Targeted drug as well as preparation method and application thereof

Abstract

The invention relates to the field of nano medicines, in particular to a targeted medicine as well as a preparation method and application thereof. The invention provides a targeted drug. The targeted drug comprises a tissue-type plasminogen activator and a targeted peptide. Thrombus targeting modification is directly carried out on a thrombolytic drug rtPA which is most widely applied clinically by utilizing a chemical method, the defects of narrow treatment time window, high dosage and high bleeding risk of the rtPA are remarkably improved, the preparation process is simple and controllable, materials required for preparation are easy to obtain, the cost is low, and the application prospect is wide. The toxic effect and degradation problems of materials such as compounds are eliminated, other instruments and equipment are not needed in the treatment process, and clinical transformation application of thrombus targeted rtPA becomes possible.

Description

Technical Field

[0001] The present invention relates to the field of nanomedicine, and in particular to targeted drugs and preparation methods and applications thereof. Background Art

[0002] Thrombotic diseases, including myocardial infarction, pulmonary embolism, ischemic stroke, etc., are the main causes of death and disability worldwide. In particular, ischemic stroke has become the second leading cause of death in humans. Acute vascular occlusion at the site of thrombus may cause severe tissue damage or even organ failure, and ultimately endanger 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 alteplase (rtPA) is the only thrombolytic drug approved by the US Food and Drug Administration for the treatment of ischemic stroke. It is also the most mature, most commonly used, and most effective therapeutic drug in clinical practice. Due to its good ability to dissolve fibrin, the main component of thrombus, it has been used for intravenous injection treatment of thrombotic diseases such as ischemic stroke, pulmonary embolism, and myocardial infarction. However, due to the short half-life of rtPA (about 4-8 minutes), the dredging efficiency is not high, and high-dose intravenous infusion is required to maintain effective drug concentrations; repeated administration and systemic application are prone to cause hemorrhagic transformation, and serious bleeding complications limit 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 be higher than the risk of bleeding, which means that less than 5% of patients can receive rtPA thrombolytic therapy clinically. Therefore, in order to improve patient prognosis, it has become a major clinical need to modify thrombolytic drugs, improve thrombolytic efficiency, and reduce bleeding complications in the treatment of thrombotic diseases.

[0003] In recent years, with the development of nanotechnology, a variety of rtPA modified by nano-targeted delivery systems have been reported. For example, rtPA is encapsulated by polymers or liposomes to extend its half-life, and rtPA-containing nanoparticles are modified by antibodies, peptides, biofilms or magnetic effects to give rtPA thrombus targeting, increase local drug concentrations, and observe more significant therapeutic effects than free rtPA at the animal level. However, due to the shortcomings of the reported rtPA modification strategies, such as complex preparation processes, the need for magnetic field or photothermal therapy assistance, and the problem of material degradation in vivo, there is still a lack of improved rtPA with good therapeutic effects, simple preparation processes, and easy conversion applications. Summary of the invention

[0004] In view of this, the present invention provides a targeted drug and a preparation method and application thereof. The present invention uses a chemical method to directly transform rtPA, the most widely used thrombolytic drug in clinical practice, into a thrombus-targeted drug, significantly improving the shortcomings of rtPA, such as a narrow treatment time window, high dosage, and high risk of bleeding. 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 materials themselves, such as compounds, are eliminated. No other instruments or equipment are required during the treatment process, making the clinical transformation and application of thrombus-targeted rtPA possible.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a targeted drug, comprising: a tissue-type plasminogen activator and a targeting peptide.

[0007] In some embodiments of the present invention, in the above-mentioned targeted drug, the tissue plasminogen activator is recombinant tissue plasminogen activator.

[0008] In some embodiments of the present invention, the above-mentioned targeted drug further includes: a cross-linking agent.

[0009] In some embodiments of the present invention, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator to the targeting peptide is 1:(10-50).

[0010] In some embodiments of the present invention, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator to the targeting peptide is 1:(10-30).

[0011] In some embodiments of the present invention, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator to the targeting peptide is 1:(15-25).

[0012] In some embodiments of the present invention, in the above-mentioned targeted drug, the molar ratio of the tissue plasminogen activator to the targeting peptide is 1:20.

[0013] In some embodiments of the present invention, 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).

[0014] In some embodiments of the present invention, 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).

[0015] In some embodiments of the present invention, 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).

[0016] In some embodiments of the present invention, 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.

[0017] In some embodiments of the present invention, in the above-mentioned targeted drug, the tissue plasminogen activator includes: alteplase.

[0018] In some embodiments of the present invention, in the above-mentioned targeted drug, the targeting peptide includes: a thrombus targeting peptide.

[0019] In some embodiments of the present invention, in the above-mentioned targeted drug, the thrombus targeting peptide is: CREKA.

[0020] In some embodiments of the present invention, in the above-mentioned targeted drug, the targeting peptide has:

[0021] (1), the amino acid sequence shown in SEQ ID NO: 1; or

[0022] (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

[0023] (3) An amino acid sequence that is at least 80% identical to the amino acid sequence shown in (1) or (2).

[0024] In some embodiments of the present invention, in the above-mentioned targeted drug, the sequence of the targeting peptide is: Cys-Arg-Glu-Lys-Ala.

[0025] In some embodiments of the present invention, in the above-mentioned targeted drug, the cross-linking agent includes: a water-soluble amine-thiol cross-linking agent.

[0026] In some embodiments of the present invention, in the above-mentioned targeted drug, the cross-linking agent includes: Sulfo-SMCC.

[0027] The present invention also provides a method for preparing the above-mentioned targeted drug, wherein 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.

[0028] In some embodiments of the present invention, 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).

[0029] In some embodiments of the present invention, 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).

[0030] In some embodiments of the present invention, 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).

[0031] In some embodiments of the present invention, 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.

[0032] In some embodiments of the present invention, in the above preparation method, after the cross-linking agent and the tissue plasminogen activator are mixed, the mixing time is 2h to 12h and the temperature is 4°C.

[0033] In some embodiments of the present invention, in the above-mentioned preparation method, the mixing time in the thrombus targeting peptide mixing is 2h to 12h, and the temperature is 4°C.

[0034] In some embodiments of the present invention, in the above preparation method, the number of centrifugal filtration is no less than 5 times.

[0035] The present invention also provides the use of the above-mentioned targeted drug and / or the targeted drug obtained by the above-mentioned preparation method in the preparation of drugs and / or preparations for treating thrombolysis.

[0036] The present invention provides a targeted drug, including: tissue plasminogen activator and targeting peptide. The thrombus-targeted rtPA of the present invention enables rtPA to have thrombus targeting ability, significantly improves the drug concentration at the thrombus site, improves the thrombolytic efficiency of rtPA, improves the treatment effect, and reduces the risk of hemorrhagic transformation; at the same time, compared with the reported rtPA transformation strategy, the present invention directly connects the thrombus-targeting peptide with rtPA through a chemical reaction to perform targeted transformation on it, the preparation process is simple and controllable, the materials required for preparation are easy to obtain and low in cost, the toxic effects and degradation problems of the materials themselves such as compounds are eliminated, and no other instruments and equipment are required during the treatment process, making the clinical transformation application of thrombus-targeted rtPA possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0038] Figure 1 The figure shows the change of molecular weight of the CREKA-rtPA conjugate synthesized in Example 1 of the present invention compared with rtPA detected by Western-blot;

[0039] Figure 2 The activity test results of CREKA-rtPA conjugates prepared at different synthesis ratios in Example 2 are shown;

[0040] Figure 3 The results of in vitro thrombus targeting detection of CREKA-rtPA conjugates prepared with different synthesis ratios in Example 3 are shown;

[0041] Figure 4 Graph showing the experimental results of evaluating the thrombolytic therapeutic effect of CREKA-rtPA conjugate using the FeCl3-induced mesenteric artery thrombosis model in Example 4;

[0042] Figure 5 The figures show the experimental results of evaluating the thrombolytic therapeutic effect of CREKA-rtPA in the mouse cerebral ischemia model induced by the photochemical method in Example 5; wherein: the left shows the TTC staining results of ischemia-reperfusion injured mice after treatment with normal saline, rtPA or CREKA-rtPA conjugate, wherein red represents normal brain tissue and white represents infarcted brain tissue; the right shows the measurement statistics of cerebral infarction volume of each group of mice in the left figure. DETAILED DESCRIPTION

[0043] The invention discloses a targeted drug and a preparation method and application thereof.

[0044] It should be understood that the expression "one or more of..." includes each of the items recited after the expression individually and in various different combinations of two or more of the recited items, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited items should be understood to have the same meaning, unless otherwise understood from the context.

[0045] The use of the terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, for example not excluding other unrecited elements or steps, unless otherwise specifically stated or otherwise understood from the context.

[0046] 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 present invention remains operable. In addition, two or more steps or actions may be performed simultaneously.

[0047] The use of any and all examples or exemplary language, such as "for example" or "including", herein is intended only to better illustrate the invention and does not limit the scope of the invention unless otherwise claimed. No language in this specification should be construed as indicating that any non-claimed element is essential to the practice of the invention.

[0048] In addition, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise expressly stated, it should be understood that all ranges, quantities, values ​​and percentages used in this disclosure are modified by "about". Here, "about" generally means that the actual value is within plus or minus 10%, 5%, 1% or 0.5% of a specific value or range.

[0049] The invention provides a targeted thrombolytic drug, which comprises a tissue-type plasminogen activator and a thrombus targeting peptide.

[0050] Preferably, the tissue plasminogen activator of the present invention is recombinant tissue plasminogen activator alteplase (rtPA). rtPA can bind to plasminogen in the fibrin network, activating plasminogen to plasmin, which plays a role in degrading the fibrin network, thereby achieving the purpose of thrombolysis and dredging blood vessels. It is currently the most widely used clinical thrombolytic drug with the best therapeutic effect; at the same time, recombinant human rtPA has high safety for the human body due to its high specificity.

[0051] Preferably, the thrombus targeting peptide of the present invention is a 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, which can be used to couple other components without affecting its thrombus targeting ability.

[0052] Preferably, the present invention utilizes a 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 primary amines exposed on the surface of rtPA, thereby connecting CREKA to the surface of rtPA and conferring thrombus targeting to rtPA.

[0053] On the other hand, the present invention provides a method for preparing and using the thrombus-targeted thrombolytic drug, wherein the method comprises: using Sulfo-SMCC to connect 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; 1: 50: 50. rtPA can be made to have thrombus targeting while maintaining thrombolytic activity, thereby improving thrombolytic efficiency, extending the treatment time window, and improving the treatment effect.

[0054] The specific steps include:

[0055] 1. Dissolve the thrombolytic drug rtPA in 0.4 M HEPES buffer, pH 7.2-7.6.

[0056] 2. Add Sulfo-SMCC to the rtPA solution, where the molar ratio of rtPA:Sulfo-SMCC is 1:10-1:50. Mix thoroughly and react at 4°C for 2-12 hours.

[0057] 3. Add CREKA to the rtPA solution containing Sulfo-SMCC, where the molar ratio of rtPA:CREKA is 1:10-1:50. Mix thoroughly and react at 4°C for 2-12 hours.

[0058] 4. Place the solution after the reaction in a 10 kDa centrifugal filter tube and centrifuge it at 4°C for 4-6 times to remove the unreacted Sulfo-SMCC and CREKA in the solution to obtain a CREKA-rtPA conjugate solution with thrombus targeting.

[0059] In Examples 1 to 5 of the present invention, all the raw materials and reagents used can be purchased from the market.

[0060] The present invention will be further described below in conjunction with embodiments:

[0061] Example 1 Synthesis of CREKA-rtPA Conjugate

[0062] (1) Dissolve the purchased thrombolytic drug rtPA (Actinib) in sterile water according to the instructions, then place the solution in a 10 kDa centrifugal filter tube and centrifuge it 5 times to remove excess amino acids and other substances in the solution. Finally, make up the volume with 0.4 M HEPES buffer (pH 7.4).

[0063] (2) Sulfo-SMCC (purchased from abcom, catalog number ab145607) was added to the rtPA solution, wherein the molar ratio of rtPA:SMCC was 1:20, and then mixed thoroughly and reacted at 4°C for 2 h.

[0064] (3) CREKA (commissioned by Shanghai Taopu Technology Co., Ltd. for synthesis) was added to the rtPA solution containing Sulfo-SMCC, wherein the molar ratio of rtPA:CREKA was 1:20. After thorough mixing, the mixture was reacted at 4°C for 12 h.

[0065] (4) The solution after the reaction was placed in a 10 kDa centrifugal filter tube and centrifuged five times to remove the unreacted Sulfo-SMCC and CREKA in the solution, thereby obtaining a CREKA-rtPA conjugate solution with thrombus targeting, i.e., a targeted drug.

[0066] Example 2 Enzyme Activity Detection of CREKA-rtPA Conjugate

[0067] 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; 1:50:50 were prepared and their enzyme activities were identified. Specifically:

[0068] (1) diluting rtPA and the prepared CREKA-rtPA conjugate to 500 ng / mL with 0.4 M HEPES buffer (pH 7.4);

[0069] (2) The detection substrate S-2288 was prepared into a 10 mM stock solution, which was then diluted ten-fold with water to prepare an application solution;

[0070] (3) Prepare Tris-HCL and adjust the pH to 8.4;

[0071] (4) Take a 96-well plate and add 100 μL of rtPA or CREKA-rtPA conjugate to each well. Then add 100 μL of S-2288 application solution and 100 μL of Tris-HCL to each well, mix well, and measure the absorbance at 405 nm using an enzyme-catalyzed reaction kinetics mode on a microplate reader at 37°C to calculate the enzyme activity of rtPA or CREKA-rtPA conjugate. Figure 2 As shown, taking rtPA as the control and defining its enzyme activity as 100%, the relative change value of the enzyme activity of the CREKA-rtPA conjugate was calculated. When the ratio of rtPA:Sulfo-SMCC:CRE KA was 1:10:10 and 1:20:20, the effect on the enzyme activity was minimal, which was about 75% of the free rtPA.

[0072] Example 3 In vitro thrombus targeting detection of CREKA-rtPA conjugate

[0073] (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).

[0074] (2) In a 96-well plate, 4 mg / mL fibrinogen (purchased from Solarbio, Catalog No. F8050), 0.4 M CaCl2, and 0.1 U / mL thrombin (purchased from Solarbio, Catalog No. T8021) were added at a volume ratio of 10:1:1, mixed, and incubated at 37°C for 60 min.

[0075] (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.

[0076] (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 is bound to the fibrin network at the bottom of the plate, and the stronger the thrombus targeting. Figure 3 As shown, compared with the fluorescence intensity of free rtPA, the fluorescence intensity of the CREKA-rtPA conjugate was significantly increased, indicating that CREKA-rtPA bound more to fibrin and had thrombus targeting properties.

[0077] Example 4: Evaluation of the thrombolytic effect of CREKA-rtPA conjugate in FeCl3-induced mesenteric artery thrombosis model

[0078] (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.

[0079] (2) Six-week-old C57Bl / 6 mice were taken and anesthetized by intraperitoneal injection of 1% sodium pentobarbital (0.1 mL / 10 g).

[0080] (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.

[0081] (4) Place the mouse in a 15 cm culture dish, wipe the mouse abdomen with a 75% alcohol cotton ball, make an incision in the abdomen, 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.

[0082] (5) Cut a 5 mm × 1 mm filter paper strip, soak it with 10% FeCl3 solution, and use tweezers to place the filter paper soaked with FeCl3 solution at the focal point of the arteriole and remove it after five minutes.

[0083] (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. Figure 4 As shown, the bright white light in the blood vessel indicates thrombosis. The normal saline group has no therapeutic effect on thrombosis. rtPA or CREKA-rtPA conjugate treatment can inhibit thrombosis by thrombolysis. Compared with rtPA, the thrombus dissolution in the CREKA-rtPA conjugate treatment group is more significant, and the thrombus can be removed more quickly and the blood vessels can be unblocked.

[0084] Example 5 Photochemical method induced mouse cerebral ischemia model to evaluate the thrombolytic effect of CREKA-rtPA conjugate

[0085] (1) Prepare Rose Bengal solution with a final concentration of 15 mg / mL (dissolved in PBS) and filter. According to the experimental method of Example 1, CREKA-rtPA conjugate was prepared with a ratio of rtPA:Sulfo-SMCC:CREKA of 1:20:20.

[0086] (2) 12-week-old C57Bl / 6 mice were taken and anesthetized.

[0087] (3) The mice were fixed, the hair on the head was removed and disinfected with alcohol, and the scalp was cut along the midline to expose the skull (the experiment was performed on a heating blanket).

[0088] (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.

[0089] (5) Intraperitoneally inject Rose Bengal solution at a volume of 10 μL / g and circulate for 5 min.

[0090] (6) Irradiate the marked area with a light intensity of 150 W for 10 minutes.

[0091] (7) Remove the light source, wipe the head with saline solution to prevent dehydration, and suture the wound.

[0092] (8) 4 hours after surgery, mice were injected with rtPA or CREKA-rtPA conjugate (5 mg / kg) via tail vein for thrombolytic therapy, and the therapeutic effect was observed by TTC staining. Figure 5As shown, TTC dye dyes normal tissue in red and infarcted tissue in white. The larger the volume of white tissue, the larger the volume of cerebral infarction 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 volume of cerebral infarction in mice, indicating that CREKA-rtPA prolongs the treatment time window of rtPA and has better thrombolytic therapy effect and a wider range of thrombolytic therapy scenarios.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Targeted drug, characterized in that: include: Tissue plasminogen activator and targeting peptides.

2. The targeted drug according to claim 1, characterized in that Also includes: 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. The method for preparing a targeted drug according to any one of claims 2 to 8, 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 targeting drug.

10. 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.

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