Radioactively labeled compounds and precursor compounds thereof, their preparation method and use

Abstract

A precursor compound of a radiolabeled compound, a radiolabeled compound of the precursor compound, or a pharma- ceutically acceptable salt of the radiolabeled compound, as shown in formula (I). The radiolabeled compound has high water solubility, good in vitro stability at room temperature, high plasma protein binding rate, and high and long-lasting bone uptake in both in vivo distribution in mice and imaging in New Zealand rabbits, and animal experiments have demonstrated the development effect. 99m It has been shown to be better than Tc-MDP. JPEG2024541269000020.jpg47149

Description

Detailed Description of the Invention

[0001] [Technical field] The present disclosure is in the technical field of nuclear medicine, and specifically relates to radiolabeled compounds, their precursor compounds, their preparation methods and their uses.

[0002] [Background technology] Bone is a common site of distant metastasis of malignant tumors, with the incidence of distant metastasis being third only to the lungs and liver. Early diagnosis and treatment of metastatic bone tumors can effectively improve the prognosis and quality of life of patients.

[0003] Current treatments for metastatic bone tumors mainly include radiation therapy, chemotherapy, radionuclide therapy, bisphosphonate therapy, analgesic therapy and palliative surgery. Targeted radionuclide therapy for metastatic bone tumors can significantly reduce bone pain and kill tumor cells, with little toxic side effects, and is therefore a safe and effective treatment method. At present, the commonly used radiopharmaceuticals in China to treat metastatic bone tumors include: 89 SrCl2 and 153 These include Sm-EDTMP. They can significantly reduce bone pain and lower the incidence of skeletal-related events. However, they all need to be produced in a reactor, are relatively expensive, and 89 Because it is difficult to use SrCl2 for imaging, 89 SrCl2 has certain limitations in its use. There is an urgent clinical need for more effective, cheaper and more readily available therapeutic radiopharmaceuticals.

[0004] 68 Ga, 177 Lu, 225 Ac, 64 Cu, and 221 All At are medical isotopes with excellent nuclear properties. 68 Ga is 68 Ge / 68 Ga generator, which is readily available and low cost. + It can emit radiation and is used in PET imaging. 177 Lu,225 Ac, 64 Cu, and 221 All At is purchased from overseas, and the supply route is smooth and stable. 177 Lu has a half-life (T1 / 2) of 6.7 days and emits three types of beta particles with energies of 497 keV (78.6%), 384 keV (9.1%), and 176 keV (12.2%) that can be used therapeutically, and gamma rays of 113 keV (6.4%) and 208 keV (11%) that are suitable for in vivo localization and imaging. 225 Ac has a relatively high biological effect and the strongest killing effect on tumor cells because α ions emit α rays with higher linear energy transfer, high beam energy and short range. 225 Ac has a half-life (T1 / 2) of 9.9 days. 225 It is a daughter nuclide of Ac. 213 Bi has a half-life (T1 / 2) of 46 minutes. 64 The Cu nuclide has a favorable half-life (12.7 hours), specific decay characteristics (β + Attenuation, β - Due to their unique properties (e.g., photoinduced decay, electron capture) and their ability to coordinate and form complexes with various ligands, they have been intensively studied in the fields of PET molecular probes and theranostic medicine. 211 The alpha rays emitted by the decay of At have an average energy of 6.8 MeV and a range of 55 to 88 μm in tissue. 211 At has a half-life of 7.2 hours and is of great clinical value. 99mTc-MDP is the most commonly used clinical bone contrast agent, but as a single-photon contrast agent, its ability to localize and display lesions is much lower than that of a positron contrast agent. Phosphonate (HEDP) is a commonly used drug in clinical research for imaging and targeting therapy of metastatic bone tumors. However, as a first-generation nitrogen-free bisphosphonate, HEDP is significantly less effective than the second- and third-generation nitrogen-containing bisphosphonates such as alendronate and ibandronate. Therefore, it has become an urgent problem for those skilled in the art to provide a drug with better imaging effect, better treatment effect, and the ability to both image and treat metastatic bone tumors.

[0005] [Contents of this disclosure] A first object of the present disclosure is to provide precursor compounds of formula I that can be nuclide-labeled to produce drugs suitable for both imaging and treating metastatic bone tumors.

[0006] A second object of the present disclosure is to provide a radiolabeled compound represented by formula II, which is obtained by labeling a compound represented by formula I with a nuclide.

[0007] A third object of the present disclosure is to provide a method for preparing the precursor compound of formula I.

[0008] A fourth object of the present disclosure is to provide a method for preparing a radiolabeled compound of formula II.

[0009] A fifth object of the present disclosure is to provide uses of the precursor compounds represented by formula I.

[0010] A sixth object of the present disclosure is to provide uses of the radiolabeled compounds of formula II.

[0011] In order to achieve the above objectives, the technical solutions adopted by the present disclosure are as follows:

[0012] The present disclosure provides precursor compounds of radiolabeled compounds having a structure according to Formula I, or pharma- ceutically acceptable salts of said radiolabeled compounds. [ka]

[0013] The present disclosure provides a radiolabeled compound of a compound of formula I, having a structure according to formula II, or a pharma- ceutically acceptable salt of said radiolabeled compound. [ka] In the formula, A is a nuclide, preferably 68 Ga, 177 Lu, 225 Ac, 64 Cu, or 221 Represents At.

[0014] The present disclosure conjugates the chelator DOTA with ibandronic acid in an inventive manner to form a new compound, DOTA-ibandronic acid. 68 Ga, 177 Lu, 225 Ac, 64 Cu, or 211 When labeled with At, the amount of precursor used is much less than that of ibandronate alone. The present inventors provide various radionuclide-labeled DOTA-ibandronate, which is a new drug for both imaging and treatment of metastatic bone tumors. This class of drug uses radionuclides against metastatic bone tumors. 68 Ga, 177 Lu, 225 Ac, 64 Cu, or 211 The imaging and therapeutic effects of At and DOTA-ibandronic acid can be better exerted, resulting in a synergistic effect in which 1+1 is greater than 2.

[0015] In some embodiments of the present disclosure, the radionuclide-labeled DOTA-ibandronic acid has a radiochemical purity of 95% or greater.

[0016] This disclosure relates to the following: Step 1, reacting compound 1 with tert-butyl acrylate to form compound 2; Step 2: adding HCl / EtOAc dropwise to an EtOAc solution of compound 2 to react with compound 3; Step 3: Add compound 3 to PhCl, add POCl3 and H3PO3 under nitrogen protection, heat, react, cool, then pour out the chlorobenzene solution, add H2O, heat and stir to produce compound 4; Step 4: adding DOTA-NHS-ester solution to the aqueous solution of compound 4, and then adding triethylamine to react to produce the compound represented by formula I; The present invention provides a method for preparing a precursor compound of a radiolabeled compound represented by formula I, comprising the steps of: [ka]

[0017] The present disclosure provides a process for preparing a radiolabeled compound of formula II comprising reacting a compound of formula I.

[0018] In some embodiments of the present disclosure, the radionuclide 68 Ga, 177 Lu or 64 In the case of Cu, a solution of the compound represented by formula I, a sodium acetate solution and a radionuclide salt solution are mixed uniformly, the pH value of the mixed solution is adjusted, reacted, the pH value is adjusted again, sterilized and filtered to obtain a radiolabeled compound; Radioactive nuclides 225 In the case of Ac, the radiolabeled compound is obtained by uniformly mixing the solution of the compound represented by formula I, the sodium citrate solution, the sodium ascorbate solution and the radionuclide salt solution, adjusting the pH value of the mixed solution, reacting, adjusting the pH value again, sterilizing and filtering, Radioactive nuclides 211In the case of At, the solution of the compound represented by formula I, the sodium borate solution and the radioactive nuclide salt solution are mixed uniformly, the pH value of the mixed solution is adjusted, reacted, the pH value is adjusted again, sterilized and filtered to obtain the radiolabeled compound.

[0019] In some embodiments of the present disclosure, the radionuclide 68 In the case of Ga, 20 to 30 μg of the compound represented by formula I is added to 0.8 to 1.4 ml of a 0.25 M sodium acetate solution, and then a solution having an activity of 20 mCi is prepared. 68 Add Ga salt solution, mix uniformly, adjust pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for reaction time of 10-30 minutes, preferably 15 minutes, and adjust pH value to 5 after reaction to obtain a radiolabeled compound, where the concentration of the solution of the compound represented by formula I is 1 mg / ml; 68 The concentration of the Ga salt solution is 5 mCi / ml to 10 mCi / ml. Radioactive nuclides 177 In the case of Lu, 20-30 μg of the compound represented by formula I is added to 0.8-1.4 ml of a 0.25 M sodium acetate solution, and then the compound having an activity of 2 mCi is added to 0.8-1.4 ml of a 0.25 M sodium acetate solution. 177 Add Lu salt solution, mix uniformly, adjust the pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for a reaction time of 10-30 minutes, preferably 15 minutes, and adjust the pH value to 4.5 after the reaction to obtain a radiolabeled compound, where the concentration of the solution of the compound represented by formula I is 1 mg / ml; 177 The concentration of the Lu salt solution is 10 mCi / ml to 20 mCi / ml. Radioactive nuclides 225 In the case of Ac, 20 to 30 μg of the compound represented by formula I is added to 0.8 to 1.4 ml of a 0.1 M sodium ascorbate solution and 0.8 to 1.4 ml of a 0.1 M sodium citrate solution, and then a solution having an activity of 0.01 mCi is added. 225Add Ac salt solution, mix uniformly, adjust the pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for a reaction time of 10-30 minutes, preferably 15 minutes, and adjust the pH value to 4.5 after the reaction to obtain a radiolabeled compound, where the concentration of the solution of the compound represented by formula I is 1 mg / ml; 225 The concentration of Ac salt solution is 0.01mCi / ml to 0.02mCi / ml. Radioactive nuclides 64 In the case of Cu, 20-30 μg of the compound represented by formula I is added to 0.8-1.4 ml of a 0.25 M sodium acetate solution, and then the compound having an activity of 5 mCi is added to 0.8-1.4 ml of a 0.25 M sodium acetate solution. 64 Add Cu salt solution, mix uniformly, adjust pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for reaction time of 10-30 minutes, preferably 15 minutes, and adjust pH value to 4 after reaction to obtain radiolabeled compound, where the concentration of the solution of the compound represented by formula I is 1mg / ml; 64 The concentration of the Cu salt solution is 5mCi / ml to 10mCi / ml. Radioactive nuclides 211 In the case of At, 20-30 μg of the compound represented by formula I is added to 0.8-1.4 ml of a 0.25 M sodium borate solution, and then a solution having an activity of 1 mCi is prepared. 211 Add At salt solution, mix uniformly, adjust the pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for a reaction time of 10-30 minutes, preferably 15 minutes, and adjust the pH value to 7 after the reaction to obtain a radiolabeled compound, where the concentration of the solution of the compound represented by formula I is 1 mg / ml; 211 The concentration of At salt solution is 1.0 mCi / ml to 2.0 mCi / ml.

[0020] The present disclosure provides the use of a compound of formula I in the manufacture of a medicament for both imaging and treating metastatic bone tumors.

[0021] The present disclosure provides the use of a compound of formula II in the manufacture of a medicament for both imaging and treating metastatic bone tumors.

[0022] Compared with the prior art, the present disclosure has the following advantageous effects:

[0023] The present disclosure provides a scientific design and a simple method for inventively combining ibandronic acid with a chelator to obtain DOTA-ibandronic acid, which is then coupled to a radionuclide. 68 Ga, 177 Lu, 225 Ac, 64 Cu, or 211 Label with At 68 Ga-, 177 Lu-, 225 Ac-, 64 Cu-, or 211 At-DOTA-ibandronic acid is obtained. 68 Ga-, 177 Lu-, 225 Ac-, 64 Cu-, or 211 At-DOTA-ibandronate is a bone imaging agent and radiotherapeutic agent with excellent performance for metastatic bone tumors due to its high water solubility, good in vitro stability at room temperature, high plasma protein binding rate, and high long-term bone uptake as shown by in vivo distribution in mice and imaging in New Zealand rabbits. Pharmacodynamic experiments showed that 68 Ga-, 177 Lu-, 225 Ac-, 64 Cu-, or 211 At-DOTA-ibandronic acid is 68 GaCl3, 177 LuCl3, 225 AcCl3, 64 CuCl2, Na 211 The results showed that the IFN-γ-γ-γ-α-γ-α-glutamate (DOTA)-ibandronate group had better efficacy in either diagnosis or treatment than the IFN-γ-γ-γ-α-glutamate (DOTA)-ibandronate group, and were useful in the diagnosis and treatment of bone metastases from malignant tumors. 68 Ga-, 177 Lu-, 225 Ac-,64 Cu-, or 211 The feasibility and efficacy of At-ibandronate are demonstrated.

[0024] 68 Ga-, 177 Lu-, 225 Ac-, 64 Cu-, or 211 The labeling method of the present disclosure for preparing At-DOTA-ibandronic acid is simple, has a short reaction time, a high labeling yield, and requires very little precursor (microgram level). The ratio of target lesion to non-target tissue (T / N value) for the labeled compound is very high, up to 10 times or more. According to literature reports, a T / N value greater than 4-5 has a high therapeutic potential value. [Brief description of the drawings]

[0025] [Figure 1] FIG. 13 shows PET imaging of 68Ga-DOTA-IBA in New Zealand rabbits after 1 hour and 3 hours in Experimental Example 5. [Diagram 2] FIG. 13 shows whole-body static SPECT imaging of 177Lu-DOTA-IBA in New Zealand rabbits 1, 3, 5, and 7 days after administration in Experimental Example 6. [Diagram 3] FIG. 13 shows whole-body static SPECT imaging of 225Ac-DOTA-IBA in New Zealand rabbits after 1, 3, and 5 days in Experimental Example 7. [Figure 4] FIG. 1 shows a high performance liquid chromatography (HPLC) profile of the precursor compound represented by formula I. [Diagram 5] FIG. 1 shows a liquid chromatography mass spectrometry (LC-MS) profile of the precursor compound represented by formula I.

[0026] [Specific Form for Carrying Out the Disclosure] In order to make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure are described below clearly and completely. If no specific conditions are specified in the embodiments, the conditions shall be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments used are not indicated, the reagents or instruments are all conventional products that can be purchased commercially.

[0027] Example 1 In this example, a method for preparing a precursor compound represented by formula I of the present disclosure is disclosed, and the synthetic route of the precursor compound is as follows: [ka]

[0028] Step 1 Preparation of compound 2 [ka] tert-Butyl acrylate (6.34 g, 49.4 mmol) was added to compound 1 (5.00 g, 24.7 mmol). The mixture was allowed to react under stirring at 25° C. for 3 hours. Thin layer chromatography (TLC) was used to monitor the completion of the reaction and the formation of a new spot. The reaction solution was concentrated to give compound 2 (7.90 g, 96.7% yield) as a colorless oil. The crude product was used directly in the next reaction without purification.

[0029] Step 2 Preparation of compound 3 [ka] HCl / EtOAc (4M, 20.0 mL) was added dropwise to a solution of compound 2 (1.90 g, 5.75 mmol) in EtOAc (2.00 mL) under ice bath condition. The reaction solution was stirred at 25° C. for 2 h. The reaction of the raw material was detected to be complete by liquid chromatography-mass spectrometry (LC-MS). The reaction solution was concentrated under vacuum to give crude compound 3 (800 mg, 79.9% yield) as a colorless oil, which was used directly in the next reaction without further purification.

[0030] Step 3 Preparation of compound 4 [ka] Compound 3 (800 mg, 3.24 mmol, HCl salt) was added to PhCl (100 mL), POCl (9.93 g, 64.7 mmol) and H3PO3 (5.31 g, 64.7 mmol) were added under nitrogen protection. The reaction mixture was heated to 80° C. and stirred for 16 h. After cooling, the chlorobenzene solution was poured out, H2O (20.0 mL) was added and stirred at 80° C. for 5 h. The presence of product agglomerates was monitored by LC-MS. The reaction solution was filtered and concentrated under vacuum, and the residue was purified by preparative HPLC (YMC-Actus Triart Diol-HILIC, 150*30 mm, 5 μm, 120 Å mobile phase: 0.2% CH3COOH, CH3CN) to give compound 4 as a white solid (90.0 mg, 8.68% yield).

[0031] Step 4 Preparation of Compound Carbs of Formula I [ka] To a solution of compound 4 (60.0 mg, 187 μmol) in HO (200 μL), a solution of DOTA-NHS-ester (141 mg, 281 μmol) in DMF (200 μL) was added, followed by the addition of triethylamine (114 mg, 1.12 mmol). The reaction solution was stirred at 25° C. for 16 h. The presence of product agglomerates was monitored by LC-MS. The reaction solution was filtered, concentrated, and the residue was purified by preparative HPLC (Hilic, 0.2% CH3COOH) to obtain the compound of formula I, Carbs, as a white solid (4.00 mg, yield 3.02%, purity 86.8%).

[0032] FIG. 4 shows the HPLC profile of the compound represented by formula I, and FIG. 5 shows the LC-MS profile.

[0033] Example 2 In this embodiment, 68 The amount of DOTA-ibandronic acid for preparing Ga-DOTA-ibandronic acid was investigated and specified as follows:

[0034] Eight EP tubes were prepared and each tube was filled with 5 μg, 10 μg, 15 μg, 20 μg, 25 μg, 30 μg, 35 μg, and 40 μg of DOTA-ibandronate (1 mg / ml). Each tube was filled with 1 mL of sodium acetate solution (0.25 M), followed by freshly rinsed 68 4 ml of GaCl3 elution solution (5 mci / ml) was added. The pH value was adjusted to about 5 with 0.25 M sodium acetate solution and 0.01 M hydrochloric acid, and the mixed solution was thoroughly shaken and mixed, and reacted in a metal bath at 95°C for 15 minutes. After the reaction was completed, the reaction solution was cooled to room temperature, the pH value of each tube was adjusted to 4-6, the reaction solution was sterilized, and filtered through a 0.22 μm filter membrane. Then, 68 The radiochemical purity of Ga-DOTA-ibandronic acid was measured using thin layer chromatography (TLC), and the results are shown in Table 1. [Table 1]

[0035] As can be seen from Table 1, when other conditions are fixed,68 The radiochemical purity of Ga-DOTA-ibandronic acid is optimal when the amount of DOTA-ibandronic acid is 20-30 μg, and the radiochemical purity gradually decreases when the amount is lower or higher than this range.

[0036] Example 3 In this example, pH values ​​in the present disclosure were investigated and identified as follows:

[0037] Seven EP tubes were prepared and each tube contained 25 μg of DOTA-ibandronic acid (1 mg / ml), 1 ml of sodium acetate solution (0.25 M), and freshly rinsed 68 4 ml of GaCl3 elution solution (5 mci / ml) was added to each tube in sequence. The pH values ​​in these tubes were adjusted to 2, 3, 4, 5, 6, 7, and 8, respectively, using 0.25 M sodium acetate solution and 0.1 M hydrochloric acid. The mixtures were thoroughly shaken and mixed, and reacted in a metal bath at 95°C for 15 minutes. After the reaction was completed, the reaction solutions were cooled to room temperature, sterilized, and filtered through a 0.22 μm filter membrane. Then, 68 The radiochemical purity of Ga-DOTA-ibandronic acid was measured using thin layer chromatography (TLC), and the results are shown in Table 2. [Table 2]

[0038] From Table 2, it can be seen that the radiochemical purity of DOTA-ibandronic acid is optimal when the pH value is 5. When the pH value is higher or lower than 5, the radiochemical purity decreases gradually. When the pH value is higher than 6, the radiochemical purity decreases rapidly.

[0039] Example 4 In this example, the amounts of sodium acetate in the present disclosure were investigated and determined as follows:

[0040] Eight EP tubes were prepared and each tube was filled with 0.2 ml, 0.4 ml, 0.6 ml, 0.8 ml, 1.0 ml, 1.2 ml, 1.4 ml, and 1.6 ml of sodium acetate solution (0.25 M). Each tube was filled with 25 μg of DOTA-ibandronic acid (1 mg / ml) and freshly rinsed 68 4 ml of GaCl3 elution solution (5 mci / ml) was added, and the pH value was adjusted to 5 with 0.25 M sodium acetate solution and 0.1 M hydrochloric acid. The mixture was thoroughly shaken and mixed, and reacted in a metal bath at 95°C for 15 minutes. After the reaction was completed, the reaction solution was cooled to room temperature, the pH value of each tube was adjusted to 5, the reaction solution was sterilized, and filtered through a 0.22 μm filter membrane. Then, 68 The radiochemical purity of Ga-DOTA-ibandronic acid was measured using thin layer chromatography (TLC), and the results are shown in Table 3 below. [Table 3]

[0041] As can be seen from Table 3, if other conditions remain unchanged, 68 The radiochemical purity of Ga-DOTA-ibandronic acid is optimal when the amount of sodium acetate solution is 0.8-1.4 ml, and the radiochemical purity gradually decreases when the amount is lower or higher than this range.

[0042] Example 5 In this example, reaction temperatures and durations in the present disclosure were investigated and identified as follows:

[0043] Eighteen EP tubes were prepared and divided into three groups: group A (room temperature 25±2°C), group B (60°C), and group C (95°C). Six tubes were taken from each group and numbered A / B / C. 1~6 Each tube contained 25 μg of DOTA-ibandronic acid (1 mg / ml), 1 ml of sodium acetate solution (0.25 M), and freshly rinsed 684 ml of GaCl3 elution solution (5 mci / ml) was added in advance, and the pH value was adjusted to about 5 with 0.25 M sodium acetate solution and 0.1 M hydrochloric acid. The mixed solution was thoroughly shaken and mixed, and then the six tubes of each group were reacted for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes at the temperature of each group. After the reaction was completed, the reaction solution was cooled to room temperature, the pH value of each tube was adjusted to 5, the reaction solution was sterilized, and filtered through a 0.22 μm filter membrane. Next, 68 The radiochemical purity of Ga-DOTA-ibandronic acid was measured using thin layer chromatography (TLC), and the results are shown in Table 4 below. [Table 4]

[0044] From Table 4, if other conditions remain unchanged, 68 It is found that the radiochemical purity of Ga-DOTA-ibandronic acid is optimal when the reaction is carried out for 15 minutes at 95° C. If the reaction time is too long, too short, or the temperature is too low, the radiochemical purity decreases.

[0045] Example 6 In this example, 177 A method for preparing Lu-DOTA-ibandronic acid is disclosed and identified as follows:

[0046] DOTA-ibandronic acid (25 μg) was diluted with 1 ml of sodium acetate solution (0.25 M), followed by fresh rinsing. 177 0.2 ml of LuCl3 elution solution (approximately 2.0 mci) was added. The pH value of the mixed solution was adjusted to approximately 5 with 0.25 M sodium acetate solution and 0.01 M hydrochloric acid, and reacted in a metal bath at 95°C for 15 minutes. The reaction solution was taken out and adjusted to approximately pH 4.5 with 0.04 M hydrochloric acid. The reaction solution was then passed through a CM column (release 177 (to remove Lu), then the product was passed through a sterile filter membrane and finally 177 Lu-DOTA-ibandronic acid was obtained.

[0047] Example 7 In this example, 225 A new method for the preparation of Ac-DOTA-ibandronic acid is disclosed and identified as follows:

[0048] DOTA-ibandronic acid (25 μg) was added to 1 ml of ascorbic acid solution (0.1 M) and 1 ml of sodium citrate solution (0.1 M), followed by fresh rinsing. 225 100 μl of AcCl3 elution solution (about 0.01 mci) was added. The mixed solution was adjusted to about pH 4.5 with 0.04 M hydrochloric acid and reacted in a metal bath at 95° C. for 15 minutes. The reaction solution was taken out and adjusted to about pH 4.5 with 0.04 M hydrochloric acid, and the product was then filtered through a sterile filtration membrane. 225 Ac-DOTA-ibandronic acid was obtained.

[0049] Example 8 In this example, 64 A new method for the preparation of Cu-DOTA-ibandronic acid is disclosed and identified as follows:

[0050] DOTA-ibandronic acid (25 μg) was diluted with 1 ml of sodium acetate solution (0.25 M), followed by fresh rinsing. 64 1 ml of CuCl2 elution solution (about 5 mci) was added. The mixed solution was adjusted to about pH 4 with 0.04 M hydrochloric acid and reacted in a metal bath at 95 °C for 15 minutes. The reaction solution was taken out and adjusted to about pH 4 with 0.04 M hydrochloric acid, and the product was then passed through a sterile filtration membrane to 64 Cu-DOTA-ibandronic acid was obtained.

[0051] Example 9 In this example, 211 A new method for the preparation of At-DOTA-ibandronic acid is disclosed and specified as follows:

[0052] DOTA-ibandronic acid (25 μg) was added to 1 ml of sodium borate solution (0.25 M), followed by freshly rinsed Na 2111 ml of At elution solution (about 1.0 mci) was added. The mixed solution was adjusted to pH about 7 and reacted in a metal bath at 95°C for 15 minutes. The reaction solution was adjusted to pH about 7, and then the product was passed through a sterilizing filtration membrane and finally 211 At-DOTA-ibandronic acid was obtained.

[0053] In Experimental Examples 1 to 5, 68 Ga-DOTA-ibandronic acid was prepared according to method number 5 in Table 1 of Example 2.

[0054] Experimental Example 1 In this experimental example, 68 An in vitro stability study of Ga-DOTA-ibandronic acid was disclosed and identified as follows:

[0055] Prepare four EP tubes and label them as 1 to 4. Add 0.1 ml of physiological saline to tubes 1 and 2, add 0.1 ml of fresh human serum diluted 10-fold to tubes 3 and 4, and then add freshly prepared 68 1.0 mci of Ga-DOTA-ibandronic acid was added to each. Nos. 1 and 3 were placed at room temperature (25±2° C.), and Nos. 2 and 4 were placed in a metal bath at 37° C. for incubation. The radiochemical purity values ​​of Nos. 1 to 4 were measured at 10 min, 30 min, 1 h, 2 h, 3 h, and 4 h, respectively, using thin layer chromatography (TLC). The results are shown in Table 5 below. [Table 5]

[0056] From Table 5, 68 It is found that Ga-DOTA-ibandronic acid has good in vitro stability at room temperature, and its radiochemical purity remains >90% after 4 hours at room temperature in normal saline and serum.

[0057] Experimental Example 2 In this experimental example, 68The lipid-water partition coefficient of Ga-DOTA-ibandronic acid was investigated and determined to be as follows:

[0058] Three 5 ml centrifuge tubes were prepared and labeled A-1, A-2, and A-3. 0.5 ml of n-octanol, 0.485 ml of deionized water, and approximately 0.5 mci of freshly prepared 68 0.25 ml of Ga-DOTA-ibandronic acid was added to each tube, the centrifuge tube was shaken by a vortex mixer for 20 minutes, and then centrifuged at 2000 r / min for 5 minutes, from which 0.1 ml of the upper liquid (organic phase) was collected in three corresponding test tubes (numbered B-1, B-2, and B-3, respectively), and 0.1 ml of the lower liquid (aqueous phase) was collected in three corresponding test tubes (numbered C-1, C-2, and C-3, respectively). The total radioactivity counts of the organic phase and the aqueous phase were measured by a gamma counter, and the lipid-water partition coefficient was calculated by the formula.

[0059] The results are 68 The lipid-water partition coefficient lgP of Ga-DOTA-ibandronic acid was shown to be −2.33, indicating that the labeled compound has high water solubility and low lipid solubility.

[0060] Experimental Example 3 In this experimental example, 68 The plasma protein binding rates of Ga-DOTA-ibandronate were investigated and determined as follows:

[0061] 1 mL of fresh human plasma anticoagulated with heparin was prepared for later use. Three EP tubes were prepared, labeled A-1, A-2, and A-3, and each tube contained 0.1 mL of fresh human plasma and approximately 0.5 mci of freshly prepared plasma. 680.25 ml of Ga-DOTA-ibandronic acid was added. They were then incubated in a metal bath at 37°C for 30 minutes. Three 5 ml centrifuge tubes were prepared and labeled as B-1, B-2, and B-3, respectively. The incubated solutions were transferred to the corresponding centrifuge tubes. Then, 1 ml of 25% trichloroacetic acid solution was added to each centrifuge tube, mixed thoroughly, and then centrifuged at 2000 r / min for 5 minutes. The supernatants were collected in three corresponding test tubes (labeled as C-1, C-2, and C-3, respectively). Centrifugation and supernatant collection were repeated three times. The total radioactivity counts of the precipitate in the centrifuge tube and the supernatant in the test tube were measured by a gamma counter, respectively, and the plasma protein binding rate (PPB) was calculated.

[0062] The results are 68 The results show that Ga-DOTA-ibandronic acid has a PPB of 81% after 30 minutes of incubation in plasma. The high plasma protein binding rate indicates that the labeled compound can be retained in the body for a long time and is not easily eliminated, achieving good imaging effect.

[0063] Experimental Example 4 In this experimental example, 68 The in vivo distribution of Ga-DOTA-ibandronate was investigated and determined as follows:

[0064] Twenty healthy Kunming mice (body weight 18-22 g) were prepared and randomly divided into four groups of five mice each. Half of the mice were male and half were female. Freshly prepared 68 Ga-DOTA-ibandronic acid, 0.5 mci / 0.1 ml, was injected via the tail vein. The animals were decapitated 15 min, 30 min, 1 h, and 2 h later, respectively. Carotid blood, brain, heart, liver, spleen, lung, kidney, stomach, small intestine, muscle, and femoral tissues were weighed, and their radioactivity counts were measured in a gamma counter, and the percentage of injected dose per gram of tissue (%ID / g) was calculated after time decay correction. 68 The in vivo distribution results of Ga-DOTA-ibandronic acid are shown in Table 6 below. [Table 6]

[0065] From Table 6, bones 68 It can be seen that Ga-DOTA-ibandronic acid has a high uptake rate, reaching a maximum value (8.365% ID / g) at 2 hours. After that, the uptake into bone decreases over time, but the percentage of injected dose per gram of tissue in bone can still reach 4.268% ID / g up to 4 hours, which is significantly higher than that of other organs and tissues. 68 This indicates that Ga-DOTA-ibandronic acid has a strong effect on bone and long retention, and therefore can achieve ideal contrast effects.

[0066] Experimental Example 5 In this example, the efficacy of the present disclosure in New Zealand rabbits was evaluated. 68 Imaging of Ga-DOTA-ibandronate at various time points was investigated and identified as follows:

[0067] A New Zealand rabbit weighing approximately 2 kg was used and freshly prepared 68 Approximately 1.0 mci / 0.2 ml of Ga-DOTA-ibandronic acid was injected via an ear vein, and whole-body PET imaging was performed 1 and 3 hours after injection (Figure 1).

[0068] From Figure 1, it can be seen that one hour after injection, the kidneys and bladder show clear images, the thoracic cavity and soft tissue show clear images, the bones of the whole body show clear images, and the joints of the limbs show clear images. Figure 2 shows that as time passes, the images of the thoracic cavity and soft tissue gradually become fainter, the images of both kidneys gradually become fainter, and gradually move to the bladder, the image of the bladder gradually becomes darker, and the image of the bladder gradually disappears as urine is discharged. Therefore, 68 Ga-DOTA-ibandronate is a contrast agent that is rapidly cleared by soft tissues, has high bone uptake, is excreted by the urinary system, and retains in bone for a relatively long time, and can provide good imaging results when applied to patients with metastatic bone cancer.

[0069] Experimental Example 6 Prepared according to the method of Example 6 in New Zealand rabbits 177 Imaging of Lu-DOTA-ibandronate at various time points was investigated and identified as follows:

[0070] A New Zealand rabbit weighing approximately 2 kg was used and freshly prepared 177 Lu-DOTA-ibandronic acid was injected at approximately 2.0 mci / 0.2 ml via an ear vein, and PET whole-body imaging was performed 1, 3, 5, and 7 days after injection (Figure 2).

[0071] Experimental Example 7 Prepared according to the method of Example 7 in New Zealand rabbits 225 Imaging of Ac-DOTA-ibandronate at various time points was investigated and identified as follows:

[0072] One New Zealand rabbit weighing approximately 2 kg was prepared fresh under the optimal labeling conditions described above. 225 Ac-DOTA-ibandronic acid was injected at approximately 0.01 mci / 2 ml via an ear vein, and whole-body PET imaging was performed 1 day, 3 days, and 5 days after injection (Figure 3).

[0073] Experimental Example 8 In this experimental example, the present disclosure was applied to tumor-bearing mice (PC-3, H1975, MDA-MB-231 bone metastasis model). 177 The therapeutic effect of Lu-DOTA-ibandronate was investigated. 177 Lu-DOTA-ibandronic acid was prepared according to the method of Example 6.

[0074] (1) Establishment of a tumor-bearing mouse model: 24 SPF male nude mice and 12 SPF female nude mice were prepared and anesthetized with isoflurane. Then, the skin around the left knee joint was disinfected, and the left hind leg was flexed. An insulin needle (29G needle) was inserted vertically into the tibia from the concave point of the tibial fossa, slowly rotated, and inserted into the medullary cavity to inject 25 μl (approximately 2 × 10 ) of cell cultures of PC-3 (12 males), H1975 (12 males), and MDA-MB-231 (12 females).6 ) was injected into the cavity. Disinfection was then performed and the cavity was sealed with sterile bone wax. For rewarming, the animals were placed on a hot plate at 37°C. After resuscitation, they were returned to their cages and continued to be housed.

[0075] (2) Tumor-bearing mouse model test: Four weeks after inoculation, 36 nude mice were scanned using Micro-CT. Each nude mouse was observed to have various degrees of bone destruction and soft tissue swelling, indicating that the bone metastasis model was successfully established.

[0076] (3) Different treatment and grouping methods: 36 successfully modeled tumor-bearing mice were randomly divided into four groups. Of these, two groups had low and high radioactivity (100 μCi, 500 μCi) with three animals in each group. 177 Lu-DOTA-ibandronic acid was injected into the tail vein, respectively. The animals in the blank control group were injected with saline, and were divided into low-volume and high-volume groups (10 μl, 50 μl), with 3 animals in each group.

[0077] (4) Detection and results of therapeutic effect: Free movement pain behavior scoring was performed on days 0, 7, 14, 21, 28 and 35 and used as the main index of bone pain relief in tumor-bearing mice. At the corresponding time points, tumor-bearing mice were placed in a transparent, smooth, flat-bottomed plastic box. The tumor-bearing mice were allowed to move freely in the box and were observed after 30 minutes of acclimation. Pain behavior scoring was performed according to the following criteria: Score 0, movement was normal, and the movement of the hind limbs on the model side and the control side was the same; Score 1, there was slight lameness in the hind limbs on the model side; Score 2, the degree of lameness in the hind limbs on the model side was between score 1 and score 3; Score 3, there was severe lameness in the hind limbs on the model side; Score 4, the hind limbs on the model side could not move at all and could not touch the ground. The results are shown in Table 7 below. [Table 7]

[0078] From Table 7, the high activity was measured on day 0 as the baseline. 177 The mean reduction in free movement pain behavior score of surviving tumor-bearing mice 5 weeks after treatment with Lu-DOTA-ibandronic acid (500 μCi) was the largest among all groups, and the number of survivors was relatively the highest, indicating that the treatment was associated with different activities. 177 It can be seen that the mean reduction in free movement pain behavior score of surviving tumor-bearing mice treated with Lu-DOTA-ibandronic acid 5 weeks later was higher than that of the corresponding control group.

[0079] The above results showed that tumor-bearing mice were highly active 177 When treated with Lu-DOTA-ibandronic acid (500 μCi), bone pain was most significantly alleviated, and the survival rate within 5 weeks of administration was relatively the highest. 177 The therapeutic efficacy of the administration of Lu-DOTA-ibandronate was higher than that of the corresponding control group in the treatment of malignant tumor bone metastases. 177 The feasibility and efficacy of Lu-DOTA-ibandronate are demonstrated.

[0080] Based on the above Examples 1 to 9 and Experimental Examples 1 to 8, 68 Ga / 177 Lu / 225 Ac / 64 Cu / 221 At-DOTA-ibandronic acid is provided by a simple labeling method with short reaction time and high labeling yield, and has high water solubility, good in vitro stability at room temperature, high plasma protein binding rate, and shows long-term high bone uptake both in vivo distribution in mice and imaging in New Zealand rabbits, indicating that the preparation invented in this application is a bone imaging agent with excellent performance and a radioactive drug for the treatment of metastatic bone tumors.

[0081] The above examples are only a part of the examples of the present disclosure, but are not all of them. The detailed description of the embodiments of the present disclosure is not intended to limit the scope of the present disclosure, but rather to represent selected embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without making inventive efforts fall within the scope sought to be protected by the present disclosure.

Claims

1. Formula I: [Formula 1] A precursor compound of a radiolabeled compound or a pharma- ceutically acceptable salt of said radiolabeled compound, having a structure represented by the following formula:

2. Formula II: [chemical 2] where A is a radionuclide, preferably ６８ G.A. １７７ Lu, ２２５ A c, ６４ Cu, or ２２１ Represents At, A radiolabeled compound of formula I, characterized by having the structure represented by:

3. 3. The radiolabeled compound of claim 2, or a pharma- ceutically acceptable salt of said radiolabeled compound, characterized by having a radiochemical purity of 95% or greater.

4. Step 1, reacting compound 1 with tert-butyl acrylate to form compound 2; Step 2: adding HCl / EtOAc dropwise to a solution of compound 2 in EtOAc to react to produce compound 3; Step 3: Compound 3 is added to PhCl and POCl is added under nitrogen protection. ３ and H ３ P.O. ３ Add, heat, react, cool, then pour off the chlorobenzene solution and add H ２ adding O, heating and stirring to produce compound 4; Step 4: adding DOTA-NHS-ester solution to the aqueous solution of compound 4, and then adding triethylamine to react to produce the compound represented by formula I; Including, The reaction procedure is [C3] 2. A method for preparing a precursor compound of the radiolabeled compound according to claim 1, characterized in that:

5. 4. A method for preparing a radiolabeled compound according to claim 2 or 3, characterized in that it comprises the step of reacting the compound of formula I with a radionuclide salt solution to obtain the radiolabeled compound of formula II.

6. The radionuclide ６８ G.A. １７７ Lu or ６４ in the case of Cu, homogeneously mixing a solution of the compound represented by formula I, a sodium acetate solution, and a radionuclide salt solution, adjusting the pH value of the mixed solution, reacting, adjusting the pH value again, sterilizing, and filtering to obtain the radiolabeled compound; The radionuclide ２２５ homogeneously mixing a solution of the compound represented by formula I, a sodium citrate solution, a sodium ascorbate solution, and a radionuclide salt solution, adjusting the pH value of the mixed solution, reacting, adjusting the pH value again, sterilizing, and filtering to obtain the radiolabeled compound; The radionuclide ２１１ homogeneously mixing a solution of the compound represented by formula I, a sodium borate solution, and a radionuclide salt solution, adjusting the pH value of the mixed solution, reacting, adjusting the pH value again, sterilizing, and filtering to obtain the radiolabeled compound; The preparation method according to claim 5, characterized in that

7. The radionuclide ６８ In the case of Ga, 20 to 30 μg of the compound represented by formula I is added to 0.8 to 1.4 ml of a 0.25 M sodium acetate solution, and then a solution having an activity of 20 mCi is added. ６８Add Ga salt solution, mix uniformly, adjust pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for reaction time of 10-30 minutes, preferably 15 minutes, and adjust pH value to 5 after reaction, wherein the concentration of the solution of the compound represented by formula I is 1 mg / ml, ６８ The concentration of the Ga salt solution is 5 mCi / ml to 10 mCi / ml. The radionuclide １７７ In the case of Lu, 20-30 μg of the compound represented by formula I is added to 0.8-1.4 ml of a 0.25 M sodium acetate solution, and then a 2 mCi active １７７ Add Lu salt solution, mix uniformly, adjust the pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for a reaction time of 10-30 minutes, preferably 15 minutes, and adjust the pH value to 4.5 after reaction, wherein the concentration of the solution of the compound represented by formula I is 1 mg / ml, and １７７ The concentration of the Lu salt solution is 10 mCi / ml to 20 mCi / ml; The radionuclide ２２５ In the case of Ac, 20-30 μg of the compound represented by formula I is added to 0.8-1.4 ml of a 0.1 M sodium ascorbate solution and 0.8-1.4 ml of a 0.1 M sodium citrate solution, and then a 0.01 mCi active ２２５ Add Ac salt solution, mix uniformly, adjust the pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for a reaction time of 10-30 minutes, preferably 15 minutes, and adjust the pH value to 4.5 after reaction, wherein the concentration of the solution of the compound represented by formula I is 1 mg / ml, and ２２５ The concentration of the Ac salt solution is 0.01 mCi / ml to 0.02 mCi / ml; The radionuclide ６４ In the case of Cu, 20-30 μg of the compound represented by formula I is added to 0.8-1.4 ml of a 0.25 M sodium acetate solution, and then a solution having an activity of 5 mCi is added. ６４Add Cu salt solution, mix uniformly, adjust pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for reaction time of 10-30 minutes, preferably 15 minutes, and adjust pH value to 4 after reaction, wherein the concentration of the solution of the compound represented by formula I is 1mg / ml, ６４ The concentration of the Cu salt solution is 5 mCi / ml to 10 mCi / ml; The radionuclide ２１１ In the case of At, 20-30 μg of the compound represented by formula I is added to 0.8-1.4 ml of a 0.25 M sodium borate solution, and then a 1 mCi active ２１１ Add At salt solution, mix uniformly, adjust the pH value of the mixed solution to 4-7, preferably 5, react at 80-100°C, preferably 95°C, for a reaction time of 10-30 minutes, preferably 15 minutes, and adjust the pH value to 7 after reaction, wherein the concentration of the solution of the compound represented by formula I is 1 mg / ml, ２１１ The concentration of the At salt solution is 1.0 mCi / ml to 2.0 mCi / ml; 7. The process according to claim 6, characterized in that

8. 13. Use of a compound of formula I as defined in claim 1 in the manufacture of a medicament for both imaging and treating metastatic bone tumors.

9. 10. Use of a compound of formula II as defined in claim 2 or 3 in the manufacture of a medicament for both imaging and treating metastatic bone tumors.

Images