA thrombolytic therapy clinically. Therefore, in order to improve patient prognosis, modifying thrombolytic drugs, improving thrombolytic efficiency, and reducing bleeding complications have become major clinical needs for the treatment of thrombotic diseases.

[0005] In recent years, with the development of nanotechnology, various rtPA modified using nano-targeted delivery systems have been reported. For example, rtPA has been encapsulated with polymers or liposomes to extend its half-life. Meanwhile, rtPA-containing nanoparticles have been modified with antibodies, peptides, biofilms, or magnetic effects to impart thrombus targeting to rtPA, increasing local drug concentrations. In animals, this has resulted in therapeutic effects that are more pronounced than those observed with free rtPA. However, due to the limitations of these reported rtPA modification strategies, such as complex preparation processes, the need for magnetic field or photothermal therapy assistance, and the risk of in vivo material degradation, there is a lack of modified rtPA with good therapeutic efficacy, simple preparation processes, and easy translational applications.

[0006] Summary of the Invention

[0007] The embodiments of the present application disclose a targeted drug, a preparation method, and an application thereof. rtPA, the most widely used thrombolytic drug in clinical practice, is directly modified for thrombus targeting using a chemical method. This significantly improves the shortcomings of rtPA, such as a narrow treatment time window, high dosage, and high bleeding risk. Furthermore, the preparation process is simple and controllable, the materials required for preparation are readily available and low-cost, and the toxic effects and degradation problems of the compounds and other materials themselves are eliminated. Furthermore, no other instruments or equipment are required during the treatment process, making the clinical translation and application of thrombus-targeted rtPA possible.

[0008] In order to achieve the above-mentioned objectives, the present application discloses, in a first aspect, a targeted drug comprising: a tissue-type plasminogen activator and a targeting peptide.

[0009] As an optional implementation of the examples of the present application, in the above-mentioned targeted drug, the tissue plasminogen activator is recombinant tissue plasminogen activator.

[0010] As an optional implementation of the embodiment of the present application, the above-mentioned targeted drug also includes: a cross-linking agent.

[0011] As an optional implementation of the examples of the present application, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator to the targeting peptide is 1:(10-50).

[0012] As an optional implementation of the example of the present application, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator to the targeting peptide is 1:(10-30).

[0013] As an optional implementation of an example of the present application, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator to the targeting peptide is 1:(15-25).

[0014] As an optional implementation of the examples of the present application, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator to the targeting peptide is 1:20.

[0015] As an optional implementation of an example of the present application, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:(10-50):(10-50).

[0016] As an optional implementation of an example of the present application, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:(10-30):(10-30).

[0017] As an optional implementation of an example of the present application, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:(15-25):(10-25).

[0018] As an optional implementation of an example of the present application, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:20:20.

[0019] As an optional implementation of the embodiment of the present application, in the above-mentioned targeted drug, the tissue plasminogen activator includes: alteplase.

[0020] As an optional implementation of the embodiment of the present application, in the above-mentioned targeted drug, the targeting peptide includes: a thrombus targeting peptide.

[0021] As an optional implementation of an example of the present application, in the above-mentioned targeted drug, the thrombus targeting peptide is: CREKA.

[0022] As an optional embodiment of the present application, in the above-mentioned targeted drug, the targeting peptide has:

[0023] (1), the amino acid sequence shown in SEQ ID NO: 1; or

[0024] (2) an amino acid sequence obtained by substituting, deleting or adding one or more amino groups of the amino acid sequence shown in (1), and having the same or similar function as the amino acid sequence shown in (1); or

[0025] (3) An amino acid sequence that is at least 80% identical to the amino acid sequence shown in (1) or (2).

[0026] As an optional implementation of the example of the present application, in the above-mentioned targeted drug, the sequence of the targeting peptide is: Cys-Arg-Glu-Lys-Ala.

[0027] As an optional implementation of an embodiment of the present application, in the above-mentioned targeted drug, the cross-linking agent includes: a water-soluble amine-thiol cross-linking agent.

[0028] As an optional implementation of the embodiment of the present application, in the above-mentioned targeted drug, the cross-linking agent includes: Sulfo-SMCC.

[0029] The second aspect of the present application discloses a preparation method, wherein the cross-linking agent and the tissue plasminogen activator are mixed, and then mixed with the thrombus targeting peptide, and the mixture is centrifuged and filtered to obtain any of the above-mentioned targeted drugs.

[0030] As an optional implementation of an example of the present application, in the above preparation method, the molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:(10-50):(10-50).

[0031] As an optional implementation of an example of the present application, in the above preparation method, the molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:(10-30):(10-30).

[0032] As an optional implementation of an example of the present application, in the above preparation method, the molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:(15-25):(15-25).

[0033] As an optional implementation of an example of the present application, in the above preparation method, the molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:20:20.

[0034] As an optional implementation of an embodiment of the present application, in the above preparation method, after the cross-linking agent and the tissue plasminogen activator are mixed, the mixing time is 2 hours to 12 hours and the temperature is 4°C.

[0035] As an optional implementation of the example of the present application, in the above preparation method, the mixing time of the thrombus targeting peptide mixture is 2 hours to 12 hours, and the temperature is 4°C.

[0036] As an optional implementation of an embodiment of the present application, in the above preparation method, the number of centrifugal filtrations is no less than 5 times.

[0037] The third aspect of the present application discloses an application of a targeted drug, which provides the application of the targeted drug of the first aspect and / or the targeted drug obtained by the preparation method of the second aspect in the preparation of drugs and / or preparations for treating thrombolysis.

[0038] Compared with the prior art, this application has the following beneficial effects:

[0039] The targeted drug provided in the present application enables rtPA to have thrombus targeting ability through thrombus-targeting rtPA, significantly increasing the drug concentration at the thrombus site, improving the thrombolytic efficiency of rtPA, improving the therapeutic effect, and reducing the risk of hemorrhagic transformation. At the same time, compared with the reported rtPA modification strategy, the present application directly connects the thrombus-targeting peptide to rtPA through a chemical reaction to perform targeted modification. The preparation process is simple and controllable, the materials required for preparation are easily available and low-cost, and the toxic effects and degradation problems of the compounds and other materials themselves are eliminated. In addition, no other instruments and equipment are required during the treatment process, making the clinical translation and application of thrombus-targeting rtPA possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] FIG1 is a schematic diagram showing the change in molecular weight of the CREKA-rtPA conjugate synthesized in Example 1 of the present application compared with rtPA detected by Western-blot;

[0042] FIG2 is a schematic diagram of the activity test results of CREKA-rtPA conjugates prepared at different synthesis ratios in Example 2;

[0043] FIG3 is a schematic diagram of the in vitro thrombus targeting test results of CREKA-rtPA conjugates prepared at different synthesis ratios in Example 3;

[0044] FIG4 is a schematic diagram of the experimental results of evaluating the thrombolytic therapeutic effect of the CREKA-rtPA conjugate using the FeCl3-induced mesenteric artery thrombosis model in Example 4;

[0045] Figure 5 is a schematic diagram of the experimental results of evaluating the thrombolytic therapeutic effect of CREKA-rtPA in the photochemically induced mouse cerebral ischemia model in Example 5; wherein: the left figure is the TTC staining results of mice with ischemia-reperfusion injury after treatment with normal saline, rtPA, or CREKA-rtPA conjugate, where red represents normal brain tissue and white represents infarcted brain tissue; the right figure is the measurement and statistics of the cerebral infarction volume of each group of mice in the left figure. DETAILED DESCRIPTION

[0046] It should be understood that the expression "one or more of" includes individually each of the items recited after the expression and various combinations of two or more of the recited items, unless otherwise apparent from the context and usage. The expression "and / or" in conjunction with three or more recited items should be understood to have the same meaning, unless otherwise apparent from the context.

[0047] The terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, e.g., not excluding other unrecited elements or steps, unless otherwise specifically stated or understood from the context.

[0048] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the application remains operable. Additionally, two or more steps or actions may be performed simultaneously.

[0049] The use of any and all examples or exemplary language, such as "such as" or "including," herein is intended merely to better illustrate the present application and does not limit the scope of the present application unless otherwise claimed. No language in this specification should be construed as indicating any non-claimed element as essential to the practice of the present application.

[0050] In addition, the numerical ranges and parameters used to define this application are approximate values. The relevant numerical values ​​in the specific examples have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual testing methods. Therefore, unless otherwise expressly stated, all ranges, amounts, values, and percentages used in this application should be understood to be modified by the word "about." As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range.

[0051] The present application provides a targeted drug, which comprises a tissue-type plasminogen activator and a thrombus-targeting peptide.

[0052] Preferably, the tissue plasminogen activator described herein is recombinant tissue plasminogen activator alteplase (rtPA). rtPA binds to plasminogen in the fibrin network, activating plasminogen to plasmin. Plasmin degrades the fibrin network, thereby achieving the purpose of thrombolysis and dredging blood vessels. It is currently the most widely used and most effective thrombolytic drug in clinical practice. Furthermore, recombinant human rtPA is highly safe for the human body due to its high specificity.

[0053] Preferably, the thrombus targeting peptide described in the present application is CREKA (Cys-Arg-Glu-Lys-Ala) polypeptide. CREKA is a pentapeptide composed of cysteine-arginine-glutamic acid-lysine-alanine. It is a thrombus targeting polypeptide obtained by screening through phage display technology. It can efficiently and specifically bind to fibrin in thrombi. Unlike targeting molecules such as antibodies, CREKA has a higher affinity for fibrin and low immunogenicity. It also has the advantages of short chain length, easy synthesis, and low cost. Existing studies have confirmed that CREKA has strong thrombus targeting, and the thiol group of the cysteine ​​residue of CREKA is not the thrombus binding site of CREKA, and can be used to couple other components without affecting its thrombus targeting ability.

[0054] Preferably, the present application utilizes the water-soluble amine-thiol crosslinker Sulfo-SMCC (4-(N-maleimidomethyl)cyclohexane-1-carboxylic acid sulfosuccinimide ester sodium salt) to react the thiol residues of CREKA with the primary amines exposed on the surface of rtPA, thereby connecting CREKA to the surface of rtPA and conferring thrombus targeting properties on rtPA.

[0055] On the other hand, the present application provides a method for preparing and using the targeted drug, which comprises: using Sulfo-SMCC to link the targeting peptide CREKA to the surface of rtPA, and adjusting the reaction ratio of CREKA to rtPA. The molar ratio of rtPA:Sulfo-SMCC:CREKA is 1:(10-50):(10-50), and examples thereof may be 1:10:10; 1:15:15; 1:20:20; 1:25:25; 1:30:30; 1:40:40; and 1:50:50. This allows rtPA to maintain thrombolytic activity while also possessing thrombus targeting, thereby increasing thrombolytic efficiency, extending the therapeutic window, and improving therapeutic efficacy.

[0056] The specific steps include:

[0057] 1. Dissolve the thrombolytic drug rtPA in 0.4 M HEPES buffer, pH 7.2-7.6.

[0058] 2. Add Sulfo-SMCC to the rtPA solution with a molar ratio of rtPA:Sulfo-SMCC of 1:10-1:50. Mix thoroughly and react at 4°C for 2-12 hours.

[0059] 3. Add CREKA to the rtPA solution containing Sulfo-SMCC, where the molar ratio of rtPA:CREKA is 1:10-1:50. After thorough mixing, react at 4°C for 2-12 hours.

[0060] 4. Place the reacted solution in a 10 kDa centrifugal filter tube and centrifuge at 4°C for 4-6 times to remove unreacted Sulfo-SMCC and CREKA in the solution to obtain a CREKA-rtPA conjugate solution with thrombus targeting.

[0061] In Examples 1 to 5 of the present application, all the raw materials and reagents used can be purchased from the market.

[0062] The present invention will be further described below in conjunction with the embodiments:

[0063] Example 1 Synthesis of CREKA-rtPA Conjugate

[0064] (1) The purchased thrombolytic drug rtPA (Aitongli) was dissolved in sterile water according to the instructions. The solution was then placed in a 10 kDa centrifugal filter tube and centrifuged five times to remove excess amino acids and other substances in the solution. Finally, the volume was fixed with 0.4 M HEPES buffer (pH 7.4).

[0065] (2) Sulfo-SMCC (purchased from abcom, product number ab145607) was added to the rtPA solution, where the molar ratio of rtPA:SMCC was 1:20, and the mixture was thoroughly mixed and reacted at 4°C for 2 h.

[0066] (3) CREKA (commissioned to Shanghai Taopu Technology Co., Ltd. for synthesis) was added to the rtPA solution containing Sulfo-SMCC, as shown in FIG1 . FIG1 is a schematic diagram of the change in molecular weight of the CREKA-rtPA conjugate synthesized in this example compared with rtPA detected by Western blot, wherein the molar ratio of rtPA:CREKA was 1:20. After thorough mixing, the mixture was reacted at 4° C. for 12 h.

[0067] (4) The reacted solution was placed in a 10 kDa centrifugal filter tube and centrifuged five times to remove unreacted Sulfo-SMCC and CREKA in the solution, thereby obtaining a CREKA-rtPA conjugate solution with thrombus targeting, i.e., a targeted drug.

[0068] Example 2 Enzyme Activity Detection of CREKA-rtPA Conjugate

[0069] According to the experimental method of Example 1, CREKA-rtPA conjugates with rtPA:Sulfo-SMCC:CREKA ratios of 1:10:10; 1:20:20; 1:30:30; 1:40:40; and 1:50:50 were prepared and their enzyme activities were identified. Specifically:

[0070] (1) Dilute rtPA and the prepared CREKA-rtPA conjugate to 500 ng / mL with 0.4 M HEPES buffer (pH 7.4);

[0071] (2) The detection substrate S-2288 was prepared into a 10 mM stock solution, which was then diluted ten-fold with water to prepare the application solution;

[0072] (3) Prepare Tris-HCl and adjust the pH to 8.4;

[0073] (4) A 96-well plate was prepared, and 100 μL of rtPA or CREKA-rtPA conjugate was added to each well. 100 μL of S-2288 application solution and 100 μL of Tris-HCl were then added to each well. The mixture was mixed and the absorbance was measured at 405 nm using a microplate reader in the enzymatic reaction kinetics mode at 37°C. The enzymatic activity of the rtPA or CREKA-rtPA conjugate was calculated. As shown in FIG2 , FIG2 is a schematic diagram of the activity test results of CREKA-rtPA conjugates prepared at different synthesis ratios in this example. With rtPA as the control, its enzyme activity was defined as 100%, and the relative change in the enzyme activity of the CREKA-rtPA conjugate was calculated. When the ratio of rtPA:Sulfo-SMCC:CREKA was 1:10:10 and 1:20:20, the effect on the enzyme activity was minimal, being approximately 75% of that of free rtPA.

[0074] Example 3 In vitro thrombus targeting detection of CREKA-rtPA conjugate

[0075] (1) rtPA and the 1:10:10 CREKA-rtPA conjugate and the 1:20:20 CREKA-rtPA conjugate prepared in Example 2 were labeled with fluorescein isothiocyanate (FITC).

[0076] (2) In a 96-well plate, 4 mg / mL fibrinogen (purchased from Solarbio, product number F8050), 0.4 M CaCl2, and 0.1 U / mL thrombin (purchased from Solarbio, product number T8021) were added at a volume ratio of 10:1:1, mixed, and incubated at 37°C for 60 min.

[0077] (3) Add 100 μL of FITC-labeled rtPA or CREKA-rtPA conjugate to the 96-well plate in step 2 and incubate at 37°C in the dark for 30 min.

[0078] (4) Discard the liquid in the 96-well plate, wash three times with PBS, and then use a small animal optical imager (IVIS) to detect the fluorescence value retained in the well plate. Among them, the higher the fluorescence value, the more rtPA or CREKA-rtPA conjugate bound to the fibrin network at the bottom of the plate, and the stronger the thrombus targeting. As shown in Figure 3, Figure 3 is a schematic diagram of the in vitro thrombus targeting test results of CREKA-rtPA conjugates prepared with different synthesis ratios in this embodiment. Compared with the fluorescence intensity of free rtPA, the fluorescence intensity of the CREKA-rtPA conjugate is significantly increased, indicating that CREKA-rtPA is more bound to fibrin and CREKA-rtPA has thrombus targeting.

[0079] Example 4: Evaluation of the Thrombolytic Effect of CREKA-rtPA Conjugate in a FeCl3-Induced Mesenteric Artery Thrombosis Model

[0080] (1) According to the experimental method of Example 1, CREKA-rtPA conjugate was prepared with rtPA:Sulfo-SMCC:CREKA at a ratio of 1:20:20.

[0081] (2) Six-week-old C57Bl / 6 mice were taken and anesthetized by intraperitoneal injection of 1% sodium pentobarbital (0.1 mL / 10 g).

[0082] (3) Rhodamine 6G was dissolved in PBS to prepare a 0.3% solution. The filter membrane was sterilized and 30 μL of the Rhodamine 6G solution was injected into the tail vein to label platelets and leukocytes.

[0083] (4) Place the mouse in a 15 cm culture dish, wipe the mouse abdomen with a 75% alcohol cotton ball, make an abdominal incision, remove the mesentery, spread the mesenteric blood vessels on the surface of the culture dish, and place the culture dish on an inverted fluorescence microscope so that the laser spot is focused on the appropriate small artery.

[0084] (5) Cut a 5 mm × 1 mm filter paper strip and soak it with 10% FeCl 3 solution. Use tweezers to place the filter paper soaked with FeCl 3 solution at the focal point of the arteriole and remove it after five minutes.

[0085] (6) Thrombosis was observed under a microscope. When thrombus formation began, mice were injected with rtPA or CREKA-rtPA conjugate (5 mg / kg) through the tail vein for thrombolytic therapy, and the therapeutic effect was observed under a microscope. As shown in FIG4 , FIG4 is a schematic diagram of the experimental results of evaluating the thrombolytic therapeutic effect of CREKA-rtPA conjugate using the FeCl3-induced mesenteric artery thrombosis model in this embodiment. The white light in the blood vessel indicates thrombus formation. The normal saline group had no therapeutic effect on thrombus formation. rtPA or CREKA-rtPA conjugate treatment can inhibit thrombus formation through thrombolysis. Compared with rtPA, the thrombus dissolution in the CREKA-rtPA conjugate treatment group was more significant, and the thrombus could be removed more quickly and the blood vessels could be unblocked.

[0086] Example 5: Evaluation of the Thrombolytic Effect of CREKA-rtPA Conjugate in a Photochemically Induced Mouse Cerebral Ischemia Model

[0087] (1) Prepare Rose Bengal solution to a final concentration of 15 mg / mL (dissolved in PBS) and filter. According to the experimental method of Example 1, a CREKA-rtPA conjugate was prepared with a ratio of rtPA:Sulfo-SMCC:CREKA of 1:20:20.

[0088] (2) 12-week-old C57Bl / 6 mice were taken and anesthetized.

[0089] (3) Fix the mouse, remove the hair from the head and disinfect it with alcohol, cut the scalp along the midline suture and expose the skull (the experiment was completed on a heating blanket).

[0090] (4) Find the bregma point, 2 mm to the right of bregma as the center, with an area of ​​about 30 mm 2 , mark the area to be irradiated.

[0091] (5) Intraperitoneally inject Rose Bengal solution at a volume of 10 μL / g and circulate for 5 minutes.

[0092] (6) Irradiate the marked area with a light intensity of 150W for 10 minutes.

[0093] (7) Remove the light source, wipe the head with saline solution to prevent dehydration, and suture the wound.

[0094] (8) 4 hours after surgery, mice were injected with rtPA or CREKA-rtPA conjugate (5 mg / kg) through the tail vein for thrombolytic therapy, and the therapeutic effect was observed by TTC staining. As shown in Figure 5, Figure 5 is a schematic diagram of the experimental results of the photochemical method-induced mouse cerebral ischemia model in this embodiment to evaluate the thrombolytic therapeutic effect of CREKA-rtPA; wherein: the left figure is the TTC staining result of mice with ischemia-reperfusion injury treated with normal saline, rtPA or CREKA-rtPA conjugate, where red represents normal brain tissue and white represents infarcted brain tissue; the right figure is the measurement and statistics of the brain infarction volume of each group of mice in the left figure. TTC dye stains normal tissue red and infarcted tissue white. The larger the volume of white tissue, the larger the brain infarction volume and the more obvious the damage. It can be seen that when rtPA is administered 4 hours after embolization, it has no obvious therapeutic effect, while CREKA-rtPA conjugate can significantly reduce the brain infarction volume of mice, indicating that CREKA-rtPA extends the therapeutic time window of rtPA, has better thrombolytic therapeutic effect and a wider range of thrombolytic treatment scenarios.

[0095] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A targeted drug, characterized in that: The targeted drugs include: tissue plasminogen activator; and Targeting peptides.

2. The targeted drug according to claim 1, characterized in that The targeted drug also includes: a cross-linking agent.

3. The targeted drug according to claim 1 or 2, characterized in that: The molar ratio of the tissue plasminogen activator to the targeting peptide is 1:(10-50).

4. The targeted drug according to claim 2 or 3, characterized in that: The molar ratio of the tissue plasminogen activator, the targeting peptide and the cross-linking agent is 1:(10-50):(10-50).

5. The targeted drug according to any one of claims 1 to 4, characterized in that: The tissue plasminogen activator includes: alteplase.

6. The targeted drug according to any one of claims 1 to 5, characterized in that: The targeting peptides include: thrombus targeting peptides.

7. The targeted drug according to any one of claims 1 to 6, characterized in that: The targeting peptide has: (1), the amino acid sequence shown in SEQ ID NO: 1; or (2) an amino acid sequence obtained by replacing, deleting or adding one or more amino groups of the amino acid sequence shown in (1), and having the same or similar function as the amino acid sequence shown in (1); or (3) An amino acid sequence that is at least 80% identical to the amino acid sequence shown in (1) or (2).

8. The targeted drug according to any one of claims 2 to 7, characterized in that: The cross-linking agent includes: a water-soluble amine-thiol cross-linking agent.

9. A preparation method, characterized in that: The cross-linking agent is mixed with the tissue plasminogen activator, and then mixed with the thrombus targeting peptide, and then centrifuged and filtered to obtain the targeted drug according to any one of claims 2 to 8.

10. An application of a targeted drug, characterized in that: The invention comprises the use of the targeted drug according to any one of claims 1 to 8 and / or the targeted drug obtained by the preparation method according to claim 9 in the preparation of drugs and / or preparations for treating thrombolysis.

Images