Technetium [99mTc]-labeled deuterated tropane derivative and application thereof

Abstract

The invention relates to a technetium [99mTc]-labeled deuterated tropane derivative and application thereof, and belongs to the technical field of nuclear medicine. The invention provides a technetium [99mTc]-labeled deuterated tropane derivative, which can be specifically combined with a dopamine transporter, and can be used for preparing the technetium [99mTc]-labeled deuterated tropane derivative. The technetium [99mTc]-labeled deuterated tropane derivative has the advantages of good affinity to a dopamine transporter, high radioactive uptake of a target region (striatum) in a brain and high target / background ratio, and has an extremely high application prospect in the aspect of SPECT (Single Photon Emission Computed Tomography) imaging of the dopamine transporter.

Description

Technical Field

[0001] The present invention relates to a 99m Tc]-labeled deuterated tropane derivative and its application, belonging to the technical field of nuclear medicine. Background Art

[0002] Functional changes in the dopamine system of the central nervous system are associated with various neuropsychiatric diseases, such as Parkinson's disease (PD) (see reference: Fazio P, et al. Mov. Disord. 2018, 33: 592 - 599), attention deficit hyperactivity disorder (see reference: Hansen FH, et al. J. Clin. Invest. 2014, 124: 3107 - 3120), drug addiction (see reference: Hou H, et al. Neurosci. Bull. 2014, 30: 765 - 776), and dementia (see reference: Siepel FJ, et al. Mov. Disord. 2016, 31: 118 - 125), etc. Dopamine transporter (DAT) is a transport protein located on the presynaptic membrane of dopamine (DA) neurons, which can transport DA in the synaptic cleft against the concentration gradient to the presynaptic neuron (see reference: Cai X, et al. Nature 2024, 635: 406 - 414). DAT plays a key role in regulating the DA concentration in the synaptic cleft of DA neurons and protecting DA neurons (see reference: Srivastava DK, et al. Nature 2024, 632: 672 - 677 and Palermo G, et al. Int. J. Mol. Sci. 2021, 22). Therefore, DAT is one of the important biological targets of the dopamine system. Research shows that the change of DAT can directly and sensitively reflect the change of the DA system. Clinically, in vivo imaging of DAT can provide important information for the diagnosis, disease progression, and efficacy monitoring of related diseases (see reference: Srivastava DK, et al. Nature 2024, 632: 672 - 677 and Palermo G, et al. Int. J. Mol. Sci. 2021, 22).

[0003] Single photon emission computed tomography (SPECT) is one of the representative technologies of modern molecular imaging techniques, providing a non-invasive molecular imaging technique for in vivo disease diagnosis, grading, and efficacy evaluation. The specific function of SPECT (i.e., the diseases for which it is used for imaging) depends on the radioactive molecular probe (also known as radioactive drug) used during imaging. Currently, the molecular structures of the radioactive drugs used for clinical SPECT imaging of DAT are all tropane derivatives, mainly including tropane derivatives labeled with radioisotopes such as iodine 123 I] and technetium 99m Tc] (see references: Varrone A, et al. J. Nucl. Med. 2010, 51: 1331 - 1334 and Abbasi Gharibkandi N, et al. Eur. J. Med. Chem. 2019, 166: 75 - 89). Among them, 123 the drugs labeled with 123 I] for SPECT imaging mainly include TM I]FP-CIT (DaTscan 123 TM ), 123 I]β-CIT, 123 I]Altropane, and 123 I]PE2I, etc. Compared with other radioisotopes used for SPECT imaging (such as 123 I), technetium 99m Tc]-labeled SPECT drugs have the advantages of a suitable half-life (6.01 h), a suitable γ-ray energy (140 KeV), convenient source (molybdenum-technetium generator), and relatively low price. Therefore, they are the most important radioisotopes for clinical SPECT imaging. Thus, technetium 99m Tc]-labeled radioactive drugs for DAT SPECT imaging have excellent clinical application prospects and have good clinical value for the diagnosis, grading research, and efficacy monitoring of DAT-related diseases.

[0004] At present, there is only one 99m Tc]-labeled SPECT drug for DAT imaging that has been successfully applied in clinical practice, namely 99m Tc-TRODAT-1 (see reference: Meegalla SK, et al. J. Med. Chem. 1997, 40: 9 - 17). Since it was first reported, 99mTc-TRODAT-1 has rapidly gained many applications in the field of basic and clinical research related to DAT, and there have been many reports on basic and clinical research in aspects such as early diagnosis, differential diagnosis, efficacy monitoring, and pathological research of DA system-related diseases (such as Parkinson's disease, multiple system atrophy, Huntington's chorea, attention deficit hyperactivity disorder, and drug addiction, etc.). Even so, 99m There are still some deficiencies or areas worthy of improvement in the use of Tc-TRODAT-1 for DAT SPECT imaging. For example, 99m The uptake of Tc-TRODAT-1 in the target regions of the brain is too low. Because 99m The radioactive concentration of Tc-TRODAT-1 in the target regions of the brain is too low, a relatively large radioactive dose (740 - 925 MBq) and a relatively long scanning time (40 - 60 min) are required during clinical SPECT imaging to collect the required amount of information (see references: Kao PF, et al. Nucl. Med. Commun. 2001, 22:151 - 154 and Chang K-W, et al. Int. J. Mol. Sci. 2023, 24:3773). Another example is 99m The target-to-background ratio of Tc-TRODAT-1 is not high. Studies have shown that within the optimal imaging time window (4 h), the target-to-background (ST / OC) ratio of normal people is only about 2.15 (see references: Kao PF, et al. Nucl. Med. Commun. 2001, 22:151 - 154 and Koch W, et al. J. Nucl. Med. 2007, 48:27 - 34). Due to the degenerative lesions of DA neurons in PD patients, the ST / OC value on the affected side is theoretically lower than that of normal people. Studies have shown that the average target-to-background (ST / OC) value on the affected side of PD patients is about 1.34 (see reference: Kao PF, et al. Nucl. Med. Commun. 2001, 22:151 - 154). Obviously, the difference in the target-to-background ratio between normal people and PD (the ST / OC of the most severely affected PD patients is close to 1 theoretically) is relatively small (1.34 vs 2.15). Due to the existence of individual differences in the human body and instrument system deviations, this result is not conducive to the accurate analysis of related diseases clinically (for example, clinically, PD needs to be classified into grades I, II, III, and IV according to the severity), nor is it conducive to monitoring the progression of the disease course and analyzing the efficacy.

[0005] As we all know, in order to obtain good image quality during clinical SPECT imaging, the radioactive probe is required to have high radioactive uptake in the target area (or target organ) to ensure sufficient radioactive signals to obtain SPECT images. In addition, the radioactive probe needs to have a high target / speech ratio to ensure the clarity of the SPECT image. The higher the target / speech ratio, the better the image clarity, which is more conducive to quantitative analysis of SPECT images and accurate diagnosis and disease course monitoring. 99m Tc-TRODAT-1 has some shortcomings such as low radioactivity concentration in the target area and low target / cost ratio. 99m Tc-labeled radiopharmaceuticals for DAT SPECT imaging with higher target area radioactive uptake and higher target / target ratio are clinically needed and are also one of the important research directions in the field of radiopharmaceuticals. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a technetium [ 99m Tc] labeled deuterated tropane derivative, the technetium [ 99m The deuterated tropane derivative labeled with Tc has the following structure:

[0007]

[0008] In one embodiment of the present invention, the technetium [ 99m The labeled precursor of the deuterated tropane derivative labeled with Tc has the following structure:

[0009]

[0010] The present invention also provides a method for preparing the above-mentioned technetium [ 99m The method comprises: mixing compound 5, trifluoroacetic acid and methanesulfonic acid and reacting them to obtain a precursor compound; using radioactive 99m The precursor compound is labeled with Tc to obtain the above-mentioned technetium [ 99m Tc]-labeled deuterated tropane derivatives;

[0011] The compound 5 has the following structure:

[0012]

[0013] The precursor compound has the following structure:

[0014]

[0015] In one embodiment of the present invention, the preparation method of Compound 5 includes: mixing Compound 4 with a tetrahydrofuran solution of deuterated borane (BD3·THF) and reacting them to obtain a reaction product; mixing the reaction product with deuterated hydrochloric acid (DCl) and reacting them to obtain Compound 5;

[0016] Compound 4 has the structure shown below:

[0017]

[0018] In one embodiment of the present invention, the preparation method of Compound 4 includes: mixing Compound 2, Compound 3 and triethylamine and reacting them to obtain Compound 4;

[0019] Compound 2 has the structure shown below:

[0020]

[0021] Compound 3 has the structure shown below:

[0022]

[0023] In one embodiment of the present invention, the use of radioactive 99m Tc to label the precursor compound includes: mixing the precursor compound, Na 99m TcO4 and the excipient for 99m Tc labeling and reacting them to obtain the above-mentioned 99m Tc]-labeled deuterated tropane derivative.

[0024] In one embodiment of the present invention, the composition of the excipient for 99m Tc labeling includes SnCl2, disodium ethylenediaminetetraacetate (EDTA-2Na), trisodium citrate, citric acid and sodium glucoheptonate (GH).

[0025] The present invention also provides the application of the above-mentioned 99m Tc]-labeled deuterated tropane derivative or the above method in the preparation of a dopamine transporter imaging agent.

[0026] In one embodiment of the present invention, the imaging agent is a SPECT imaging agent.

[0027] The present invention also provides an imaging agent targeting the dopamine transporter, and the imaging agent contains the above-mentioned 99m Tc]-labeled deuterated tropane derivative.

[0028] In one embodiment of the present invention, the imaging agent is a SPECT imaging agent.

[0029] The technical solution of the present invention has the following advantages:

[0030] The present invention provides a 99m technetium 99m Tc]-labeled deuterated tropane derivative, and this 99m technetium Brief Description of the Drawings

[0031] Figure 1 : 99m Synthesis route of

[0032] Figure 2 : 99m Radioactive HPLC analysis chromatograms of 99m Tc-TRODAT-1 and

[0033] Figure 3 : 99m Comparative analysis of the uptake values (a) and ST / CB values (b) of

[0034] Figure 4 : 99m Comparison of the uptake values (a) and ST / CB ratios (b) of 99m Tc-TRODAT-d4 and

[0035] Figure 5 : 99m Tc-TRODAT-1 group, 99m Tc-TRODAT-d4 group and 99m Radioautographs (a) and ST / CB ratio analysis (b, c) of the brains of rats in the

[0036] Figure 6 : 99m Tc-TRODAT-d4 group and 99mMicroSPECT / CT imaging of the rat brain in the Tc-TRODAT-1 group (a) and ST / CB ratio analysis (b) (mean±SD, n = 3, **P < 0.01). Detailed implementation mode

[0037] The following embodiments are provided to better understand the present invention further. It is not limited to the best implementation mode, and does not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with those of other prior arts falls within the protection scope of the present invention.

[0038] For those not specifying specific experimental steps or conditions in the following embodiments, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For reagents or instruments not indicating the manufacturer, they are all conventional reagent products that can be obtained through commercial purchase.

[0039] Example 1: A technetium 99m Tc]-labeled deuterated tropane derivative 99m Tc-TRODAT-d4

[0040] This example provides a technetium 99m Tc]-labeled deuterated tropane derivative 99m Tc-TRODAT-d4, and the technetium 99m Tc]-labeled deuterated tropane derivative 99m Tc-TRODAT-d4 has the following structure:

[0041]

[0042] Example 2: A method for preparing a technetium 99m Tc]-labeled deuterated tropane derivative 99m Tc-TRODAT-d4

[0043] This example provides a method for preparing the technetium 99m Tc]-labeled deuterated tropane derivative 99m Tc-TRODAT-d4 in Example 1. The method includes the following steps (the synthesis route is shown in Figure 1 ):

[0044] Step 1: Synthesize compound 1 with reference to the literature "Meegalla SK, et al. J. Med. Chem. 1997, 40: 9 - 17"; synthesize compound 3 with reference to the literature "Liu Chunyi, et al. Chemical Research and Application 2009, 21: 824 - 827"; dissolve compound 1 (140 mg, 0.5 mmol) in 5 mL of dichloromethane to obtain a solution; add a 2 mol / L oxalyl chloride solution (0.5 mL, aqueous solution) to the solution under a nitrogen atmosphere to obtain a reaction mixture; stir the reaction mixture at room temperature (25 °C) (stirring speed 400 rpm) for 1.5 hours to obtain a reaction product; after removing the solvent by vacuum distillation of the reaction product, take the residue and dry it in vacuo to obtain compound 2 (white foamy solid). Compound 2 is used for the next reaction without purification.

[0045] Step 2: Dissolve compound 2 in 5 mL of dichloromethane to obtain a solution; cool the solution to -10 °C under a nitrogen atmosphere, stir for 15 minutes first, then slowly dropwise add compound 3 (217 mg, 0.5 mmol, pre-dissolved in 5 mL of dichloromethane), and then slowly dropwise add triethylamine (0.14 ml, 1 mmol) to obtain a reaction mixture; stir the reaction mixture for 30 minutes, first return to room temperature, and then continue to stir at room temperature for 20 hours to obtain a reaction product; add 10 mL of water to the reaction product, stir for 5 min, let it stand for liquid separation, and separate the organic phase; extract the aqueous phase with dichloromethane (15 mL × 2), and combine all the organic phases; dry the organic phase with anhydrous sodium sulfate, first concentrate it under reduced pressure, and then purify it by silica gel column chromatography (mobile phase: ethyl acetate / methanol / triethylamine = 90 / 10 / 1, v / v / v) to obtain compound 4 (pale yellow solid, 220 mg, yield 63%). The mass spectrometry MS (ESI) data of compound 4: [M + H] + Theoretical value (C 37 H 46 ClN3O4S2) is m / z 696.26, and the measured value is m / z 696.69.

[0046] Step 3: Dissolve compound 4 (695 mg, 1 mmol) in 20 mL of tetrahydrofuran to obtain a solution. Under a nitrogen atmosphere, cool the solution to 4 °C in an ice-water bath, then slowly drip in a tetrahydrofuran solution containing 1.0 mol / L deuterated borane (BD3) (20 mL, 20 mmol), and then heat under reflux at 70 °C for 18 hours to obtain reaction product A. After cooling reaction product A to 4 °C in an ice-water bath, slowly drip in a 1.0 mol / L deuterated hydrochloric acid (DCl) solution (6 mL, aqueous solution), stir evenly, then concentrate under reduced pressure to remove the solvent, and then add a 1.0 mol / L DCl solution (10 mL, aqueous solution), heat under reflux at 90 °C for 30 minutes to obtain reaction product B. After cooling reaction product B to 4 °C in an ice-water bath, first add concentrated ammonia water (aqueous solution of ammonia gas) with a concentration of 25% (w / v, g / 100 mL) to adjust the pH to ~10, and then extract with dichloromethane (10 mL × 3), and combine the organic phases. After drying the organic phases with anhydrous sodium sulfate, first concentrate under reduced pressure, and then purify by silica gel column chromatography (mobile phase: ethyl acetate / methanol / triethylamine = 100 / 1 / 1, v / v / v) to obtain compound 5 (280 mg, yield 40.1%). Mass spectrometry MS (ESI) data of compound 5: [M+H] + The theoretical value (C 37 H 46 ClN3O4S2) is m / z 672.33, and the measured value is m / z 672.75.

[0047] Step 4: Take compound 5 (280 mg, 0.42 mmol) and anisole (137 μL, 1.26 mmol) and dissolve them in 4 mL of trifluoroacetic acid to obtain a solution. Under a nitrogen atmosphere, cool the solution to 4 °C in an ice-water bath, then slowly drip in methanesulfonic acid (1.4 mL), and then stir and react at room temperature for 1 hour to obtain reaction product A. After vacuum concentrating reaction product A, first cool it to 4 °C in an ice-water bath, and then add 20 mL of anhydrous ether and 20 mL of water to the residue and stir and react for 10 minutes to obtain reaction product B. Let reaction product B stand and separate layers, and separate the organic phase. Adjust the pH of the aqueous phase to ~7 with solid NaHCO3, then extract with dichloromethane (20 mL), and combine all the organic phases. After drying the organic phases with anhydrous sodium sulfate, first concentrate under reduced pressure, then add anhydrous ether (10 mL) for washing, and take the filtrate. Pass dry HCl gas into the filtrate for 5 min, and white solid is formed in the solution to obtain reaction product C. After concentrating reaction product C under reduced pressure to remove the solvent, dry it under vacuum to obtain compound 6 (i.e., the precursor compound, white solid, hydrochloride, 110 mg, yield 60.8%). Mass spectrometry MS (ESI) data of compound 6: [M+H] + The theoretical value (C 37 H 46The m / z of (ClN3O4S2) is 432.21, and the measured value is m / z 432.54.

[0048] Step 5: Prepare an auxiliary solution (1.0 mL) for 99m Tc labeling containing 30 μg of SnCl2·2H2O, 0.9 mg of EDTA-2Na, 28.8 mg of trisodium citrate, 0.42 mg of citric acid, and 10 mg of sodium glucoheptonate (GH); add an ethanol solution (50 μL) containing 1.0 mg / mL of compound 6 and Na 99m TcO4 solution (~740 MBq, 1.0 mL) to the auxiliary solution to obtain a reaction mixture; let the reaction mixture stand for 5 minutes and then heat it at 100 °C for 30 minutes to obtain a solution of 99m Tc-labeled deuterated tropane derivative 99m Tc-TRODAT-d4 (i.e., compound 7).

[0049] Using 99m Tc-TRODAT-1 as a control, analyze 99m Tc-TRODAT-d4 by high performance liquid chromatography (HPLC) method (refer to the patent application text with publication number CN114689739A). The HPLC conditions are as follows: C 18 Reverse chromatographic column (5 μm, 4.6×250 mm), mobile phase is CH3OH / H2O / TFA = 55 / 45 / 0.1% (v / v / v), flow rate is 1.0 mL / min, and the radioactivity detector is Perkin Elmer TR610 radioactivity detector. 99m Tc-TRODAT-1 and 99m The radioactive HPLC analysis results of Figure 2 . As Figure 2 shown, the elution times and peak shapes of the radioactive signal peaks of the two are basically the same, and this result verifies 99m the chemical structure of 99m Tc-TRODAT-d4. At the same time, integrate and calculate the peak area of the main peak of 99m Tc-TRODAT-1 and 99m the two stereoisomers of 99m Tc-TRODAT-d4 in the figure. The radiochemical purity of

[0050] Experimental Example 1: Biodistribution experiment of 99m Tc-labeled deuterated tropane derivative 99m Tc-TRODAT-d4 in the brain

[0051] This experimental example provides a biodistribution experiment of deuterated tropane derivative labeled with technetium 99m Tc] in the brain, namely 99m Tc-TRODAT-d4. The specific process is as follows:

[0052] Take a number of normal rats (SD rats, purchased from Changzhou Cavens Experimental Animal Co., Ltd.) and randomly divide them into 5 groups, with 5 rats in each group. Each rat is injected with ~15 MBq of 99m Tc-TRODAT-d4 via the tail vein, and is decapitated at 2 min, 30 min, 1 h, 2 h, and 4 h after administration respectively. The brain tissue is quickly removed, and the striatum (ST), cerebellum (CB), hippocampus (HP), cortex (CX) tissues and the remaining brain are separated. After weighing the wet weight respectively, they are placed in γ counting tubes, and the radioactivity counts of each brain tissue are measured with a γ counter. Then, according to the wet weight and radioactivity count of each brain tissue, the radioactive concentration value ID% / g of each brain tissue is calculated.

[0053] The results of the radioactive concentration of each brain tissue are shown in Table 1. At 2 min after administration, the radioactive concentration differences in each brain region are not significant. However, after 30 min, the radioactive concentration in the striatum (ST) region with high DAT content (see the literature: Meegalla SK, et al. J. Med. Chem. 1997, 40: 9 - 17) is higher than other regions, while in the cerebellum (CB) region without DAT, the radioactive concentration is the lowest. The ST / CB values are 1.95, 2.20, 2.90, and 3.79 at 30, 60, 120, and 240 min respectively. This result indicates that 99m Tc-TRODAT-d4 can enter the brain tissue, has good affinity for DAT in the brain, and has high radioactive accumulation in the target region (striatum).

[0054] Table 1 99m Brain distribution of

[0055] 2 min 30 min 60 min 120 min 240 min Striatum (ST) 0.249±0.044 0.146±0.026 0.106±0.018 0.068±0.022 0.035±0.007 Hippocampus (HP) 0.273±0.055 0.126±0.026 0.081±0.012 0.038±0.006 0.019±0.003 Cerebellum (CB) 0.316±0.060 0.075±0.011 0.048±0.006 0.026±0.005 0.011±0.002 Cortex (CX) 0.353±0.066 0.128±0.026 0.076±0.013 0.034±0.001 0.013±0.003 ST / CB 0.790±0.022 1.95±0.25 2.20±0.25 2.90±0.24 3.79±0.85

[0056] Experimental example 2: Specific in vivo DAT binding experiment of deuterated tropane derivative labeled with technetium 99m Tc] 99m Tc-TRODAT-d4

[0057] This experimental example provides a specific in vivo DAT binding experiment of deuterated tropane derivative labeled with technetium 99m Tc] 99m Tc-TRODAT-d4. The specific process is as follows:

[0058] The experiment was divided into three groups: the normal group, the DAT inhibitor group (blocking group), and the 99m Tc-TRODAT-1 control group. The radioactive distribution in the target area and background area of the brain in different groups was evaluated from the perspective of radioactive concentration to evaluate 99m the specificity of Tc-TRODAT-d4 for DAT binding and compare it with the reported 99m Tc-TRODAT-1.

[0059] Normal group (Control): Approximately 15 MBq of 99m Tc-TRODAT-d4 was injected into normal rats (SD rats, purchased from Changzhou Cavens Experimental Animal Co., Ltd.) via the tail vein. After 2 h of drug administration, the rats were decapitated, and the brain tissues were quickly removed. The striatum (ST), cerebellum (CB), hippocampus (HP), cortex (CX) tissues, and the remaining brain were isolated, weighed wet, placed in γ counting tubes, and the radioactive counts of each brain tissue were measured with a γ counter. Then, based on the wet weight and radioactive count of each brain tissue, the radioactive concentration value ID% / g of each brain tissue was calculated.

[0060] DAT inhibitor group (blocking group, blocking): Approximately 15 MBq of 99m Tc-TRODAT-d4 and the DAT blocker CFT (a DAT-selective specific ligand, synthesized with reference to the literature "Li Xiaomin, et al. Chemical Reagents, 2004, 26: 185 - 186", and the dose of CFT was 1.0 mg / kg based on the rat body weight) were injected into normal rats (SD rats, purchased from Changzhou Cavens Experimental Animal Co., Ltd.) via the tail vein. After 2 h of drug administration, the rats were decapitated, and the brain tissues were quickly removed. The striatum (ST), cerebellum (CB), hippocampus (HP), cortex (CX) tissues, and the remaining brain were isolated, weighed wet, placed in γ counting tubes, and the radioactive counts of each brain tissue were measured with a γ counter. Then, based on the wet weight and radioactive count of each brain tissue, the radioactive concentration value ID% / g of each brain tissue was calculated.

[0061] 99m Tc-TRODAT-1 control group: The experimental method was the same as that of the normal group, except that the injected drug was 99m Tc-TRODAT-1 ( 99m Tc-TRODAT-1 was synthesized with reference to the literature "Chen Zhengping, et al. Chinese Journal of Nuclear Medicine, 2006, 26: 235 - 237"), and the injection dose was also approximately 15 MBq.

[0062] The comparison results between the normal group and the blocking group are as Figure 3 shown. 99mAt the specified time points after administration, the radioactivity uptake value of the target region ST for Tc-TRODAT-d4 was 0.046% ID / g. After blocking DAT with CFT, the radioactivity uptake value of ST decreased to 0.027% ID / g, showing a significant statistical difference compared with the result before blocking (P < 0.001), and the reduction amplitude reached 41%. At the same time, 99m The ST / CB (target / background ratio) value of Tc-TRODAT-d4 in the normal rat brain was 4.03. After blocking DAT with CFT, ST / CB decreased to 1.05, and the reduction amplitude reached 74%. The above results indicate that 99m Tc-TRODAT-d4 has specificity for the binding of DAT in the brain.

[0063] 99m The comparison results of Tc-TRODAT-d4 and 99m Tc-TRODAT-1 are as Figure 4 shown. 99m The drug concentration of Tc-TRODAT-d4 in the striatum (0.046% ID / g) was significantly higher than that of 99m Tc-TRODAT-1 (0.040% ID), and there was a statistical difference between the two (P < 0.05). This result indicates that 99m The radioactive concentration of Tc-TRODAT-d4 in the target region was significantly higher than that of 99m Tc-TRODAT-1, which is more conducive to in vivo imaging studies. In terms of the target / background ratio, 99m the ST / CB ratio of Tc-TRODAT-d4 (ST / CB = 4.03) was significantly higher than that of 99m Tc-TRODAT-1 (ST / CB = 3.05), and the increase ratio reached 32% (P < 0.05). This result indicates that 99m the target / background ratio of Tc-TRODAT-d4 was significantly higher than that of 99m Tc-TRODAT-1, which is beneficial to improving the contrast during DAT imaging.

[0064] Experimental Example 3: Autoradiography experiment of technetium 99m Tc]-labeled deuterated tropane derivative 99m Tc-TRODAT-d4

[0065] This experimental example provides an autoradiography experiment of technetium 99m Tc]-labeled deuterated tropane derivative 99m Tc-TRODAT-d4. The specific process is as follows:

[0066] The experiment was divided into three groups, namely the normal group, the DAT inhibitor group (blocking group), and 99mTc-TRODAT-1 control group. The radioactivity distribution of the target area and background area in the brain of different groups was further evaluated from the image perspective to evaluate the 99m The specificity of Tc-TRODAT-d4 for DAT binding is consistent with the reported 99m Tc-TRODAT-1 was used for comparison.

[0067] Normal group (Control): Normal rats (SD rats, purchased from Changzhou Cavens Laboratory Animal Co., Ltd.) were injected with 185 MBq of 99m Tc-TRODAT-d4 was used. Two hours after administration, rats were killed by cervical dislocation. The brain and cerebellum were quickly removed and embedded in a cryoembedding medium (purchased from Wuxi Jiangyuan Experimental Technology and Trade Corporation). The brain and cerebellum were first placed on a freezing microtome and stored at -25°C for 2 hours. Then, the brain and cerebellum were cut into coronal sections with a thickness of 30 μm. The obtained coronal sections were attached to glass slides and first dried at room temperature (25°C). The dried glass slides were then placed on an imaging plate and exposed for 8 hours. The imaging plate was then placed in a phosphor screen imager for imaging to obtain autoradiographic images of the normal rat brain and cerebellum. Finally, the image analysis was performed using the instrument's own Opti Quant software. The striatum (ST), cerebellum (CB) and other regions were delineated, the optical density values of each region were obtained, and the ST / CB ratio was calculated.

[0068] DAT inhibitor group (blocking group): Normal rats (SD rats, purchased from Changzhou Cavens Laboratory Animal Co., Ltd.) were injected with 185 MBq of DAT inhibitor via the tail vein. 99m Tc-TRODAT-d4 and DAT blocker CFT (DAT selection specific ligand, synthesized with reference to the literature "Li Xiaomin, et al. Chemical Reagents, 2004, 26:185-186", the dose of CFT is 1.0 mg / kg based on rat body weight), and 2 hours after administration, the rats were killed by cervical dislocation, and the brain and cerebellum were quickly removed and embedded with freezing embedding medium (purchased from Wuxi Jiangyuan Experimental Technology and Trade Corporation). They were first placed on a freezing microtome and stored at -25°C for 2 hours, and then cut into coronal sections with a thickness of 30 μm. The obtained coronal sections were attached to slides and first dried at room temperature (25°C). The dried slides were then placed on an imaging plate for exposure for 8 hours. The imaging plate was then placed in a phosphor screen imager for imaging to obtain radioautographic images of the normal rat brain and cerebellum. Finally, the instrument's built-in Opti Quant software was used for image analysis to delineate the striatum (ST), cerebellum (CB) and other regions, and the optical density value of each region was obtained, and then the ST / CB ratio was calculated.

[0069] 99m Tc-TRODAT-1 control group: The experimental method is the same as the normal group, except that the injection of drugs is99m Tc-TRODAT-1( 99m Tc-TRODAT-1 was synthesized according to the reference literature "Chen Zhengping, et al. Chinese Journal of Nuclear Medicine, 2006, 26: 235-237", and the injection dose was also ~185 MBq.

[0070] The autoradiographic imaging results were as Figure 5 shown, 99m Tc-TRODAT-d4 had high radioactive uptake in the striatal region of the brain. The target region, the striatum (ST), was clearly visualized. The ratios of the target region to the background region, the cerebellum (CB), were: ST / CB = 4.11. After blocking with the DAT inhibitor CFT, the ST was not visualized and the radioactive uptake value decreased to the background level (ST / CB = 1.11). There was a significant statistical difference in the ST / CB value before and after blocking (***P < 0.001, n = 3). This result indicated that 99m Tc-TRODAT-d4 had specific binding to DAT.

[0071] Meanwhile, it could be seen from Figure 5 that although 99m Tc-TRODAT-1 also had radioactive accumulation in the ST region of the brain, its radioactive concentration was lower than that of 99m Tc-TRODAT-d4, and the image clarity was inferior to that of 99m Tc-TRODAT-d4. After calculation, 99m the target-to-background ratio of Tc-TRODAT-1 was ST / CB = 3.27. 99m The target-to-background ratio of Tc-TRODAT-d4 (ST / CB = 4.11) was significantly higher than that of 99m Tc-TRODAT-1 (ST / CB = 3.27) (***P < 0.001, n = 3), and the increase amplitude was 26%. This result indicated that 99m Tc-TRODAT-d4 had higher imaging contrast than 99m Tc-TRODAT-1 and was more conducive to imaging analysis of DAT in the brain.

[0072] Experimental Example 4: microSPECT / CT imaging experiment of the deuterated tropane derivative 99m labeled with technetium 99m Tc-TRODAT-d4

[0073] This experimental example provided a microSPECT / CT imaging experiment of the deuterated tropane derivative 99m labeled with technetium 99m Tc-TRODAT-d4. The specific process was as follows:

[0074] The experiment was divided into two groups: 99m Tc-TRODAT-d4 group and 99m Tc-TRODAT-1 control group. The radioactivity distribution in the target area and background area of the brain in different groups was further evaluated from the perspective of microSPECT imaging and compared with the reported 99m Tc-TRODAT-1 was used for comparison.

[0075] 99m Tc-TRODAT-d4 group: Normal rats (SD rats, purchased from Changzhou Cavens Laboratory Animal Co., Ltd.) were anesthetized with isoflurane and injected with 1.0 mL of 20% (w / v, g / 100 mL) mannitol (mannitol has the function of opening the blood-brain barrier and improving 99m Tc-TRODAT-d4 brain uptake value), 20 minutes after injection, 111 MBq of 99m Tc-TRODAT-d4, injected 99m Forty-one hours after Tc-TRODAT-d, the rats were killed by cervical dislocation, and the cerebrum and cerebellum were rapidly removed and placed on a microSPECT / CT imaging bed (Albira Si, Bruker, Germany) equipped with a multi-hole collimator. MicroSPECT signal acquisition was then performed for 45 minutes, followed by CT imaging for 15 minutes. Image reconstruction was performed using the OSEM2D method (12 iterations) using the software included with the microSPECT / CT instrument. The images were analyzed using PMOD (version 4.3, Bruker, Germany) software to delineate regions such as the striatum (ST) and cerebellum (CB). Pixel values were then obtained for each region (the pixel values reflect the relative concentration of the radioactive drug), and the ST / CB ratio was calculated.

[0076] The microSPECT / CT imaging results are as follows Figure 6 As shown, 99m Tc-TRODAT-d4 has high radioactive uptake in the striatum of the brain. The target area striatum (ST) is clearly visualized, and the ratio of the target area to the background area cerebellum (CB) is: ST / CB=2.58. 99m Tc-TRODAT-1 also accumulates radioactivity in the ST region of the brain, but its radioactivity concentration is lower than 99m Tc-TRODAT-d4, the image clarity is not as good as 99m Tc-TRODAT-d4. After calculation, 99m The target / CB ratio of Tc-TRODAT-1 is ST / CB=1.94. 99mThe target-to-background ratio (ST / CB = 2.58) of Tc-TRODAT-d4 was 99m significantly higher than that of Tc-TRODAT-1 (ST / CB = 1.94), with an increase of 33%. This result indicates that 99m Tc-TRODAT-d4 has 99m higher imaging contrast than Tc-TRODAT-1, which is more conducive to imaging analysis of DAT in the brain.

[0077] Obviously, the above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A technetium 99m Tc]-labeled deuterated tropane derivative, characterized in that The said technetium 99m Tc]-labeled deuterated tropane derivative has the structure shown below:

2. The technetium 99m Tc]-labeled deuterated tropane derivative according to claim 1, characterized in that The said technetium 99m The labeling precursor of the deuterated tropane derivative labeled with Tc] has the structure shown below:

3. A method for preparing the deuterated tropane derivative labeled with 99m Tc] as claimed in claim 1, characterized in that The method includes: mixing compound 5, trifluoroacetic acid and methanesulfonic acid and reacting them to obtain a precursor compound; using radioactive 99m Tc to label the precursor compound to obtain the 99m Tc]-labeled deuterated tropane derivative as claimed in claim 1; The compound 5 has the structure shown below: The precursor compound has the structure shown below:

4. The method according to claim 3, wherein The preparation method of the compound 5 includes: mixing a tetrahydrofuran solution of compound 4 and deuterated borane for reaction to obtain a reaction product; mixing the reaction product and deuterated hydrochloric acid for reaction to obtain the compound 5; The compound 4 has the structure shown below:

5. The method according to claim 4, characterized in that, The preparation method of the compound 4 includes: mixing compound 2, compound 3 and triethylamine for reaction to obtain the compound 4; The compound 2 has the structure shown below: The compound 3 has the structure shown below:

6. The method according to any one of claims 3 to 5, characterized in that, The use of radioactive 99m Tc labeling of the precursor compound includes: 99m TcO4 and used for 99m The Tc-labeled auxiliary materials are mixed and reacted to obtain the technetium [ 99m Tc]-labeled deuterated tropane derivatives.

7. The method according to claim 6, characterized in that The said one for 99m The composition of the excipient labeled with Tc contains SnCl2, disodium ethylenediaminetetraacetate, trisodium citrate, citric acid and sodium glucoheptonate.

8. Use of the deuterated tropane derivative labeled with technetium 99m Tc] according to claim 1 or 2 or the method according to any one of claims 3 to 7 in the preparation of a dopamine transporter imaging agent.

9. The application according to claim 8, characterized in that The imaging agent is a SPECT imaging agent.

10. A radiopharmaceutical targeting dopamine transporter, characterized in that, The imaging agent contains the technetium 99m Tc]-labeled deuterated tropane derivative as claimed in claim 1 or 2.

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