A F-18 labeled PSMA targeted PET probe and preparation method thereof

Abstract

The present invention discloses an F-18 labeled PSMA targeted PET probe and a preparation method thereof. The PET probe is obtained by reacting a labeled intermediate with a precursor small molecule. The labeled intermediate is a fluoroaryl vinyl sulfone labeled intermediate, and the precursor small molecule is a precursor small molecule containing a thiol group and having Lys-urea-Glu as a parent core structure. The present invention obtains an F-18 labeled PSMA targeted probe for prostate cancer imaging diagnosis by reacting a fluoroaryl vinyl sulfone labeled intermediate with a thiol group-containing precursor with Lys-urea-Glu as a parent core structure. Compared with the FDA-approved PET imaging agent [ 68 Ga]-PSMA-11, which has a better tumor lesion detection ability, with a tumor uptake value of about three times that of the drug. The drug is metabolized through the liver and kidneys at a slower rate, with a low image background and clear target tissue imaging, overcoming the technical problems of existing imaging agents.

Description

Technical Field

[0001] The present invention relates to the technical field of PET imaging diagnosis, and in particular to an F-18 labeled PSMA targeted PET probe and a preparation method thereof. Background Art

[0002] Prostate-specific membrane antigen (PSMA) is located in prostate epithelial cells and is a transmembrane cell glycoprotein. PSMA is expressed at high levels in 95% of prostate cancer patients, and its expression level is upregulated in castration-resistant prostate cancer (CRPC) and metastatic prostate cancer. Therefore, PSMA can be used as an ideal target for the diagnosis and treatment of prostate cancer and its metastatic lesions. Currently, there are a variety of molecular probes targeting PSMA in the clinical trial stage. Common PSMA molecular probes include monoclonal antibodies, small analytical inhibitors, etc. For example, 111 In-labeled 7E11 is the first radiolabeled PSMA monoclonal antibody and is currently a relatively successful drug for SPECT imaging of prostate cancer. However, 7E11 can only bind to the intramembrane segment of PSMA and can therefore only be taken up by necrotic and apoptotic cells, resulting in low imaging sensitivity. PSMA small molecule inhibitors have the advantages of good cell permeability and rapid blood clearance, and mainly include three categories: 1. Derivatives such as phosphates, phosphites, phosphonates, and phosphoramides; 2. Thiol, indole-thiol, hydroxamic acid, and sulfonamide derivatives; 3. Urea derivatives. Currently, the urea derivative small molecule inhibitors that have entered the clinical trial stage mainly include PSMA-11, PSMAI&T, PSMA-617, etc. PSMA small molecule inhibitors can be labeled 18 F. 68 Ga is used for prostate cancer imaging and can also be used to label 111 Lu, 90 Y. 131 I is used for the treatment of prostate cancer (see the literature "Progress in PSMA-targeted PET imaging and radionuclide therapy for prostate cancer", Feng Yaqi, Wang Peng, etc., Journal of Huazhong University of Science and Technology, Vol. 49, No. 1, February 2020). However, the existing PSMA-targeted PET imaging agent labeled radionuclide Ga-68 has a short half-life, limited effective utilization time, and unclear tumor uptake in the prostate cancer cell metastasis model, and the imaging effect needs to be improved.

[0003] The Chinese paper "Development and PET Scanning Study of PSMA Targeted Contrast Agent 18F-Glu-Urea-Lys for Prostate Cancer" (authored by Zhang Zhiwei, the First Affiliated Hospital of Dalian Medical University) successfully developed 18 The F-Glu-urea-RPET / CT molecular probe was successfully synthesized by replacing the R group with labeled amino acids and using magnetic resonance spectroscopy and mass spectrometry to determine the compound structure. 18F-Glu-Urea-Lys contrast agent has good imaging effect on target tumors, rapid and clear imaging, less non-specific binding, and rapid excretion through the kidneys. However, this contrast agent is highly lipophilic, with high background uptake in the liver and abdomen. Compared with the existing Ga-68-PSMA-11, the tumor tissue has low uptake of the contrast agent, and the uptake ratio of the contrast agent target / non-target tissue is low. Summary of the invention

[0004] The purpose of the present invention is to provide an F-18 labeled PSMA targeted PET probe and a preparation method thereof in view of the above-mentioned problems. The present invention uses a fluorinated aryl vinyl sulfone labeled intermediate to react with a thiol-containing precursor with Lys-urea-Glu as the parent core structure to obtain an F-18 labeled PSMA targeted probe for prostate cancer imaging diagnosis. Compared with the FDA-approved PET imaging agent [ 68 Ga]-PSMA-11, which has a more excellent tumor lesion detection ability, with a tumor uptake value of about three times that of the drug, is metabolized by the liver and kidneys, has low uptake in non-target tissues, and provides clear imaging of target tissues, overcoming the technical problems of existing imaging agents.

[0005] The technical solution adopted by the present invention is as follows: an F-18 labeled PSMA targeted PET probe, wherein the PET probe is obtained by reacting a labeled intermediate with a precursor small molecule, wherein the labeled intermediate is a fluoroaryl vinyl sulfone labeled intermediate, and the precursor small molecule is a thiol-containing precursor small molecule with Lys-urea-Glu as a parent core structure.

[0006] Further, the labeled intermediate is labeled intermediate 1 or labeled intermediate 2, and its molecular structure is as follows:

[0007] The molecular structure of the labeled intermediate 1 is:

[0008]

[0009] The molecular structure of the labeled intermediate 2 is:

[0010]

[0011] In the above molecular structure, the value range of m is 1-3, for example, it can be 1, 2, or 3.

[0012] Furthermore, the precursor small molecule is a precursor small molecule a or a precursor small molecule b, and its molecular structure is as follows:

[0013] The molecular structure of the precursor small molecule a is as follows:

[0014]

[0015] The molecular structure of the precursor small molecule b is as follows:

[0016]

[0017] In the above molecular structure, the value range of n is 1-3, for example, it can be 1, 2, or 3.

[0018] Furthermore, the labeled intermediate reacts with the precursor small molecule in an alkaline buffer having a pH value of 8-9 (for example, 8.1, 8.2, 8.3, 8.4, 8.5, 8.8, 9.0, etc., preferably 8.5), and is separated and purified by high performance liquid chromatography to obtain a PET probe; the alkaline buffer is selected from sodium carbonate buffer, sodium borate buffer, potassium bicarbonate buffer, phosphate buffer, HEPES buffer or MES buffer.

[0019] Further, the PET probe is PET probe a-1, a-2, b-1 or b-2, and its molecular structure is:

[0020] The molecular structure of PET probe a-1 is:

[0021]

[0022] The molecular structure of PET probe a-2 is:

[0023]

[0024] The molecular structure of PET probe b-1 is:

[0025]

[0026] The molecular structure of PET probe b-2 is:

[0027]

[0028] In the above molecular structure, the value range of n is 1-3, for example, it can be 1, 2, 3; the value range of m is 1-3, for example, it can be 1, 2, 3.

[0029] Furthermore, the present invention also includes a method for preparing an F-18 labeled PSMA-targeted PET probe, comprising the following steps:

[0030] S1, adding the F-18 ion compound to the vinyl sulfone organic matter and heating for reaction, and after cooling, separating the product by HPLC;

[0031] S2, diluting the product with water, first passing it through an alumina column, and then passing it through a solid phase extraction column to obtain a separated and purified fluoroaryl vinyl sulfone labeled intermediate;

[0032] S3, adding the precursor small molecule and the fluoroaryl vinyl sulfone labeled intermediate into an alkaline buffer, reacting at 100° C. for 5-60 min, and after the reaction, purifying the product by HPLC;

[0033] S4, collecting the eluate, diluting the eluate with water, controlling the content of organic solvent in the eluate to be below 5v%, then hanging it on a solid phase extraction column, washing away the acidic solvent with water, rinsing it with ethanol into a product bottle, and finally diluting it with physiological saline until the content of ethanol is below 10v%.

[0034] Further, the chromatographic separation conditions of the HPLC are:

[0035] Chromatographic column: Eclipse Plus C18 5μm, 4.6×250mm;

[0036] Flow rate: 1 mL / min; wavelength: 254 nm, column temperature: 35 °C;

[0037] Mobile phase A: HPLC grade acetonitrile containing 0.1 v% TFA; Mobile phase B: Water containing 0.1 v% TFA;

[0038] Elution conditions:

[0039] 0→2min (within the first 2min): the volume ratio of mobile phase A / mobile phase B is 5 / 95;

[0040] 2→15min (within the next 15min): the volume ratio of mobile phase A / mobile phase B changes uniformly to 95 / 5.

[0041] Furthermore, in step S1, the F-18 ion compound is first dissolved in anhydrous acetonitrile and then added to the vinyl sulfone organic matter for heating reaction. The heating reaction temperature is 80-100° C. and the reaction time is 5-60 min.

[0042] Furthermore, the vinyl sulfone organic compound is a labeling precursor 1 or a labeling precursor 2, and its molecular structure is:

[0043] The molecular structure of the labeled precursor 1 is:

[0044]

[0045] The molecular structure of the labeled precursor 2 is:

[0046]

[0047] In the above, Ar = 2,6-diisopropylphenyl.

[0048] Further, the marker precursor 1 can be specifically

[0049] 1,3-diphenyl-2-(4-(vinylsulfonyl)phenoxy)-1H-imidazol-3-ium chloride, 1,3-bis(2,6-diisopropylphenyl)-2-(4-(vinylsulfonyl)phenoxy)-1H-imidazol-3-iumchloride, 1,3-bis(2,6-dimethylphenyl)-2-(4-(vinylsulfonyl)phenoxy)-1H-imidazol-3-iumchloride, etc.

[0050] Correspondingly, the labeling precursor 2 can specifically be 2-(4-(vinylsulfonyl)phenoxy)ethyl4-nitrobenzenesulfonate, 2-(4-(vinylsulfonyl)phenoxy)ethyl4-methylbenzenesulfonate, 2-(4-(vinylsulfonyl)phenoxy)ethyl methanesulfonate, 2-(2-(4-(vinylsulfonyl)phenoxy)ethoxy)ethyl 4-nitrobenzenesulfonate, 2-(2-(4-(vinylsulfonyl)phenoxy)ethoxy)ethyl 4-methylbenzenesulfonate, 2-(2-(4-(vinylsulfonyl)phenoxy)ethoxy)ethyl methanesulfonate, 2-(2-(2-(4-(vinylsulfonyl)phenoxy)ethoxy)ethoxy)ethyl 4-nitrobenzenesulfonate, 2-(2-(2-(4-(vinylsulfonyl)phenoxy)ethoxy)ethoxy)ethyl4-methylbenzenesulfonate, 2-(2-(2-(4-(vinylsulfonyl)phenoxy)ethoxy)ethoxy)ethyl methanesulfonate, etc.

[0051] Furthermore, the present invention also includes a use of an F-18 labeled PSMA targeted PET probe for preparing a PET imaging agent.

[0052] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0053] 1. The present invention uses a fluorinated aryl vinyl sulfone-labeled intermediate to react with a thiol-containing precursor with Lys-urea-Glu as the parent core structure to obtain an F-18-labeled PSMA-targeted probe for prostate cancer imaging diagnosis. Compared with the FDA-approved PET imaging agent [ 68 Ga]-PSMA-11, which has better tumor lesion detection ability, with tumor uptake value about three times higher than that of the conventional imaging agent. The drug is metabolized by the liver and kidneys at a slower rate, with low image background and clear target tissue imaging, overcoming the technical problems of existing imaging agents;

[0054] 2. The inventive point of the present invention is that the F-18 labeling method enables the labeled small molecule PET imaging agent to have an appropriate logP, high labeling efficiency, good in vivo and in vitro stability of the imaging agent, and is not prone to metabolic de-F-18 ions. Compared with the existing ones, its special point is that, in animal model imaging, it is different from the current PET imaging agent representative PSMA-11, and the imaging agent of the present invention shows better tumor lesion detection ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The spectrum detected by the radioactive detector for the labeled intermediate 2;

[0056] Figure 2 The spectrum was detected by a UV detector for marking intermediate 2, and the detection wavelength was 254 nm;

[0057] Figure 3 is the spectrum detected by the radioactive detector of the imaging agent a-2 (n=1, m=1);

[0058] Figure 4 The UV detector detection spectrum of the developer a-2 (n=1) has a detection wavelength of 254 nm;

[0059] Figure 5 For radioactive probes 68 Small animal PET / CT imaging evaluation of Ga]-PSMA-11 at 30 min, 60 min, and 120 min after tail vein injection in LNCaP tumor-bearing mice;

[0060] Figure 6 Small animal PET / CT imaging evaluation at 30 min, 60 min, and 120 min after tail vein injection of imaging agent a-2 (n=1, m=1) in LNCaP tumor-bearing mice;

[0061] Figure 7 Small animal PET / CT imaging evaluation at 30 min, 60 min, and 120 min after tail vein injection of imaging agent a-1 (n=1) in LNCaP tumor-bearing mice;

[0062] Figure 8 Small animal PET / CT imaging evaluation was performed 30 min, 60 min, and 120 min after tail vein injection of imaging agent a-1 (n=3) into LNCaP tumor-bearing mice. DETAILED DESCRIPTION

[0063] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0064] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0065] The F-18 labeled PSMA targeted PET probe of the present invention is obtained by reacting a labeled intermediate with a precursor small molecule, wherein the labeled intermediate is a fluoroaryl vinyl sulfone labeled intermediate, and the precursor small molecule is a precursor small molecule containing a thiol group and having Lys-urea-Glu as a parent core structure, wherein the fluoroaryl vinyl sulfone labeled intermediate is a labeled intermediate 1 or a labeled intermediate 2, and its molecular structure is as follows:

[0066] The molecular structure of the labeled intermediate 1 is:

[0067]

[0068] The molecular structure of the labeled intermediate 2 is:

[0069]

[0070] In the above molecular structure, the value range of m is 1-3, for example, it can be 1, 2, or 3.

[0071] For the labeled intermediate 1, its specific substance can be [ 18 F]-1-fluoro-4-(vinylsulfonyl)benzene,[ 18 F]-1-fluoro-3-(vinylsulfonyl)benzene,[ 18 F]-1-fluoro-2-(vinylsulfonyl)benzene et al.

[0072] Accordingly, for the labeled intermediate 2, its specific substance can be

[0073] [ 18 F]-1-(2-fluoroethoxy)-4-(vinylsulfonyl)benzene,

[0074] [ 18 F]-1-(2-(2-fluoroethoxy)ethoxy)-4-(vinylsulfonyl)benzene,

[0075] [ 18 F]-1-(2-(2-(2-fluoroethoxy)ethoxy)ethoxy)-4-(vinylsulfonyl)benzene, etc.

[0076] Further, the liquid phase spectrum of the labeled intermediate 2 is as follows Figure 1 and Figure 2 As shown, in Figure 1 In the figure, the radioactivity detector detected a single radioactivity peak, and the peak time was around 14.5 minutes. Figure 2 It shows that the UV detector did not detect any obvious non-radioactive impurity peaks.

[0077] For fluoroaryl vinyl sulfone labeled intermediates, generally, F-18 ion compound is added to vinyl sulfone organic matter for heating reaction, and then separated and purified by HPLC. For example, taking labeled intermediate 2 as an example, as a preparation example, its preparation method is:

[0078] S1. Add 1-2 mg of 1-nitro-4-((2-(4-(vinylsulfonyl)phenoxy)ethyl)sulfonyl)benzene to a mixture containing [ 18 F] fluoride ion anhydrous acetonitrile solution (20 μL / 16 mCi), then heated to 90 ° C, reacted for 20 min, cooled, and the obtained product was separated by HPLC;

[0079] S2. Collect the product peak, dilute it with 10 mL of water and pass it through a Sep-Pak alumina column, then load it onto an HLB solid phase extraction column, wash the HLB column with 10 mL of pure water, and then elute it from the HLB solid phase extraction column with 200 μL of methanol to obtain purified 1-(2-(18F)ethoxy)-4-(vinylsulfonyl)benzene, the reaction equation of which is as follows:

[0080]

[0081] Furthermore, the molecular structure of the above-mentioned precursor small molecule precursor small molecule a or precursor small molecule b is as follows:

[0082] The molecular structure of the precursor small molecule a is as follows:

[0083]

[0084] The molecular structure of the precursor small molecule b is as follows:

[0085]

[0086] In the above molecular structure, the value range of n is 1-3, for example, it can be 1, 2, or 3.

[0087] For the precursor small molecule a, its specific substance can be (S)-2-(3-((S)-1-carboxy-3-(2-mercaptoacetamido)propyl)ureido)pentanedioic acid, (S)-2-(3-((S)-1-carboxy-3-(3-mercaptopropanamido)propyl)ureido)pentanedioic acid, (S)-2-(3-((S)-1-carboxy-3-(4-mercaptobutanamido)propyl)ureido)pentanedioic acid, etc.

[0088] Correspondingly, for the precursor small molecule b, its specific substance can be (S)-2-(3-((S)-3-((R)-2-amino-3-mercaptopropanamido)-1-carboxypropyl)ureido)pentanedioic acid, (S)-2-(3-((S)-3-((S)-2-amino-4-mercaptobutanamido)-1-carboxypropyl)ureido)pentanedioic acid, (S)-2-(3-((S)-3-((S)-2-amino-5-mercaptopentanamido)-1-carboxypropyl)ureido)pentanedioic acid, etc.

[0089] The labeled intermediate and the precursor small molecule react in an alkaline buffer with a pH value of 8-9, and are separated and purified by high performance liquid chromatography to obtain a PET probe. The alkaline buffer is selected from a sodium carbonate buffer, a sodium borate buffer, a potassium bicarbonate buffer, a phosphate buffer, a HEPES buffer or a MES buffer. Since there are two types of labeled intermediates and precursor small molecules, after two-by-two combination, four types of PET probes can be obtained, and their molecular structures are respectively:

[0090] PET probe a-1 (obtained by the reaction of labeled intermediate 1 and precursor small molecule a):

[0091]

[0092] PET probe a-2 (obtained by the reaction of labeled intermediate 2 and precursor small molecule a):

[0093]

[0094] PET probe b-1 (obtained by the reaction of labeled intermediate 1 and precursor small molecule b):

[0095]

[0096] PET probe b-2 (obtained by the reaction of labeled intermediate 2 and precursor small molecule b):

[0097]

[0098] In the above molecular structure, the value range of n is 1-3, for example, 1, 2, 3; the value range of m is 1-3, for example, 1, 2, 3. Taking the developer a-2 as an example, its reaction equation is:

[0099]

[0100] Further, in order to better illustrate the present invention, specific embodiments are listed below:

[0101] Example 1 (Developer a-2, m=1, n=1)

[0102] An F-18 labeled PSMA targeting PET probe (a-2), the preparation method of which comprises the following steps:

[0103] S1. Add 1-2 mg of labeled precursor 2 to a 18 F] fluoride ion anhydrous acetonitrile solution (20 μL / 16 mCi), then heated to 90 ° C, reacted for 20 min, cooled, and the obtained product was separated by HPLC;

[0104] S2. Collect the product peak, dilute it with 10 mL of water and pass it through a Sep-Pak alumina column, then load it onto an HLB solid phase extraction column, wash the HLB column with 10 mL of pure water, and then elute it from the HLB solid phase extraction column with 200 μL of methanol to obtain purified 1-(2-(18F)ethoxy)-4-(vinylsulfonyl)benzene.

[0105] S3, adding 100-200 μg of the precursor small molecule a to 100 μg of sodium borate buffer (pH=8.5), and then adding 100 μg of the methanol solution containing 1-(2-(18F)ethoxy)-4-(vinylsulfonyl)benzene prepared above, and heating the reaction at 85°C for 15 min;

[0106] S4. After the reaction is completed, the product is purified by HPLC, and the identity of the labeled compound is confirmed by co-injection with the corresponding non-radioactive standard;

[0107] S5. Collect the eluate with a peak time of 11.8 min, dilute the collected eluate with water to a content of organic solvent acetonitrile below 5%, then hang it on an HLB solid phase extraction column, wash away excess acidic solvent with 10 mL of water, and finally rinse it into the product bottle with 200 μL of ethanol, and then dilute it with physiological saline to a content of ethanol below 10%, thereby obtaining PET probe a-2.

[0108] In the above, Shimadzu analytical HPLC was used, and the HPLC conditions were:

[0109] Chromatographic column: Eclipse Plus C18 5μm, 4.6×250mm;

[0110] Flow rate: 1 mL / min; PDA wavelength setting: 254 nm, column temperature: 35 °C;

[0111] Mobile phase A: HPLC grade acetonitrile containing 0.1 v% TFA (trifluoroacetic acid); Mobile phase B: water containing 0.1 v% TFA;

[0112] Elution conditions:

[0113] In the initial 2 minutes, mobile phase A / mobile phase B = 5 / 95 (v / v), and in 2-15 minutes, mobile phase A / mobile phase B = 5 / 95 (v / v) and then changed uniformly to mobile phase A / mobile phase B = 95 / 5 (v / v).

[0114] The F-19 standard corresponding to the PET probe obtained above was characterized by mass spectrometry m / z: [M+H]: Calcd for C 24 H 34 18 F3O 11 S2624.18, find 624.10. The prepared probe was subjected to radioactive HPLC analysis, and the spectrum detected by the radioactive detector and the spectrum detected by the UV detector were as follows: Figure 3 and Figure 4 As shown. Figure 3 In the figure, the radioactive detector detected a single radioactive peak of the product (imaging agent a-2, m=1, n=1), and the peak time was about 12 minutes. Figure 4 It shows that the UV detector did not detect any obvious non-radioactive impurity peaks in the sample.

[0115] Example 2

[0116] An F-18 labeled PSMA targeting PET probe a-1 (n=1), the preparation method of which comprises the following steps:

[0117] S1. Add 1-2 mg of labeled precursor 1 to a 18 F] fluoride ion anhydrous acetonitrile solution (20 μL / 16 mCi), then heated to 90 ° C, reacted for 20 min, cooled, and the obtained product was separated by HPLC;

[0118] S2, collecting the product peak, diluting it with 10 mL of water and passing it through a Sep-Pak alumina column, and then loading it onto an HLB solid phase extraction column, washing the HLB column with 10 mL of pure water, and then eluting it from the HLB solid phase extraction column with 200 μL of methanol to obtain purified 1-18-fluoro-4-(vinylsulfonyl)benzene;

[0119] S3, adding 100-200 μg of the precursor small molecule a (n=1) to 100 μg of sodium borate buffer (pH=8.5), and then adding 100 μg of the methanol solution containing 1-18-fluoro-4-(vinylsulfonyl)benzene prepared above, and heating the reaction at 85°C for 15 min;

[0120] S4. After the reaction is completed, the product is purified by HPLC, and the identity of the labeled compound is confirmed by co-injection with the corresponding non-radioactive standard;

[0121] S5. Collect the eluate with a peak time of 12.6 min, dilute the collected eluate with water to a content of organic solvent acetonitrile below 5%, then hang it on an HLB solid phase extraction column, wash away excess acidic solvent with 10 mL of water, and finally rinse it into the product bottle with 200 μL of ethanol, and then dilute it with physiological saline to a content of ethanol below 10%, thereby obtaining PET probe a-1 (n=1).

[0122] Example 3

[0123] An F-18 labeled PSMA targeting PET probe a-1 (n=3), the preparation method of which comprises the following steps:

[0124] S1. Add 1-2 mg of labeled precursor 1 to a 18 F] fluoride ion anhydrous acetonitrile solution (20 μL / 16 mCi), then heated to 90 ° C, reacted for 20 min, cooled, and the obtained product was separated by HPLC;

[0125] S2, collecting the product peak, diluting it with 10 mL of water and passing it through a Sep-Pak alumina column, and then loading it onto an HLB solid phase extraction column, washing the HLB column with 10 mL of pure water, and then eluting it from the HLB solid phase extraction column with 200 μL of methanol to obtain purified 1-18-fluoro-4-(vinylsulfonyl)benzene;

[0126] S3, adding 100-200 μg of the precursor small molecule a (n=3) to 100 μg of sodium borate buffer (pH=8.5), and then adding 100 μg of the methanol solution containing 1-18-fluoro-4-(vinylsulfonyl)benzene prepared above, and heating the reaction at 85°C for 15 min;

[0127] S4. After the reaction is completed, the product is purified by HPLC, and the identity of the labeled compound is confirmed by co-injection with the corresponding non-radioactive standard;

[0128] S5. Collect the eluate with a peak time of 14 min, dilute the collected eluate with water to a content of organic solvent acetonitrile below 5%, then hang it on an HLB solid phase extraction column, wash away excess acidic solvent with 10 mL of water, and finally rinse it into the product bottle with 200 μL of ethanol, and then dilute it with physiological saline to a content of ethanol below 10%, thereby obtaining PET probe a-1 (n=3).

[0129] Example 4

[0130] An F-18 labeled PSMA targeting PET probe b-1 (n=1), the preparation method of which comprises the following steps:

[0131] S1. Add 1-2 mg of labeled precursor 1 to a 18 F] fluoride ion anhydrous acetonitrile solution (20 μL / 16 mCi), then heated to 90 ° C, reacted for 20 min, cooled, and the obtained product was separated by HPLC;

[0132] S2, collecting the product peak, diluting it with 10 mL of water and passing it through a Sep-Pak alumina column, and then loading it onto an HLB solid phase extraction column, washing the HLB column with 10 mL of pure water, and then eluting it from the HLB solid phase extraction column with 200 μL of methanol to obtain purified 1-18-fluoro-4-(vinylsulfonyl)benzene;

[0133] S3, adding 100-200 μg of the precursor small molecule b (n=1) to 100 μg of sodium borate buffer (pH=8.5), and then adding 100 μg of the methanol solution containing 1-18-fluoro-4-(vinylsulfonyl)benzene prepared above, and heating the reaction at 85°C for 15 min;

[0134] S4. After the reaction is completed, the product is purified by HPLC, and the identity of the labeled compound is confirmed by co-injection with the corresponding non-radioactive standard;

[0135] S5. Collect the eluate with a peak time of 14.6 min, dilute the collected eluate with water to a content of organic solvent acetonitrile below 5%, then hang it on an HLB solid phase extraction column, wash away excess acidic solvent with 10 mL of water, and finally rinse it into the product bottle with 200 μL of ethanol, and then dilute it with physiological saline to a content of ethanol below 10%, thereby obtaining the PET probe b-1 (n=1).

[0136] Test process and results

[0137] Experimental animal model:

[0138] LNCaP cells are generally cultured in ATCC 1640 medium containing 10% fetal bovine serum and 1% double antibody in a 37°C, 5% CO2 incubator, and passaged every 1-2 days at a rate of one to three. Nod / scid male mice were inoculated with 2×10 6 LNCaP cells were mixed with RPMI 1640 pure culture medium and Matrigel in a 1:1 ratio. One month after inoculation, the tumor grew to 500-1000mm 3 , experiments can be carried out.

[0139] Small Animal PET / CT Imaging:

[0140] The tumor-bearing mice were anesthetized with gas (0.8 mL / min oxygen, 1.5% isoflurane), and the imaging agent was injected via the tail vein at a dose of 25-35 μCi. Static scanning and PET / CT images were collected at 0.5 h, 1 h, and 2 h after injection. The PET collection lasted for 20 min. After image collection and reconstruction, the region of interest (ROI) was outlined and the uptake dose %ID / g was calculated.

[0141] Test results

[0142] Example 1: Figure 6 As shown, imaging agent a-2 (n=1, m=1) was used for small animal PET / CT imaging of LnCap tumor-bearing mice. 2 hours after tail vein injection, the small animal PET / CT static scanning imaging showed that the tumor uptake of the probe could reach 5.32% ID / g, and the muscle uptake was 0.07 ID / g, with a relatively high (76) tumor / muscle ratio.

[0143] Example 2: Figure 7As shown, imaging agent a-1 (n=1) was used for small animal PET / CT imaging of LnCap tumor-bearing mice. 2 hours after tail vein injection, the small animal PET / CT static scanning imaging showed that the tumor uptake of the probe could reach 11.37% ID / g, and the muscle uptake was 0.10% ID / g, with a relatively high (113.70) tumor / muscle ratio.

[0144] Example 3: Figure 8 As shown, imaging agent a-1 (n=3) was used for small animal PET / CT imaging of LnCap tumor-bearing mice. 2 hours after tail vein injection, the small animal PET / CT static scanning imaging showed that the tumor uptake of the probe could reach 2.86%ID / g, and the muscle uptake was 0.13%ID / g, with a high (22) tumor / muscle ratio.

[0145] Comparative Example 1: Figure 5 As shown, in the same batch of LNCaP tumor-bearing mice, [ 68 At 2 h after injection of Ga]-PSMA-11, tumor uptake was 3.85% ID / g, muscle uptake was 0.07% ID / g, and the tumor / muscle ratio was 55.

[0146] From the above structure, it can be seen that compared with the FDA-approved prostate cancer imaging agent [ 68 Ga]-PSMA-11, the tumor uptake value of imaging agent a-1 (n=1) is about 3 times that of imaging agent a-2 (n=1, m=1) is about 1.5 times that of imaging agent a-2. The above two imaging agents are metabolized by the liver and kidneys, with low image background and clear imaging of target tissues.

[0147] At the same time, in the paper "Development and PET Scanning Study of PSMA Targeted Contrast Agent 18F-Glu-Urea-Lys for Prostate Cancer", the public images show (the original document (ONCOLOGY LETTERS, 10: 2299-2302, 2015) does not have clear uptake values ​​and image color bars, and cannot provide a comparison of specific uptake values, but from its images, there is a large amount of imaging agent concentration in the liver and abdomen of mice, the image target / non-target ratio is low, and the background is not clear), the uptake of the imaging agent in the liver and intestine is high, while the uptake of the target tissue tumor is only slightly higher than that of the muscle tissue. By comparison, the imaging agent of the present invention is higher than that of the present invention. 18 F-Glu-Urea-Lys contrast agent has the advantages of mild labeling conditions, good in vivo distribution characteristics, and high tumor target tissue uptake.

[0148] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An F-18 labeled PSMA targeting PET probe, characterized in that: The PET probe is obtained by reacting a labeling intermediate with a precursor small molecule, wherein the labeling intermediate is a fluoroaryl vinyl sulfone labeling intermediate, and the precursor small molecule is a precursor small molecule containing a thiol group and having Lys-urea-Glu as a parent core structure; the labeling intermediate is a labeling intermediate 1 or a labeling intermediate 2, and its molecular structure is as follows: The molecular structure of the labeled intermediate 1 is: The molecular structure of the labeled intermediate 2 is: In the above molecular structure, the value of m ranges from 1 to 3; The precursor small molecule is a precursor small molecule a or a precursor small molecule b, and its molecular structure is as follows: The molecular structure of the precursor small molecule a is as follows: The molecular structure of the precursor small molecule b is as follows: In the above molecular structure, the value of n ranges from 1 to 3; The labeled intermediate reacts with the precursor small molecule in an alkaline buffer with a pH value of 8-9, and is separated and purified by high performance liquid chromatography to obtain a PET probe; the alkaline buffer is selected from sodium carbonate buffer, sodium borate buffer, potassium bicarbonate buffer, phosphate buffer, HEPES buffer or MES buffer.

2. The F-18 labeled PSMA targeted PET probe according to claim 1, characterized in that: The PET probe is PET probe a-1, a-2, b-1 or b-2, and its molecular structure is: The molecular structure of PET probe a-1 is: The molecular structure of PET probe a-2 is: The molecular structure of PET probe b-1 is: The molecular structure of PET probe b-2 is: In the above molecular structure, the value range of n is 1-3, and the value range of m is 1-3.

3. The method for preparing the F-18 labeled PSMA targeting PET probe according to claim 1, characterized in that: The following steps are involved: S1, adding the F-18 ion compound to the vinyl sulfone organic matter and heating for reaction, and after cooling, separating the product by HPLC; S2, diluting the product with water, first passing it through an alumina column, and then passing it through a solid phase extraction column to obtain a separated and purified fluoroaryl vinyl sulfone labeled intermediate; S3, adding the precursor small molecule and the fluoroaryl vinyl sulfone labeled intermediate into an alkaline buffer, reacting at 100° C. for 5-60 min, and after the reaction, purifying the product by HPLC; S4, collecting the eluate, diluting the eluate with water, controlling the content of organic solvent in the eluate to be below 5v%, then hanging it on a solid phase extraction column, washing away the acidic solvent with water, rinsing it with ethanol into a product bottle, and finally diluting it with physiological saline until the content of ethanol is below 10v%.

4. The preparation method according to claim 3, characterized in that: The chromatographic separation conditions of the HPLC are: Chromatographic column: Eclipse Plus C18 5μm, 4.6×250mm; Flow rate: 1 mL / min; Wavelength: 254nm, column temperature: 35℃; Mobile phase A: HPLC grade acetonitrile containing 0.1 v% TFA; Mobile phase B: Water containing 0.1 v% TFA; Elution conditions: 0→2min: the volume ratio of mobile phase A / mobile phase B is 5 / 95; 2→15min: The volume ratio of mobile phase A / mobile phase B changes uniformly to 95 / 5.

5. The preparation method according to claim 3, characterized in that: In step S1, the F-18 ion compound is first dissolved in anhydrous acetonitrile and then added to the vinyl sulfone organic matter for heating reaction. The heating reaction temperature is 80-100° C. and the reaction time is 5-60 min.

6. The preparation method according to claim 3, characterized in that: The vinyl sulfone organic compound is a labeling precursor 1 or a labeling precursor 2, and its molecular structure is: The molecular structure of the labeled precursor 1 is: The molecular structure of the labeled precursor 2 is: In the above, Ar = 2,6-diisopropylphenyl.

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