Pharmacokinetics modified FAP-α specific radiopharmaceutical and use thereof

Abstract

The present invention relates to a pharmacokinetics modified FAP-α specific radiopharmaceutical and a use thereof, and specifically provides a novel pharmacokinetic linker modified OncoFAP molecule. The molecule can be coupled to bifunctional chelators (BFCs), including HYNIC, MAG2, MAG3, DTPA, DOTA, NOTA, (±)-H3RESCA, TETA, etc., for labeling nuclides such as 99mTc, 68Ga, 64Cu, 18F, 111In, 90Y, and 177Lu, and then, by using nuclear medicine imaging technology, imaging diagnosis and nuclide therapy are carried out on FAP-positive tumors or fibrotic diseases.

Description

A pharmacokinetic modified FAP-α specific radiopharmaceutical and its application Technical Field

[0001] The present invention relates to the field of medicine, and in particular to a pharmacokinetic modified FAP-α specific radiopharmaceutical and application thereof. Background Art

[0002] Cancer is the second leading cause of death in the world. Despite significant advances in diagnosis and treatment, most developed therapies target tumor cells while ignoring the tumor microenvironment.

[0003] Tumor entities contain not only tumor cells, but also stromal cells such as vascular cells, inflammatory cells, and fibroblasts. The stroma in tumors usually accounts for a large part of the malignant tumor entity, and can even account for more than 90% of the tumor mass. A complex network of interactions exists between the stroma and tumor cells. In particular, a cell subpopulation called cancer-associated fibroblasts (CAFs) is involved in almost all stages of tumorigenesis, playing a role in tumor initiation, progression, and metastasis. Therefore, CAFs have become one of the hot topics in the field of tumor research.

[0004] CAFs have diverse origins, potentially originating from tumor-localized fibroblasts, circulating fibroblasts, vascular endothelial cells, adipocytes, bone marrow-derived stem cells, and even cancer cells. Differences in tissue type contribute to CAF heterogeneity. Due to the heterogeneity in CAF origin and expression patterns, it is difficult to identify all CAF subpopulations using a single, unified marker. However, fibroblast activation protein (FAP) has been found to be highly expressed in stromal CAFs of many tumors. FAP is a type II membrane-bound glycoprotein that belongs to the type II serine protease family and possesses both dipeptidyl peptidase and endopeptidase activities. This enzyme is transiently expressed during embryonic development and is absent or extremely low in normal adult tissues. However, it is highly expressed in over 90% of epithelial cancers, including head and neck cancer, breast cancer, lung cancer, pancreatic cancer, esophageal cancer, colorectal cancer, ovarian cancer, gastric cancer, and liver cancer. High FAP expression in CAFs has been shown to be a marker of tumor aggressiveness and poor prognosis. Moreover, compared with tumors, the differentially low expression of FAP in normal tissues provides excellent conditions for radionuclide-labeled FAP-targeted nuclear medicine imaging. At the same time, its high expression also facilitates subsequent radio-targeted therapy or targeted drug delivery.

[0005] Since the origin, number, distribution, and number of FAP molecules in each cell of FAP-expressing CAFs in human tumors may vary, in order to better perform nuclear medicine probe imaging of tumors with relatively low FAP expression levels in clinical practice, it is necessary to optimize the existing FAP small molecule nuclear medicine probes to improve their tumor targeting, improve their in vivo stability, achieve higher tumor uptake and faster systemic background clearance rate, and improve their in vivo metabolic properties, thereby obtaining significant tumor / normal tissue contrast and improving the lesion detection rate.

[0006] However, the FAP-like molecules currently under investigation are rapidly cleared from the body, and researchers need to continue developing new molecular structures to modulate pharmacokinetic characteristics, increase their circulation time in the body, and thus enhance tumor uptake and retention. Furthermore, they need to further optimize drug uptake in specific tissues to achieve higher tumor uptake in different lesions and better contrast between tumor and non-target tissues. These performance improvements will help to increase the detection rate and accuracy of FAP-positive tumors, significantly enhancing detection efficacy.

[0007] Summary of the Invention

[0008] One of the purposes of the present invention is to provide a new class of oncoFAP radiopharmaceuticals modified with a pharmacokinetic linker. The novel oncoFAP molecules modified with a pharmacokinetic linker designed in the present invention can be coupled with bifunctional chelators (BFCs), including HYNIC, MAG2, MAG3, DTPA, DOTA, NOTA, (±)-H3RESCA, TETA, etc., for 99m Tc, 68 Ga, 64 Cu, 18 F. 111 In, 90 Y. 177 Lu and other radionuclides are labeled, and then nuclear medicine imaging technology is used to perform imaging diagnosis and radionuclide therapy of FAP-positive tumors or fibrotic diseases.

[0009] To this end, in the first aspect of the present invention, the present invention provides a compound represented by formula I or a pharmaceutically acceptable salt thereof,

[0010] Wherein, n is selected from any integer between 6 and 24 (e.g., 6, 7, 8, 9, 10, 11, 12).

[0011] In some embodiments, the compound is selected from:

[0012] In a second aspect of the present invention, the present invention provides a precursor compound for forming a radionuclide complex or a pharmaceutically acceptable salt thereof, wherein the precursor compound is formed by covalently linking the aforementioned compound and a bifunctional chelating agent.

[0013] In some embodiments, the bifunctional chelator is selected from HYNIC, MAG2, MAG3, DTPA, DOTA, NOTA, (±)-H3RESCA, TETA.

[0014] In some embodiments, the precursor compound for forming the radionuclide complex has the structure shown in Formula II,

[0015] in:

[0016] n is selected from any integer between 6 and 24 (e.g., 6, 7, 8, 9, 10, 11, 12);

[0017] R is a bifunctional chelating agent group selected from

[0018] In some embodiments, the precursor compound used to form the radionuclide complex is selected from:

[0019] In the third aspect of the present invention, the present invention provides a radionuclide complex, which is obtained by labeling the aforementioned precursor compound or a pharmaceutically acceptable salt thereof with a radionuclide.

[0020] Those skilled in the art will understand that for the radionuclide complex, when the bifunctional chelating agent as a ligand cannot occupy all positions of the radionuclide, a cooperative ligand is required. The radionuclides and bifunctional chelating agents that require cooperative ligands in the present invention are well known to those skilled in the art. For example 99m When Tc uses HYNIC as a bifunctional chelating agent, the cooperating ligands may be the same or different and are all known in the prior art. Common cooperating ligands include water-soluble phosphines (e.g., triphenylphosphine tris-metasulfonic acid sodium salt TPPTS), N-tris(hydroxymethyl)methylglycine (Tricine), N-bis(hydroxyethyl)glycine, glucoheptonic acid salt, ethylenediamine-N,N'-diacetate (EDDA), 3-benzoylpyridine (BP), pyridine-2-azo-p-dimethylaniline (PADA), etc. Thus, in some embodiments, the preparation method of the radionuclide complex comprises: reacting the precursor compound represented by the aforementioned formula II or a pharmaceutically acceptable salt thereof with a compound containing a radionuclide (e.g., Na 99mIn other embodiments, the preparation method of the radionuclide complex comprises: reacting the precursor compound represented by the aforementioned formula II or a pharmaceutically acceptable salt thereof and a cooperative ligand (such as triphenylphosphine tris-metasulfonic acid sodium salt TPPTS) with a compound containing a radionuclide (such as Na 99m TcO4) to react in order to obtain the radionuclide complex.

[0021] In some embodiments, the radionuclide is selected from 43 Sc, 44 Sc, 51 Mn, 52 Mn, 64 Cu, 67 Ga, 68 Ga, 86 Y. 89 Zr, 99m Tc, 111 In, 149 Tb, 152 Tb, 155 Tb, 201 Tl, 203 Pb, 18 F. In some preferred embodiments, the radionuclide is selected from 64 Cu, 68 Ga, 99m Tc.

[0022] In some embodiments, the radionuclide is selected from 47 Sc, 67 Cu, 89 Sr. 90 Y. 153 Sm, 149 Tb, 161 Tb, 177 Lu, 186 Re、 188 Re、 212 Pb, 213 Bi, 223 Ra, 225 Ac, 226 Th, 227 Th, 211 In some preferred embodiments, the radionuclide is 177 Lu.

[0023] In some embodiments, the radionuclide is 99m Tc, the bifunctional chelating agent is HYNIC.

[0024] In some embodiments, the radionuclide is selected from 64 Cu, 68 Ga, 177 Lu, the bifunctional chelating agent is selected from DOTA and NOTA.

[0025] In some embodiments, the radionuclide complex is selected from the group consisting of:

[0026] In the fourth aspect of the present invention, the present invention provides a pharmaceutical composition comprising the compound represented by the aforementioned formula I or a pharmaceutically acceptable salt thereof, or the precursor compound represented by the aforementioned formula II or a pharmaceutically acceptable salt thereof, or the aforementioned radionuclide complex; optionally, further comprising a pharmaceutically acceptable carrier and / or excipient.

[0027] In some embodiments, the pharmaceutical composition is an injectable formulation.

[0028] In some embodiments, the injection preparation is a colorless and transparent injection preparation.

[0029] In a fifth aspect, the present invention provides an imaging diagnostic agent and / or a radioactive targeted therapeutic agent, which comprises the aforementioned radionuclide complex.

[0030] In some embodiments, the imaging is SPECT imaging, PET imaging, and / or CT imaging.

[0031] In the sixth aspect of the present invention, the present invention provides a kit comprising the compound represented by the aforementioned formula I or a pharmaceutically acceptable salt thereof, or the precursor compound represented by the aforementioned formula II or a pharmaceutically acceptable salt thereof, or the aforementioned radionuclide complex, or the aforementioned pharmaceutical composition, or the aforementioned imaging agent and / or radioactive targeted therapeutic agent.

[0032] In the seventh aspect of the present invention, the present invention provides the use of the compound represented by the aforementioned formula I or a pharmaceutically acceptable salt thereof, or the precursor compound represented by the aforementioned formula II or a pharmaceutically acceptable salt thereof, or the aforementioned radionuclide complex, or the aforementioned pharmaceutical composition in the preparation of a reagent or drug for diagnosing and / or treating diseases related to overexpression of fibroblast activation protein (FAP).

[0033] In an eighth aspect, the present invention provides the aforementioned radionuclide complex or the aforementioned pharmaceutical composition for use in diagnosing and / or treating diseases associated with overexpression of fibroblast activation protein (FAP).

[0034] In its ninth aspect, the present invention provides a method for diagnosing and / or treating a disease associated with overexpression of fibroblast activation protein (FAP), comprising administering to a subject in need thereof an effective amount of the aforementioned radionuclide complex or the aforementioned pharmaceutical composition.

[0035] In some embodiments, the diagnosis is an imaging diagnosis, and the imaging is selected from SPECT imaging and PET imaging.

[0036] In some embodiments, the treatment is radiotargeted therapy.

[0037] In some embodiments, the disease is selected from a FAP-positive tumor, a FAP-positive fibrotic disease.

[0038] In some embodiments, the FAP-positive tumor is selected from the group consisting of head and neck cancer, breast cancer, lung cancer, pancreatic cancer, esophageal cancer, colorectal cancer, colon cancer, sigmoid colon cancer, ovarian cancer, gastric cancer, gastric antral cancer, and liver cancer.

[0039] In some embodiments, the FAP-positive tumor is colon cancer. In some embodiments, the diagnosis and / or treatment time is no more than 4 hours (such as 1 hour, 2 hours, 3 hours or 4 hours, etc.).

[0040] In some embodiments, the FAP-positive fibrotic disease is selected from pulmonary fibrosis, liver fibrosis, and renal fibrosis.

[0041] Definition of terms

[0042] In the present invention, the term "pharmaceutically acceptable salt" refers to a salt formed by a basic functional group present in the compound provided by the present invention and an appropriate inorganic or organic anion (acid), and includes, but is not limited to, hydrohalides, such as hydrofluorides, hydrochlorides, hydrobromides, hydroiodides, etc.; inorganic acid salts, such as nitrates, perchlorates, sulfates, phosphates, etc.; lower alkanesulfonates, such as methanesulfonates, trifluoromethanesulfonates, ethanesulfonates, etc.; arylsulfonates, such as benzenesulfonates, p-toluenesulfonates, etc.; organic acid salts, such as acetates, malates, fumarates, succinates, citrates, tartrates, oxalates, maleates, etc.; amino acid salts, such as glycine, trimethylglycine, arginine, ornithine, glutamate, aspartate, etc.; or or salts formed by the acidic functional groups present in the compounds provided by the present invention and appropriate inorganic or organic cations (bases), and include but are not limited to alkali metal salts, such as sodium salts, potassium salts, lithium salts, etc.; alkaline earth metal salts, such as calcium salts, magnesium salts, etc.; other metal salts, such as aluminum salts, iron salts, zinc salts, copper salts, nickel salts, cobalt salts, etc.; inorganic base salts, such as ammonium salts; organic base salts, such as tert-octylamine salts, dibenzylamine salts, morpholine salts, glucosamine salts, phenylglycine alkyl ester salts, ethylenediamine salts, N-methylglucosamine salts, guanidine salts, diethylamine salts, triethylamine salts, dicyclohexylamine salts, N,N'-dibenzylethylenediamine salts, chloroprocaine salts, procaine salts, diethanolamine salts, N-benzyl-phenethylamine salts, piperazine salts, tetramethylamine salts, tris(hydroxymethyl)aminomethane salts, etc.

[0043] In the present invention, "treating" generally refers to obtaining the desired pharmacological and / or physiological effect, including: (a) inhibiting the symptoms of the disease, i.e., preventing its development; or (b) alleviating the symptoms of the disease, i.e., causing regression of the disease or symptoms.

[0044] In the present invention, "subject" refers to a vertebrate. In certain embodiments, the vertebrate refers to a mammal. Mammals include, but are not limited to, livestock (such as cattle), pets (such as cats, dogs, and horses), primates, mice, and rats. In certain embodiments, the mammal refers to a human.

[0045] As used herein, the term "effective amount" refers to an amount sufficient to achieve, or at least partially achieve, the desired effect. Determination of such an effective amount is well within the capabilities of those skilled in the art. For example, an amount effective for therapeutic use will depend on the severity of the disease being treated, the overall state of the patient's own immune system, the patient's general condition such as age, weight, and sex, the mode of administration of the drug, and any other concurrently administered treatments. It will be further understood that for any particular individual, the specific dosing regimen may be adjusted over time based on individual needs and the mode of administration or the professional judgment of the person supervising administration. Beneficial effects

[0046] 1. The radiopharmaceutical of the present invention is a new FAP-targeted molecular imaging probe that can be applied to nuclear medicine molecular imaging of various FAP-expressing tumors or FAP-positive fibrotic diseases (such as pulmonary fibrosis, liver fibrosis, etc.), thereby achieving early diagnosis and screening of the disease. Based on the small molecule oncoFAP, the present invention has modified the structure to obtain a ligand compound with a larger molecular weight and volume. The prepared radiopharmaceutical has significantly excellent in vivo stability, stronger tumor targeting, and higher contrast between tumors and non-target tissues. At the same time, the biocompatibility of the probe is improved and the pharmacokinetic properties are optimized. In addition, the ligand compound of the present invention has a wider range of applications. In addition to chelating with HYNIC, it can also chelate with DOTA and the like, and can be used for 68 Ga, 64 Cu and 177 Lu and other markers, and then applied to the imaging (PET, SPECT, etc.) and radionuclide targeted radiotherapy of more FAP-expressing tumors.

[0047] 2. Compared with oncoFAP known in the prior art, the compounds of the present invention have higher tumor uptake and imaging contrast, better tumor-specific targeting ability, and faster clearance from the blood, which reduces the background of other organs and thus presents better contrast in nuclear medicine imaging. The structural modifications and improvements made by the present invention on the basis of oncoFAP, especially PEG 6-24 The modification of the chain makes the compound of the present invention have better tumor targeting properties and in vivo metabolic properties, and thus has excellent application performance and value. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1. Synthesis route of HYNIC-C2-oncoFAP.

[0049] Figure 2. Synthesis route of HYNIC-PEG6-oncoFAP.

[0050] Figure 3. HYNIC-PEG 12 -synthetic route of oncoFAP.

[0051] Figure 4. (A) 99m Tc-HYNIC-C2-oncoFAP, (B) 99m Tc-HYNIC-PEG6-oncoFAP, (C) 99m Tc-HYNIC-PEG 12 -Schematic diagram of the marker structure of oncoFAP.

[0052] Figure 5. 99m Tc-HYNIC-C2-oncoFAP, 99mTc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -oncoFAP lipid-water partition coefficient (LogP o / w ) and radio-HPLC analysis chart.

[0053] Figure 6. 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -Small animal SPECT / CT imaging results 0.5, 1, 2, and 4 hours after oncoFAP injection.

[0054] Figure 7. 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -OncoFAPP biodistribution and blood clearance experimental results 0.5, 1, 2 and 4 hours after injection.

[0055] Figure 8. Injection of dimer probes in colon cancer patients 99m Tc-HYNIC-oncoFAP2 and monomeric probes 99m Comparison of SPECT / CT images 1 hour after Tc-HYNIC-C2-oncoFAP. Images (A) and (B) are images 1 hour after injection of the dimer; images (C) and (D) are images 1 hour after injection of the monomer (Note: red arrows—pancreas; brown arrows—gallbladder; blue arrows—primary colon lesions; yellow arrows—physiological accumulation of the imaging agent in the common bile duct) (A, C—MIP images; B, D—local cross-sectional SPECT / CT fusion images).

[0056] Figure 9. Injection in patients with colon cancer 99m SPECT / CT images 1 and 4 hours after Tc-HYNIC-C2-oncoFAP. Images (A, B, and C) are 1 hour after injection; images (D, E, and F) are 4 hours after injection (note: red arrows—gallbladder; green arrows—pancreas; blue arrows—primary colon lesions). (A, F—MIP images; C, E—local cross-sectional SPECT images; B, D—local cross-sectional SPECT / CT fusion images).

[0057] Figure 10. Injection in patients with colon cancer 99mSPECT / CT images 1 and 4 hours after Tc-HYNIC-PEG6-oncoFAP injection. Images A, B, and C are 1 hour after injection; images D, E, and F are 4 hours after injection (note: red arrows – gallbladder; green arrows – pancreas; blue arrows – primary colon lesion). (A, F – MIP images; C, E – local cross-sectional SPECT images; B, D – local cross-sectional SPECT / CT fusion images).

[0058] Figure 11. Injection in patients with colon cancer 99m Tc-HYNIC-C2-oncoFAP and 99m Comparison of SPECT / CT images of the in situ lesion 1 hour after Tc-HYNIC-PEG6-oncoFAP injection. 99m Images taken 1 hour after injection of Tc-HYNIC-C2-oncoFAP imaging agent. 99m Images 1 hour after administration of Tc-HYNIC-PEG6-oncoFAP imaging agent (Note: red arrows-colon lesions; yellow arrows-colon lesions) (B, E-local cross-sectional SPECT images; A, D-local cross-sectional SPECT / CT fusion images; C, F-cross-sectional CT images).

[0059] Figure 12 Injection in patients with sigmoid colon cancer 99m Tc-HYNIC-PEG 12 -SPECT / CT image 1 hour after oncoFAP. (Note: red arrows indicate sigmoid colon lesions)

[0060] Figure 13 Injection in patients with gastric antral cancer 99m Tc-HYNIC-PEG 12 -SPECT / CT image 1 hour after oncoFAP. (Note: Red arrows – primary lesion of gastric antrum cancer; blue arrows – metastatic lymph nodes in the hepatogastric space; green arrows – bone metastases; yellow arrows – retroperitoneal para-aortic lymph nodes) DETAILED DESCRIPTION

[0061] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, but it will be understood by those skilled in the art that the following drawings and examples are intended only to illustrate the present invention and are not intended to limit the scope of the invention. Various objects and advantages of the present invention will become apparent to those skilled in the art based on the following detailed description of the accompanying drawings and preferred embodiments.

[0062] Materials used in the present invention:

[0063] HYNIC-NHS (nicotinamide hydrazide) was purchased from Noca-biochem, USA. DOTA-NHS (tetraazacyclododecane tetraacetic acid-succinimidyl ester), NOTA-NHS (1H-1,4,7-triazine-1,4,7-triacetic acid, hexahydro, 1-(2,5-dioxa-1-pyrrolidinyl) ester), and (±)-H3RESCA-TFP (4-[[[[(1R,2R)-2-[bis(carboxymethyl)amino]cyclohexyl][carboxymethyl]amino]methyl]-, 1-(2,3,5,6-tetrafluorophenyl)phenylacetate) were purchased from Xi'an Ruixi Biotechnology Co., Ltd. NH2-PEG 6 / 12 -NH2-Boc was purchased from Xi'an Ruixi Biotechnology Co., Ltd. Dichloromethane (DCM), 4-dimethylaminopyridine (DMAP), and tetrahydrofuran (THF) were all purchased from Beijing Tongguang Fine Chemical Co., Ltd. Succinic acid, disodium succinate hexahydrate, trisodium triphenylphosphine-3,3',3"-trisulfonate (TPPTS), N,N-Dimethylformamide (DMF), tricine, trifluoroacetic acid (TFA), and N-Ethyldiisopropylamine (DIPEA) were all purchased from Sigma-Aldrich, USA. Na 99m TcO4 eluent was purchased from Beijing Atom High-Tech Co., Ltd.

[0064] Preparation Example

[0065] 1.1 Preparation of HYNIC-C2-oncoFAP

[0066] The specific steps are as follows:

[0067] a. Preparation of oncoFAP

[0068] 8-Aminoquinoline-4-carboxylic acid (1 eq), (S)-1-(2-aminoacetyl)-4,4-difluoropyrrolidine-2-carbonitrile hydrochloride (1 eq), and HATU (1 eq) were added to a 25 mL round-bottom flask and dissolved in 900 μL of DMF and 4 mL of DCM. DIEA (4 eq) was then added dropwise with stirring. The crude product was diluted with DCM, washed with water, dried over Na2SO4, filtered, and the solvent was removed on a rotary evaporator to yield the crude product (S)-8-amino-N-(2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-carbonylethyl)quinoline-4-carboxamide. The crude product (1 eq), succinic anhydride (50 eq), and DAMP (0.5 eq) were added to a 25 mL round-bottom flask and dissolved in 3 mL of THF. The reaction was allowed to proceed at 60°C for 6 hours. The reaction solution was subjected to a rotary evaporator to remove the solvent, diluted with water, extracted with DCM, dried with Na2SO4, filtered, and dried. The TOF MS (ES+) mass spectrometry analysis showed m / z = 460.1 ([M+H] + ), confirmed to be the expected product oncoFAP.

[0069] b. Preparation of C2-oncoFAP

[0070] Weigh oncoFAP (1 eq) and HATU (1.5 eq) into an EP tube, dissolve in 200 μL DMF, add DIEA (2 eq), and react at room temperature for about 30 minutes. Then weigh N-tert-butyloxycarbonylethylenediamine (N-Boc-ethylenediamine, CAS: 57260-73-8) (1.5 eq) and add it to the above reaction solution, add DIEA to adjust the pH to 8.5-9.0, react at room temperature overnight, and use high performance liquid chromatography to monitor the reaction and separate and purify the target product. Collect the elution peak, and the eluate is freeze-dried using a vacuum freeze-drying method to obtain the expected product Boc-C2-oncoFAP. The lyophilized product is dissolved in 1 mL TFA and reacted at room temperature for 10 minutes. The reaction solution is blown dry with nitrogen, and the obtained product is analyzed by TOF MS (ES+) mass spectrometry, m / z = 502.21 ([M+H] + ), confirmed to be the expected product C2-oncoFAP.

[0071] c. Preparation of HYNIC-C2-oncoFAP

[0072] C2-oncoFAP (1 eq) and HYNIC-NHS (1 eq) were dissolved in DMF, DIEA was added to adjust the pH to 8.5-9.0, and the reaction was allowed to proceed overnight at room temperature. The reaction was monitored by high performance liquid chromatography, and the target product was isolated and purified. The eluted peak was collected and lyophilized by vacuum freeze drying to obtain a solid product. MALDI-TOF mass spectrometry analysis showed m / z = 805.2 ([M+H]+ ), confirmed to be the expected product HYNIC-C2-oncoFAP (the synthesis methods of DOTA-C2-oncoFAP, NOTA-C2-oncoFAP, and (±)-H3RESCA-C2-oncoFAP are the same as above).

[0073] The synthetic route can be found in Figure 1.

[0074] 1.2 Preparation of radionuclide-labeled HYNIC-C2-oncoFAP

[0075] Prepare a solution containing 25 μg of HYNIC-C2-oncoFAP, 5.0 mg of sodium triphenylphosphine trisulfonate (TPPTS), and 6.5 mg of trihydroxymethylglycine (Tricine) dissolved in 1 mL of 0.5 M succinic acid buffer solution (pH 4.8). Place the mixed solution in a 10 mL vial and lyophilize the mixture to obtain a labeled kit. Add 1.0-1.5 mL of Na 99m The TcO4 solution is placed in a heating reactor such as a water bath, air bath or metal bath at 75-110°C and heated for 20-30 minutes. After the reaction is completed, it is cooled to room temperature for 5 minutes to prepare 99m Tc-HYNIC-C2-oncoFAP was analyzed by radio-HPLC and then used.

[0076] 2.1 Preparation of HYNIC-PEG6-oncoFAP

[0077] The specific steps are as follows:

[0078] a. Preparation of NH2-PEG6-oncoFAP

[0079] Weigh oncoFAP (1 eq) and HATU (1.5 eq) in an EP tube, dissolve in 200 μL DMF, add DIEA (2 eq), and react at room temperature for about 30 minutes. Then weigh 22-amino-5,8,11,14,17,20-hexaoxa-2-azaeicosanoic acid 1,1-dimethylethyl ester (Boc-NH2-PEG6-NH2, CAS: 1091627-77-8) (1.5 eq) and add it to the above reaction solution. Add DIEA to adjust the pH value to 8.5-9.0. React at room temperature overnight. Use high performance liquid chromatography to monitor the reaction and separate and purify the target product. Collect the elution peak, and the eluate is freeze-dried by vacuum freeze drying to obtain the expected product Boc-NH2-PEG6-oncoFAP. The freeze-dried product is dissolved in 1 mL TFA and reacted at room temperature for 10 minutes. The reaction solution is blown dry with nitrogen, and the obtained product is analyzed by TOF MS (ES +) Mass spectrometry analysis confirmed that it was the expected product NH2-PEG6-oncoFAP.

[0080] b. Preparation of HYNIC-PEG6-oncoFAP

[0081] NH2-PEG6-oncoFAP (1 eq) and HYNIC-NHS (1 eq) were dissolved in DMF, DIEA was added to adjust the pH to 8.5-9.0, and the reaction was allowed to proceed overnight at room temperature. The reaction was monitored by high performance liquid chromatography, and the target product was separated and purified. The elution peak at 14.5 minutes was collected, and the eluate was freeze-dried by vacuum freeze drying to obtain a solid product. MALDI-TOF (ES - ) Mass spectrometry analysis, m / z = 1067.42 ([MH]) - , confirmed to be the expected product HYNIC-PEG6-oncoFAP (the synthesis methods of DOTA-PEG6-oncoFAP, NOTA-PEG6-oncoFAP, and (±)-H3RESCA-PEG6-oncoFAP are the same as above).

[0082] The synthetic route can be found in Figure 2.

[0083] 2.2 Preparation of radionuclide-labeled HYNIC-PEG6-oncoFAP

[0084] Prepare a solution containing 25 μg of HYNIC-PEG6-oncoFAP, 5.0 mg of sodium triphenylphosphine trisulfonate (TPPTS), and 6.5 mg of trihydroxymethylglycine (Tricine) dissolved in 1 mL of 0.5 M succinic acid buffer solution (pH 4.8). Place the mixed solution in a 10 mL vial and lyophilize the mixture to obtain a labeled kit. Add 1.0-1.5 mL of Na 99m The TcO4 solution is placed in a heating reactor such as a water bath, air bath or metal bath at 75-110°C and heated for 20-30 minutes. After the reaction is completed, it is cooled to room temperature for 5 minutes to prepare 99m Tc-HYNIC-PEG6-oncoFAP was analyzed by radio-HPLC and then used.

[0085] 3.1 HYNIC-PEG 12 Preparation of -oncoFAP

[0086] The specific steps are as follows:

[0087] a、NH2-PEG 12 Preparation of -oncoFAP

[0088] Weigh oncoFAP (1 eq) and HATU (1.5 eq) into an EP tube, dissolve in 200 μL DMF, add DIEA (2 eq), and react at room temperature for about 30 minutes. Then weigh tert-butyloxycarbonyl dodecapolyethylene glycol amino (Boc-NH2-PEG 12 -NH2, CAS: 1642551-09-4) (1.5eq) was added to the above reaction solution, DIEA was added to adjust the pH to 8.5-9.0, and the reaction was allowed to proceed overnight at room temperature. The reaction was monitored by high performance liquid chromatography, and the target product was separated and purified. The elution peak was collected and the eluate was freeze-dried by vacuum freeze drying to obtain the expected product Boc-NH2-PEG. 12 The lyophilized product was dissolved in 1 mL of TFA and reacted at room temperature for 10 min. The reaction solution was blown dry with nitrogen. The obtained product was analyzed by TOF MS (ES+) mass spectrometry and confirmed to be the expected product NH2-PEG 12 -oncoFAP.

[0089] b. HYNIC-PEG 12 Preparation of -oncoFAP

[0090] NH2-PEG 12 -oncoFAP (1 eq) and HYNIC-NHS (1 eq) were dissolved in DMF, DIEA was added to adjust the pH to 8.5-9.0, and the reaction was allowed to proceed overnight at room temperature. The reaction was monitored by HPLC, and the target product was isolated and purified. The eluted peak was collected and lyophilized by vacuum freeze drying to obtain a solid product. MALDI-TOF mass spectrometry analysis showed m / z = 1333.503 ([M+H] + ), confirmed to be the expected product HYNIC-PEG 12 -oncoFAP(DOTA-PEG 12 -oncoFAP, NOTA-PEG 12 -oncoFAP, (±)-H3RESCA-PEG 12 -oncoFAP synthesis method is the same as above).

[0091] The synthetic route can be found in Figure 3.

[0092] 3.2 Radionuclide-labeled HYNIC-PEG 12 Preparation of -oncoFAP

[0093] Prepare 25 μg of HYNIC-PEG 12-oncoFAP, 5.0 mg of sodium triphenylphosphine trisulfonate (TPPTS) and 6.5 mg of trihydroxymethylglycine (Tricine) were dissolved in 1 mL of 0.5 M succinic acid buffer solution (pH 4.8). The mixed solution was placed in a 10 mL vial and lyophilized to obtain a labeled kit. 1.0-1.5 mL of Na 99m The TcO4 solution is placed in a heating reactor such as a water bath, air bath or metal bath at 75-110°C and heated for 20-30 minutes. After the reaction is completed, it is cooled to room temperature for 5 minutes to prepare 99m Tc-HYNIC-PEG 12 - oncoFAP. Analyzed by radio-HPLC.

[0094] Wherein, the above-mentioned HPLC method is as follows:

[0095] The target product was isolated and purified by high performance liquid chromatography using an Agilent 1260 HPLC system equipped with a YMC-Pack ODS-A C18 semi-preparative column (250×10 mm L.DS-5 μm, 12 nm). Gradient elution was performed over 25 min at a flow rate of 2.5 mL / min. Mobile phase A consisted of deionized water (containing 0.05% TFA) and mobile phase B consisted of acetonitrile (containing 0.05% TFA). The elution gradient was set as 80% A and 20% B at the start, 20% A and 80% B at 20 min, and 80% A and 20% B at 25 min.

[0096] Radioactive HPLC method: An Agilent 1260 HPLC system was equipped with a YMC-Pack ODS-A C18 analytical column (250 × 4.6 mm, 1.DS-5 μm, 12 nm). Gradient elution was performed over 20 min at a flow rate of 1.0 mL / min. The mobile phase A consisted of deionized water (containing 0.05% TFA) and the mobile phase B consisted of acetonitrile (containing 0.05% TFA). The elution gradient was set as 90% A and 10% B at the start, 60% A and 40% B at 17.5 min, and 90% A and 10% B at 20 min.

[0097] Radionuclide complexes such as 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 The structural formula of -oncoFAP is shown in Figure 4 .

[0098] Radionuclide complexes such as 99m Tc-HYNIC-C2-oncoFAP, 99mTc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 Figure 5 shows the radioactive HPLC analysis of -oncoFAP. The radionuclide labeling efficiency for each marker was greater than 95%. The HPLC retention times of the markers modified with PEG chains were extended to approximately 10.0 min, 13.0 min, and 15.1 min, respectively. As the number of PEG chains increases, the molecular size also increases, resulting in a corresponding delay in retention time.

[0099] Example 1: Pharmacokinetics of oncoFAP modified with a linker (e.g. 99m The lipid-water distribution coefficient (LogP o / w ) determination

[0100] a. Methods:

[0101] In order to measure 99m To investigate the hydrophilicity of Tc-labeled oncoFAP probes, 5 mL of PBS and 5 mL of n-octanol were placed in a 15 mL centrifuge tube, and 0.037 MBq of 99m Tc-labeled oncoFAP probe was shaken vigorously at room temperature for about 2 hours. Centrifugation (8000 rpm, 5 min) was performed to completely separate the PBS and n-octanol layers. 500 μL of the upper (organic phase) and lower (aqueous phase) solutions were taken and placed in radioimmunoassay tubes to measure the gamma counts (CPM). The lipid-water distribution coefficient (LogP o / w ) is calculated by the following formula: LogP o / w =Log(organic phase count / aqueous phase count).

[0102] b. Result analysis:

[0103] LogP o / w The smaller the value, the better the hydrophilicity of the probe. The experimental results are shown in Figure 5. It can be seen that 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -LogP of oncoFAP o / w They are -2.89±0.06, -3.39±0.13 and -3.34±0.09 respectively. It can be seen that the hydrophilicity of the molecule is significantly increased after PEG chain modification.

[0104] Example 2: Pharmacokinetics of oncoFAP modified with a linker (e.g. 99m SPECT / CT imaging of tumor-bearing mice using Tc-labeled radioactive probes

[0105] The radionuclide complex of the present invention is 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -oncoFAP imaging in U87MG tumor-bearing mouse model:

[0106] a. Methods:

[0107] The prepared radionuclide complex is 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -oncoFAP was diluted with normal saline to 37MBq / 100μL, and each mouse was injected with 100μL (37MBq) via the tail vein. Small animal SPECT / CT imaging was performed 0.5, 1, 2, and 4 hours after injection. Mice were anesthetized with 1.5% isoflurane-oxygen during imaging. After imaging, SPECT images were reconstructed and fused with CT images to generate 3D images. The posterior view was used for display, and the tumor location was marked with an arrow.

[0108] b. Analysis of imaging results:

[0109] 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 The imaging results of -oncoFAP are shown in Figure 6. In the U87MG tumor-bearing mouse model, the radionuclide complex prepared by the present invention is as follows 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -oncoFAP showed significant tumor uptake and high imaging contrast, demonstrating that the PEG-chain-optimized radioactive probes of the present invention still maintain good tumor-specific targeting capabilities. Specifically, the PEG-chain-optimized radioactive probes exhibited relatively clearer systemic background uptake. The modified probes are primarily metabolized by the kidneys, resulting in more pronounced renal uptake than the unmodified probes.

[0110] Example 3: Pharmacokinetics of oncoFAP modified with a linker (e.g. 99m Biodistribution of Tc-labeled radioactive probe in tumor-bearing mice

[0111] The radionuclide complex of the present invention is 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 Biodistribution of -oncoFAP in tumor-bearing mice:

[0112] a. Methods:

[0113] BALB / c nude mice bearing U87MG tumors were divided into 3 groups, with 4 mice in each group. Each group of mice was injected via the tail vein with 100 μL (~74 kBq) of the radionuclide complex prepared by the present invention. 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP, 99m Tc-HYNIC-PEG 12 -oncoFAP was administered and sacrificed 0.5, 1, 2, and 4 hours after injection. Blood and major organs were collected, weighed, and radioactivity counts were measured. The percentage injected dose per gram of tissue (%ID / g) was calculated after decay correction. Biodistribution results are expressed as mean ± standard deviation (mean ± SD, n = 4).

[0114] b. Analysis of biodistribution results:

[0115] 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 The experimental results of the biodistribution of -oncoFAP are shown in FIG7 . 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -oncoFAP had significant uptake in the tumors of the mouse model, and the tumor uptake at 0.5, 1, 2, and 4 h was as follows: HYNIC-C2-oncoFAP (8.39±1.03%ID / g, 5.90±0.83%ID / g, 5.51±0.80%ID / g, 4.16±0.40%ID / g);99m Tc-HYNIC-PEG6-oncoFAP (9.31±3.31%ID / g, 9.39±0.83%ID / g, 8.12±1.99%ID / g, 5.28±0.32%ID / g); 99m Tc-HYNIC-PEG 12 -oncoFAP (11.49±3.44%ID / g, 10.83±1.88%ID / g, 11.35±1.96%ID / g, 9.87±1.02%ID / g). The results showed that the PEG chain-optimized probe had increased tumor uptake and retention, indicating that the PEG-optimized radioactive probe of the present invention still maintained good tumor-specific targeting ability and enhanced tumor retention ability. The PEG-optimized radioactive probe had more obvious renal uptake, indicating that it was mainly metabolized by the kidneys, which is consistent with the trend of the results of the lipid-water partition coefficient. PEG modification brings higher hydrophilicity, so the probe is more prone to renal metabolism. The imaging background of the probe excreted through renal metabolism is cleaner, especially the background uptake in the chest cavity is lower, which is conducive to the imaging of tumors in the chest cavity.

[0116] The blood uptake at 0.5, 1, 2, and 4 h in the mouse model were as follows: HYNIC-C2-oncoFAP (9.71±1.01%ID / g, 8.36±2.14%ID / g, 5.37±0.41%ID / g, 3.49±0.41%ID / g); 99m Tc-HYNIC-PEG6-oncoFAP (7.99±0.70%ID / g, 7.24±1.28%ID / g, 5.31±

[0117] 0.84%ID / g, 2.97±0.44%ID / g); 99m Tc-HYNIC-PEG 12 -oncoFAP (6.88±1.16%ID / g, 5.50±0.37%ID / g, 4.27±1.11%ID / g, 1.90±0.32%ID / g). The results showed that the probe uptake in the blood decreased with increasing PEG-modified molecule size, accelerating its clearance from the blood, which is consistent with the results of blood clearance experiments.

[0118] The renal uptake at 0.5, 1, 2, and 4 h in the mouse model were as follows: HYNIC-C2-oncoFAP (4.98 ± 0.35% ID / g, 4.30 ± 0.48% ID / g, 5.11 ± 0.74% ID / g, 4.37 ± 0.35% ID / g); 99mTc-HYNIC-PEG6-oncoFAP (9.67±0.48%ID / g, 11.09±0.75%ID / g, 12.60±0.90%ID / g, 13.82±2.42%ID / g); 99m Tc-HYNIC-PEG 12 -oncoFAP (6.46±0.42%ID / g, 6.53±0.36%ID / g, 7.09±0.91%ID / g, 7.78±0.58%ID / g). The results indicate that renal uptake increases with PEG-modified molecules. The introduction of PEG increases the molecule's hydrophilicity, thereby shifting the drug's metabolic pathway toward renal metabolism. This result is consistent with the hydrophilicity trend of the lipid-water distribution coefficient and the imaging results.

[0119] There was no significant difference in the uptake of the three groups of probes in other organs.

[0120] Example 4: Pharmacokinetics of oncoFAP modified with a linker (e.g. 99m Blood clearance experiment of Tc-labeled radioactive probe in normal mice

[0121] The radionuclide complex of the present invention is 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 Blood clearance experiment of oncoFAP in tumor-bearing mice:

[0122] a. Methods:

[0123] Nine ICR mice were randomly divided into three groups (n=3), and each group of mice was injected with 100 μL (~74 kBq) 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -oncoFAP. Blood was collected via the epicanthus vein at designated time points between 0 and 480 minutes after administration. The blood was weighed and gamma counts were measured to calculate the percent injected dose per gram (%ID / g). The %ID / g at different time points was analyzed by nonlinear regression using GraphPad Prism 9 software, and the rapid and slow half-lives were calculated using a two-compartment model.

[0124] b. Analysis of blood clearance test results:

[0125] The results of the blood clearance experiment are shown in FIG7 .99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 The fast half-lives of oncoFAP in the blood were 6.512, 2.713, and 1.666 minutes, respectively, and the slow half-lives were 139.0, 89.54, and 76.11 minutes, respectively. These results demonstrate that PEG chain modification can significantly affect the blood half-life of oncoFAP molecules, accelerating their clearance from the blood and reducing background uptake.

[0126] Example 5: Pharmacokinetics of oncoFAP modified with a linker (e.g. 99m Comparison of SPECT / CT imaging using Tc-labeled radioactive probes in patients with colon cancer

[0127] The radionuclide complex of the present invention is 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -oncoFAP and 99m Comparison of SPECT / CT imaging of Tc-HYNIC-oncoFAP2 in patients with colon cancer:

[0128] a. Methods:

[0129] Intravenous injection of the radionuclide complex prepared by the present invention 99m Tc-HYNIC-C2-oncoFAP, 99m Tc-HYNIC-PEG6-oncoFAP and 99m Tc-HYNIC-PEG 12 -oncoFAP and 99m Tc-HYNIC-oncoFAP2 was administered at a dose of 0.3 mCi / kg. Whole-body SPECT / CT scans were performed 1 and 4 hours after injection. Image processing was routine for qualitative and quantitative imaging of the patient's tumor.

[0130] b. Analysis of imaging results:

[0131] Clinical imaging images 8-11 are data comparisons of the same patient, who is a 34-year-old male with colon cancer.

[0132] Figure 8 shows the injection of dimer probes in colon cancer patients. 99m Tc-HYNIC-oncoFAP2 and monomeric probes99m Comparison of SPECT / CT images 1 hour after Tc-HYNIC-C2-oncoFAP. Images A and B are images taken 1 hour after injection of the dimer imaging agent, showing physiological accumulation in the pancreas and no physiological accumulation in the gallbladder. Images C and D are images taken 1 hour after injection of the monomeric imaging agent, showing physiological accumulation in the gallbladder with partial excretion into the biliary system, and reduced physiological accumulation in the pancreas. These results demonstrate that dimer and monomeric probes have different drug distribution characteristics in the body, allowing for different applications in tumor diagnosis. Compared to the dimer probe, the monomeric probe exhibits reduced physiological uptake in the pancreas, facilitating the observation of peripancreatic lesions. However, physiological accumulation in the gallbladder occurs and is excreted into the intestine through the biliary system within approximately 1 hour, potentially compromising subsequent observation of intestinal lesions. Because the monomeric probe primarily suffers from gallbladder uptake, the present invention primarily addresses this issue through pharmacokinetic modification.

[0133] Figure 9 99m SPECT / CT imaging of Tc-HYNIC-C2-oncoFAP: Images A, B, and C are 1 hour after injection of the contrast agent. Results show physiological concentration in the gallbladder and partial excretion into the biliary system, while physiological concentration in the pancreas is lower. This suggests that detection of intestinal lesions should be performed approximately 1 hour after injection. Otherwise, subsequent excretion of the gallbladder contrast agent into the intestine will impair lesion observation. Images D, E, and F are 4 hours after injection of the contrast agent. Results show physiological concentration in the gallbladder and excretion into the intestine, resulting in high intestinal uptake and interference with colonic lesion observation. Furthermore, physiological concentration in the pancreas is higher than at earlier time points.

[0134] Figure 10 shows the injection of imaging agents. 99m SPECT / CT imaging of Tc-HYNIC-PEG6-oncoFAP: Images A, B, and C are taken one hour after contrast agent injection, demonstrating no gallbladder accumulation and low physiological pancreatic accumulation. Images D, E, and F are taken four hours after contrast agent injection, showing physiological gallbladder accumulation but not yet excreted into the intestine. This indicates that imaging within four hours of contrast agent injection is not affected by physiological intestinal accumulation. Therefore, imaging of intestinal lesions within four hours of contrast agent injection is feasible. This capability allows for delayed imaging, a wider imaging window, and greater clinical convenience.

[0135] Figure 11 99m Tc-HYNIC-C2-oncoFAP and 99m Contrast imaging of Tc-HYNIC-PEG6-oncoFAP. A, B, and C are injections of 99m Images taken 1 hour after injection of Tc-HYNIC-C2-oncoFAP imaging agent. 99mImage taken 1 hour after administration of the Tc-HYNIC-PEG6-oncoFAP imaging agent. The results showed that the two imaging agents had similar imaging effects on intestinal lesions, indicating that the PEG chain modification did not affect the probe's diagnostic efficacy for lesions.

[0136] Clinical imaging Figures 12-13 are 99m Tc-HYNIC-PEG 12 -oncoFAP imaging performance in patients with colon and gastric antral cancer. Figure 12 shows clear imaging of lesions in a patient with sigmoid colon cancer, with low background uptake throughout the body, and relatively low uptake in the gallbladder and pancreas. Figure 13 shows clear imaging of lesions in a patient with gastric antral cancer, including hepatogastric interstitial lymph node metastases, bone metastases, and retroperitoneal para-aortic lymph node metastases.

[0137] In summary, the imaging effect of the PEG-modified imaging agent for intestinal lesions about 1 hour after addition is similar to that of the original structure, but its gallbladder physiological concentration is significantly lower than that of the non-PEG-modified one, indicating that the properties of the marker are significantly changed after PEG modification, which brings about significant changes in the metabolic behavior characteristics in vivo. The time for its metabolism in the gallbladder and intestine is significantly delayed. 4 hours after injection, the PEG-modified marker still has no obvious uptake in the intestine, which is more conducive to the detection of colon lesions than the non-PEG-modified marker. Therefore, the time window for intestinal lesion imaging is wider, and delayed imaging can be performed, which is convenient for clinical use.

[0138] It should be understood that the invention described herein is not limited to specific methodology, experimental protocols or reagents, as these may vary. The discussion and examples provided herein are presented only to describe specific embodiments and are not intended to limit the scope of the invention, which is limited only by the claims.

Claims

1. A compound represented by formula I or a pharmaceutically acceptable salt thereof, in, n is selected from any integer between 6 and 24.

2. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein The compound is selected from:

3. A precursor compound for forming a radionuclide complex or a pharmaceutically acceptable salt thereof, wherein: The precursor compound is formed by covalently linking the compound according to any one of claims 1 to 2 with a bifunctional chelating agent; Preferably, the bifunctional chelating agent is selected from HYNIC, MAG2, MAG3, DTPA, DOTA, NOTA, (±)-H3RESCA, TETA.

4. The precursor compound or pharmaceutically acceptable salt thereof according to claim 3, wherein: The precursor compound has a structure shown in Formula II, in: n is selected from any integer between 6 and 24; R is a bifunctional chelating agent group selected from 5. The precursor compound or a pharmaceutically acceptable salt thereof according to any one of claims 3 to 4, wherein: The precursor compound is selected from:

6. A radionuclide complex, which is obtained by labeling a radionuclide with the precursor compound or a pharmaceutically acceptable salt thereof according to any one of claims 3 to 5; Preferably, the radionuclide is selected from 43 Sc, 44 Sc, 51 Mn, 52 Mn, 64 Cu, 67 Ga, 68 Ga, 86 Y. 89 Zr, 99m Tc, 111 In, 149 Tb, 152 Tb, 155 Tb, 201 Tl, 203 Pb, 18 F; More preferably, the radionuclide is selected from 64 Cu, 68 Ga, 99m Tc; Preferably, the radionuclide is selected from 47 Sc, 67 Cu, 89 Sr. 90 Y. 153 Sm, 149 Tb, 161 Tb, 177 Lu, 186 Re, 188 Re, 212 Pb, 213 Bi, 223 Ra, 225 Ac, 226 Th, 227 Th, 211 At; More preferably, the radionuclide is 177 Lu; Preferably, the radionuclide is 99m Tc, the bifunctional chelator is HYNIC; or the radionuclide is selected from 64 Cu, 68 Ga, 177 Lu, the bifunctional chelating agent is selected from DOTA and NOTA; Preferably, the radionuclide complex is selected from:

7. A pharmaceutical composition comprising the compound according to any one of claims 1 to 2 or a pharmaceutically acceptable salt thereof, or the precursor compound according to any one of claims 3 to 5 or a pharmaceutically acceptable salt thereof, or the radionuclide complex according to claim 6; optionally, further comprising a pharmaceutically acceptable carrier and / or excipient; Preferably, the pharmaceutical composition is an injection preparation; Preferably, the injection preparation is a colorless and transparent injection preparation.

8. An imaging diagnostic agent and / or a radioactive targeted therapeutic agent, comprising the radionuclide complex according to claim 6; Preferably, the imaging is SPECT imaging, PET imaging and / or CT imaging.

9. A kit comprising a compound according to any one of claims 1 to 2 or a pharmaceutically acceptable salt thereof, or a precursor compound according to any one of claims 3 to 5 or a pharmaceutically acceptable salt thereof, or a radionuclide complex according to claim 6, or a pharmaceutical composition according to claim 7, or an imaging agent and / or a radioactive targeted therapeutic agent according to claim 8.

10. Use of the compound according to any one of claims 1 to 2 or a pharmaceutically acceptable salt thereof, or the precursor compound according to any one of claims 3 to 5 or a pharmaceutically acceptable salt thereof, or the radionuclide complex according to claim 6, or the pharmaceutical composition according to claim 7 in the preparation of an agent or drug for diagnosing and / or treating a disease associated with overexpression of fibroblast activation protein (FAP); Preferably, the diagnosis is an imaging diagnosis, and the imaging is selected from SPECT imaging, PET imaging, and CT imaging; Preferably, the treatment is radio-targeted therapy; Preferably, the disease is selected from FAP-positive tumors, FAP-positive fibrotic diseases; Preferably, the FAP-positive tumor is selected from the group consisting of head and neck cancer, breast cancer, lung cancer, pancreatic cancer, esophageal cancer, colon cancer, colorectal cancer, sigmoid colon cancer, ovarian cancer, gastric cancer, gastric antral cancer, and liver cancer; Preferably, the FAP-positive fibrotic disease is selected from pulmonary fibrosis, liver fibrosis, and renal fibrosis.

Images