Formulation of PSMA imaging agents

Abstract

To provide formulations of radiolabeled compounds for use in radiotherapy and diagnostic imaging related to prostate specific membrane antigen (PSMA).SOLUTION: The present invention relates to formulations of radiolabeled compounds for use in radiotherapy and diagnostic imaging related to prostate specific membrane antigen (PSMA).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a formulation of a radiolabeled compound used in radiotherapy and diagnostic imaging related to prostate-specific membrane antigen (PSMA). [Background technology]

[0002] Prostate cancer is the leading cause of cancer-related death in men, and mortality is often attributed to the difficulty in detecting and subsequently treating the disease. Increased expression of prostate-specific membrane antigen (PSMA) is frequently observed in prostate-related tumors. PSMA is an enzyme normally expressed in prostate tissue, but is often elevated in some prostate cancers. This means that PSMA is an excellent biomarker or target for imaging, diagnostic, and prognostic purposes. However, successful imaging of prostate cancer is challenging because PSMA is expressed in other tissues as well, in both normal and malignant tissues. Radiolabeled complexes can be used for imaging and treatment of cancers such as prostate cancer, but some complexes containing radioisotopes or radionuclides and target-directing ligands can be unstable and prone to dissociation. If the formed complex is not strong enough, dissociation can occur immediately after formation, i.e., during the radiolabeling process. Although radiolabeling processes are known, these processes may not result in complex formation in sufficient yield, or the entire complex solution may not be radiochemically pure. Furthermore, even if radiolabeled complexes can be generated, purification and isolation procedures that allow for obtaining complete complexes in good yield are preferred.

[0003] Even if a radiolabeled complex is obtained, the complex may be unstable and prone to decomposition. This can lead to dissociation of the radioisotope, decreased radiochemical yield and purity of the complex-containing formulation, and limited efficiency of the formulation. If the radioisotope is lost and not delivered to the target cancer site, imaging and / or treatment will be of reduced or inadequate quality. In radiolabeled complexes, radiolysis may also easily occur due to the natural decay of radioisotopes, in which the activity of the radioisotope causes the destruction and decomposition of the ligand. This leads to the release of radioisotopes. As a result of the cardiovascular system, if free radioisotopes diffuse into other areas, it may result in the delivery of radioactivity to places where delivery is not desired. There is a need for a stable formulation of radiolabeled complexes suitable for prostate cancer imaging and treatment. An effective method for preparing such a stable formulation is also needed.

Summary of the Invention

[0004] In one aspect of the present invention, there is provided an aqueous formulation for parenteral administration containing a compound of formula (I) complexed with Cu ions or a salt thereof, further comprising at least one of gentisic acid, ascorbic acid, L-methionine, pyridoxine, or a salt thereof.

Chemical formula

[0005] In a further aspect, there is provided an aqueous formulation for parenteral administration containing a compound of formula (Ia) complexed with Cu ions or a salt thereof, further comprising at least one of gentisic acid, ascorbic acid, L-methionine, pyridoxine, or a salt thereof.

Chemical formula

[0006] In another aspect of the present invention, there is provided an aqueous formulation for parenteral administration containing a compound of formula (I) complexed with Cu ions or a salt thereof, further comprising a buffer solution.

Chemical formula

[0007] In a further embodiment, an aqueous formulation for parenteral administration is provided, comprising a compound of formula (Ia) or a salt thereof that forms a complex with a Cu ion, further comprising a buffer solution. [ka] Equation (Ia)

[0008] In one embodiment, the aqueous formulation comprises gentisic acid or a salt thereof. In another embodiment, the aqueous formulation comprises ascorbic acid or a salt thereof. In another embodiment, the aqueous formulation comprises L-methionine or a salt thereof. In another embodiment of the present invention, a method for preparing a formulation comprising a compound of formula (I) that has formed a complex with a Cu radioisotope, i) A step of adding a certain amount of the compound of formula (I) to an acetate buffer, ii) A step of adding a hydrochloric acid solution of a Cu radioactive isotope to the compound of formula (I) and an acetate buffer, and iii) Heating the mixture from step ii) for a time and under conditions necessary to form a complex between formula (I) and a Cu radioisotope. A method is provided that includes this.

[0009] [ka] Equation (I)

[0010] In another embodiment of the present invention, a method for preparing a formulation comprising a compound of formula (I) that has formed a complex with a Cu radioisotope, i) A step of adding a certain amount of the compound of formula (I) to a phosphate buffer, ii) The step of adding a hydrochloric acid solution of a Cu radioactive isotope to the compound of formula (I) and a phosphate buffer, and iii) The step of reacting the mixture from step ii) with formula (I) and a Cu radioisotope for a time and under conditions necessary to form a complex. A method is provided that includes this. [ka] Equation (I)

[0011] In embodiments of the methods for preparing the complexes defined herein, the compound of formula (I) has the structure of the compound of formula (Ia). [ka] Equation (Ia) In one embodiment, the Cu radioactive isotope is 61 It is Cu. In one embodiment, the Cu radioactive isotope is 64 It is Cu. In another embodiment, the Cu radioactive isotope is 67 It is Cu. In further embodiments, the pH of the formulation is maintained in a range between approximately 4 and approximately 8. In another embodiment of the present invention, a method for purifying a compound of formula (I) that has formed a complex with a Cu radioisotope, i) A step of filling a solid-phase extraction cartridge with a solution of the compound of formula (I) that has formed a complex with a Cu radioactive isotope. ii) A step of eluting the compound of formula (I) that has formed a complex with a Cu radioisotope using an eluent containing water, ethanol, and sodium chloride. A method is provided that includes this.

[0012] [ka] Equation (I)

[0013] In embodiments of the method for purifying complexes as defined herein, the compound of formula (I) has the structure of the compound of formula (Ia). [ka] Equation (Ia) In one embodiment, a purified compound of formula (I) or a salt thereof, which has been purified according to a prior embodiment and formed a complex with a Cu radioisotope, is prepared according to another embodiment of the present invention. In one embodiment, a compound of formula (I) or a salt thereof, which has formed a complex with a Cu radioisotope, is prepared according to another aspect of the present invention. [Brief explanation of the drawing]

[0014] [Figure 1] This graph shows the radiochemical purity of the complex solution of purified formula (Ia) with 64Cu. The solution contained either gentisic acid, ascorbic acid, or L-methionine and was monitored for 48 hours. [Modes for carrying out the invention]

[0015] Formulation of the complex of formula (I) This invention relates to stable formulations of specific radioisotope-ligand complexes. The inventors have found that the formulations of the complexes disclosed herein minimize the dissociation of radioisotopes from the ligand and / or radiolysis of the ligand due to the radioisotopes. The radioisotope-ligand complex formulations referred to herein are stable for a period of time in solution and under physiological conditions. The stability of the formulation is related to the stability of the complex. Radioisotopes may dissociate from the complex, which reduces the amount of radioactivity delivered to the ligand-binding site. Because radioisotopes undergo spontaneous decay or release energy, this released energy may lead to the decomposition of the ligand, known as radiolysis. The radiostability of the complex can be measured by considering the radiochemical purity of the formulation. Radiochemical purity is defined as the amount of radioisotopes complexed with the sarcofazine ligand and is expressed as a percentage of the total amount of radioisotopes present in the formulation. Radioisotopes may be present in the formulation as complexes with the sarcofazine ligand, as free radioisotopes, or as part of radiolysis products.

[0016] Ligands containing a urea-based motif have been found to bind to the catalytic site of prostate-specific membrane antigen (PSMA), which is normally expressed in prostate tissue and increases in some prostate cancers. An example of such a motif-containing ligand is Sar-bisPSMA, which is the macrocyclic ligand 1,8-diamino-3,6,10,13,16,19-hexazabicyclo[6.6.6]icosane (also known as sarcofazine or "Sar"). In this compound, each terminal amine group is bound to a linker group and a urea-based motif. The Sar-bisPSMA is shown in equation (I). [ka] Equation (I) The compound of formula (I) may be produced by a series of coupling reactions between a sarcofazine ligand, a linker, and a urea motif. The procedure for preparing the compound of formula (I) can be found in WO2018 / 223180.

[0017] The compound of formula (I) may have the structure of formula (Ia) shown below, where the stereochemistry of the compound is determined. [ka] Equation (Ia) Unless otherwise specified, any reference to the compound of formula (I) below should be interpreted as also including a reference to the compound of formula (Ia).

[0018] The present invention relates to the use of compounds of formula (I) and (Ia) in formulations. Compounds of formula (I) and (Ia) can be used as pharmaceutically acceptable salts. Compounds of formula (I) and (Ia) contain two urea motifs that can independently bind to the catalytic site of PSMA. The inventors believe that the increased binding affinity of compound (I) at a desired site is due to the presence of the second urea motif. While not wishing to be bound by theory, the inventors believe that the additional binding affinity of compound (I), which appears to be more effective than using twice the amount of a similar compound having only one urea motif, is related to the presence of the second urea motif. Subsequently, formulations described herein containing compound (I) or (Ia) exhibit superior efficacy compared to formulations of similar compounds containing urea motifs.

[0019] The term “pharmaceutically acceptable salt” refers to a salt of the compounds identified above that retains the desired biological activity, and includes pharmaceutically acceptable acid addition salts and base addition salts. Suitable pharmaceutically acceptable acid addition salts of the compounds of formulas (I) and (Ia) may be prepared from inorganic or organic acids. Examples of such inorganic acids are hydrochloric acid, sulfuric acid, and phosphoric acid. Suitable organic acids can be selected from the classes of aliphatic, alicyclic, aromatic, heterocyclic carboxylic acids, and sulfonic acids, examples of which are formic acid, acetic acid, propionic acid, succinic acid, glycolic acid, gluconic acid, lactic acid, malic acid, tartaric acid, citric acid, fumaric acid, maleic acid, alkylsulfonic acids, and arylsulfonic acids. Additional information on pharmaceutically acceptable salts can be found in Remington's Pharmaceutical Sciences, 19th Edition, Mack Publishing Co., Easton, PA 1995. In the case of solid pharmaceuticals, the compounds, pharmaceuticals, and salts of the present invention may exist in various crystalline or polymorphic forms, all of which are intended to be within the scope of the present invention and the prescribed formulations, as will be understood by those skilled in the art.

[0020] In a preferred embodiment, the compound of formula (I) is provided as an acetate salt. The formulations of the present invention contain a compound of formula (I) or a salt thereof, and a radioisotope. The radioisotope, also called a radionuclide, can be a metal or a metal ion. The compound of formula (I) herein has been found to be particularly effective in complexing copper ions, especially Cu 2+ ions. Those skilled in the art will understand that a complex of the compound of formula (I) can be formed by contacting the compound of formula (I) with a desired radioisotope. Here, the radioisotope is Cu 2+ ions. In one embodiment, the ligand is forming a complex with Cu ions. The copper ions may be radioactive and thus may be a radioactive nuclide or radioisotope of copper. In one embodiment, the ligand is 60 forming a complex with Cu. In another embodiment, the ligand is 61 forming a complex with Cu. In another embodiment, the ligand is 64 forming a complex with Cu. In another embodiment, the ligand is 67 forming a complex with Cu. In a preferred embodiment, the ligand is 64 forming a complex with Cu. In another preferred embodiment, the ligand is 67 forming a complex with Cu. The complex of formula (I) and the Cu radioisotope is unstable and may be prone to radiolysis when in solution. The inventors have found that when one or more stabilizers are added to the formulation containing the complex, the solubilized complex can be stabilized. Such stabilizers include gentisic acid, ascorbic acid, L-methionine, pyridoxine and their salts.

[0021] The formulations of the present invention may comprise at least one of gentisic acid, ascorbic acid, L-methionine, and pyridoxine, or salts thereof. The inventors have confirmed that the addition of gentisic acid, ascorbic acid, L-methionine, and / or pyridoxine to the formulations of the present invention helps prevent or minimize the radiolysis of the complex of formula (I), and therefore improves the radiostability of the complex and its formulations. Gentisic acid is also known as 2,5-dihydroxybenzoic acid, 5-hydroxysalicylic acid, or hydroquinone carboxylic acid. Salts of gentisic acid may include sodium salts and sodium salt hydrates. Any reference to gentisic acid may include references to its salts, where relevant. Other isomers of dihydroxybenzoic acid are also considered. Examples of other isomers include 2,4-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid, as well as their salts. In one embodiment, gentisic acid is present in the formulation at an amount of about 0.02% to about 0.1% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.02% (w / v). In yet another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.025% (w / v). In yet another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.03% (w / v). In yet another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.035% (w / v). In yet another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.04% (w / v). In yet another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.045% (w / v). In yet another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.05% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.055% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.6% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.065% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.07% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.075% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.08% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.085% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.09% (w / v). In another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.095% (w / v). In yet another embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of about 0.1% (w / v). In yet another embodiment, the present invention also considers gentisic acid or a salt thereof in a range between the aforementioned amounts. In a preferred embodiment, gentisic acid or a salt thereof is present in the formulation at an amount of 0.056% (w / v) or less.

[0022] L-methionine is an amino acid containing a thiol ether side chain and is also known as Met or L-Met. Salts of L-methionine include the sodium salt. Any reference to L-methionine may include references to its salts, where relevant. In one embodiment, L-methionine or a salt thereof is present in the formulation in an amount of about 1 mg / mL to about 4 mg / mL. In another embodiment, L-methionine or a salt thereof is present in the formulation in an amount of about 1.0 mg / mL. In yet another embodiment, L-methionine or a salt thereof is present in the formulation in an amount of about 1.5 mg / mL. In yet another embodiment, L-methionine or a salt thereof is present in the formulation in an amount of about 2.0 mg / mL. In yet another embodiment, L-methionine or a salt thereof is present in the formulation in an amount of about 2.5 mg / mL. In yet another embodiment, L-methionine or a salt thereof is present in the formulation in an amount of about 3.0 mg / mL. In yet another embodiment, L-methionine or a salt thereof is present in the formulation in an amount of about 3.5 mg / mL. In yet another embodiment, L-methionine or a salt thereof is present in the formulation in an amount of about 4.0 mg / mL. In other embodiments, the present invention also considers L-methionine or a salt thereof in a range between the amounts described above. In a preferred embodiment, L-methionine is present in the formulation at an amount of approximately 3 mg / mL.

[0023] Ascorbic acid is also known as 2,3-didehydro-L-threohexano-1,4-lactone or vitamin C. Salts of ascorbic acid include sodium ascorbate, potassium ascorbate, calcium ascorbate, and magnesium ascorbate. Any reference to ascorbic acid may include references to its salts, where relevant.

[0024] In one embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 5 mg / mL to about 50 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 5 mg / mL. In yet another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 6 mg / mL. In yet another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 7 mg / mL. In yet another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 8 mg / mL. In yet another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 9 mg / mL. In yet another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 10 mg / mL. In yet another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 11 mg / mL. In yet another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 12 mg / mL. In yet another embodiment, ascorbic acid or a salt thereof is present in the formulation in an amount of about 13 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 14 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 15 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 20 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 25 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 30 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 35 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 40 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 45 mg / mL. In another embodiment, ascorbic acid or a salt thereof is present in the formulation at an amount of about 50 mg / mL. In other embodiments, the present invention also considers ascorbic acid or a salt thereof in amounts ranging between the amounts described above. In a preferred embodiment, ascorbic acid is present in the formulation at an amount of approximately 10 mg / mL.

[0025] Pyridoxine is also known as 4,5-bis(hydroxymethyl)-2-methylpyridine-3-ol or vitamin B6. Pyridoxine salts may include hydrochloride salts. In one embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 5 mg / mL to about 15 mg / mL. In another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 5 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 6 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 7 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 8 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 9 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 10 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 11 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 12 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation in an amount of about 13 mg / mL. In another embodiment, pyridoxine or a salt thereof is present in the formulation at an amount of about 14 mg / mL. In yet another embodiment, pyridoxine or a salt thereof is present in the formulation at an amount of about 15 mg / mL. In a preferred embodiment, pyridoxine is present in the formulation at an amount of about 10 mg / mL.

[0026] The formulations of the present invention may contain ethanol as an ingredient. The ethanol used in the formulation may be anhydrous ethanol. Alternatively, the ethanol used in the formulation may not have been subjected to a drying process and may be hydrated. The ethanol is preferably pharmaceutical-grade ethanol. The ethanol present in the formulation may further help prevent the radiolysis of the radiolabeled complex of formula (I).

[0027] In one embodiment, ethanol is present in the formulation at an amount of about 7% to about 13% (v / v). In another embodiment, ethanol is present in the formulation at an amount of about 7% (v / v). In yet another embodiment, ethanol is present in the formulation at an amount of about 8% (v / v). In yet another embodiment, ethanol is present in the formulation at an amount of about 9% (v / v). In yet another embodiment, ethanol is present in the formulation at an amount of about 10% (v / v). In yet another embodiment, ethanol is present in the formulation at an amount of about 11% (v / v). In yet another embodiment, ethanol is present in the formulation at an amount of about 12% (v / v). In yet another embodiment, ethanol is present in the formulation at an amount of about 13% (v / v). In a preferred embodiment, ethanol is present in the formulation at an amount of about 10% (v / v). In other embodiments, the present invention also considers ethanol in a range between the amounts described above.

[0028] The formulation of the present invention may also contain sodium chloride as an ingredient. The sodium chloride in the formulation of the present invention may be provided as saline solution. Saline solution is defined as an aqueous solution of sodium chloride. For example, physiological saline is defined as an aqueous solution of sodium chloride with a concentration of 0.9% (w / v). In one embodiment of the present invention, the sodium chloride in the formulation is provided as saline solution. In one embodiment, sodium chloride is present in the formulation at an amount of about 0.6% to 1.2% (w / v). In another embodiment, sodium chloride is present at an amount of about 0.6% (w / v). In yet another embodiment, sodium chloride is present at an amount of about 0.7% (w / v). In yet another embodiment, sodium chloride is present at an amount of about 0.8% (w / v). In yet another embodiment, sodium chloride is present at an amount of about 0.9% (w / v). In yet another embodiment, sodium chloride is present at an amount of about 1.0% (w / v). In yet another embodiment, sodium chloride is present at an amount of about 1.1% (w / v). In yet another embodiment, sodium chloride is present at an amount of about 1.2% (w / v). In a preferred embodiment, sodium chloride is present in the formulation at an amount of about 0.9% (w / v). In other embodiments, the present invention also considers sodium chloride in amounts ranging from those described above.

[0029] The formulations of the present invention have a pH of about 4 to about 8. Those skilled in the art will understand that the pH of the formulation is an inherent characteristic of the formulation, resulting from the combination of the compound of formula (I) or its complex with the remaining excipients of the formulation. Alternatively, the pH of the formulation may be changed to a desired value by the addition of one or more buffers. An example of a suitable buffer solution is an acetate buffer, which may contain a mixture of sodium acetate and acetic acid. In certain embodiments, the formulations of the present invention contain an acetate buffer. Another suitable buffer solution is a phosphate buffer, which may contain a mixture of various phosphates or their hydrates. Examples of suitable phosphates include sodium dihydrogen phosphate (NaH2PO4), disodium hydrogen phosphate (Na2HPO4), potassium dihydrogen phosphate (KH2PO4), and dipotassium hydrogen phosphate (K2HPO4). In one embodiment, the phosphate buffer contains a sodium phosphate salt. In another embodiment, the phosphate buffer contains a potassium phosphate salt. In yet another embodiment, the phosphate buffer contains a mixture of sodium phosphate and potassium phosphate salts.

[0030] As used herein, the term “buffer” refers to a component that maintains the pH of the medium to which it is added at a constant level. In the context of this disclosure, gentisic acid, ascorbic acid, L-methionine, and pyridoxine, their salts, or aqueous solutions are not considered buffers. In one embodiment, the pH of the formulation is approximately 4 to approximately 8. In another embodiment, the pH of the formulation is approximately 4. In yet another embodiment, the pH of the formulation is approximately 4.5. In yet another embodiment, the pH of the formulation is approximately 5.0. In one embodiment, the pH of the formulation is approximately 5.5. In yet another embodiment, the pH of the formulation is approximately 5.6. In yet another embodiment, the pH of the formulation is approximately 5.7. In yet another embodiment, the pH of the formulation is approximately 5.8. In yet another embodiment, the pH of the formulation is approximately 5.9. In yet another embodiment, the pH of the formulation is approximately 6.0. In yet another embodiment, the pH of the formulation is approximately 6.1. In yet another embodiment, the pH of the formulation is approximately 6.2. In yet another embodiment, the pH of the formulation is approximately 6.3. In yet another embodiment, the pH of the formulation is approximately 6.4. In yet another embodiment, the pH of the formulation is approximately 6.5. In yet another embodiment, the pH of the formulation is approximately 7.0. In yet another embodiment, the pH of the formulation is approximately 7.5. In another embodiment, the pH of the formulation is about 8.0. In a preferred embodiment, the pH of the formulation is about 6.0. In another preferred embodiment, the pH of the formulation is about 5.0.

[0031] The inventors have confirmed that when the compound of formula (I) is formulated as an aqueous solution, the compound is relatively unstable and easily oxidized and decomposed. One way to overcome the observed instability may be to add one or more components, which are antioxidants and / or stabilizers, to the formulation; however, including further components in the formulation introduces potential reactivity problems between the compound of formula (I) and these added components. For example, the addition of antioxidants may actually react with the compound of formula (I), and thus potentially alter the structure and function of the compound, which is undesirable. However, the inventors have now found that the addition of certain stabilizers may, in some cases, be sufficient to provide formulations containing the compound of formula (I). As disclosed herein, stabilizers such as gentisic acid, ascorbic acid, L-methionine, or pyridoxine do not appear to react with the compound of formula (I) and can provide the necessary stability; therefore, formulations of the compound of formula (I) containing these stabilizers are considered.

[0032] However, it is now known that formulations containing a buffer and the compound of formula (I) provide the compound with the necessary stability. Therefore, in addition to providing a formulation with a pH suitable for parenteral administration, the inventors have found that the presence of a buffer provides a formulation in which the compound of formula (I) has the necessary stability. Surprisingly, the inventors have found that while the addition of stabilizers such as gentisic acid, ascorbic acid, and other agents described herein can provide the necessary stability, the stability of the formulation can also be achieved by the use of buffers alone, i.e., in the absence of stabilizers.

[0033] Method for preparing the complex of formula (I) The present invention also relates to a radiolabeled complex of the compound of formula (I) and a method for preparing a formulation thereof. As previously mentioned, the compound of formula (I) can form complexes with radioisotopes such as Cu ions. Therefore, the present invention relates to a method for preparing a formulation comprising the compound of formula (I) that has formed a complex with a Cu radioisotope, i) A step of adding a certain amount of the compound of formula (I) to an acetate buffer, ii) A step of adding a hydrochloric acid solution of a Cu radioactive isotope to the compound of formula (I) and an acetate buffer, and iii) Heating the mixture from step ii) for a time and under conditions necessary to form a complex between formula (I) and a Cu radioisotope. This provides a method that includes [something].

[0034] [ka] Equation (I) The present invention also relates to a method for preparing a formulation comprising a compound of formula (I) that has formed a complex with a Cu radioisotope, i) A step of adding a certain amount of the compound of formula (I) to a phosphate buffer solution, ii) The step of adding a hydrochloric acid solution of a Cu radioactive isotope to the compound of formula (I) and a phosphate buffer solution, iii) The step of reacting the mixture from step ii) with formula (I) and a Cu radioisotope for a time and under conditions necessary to form a complex. This provides a method that includes [something].

[0035] [ka] Equation (I) In certain embodiments, the compound of formula (I) has the structure of the compound of formula (Ia). [ka] Equation (Ia)

[0036] In one embodiment, the method further includes the step of adding a sodium ascorbate solution to the mixture of the compound of formula (I) and the Cu radioisotope after the reaction between the compound of formula (I) and the Cu radioisotope is complete. The compound of formula (I) may be provided as part of a stock solution. Before preparing the stock solution of formula (I), the compound may be subjected to a drying process such as freeze-drying. The compound of formula (I) can be dissolved in a mixture of ethanol and water to produce a stock solution of the compound of formula (I). In one embodiment, the compound of formula (I) is dissolved in a mixture of ethanol and water in a ratio of about 1:1. In one embodiment, the compound of formula (I) is provided as a stock solution at a concentration of about 1 nmol / μL.

[0037] The compound of formula (I) may be present in an amount between about 1 nmol and about 10 nmol. In one embodiment, the compound of formula (I) is present in an amount of about 1 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 2 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 3 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 4 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 5 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 6 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 7 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 8 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 9 nmol. In another embodiment, the compound of formula (I) is present in an amount of about 10 nmol. Those skilled in the art will understand that the required amount of stock solution of compound formula (I) depends on the initial concentration of the stock solution. Those skilled in the art will also understand that a larger quantity of the compound of formula (I) may be used, and the amounts of other reagents, buffers, and solvents may be changed accordingly. In one embodiment, the buffer solution may be an acetate buffer. The acetate buffer used in this method may be prepared from sodium acetate and acetic acid. The acetate buffer maintains a pH within a range suitable for complex formation between the compound of formula (I) and the Cu radioisotope. The pH of the buffer solution may be about 5.0. The acetate buffer may have a concentration of about 1.0 M. The acetate buffer may also contain ethanol. In one embodiment, the acetate buffer contains an amount of ethanol between about 10% and about 30%. In one embodiment, the acetate buffer contains an amount of ethanol about 10%. In one embodiment, the acetate buffer contains an amount of ethanol about 20%. In one embodiment, the acetate buffer contains an amount of ethanol about 30%. In a preferred embodiment, the acetate buffer contains an amount of ethanol about 20%.

[0038] In another embodiment, the buffer solution may be a phosphate buffer. The phosphate buffer may contain a mixture of various phosphates or their hydrates. Suitable examples of phosphates include sodium dihydrogen phosphate (NaH2PO4), disodium hydrogen phosphate (Na2HPO4), potassium dihydrogen phosphate (KH2PO4), and dipotassium hydrogen phosphate (K2HPO4). In one embodiment, the phosphate buffer contains a sodium phosphate salt. In another embodiment, the phosphate buffer contains a potassium phosphate salt. In yet another embodiment, the phosphate buffer contains a mixture of sodium phosphate and potassium phosphate. The phosphate buffer may also contain saline solution and / or water. In one embodiment, the phosphate buffer contains a mixture of sodium hydrogen phosphate and saline solution. An aliquot containing a certain amount of the compound of formula (I) is taken from a stock solution of the compound of formula (I) in a mixture of ethanol and water, and mixed with a certain amount of acetate buffer. In one embodiment, the compound of formula (I) is added to the acetate buffer, which contains about 20% ethanol. In one embodiment, the compound of formula (I) is added to the acetate buffer at room temperature.

[0039] As described above, the compound of formula (I) complexes Cu ions. In one embodiment, the Cu ions are radioactive isotopes of Cu. In one embodiment, the radioactive isotopes of Cu are 60 It is Cu. In another embodiment, the radioactive isotope of Cu is 61 It is Cu. In another embodiment, the radioactive isotope of Cu is 64 It is Cu. In another embodiment, the radioactive isotope of Cu is 67 It is Cu. The radioactive isotope of Cu is provided as a Cu salt. In one embodiment, the Cu salt is Cu 2+ It is provided as a chloride salt. In one embodiment, the Cu salt is [ 64 The Cu radioisotope is provided as a Cu]CuCl2 salt. The Cu radioisotope is provided as a hydrochloric acid solution. In one embodiment, the Cu radioisotope is 64It is Cu, provided as a hydrochloric acid solution, the hydrochloric acid having a concentration of about 0.02 M. In one embodiment, the Cu radioactive isotope is in the hydrochloric acid solution [ 64 It is provided as a Cu]CuCl2 solution, the hydrochloric acid having a concentration of about 0.02 M. Those skilled in the art will understand that the Cu salt may be provided in hydrochloric acid of other concentrations. In another embodiment, the Cu radioactive isotope is Cu 2+ It is provided as an acetate. In one embodiment, the Cu salt is [ 64 It is provided as Cu]Cu(OAc)2 salt.

[0040] A solution of Cu salt provided as a hydrochloric acid solution will have a specific starting radioactivity. The starting radioactivity of the solution may vary depending on a particular batch of radioisotopes. Those skilled in the art will understand that the final radioactivity of the compound of formula (I) complexed with Cu ions depends on the radioactivity of the Cu salt used to complex the compound of formula (I), and that the radioactivity of the Cu salt depends on the radioactivity of the solution of Cu salt in hydrochloric acid. The total radiochemical yield of the complex of formula (I) with the copper salt can be determined using the amount of radioactivity initially present in the solution of Cu salt. Aliquots of the Cu radioisotope in a hydrochloric acid solution are added to the compound of formula (I) in acetate buffer. Those skilled in the art will understand that the radiochemical purity can be measured by radio-HPLC or a similar method.

[0041] In one embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity between approximately 100 and approximately 5000 MBq. In one embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of about 100 MBq. In another embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of about 250 MBq. In another embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of about 500 MBq. In another embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of approximately 750 MBq. In another embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of about 1000 MBq. In another embodiment,64 A solution of a Cu radioactive isotope has a radioactivity of approximately 1500 MBq. In another embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of approximately 2000 MBq. In another embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of approximately 2500 MBq. In another embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of approximately 3000 MBq. In another embodiment, 64 A solution of a Cu radioactive isotope has a radioactivity of approximately 4000 MBq. In another embodiment, 64 A solution of the radioactive isotope Cu has a radioactivity of approximately 5000 MBq.

[0042] In one embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity between approximately 100 and approximately 5000 MBq. In one embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of about 100 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of about 250 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of about 500 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of approximately 750 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of about 1000 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of approximately 1500 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of approximately 2000 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of approximately 2500 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of approximately 3000 MBq. In another embodiment, 61 A solution of a Cu radioactive isotope has a radioactivity of approximately 4000 MBq. In another embodiment, 61A solution of the radioactive isotope Cu has a radioactivity of approximately 5000 MBq.

[0043] In one embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity between approximately 100 and approximately 3000 MBq. In one embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of about 100 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of about 250 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of about 500 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of approximately 750 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of about 1000 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of approximately 1500 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of approximately 2000 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of approximately 2500 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of approximately 3000 MBq. In another embodiment, 67 A solution of a Cu radioactive isotope has a radioactivity of approximately 4000 MBq. In another embodiment, 67 A solution of the radioactive isotope Cu has a radioactivity of approximately 5000 MBq. The Cu radioisotope may be provided as a hydrochloric acid solution. In one embodiment, the Cu radioisotope is provided in a hydrochloric acid solution having a concentration between about 0.01 M and about 0.05 M. In one embodiment, the concentration of the hydrochloric acid solution is about 0.01 M. In another embodiment, the concentration of the hydrochloric acid solution is about 0.02 M. In another embodiment, the concentration of the hydrochloric acid solution is about 0.03 M. In another embodiment, the concentration of the hydrochloric acid solution is about 0.04 M. In another embodiment, the concentration of the hydrochloric acid solution is about 0.05 M. In a further embodiment, the concentration of the hydrochloric acid solution is between about 0.02 M and about 0.05 M.

[0044] Next, a solution containing a mixture of the Cu radioisotope, the compound of formula (I), and an acetate buffer is mixed at a specific temperature for a certain period of time to allow complex formation between the compound of formula (I) and the Cu radioisotope. The solution can be mixed using appropriate equipment. For example, when small amounts are used, an Eppendorf tube may be a suitable container, and as a result, an Eppendorf thermomixer can be used to both mix the solution and, if necessary, heat it. In one embodiment, the solution is mixed at room temperature. In one embodiment, the solution is mixed at about 40°C. The inventors have found that when the solution is mixed at a temperature of about 40°C, the complexation of the radioisotope is completed within about 5 minutes. A lower temperature of about 21°C, i.e., room temperature, can be used for mixing, and the complex formation reaction may not be completed in 5 minutes, but it is completed in about 15 minutes. The inventors have also found that temperatures higher than about 40°C, such as 60°C, result in some decomposition of the compound of formula (I), and therefore a decrease in the yield of the complex. In one embodiment, the solution is mixed at approximately 40°C for approximately 5 minutes. In another embodiment, the solution is mixed at approximately 40°C for approximately 10 minutes. In yet another embodiment, the solution is mixed at approximately 40°C for approximately 15 minutes. In yet another embodiment, the solution is mixed at approximately 21°C for approximately 10 minutes. In yet another embodiment, the solution is mixed at approximately 21°C for approximately 15 minutes.

[0045] In certain embodiments, the compound of formula (I) is added to a phosphate buffer solution to which a solution containing a Cu radioisotope in hydrochloric acid is added. The mixture containing the compound of formula (I), the phosphate buffer solution, and the Cu radioisotope is reacted for a certain period of time and under certain conditions to yield a complex of formula (I) and the Cu radioisotope. In one embodiment, the solutions are mixed at room temperature. In one embodiment, the solutions are mixed at room temperature for about 10 minutes. In another embodiment, the solutions are mixed at room temperature for about 15 minutes. In yet another embodiment, the solutions are mixed at room temperature for about 20 minutes. In a further embodiment, the solutions are mixed at room temperature for about 25 minutes. Once the complex of formula (I) and the Cu radioisotope is formed, the solution is diluted with sodium ascorbate solution. The addition of sodium ascorbate introduces a reducing agent into the mixture, resulting in a radiostabilizing effect on the complex of formula (I) and the Cu radioisotope. This, in turn, enhances the overall stability of the formulation, leading to a longer shelf life for the complex-containing formulation. The sodium ascorbate solution may have a concentration between approximately 25 mg / mL and approximately 75 mg / mL. In one embodiment, the sodium ascorbate solution may have a concentration of approximately 25 mg / mL. In another embodiment, the sodium ascorbate solution may have a concentration of approximately 50 mg / mL. In yet another embodiment, the sodium ascorbate solution may have a concentration of approximately 75 mg / mL. A certain amount of sodium ascorbate solution of a specific concentration is added to ensure that any remaining Cu radioisotope is sufficiently diluted. Those skilled in the art will understand that the amount of solution added depends on the amount of uncomplexed Cu radioisotopes and the concentration of the sodium ascorbate solution.

[0046] The inventors have found that the method for preparing the compound of formula (I) complexed with a Cu radioisotope disclosed herein enables efficient radiolabeling of the compound and allows for obtaining a high radiochemical yield. The inventors have found that complex formation between the compound of formula (I) and the Cu radioisotope is faster when an acetate buffer containing a certain amount of ethanol is used. According to one embodiment of the present invention, the method comprises adding the compound of formula (I) to an acetate buffer containing ethanol. In one embodiment, the method is i) A step of adding a certain amount of the compound of formula (I) to an acetate buffer containing ethanol, ii) In hydrochloric acid [ 64 The steps include adding a solution of Cu]CuCl2 to an acetate buffer containing the compound of formula (I) and ethanol, and iii) Heat the mixture from step ii) at 40°C for approximately 5 minutes. Includes.

[0047] In another embodiment, the method is i) Adding a certain amount of the compound of formula (I) to a phosphate buffer containing ethanol and sodium gentisate, ii) In hydrochloric acid [ 64 The steps include adding a solution of Cu]CuCl2 to a phosphate buffer containing the compound of formula (I) and sodium gentisate, and iii) The step of reacting the mixture from step ii) with formula (I) and a Cu radioisotope for a time and under conditions necessary to form a complex. Includes. Process for purifying the complex of formula (I) Once the process of preparing the compound of formula (I) complexed with the Cu radioisotope is complete, the complex must be purified and isolated. Those skilled in the art will understand that material loss may occur during the purification and isolation process, and therefore the total chemical and radiochemical yield may decrease. These losses may result from material loss in the transport and handling process, in syringes and other equipment used in the purification process, or from material retention in the reaction vessel. The purification process usually involves a filtration step using a solid phase medium, and material retention by the solid phase often leads to a decrease in yield. The purification process often relies on washing the solid phase with various solvents to elute the complex, but the use of large amounts of solvent results in a dilute solution of the complex, which is undesirable. Decomposition of the complex may also occur during purification, resulting in a decrease in the yield of the complex and loss of the free radioisotope. The inventors have found that the purification of the complex of formula (I) with the Cu radioisotope can be advantageously achieved, and as a result, the complex can be isolated in high chemical and radiochemical yield.

[0048] According to another aspect of the present invention, a method for purifying a compound of formula (I) that has formed a complex with a Cu radioisotope, i) A step of filling a solid-phase extraction cartridge with a solution of the compound of formula (I) that has formed a complex with a Cu radioactive isotope. ii) A step of eluting the compound of formula (I) that has formed a complex with a Cu radioisotope using an eluent containing water, ethanol, and sodium chloride. A method is provided that includes this. [ka] Equation (I)

[0049] In one embodiment of the method, the compound of formula (I) has the structure of the compound of formula (Ia). [ka] Equation (Ia)

[0050] In one embodiment, a solution of the compound of formula (I) that has formed a complex with a Cu radioisotope is obtained according to another embodiment of the present invention. Once the reaction to prepare the complex of formula (I) with the Cu radioisotope is complete, the resulting solution is subjected to a purification process. A solution containing a complex of formula (I) and a Cu radioisotope is packed into a solid-phase extraction cartridge. The solid-phase extraction cartridge contains a stationary phase that holds the complex and other components present in the solution. As used herein, the term “stationary phase” refers to a resin-like material held within the solid-phase extraction cartridge that allows for the separation of compounds based on their polarity. The solid-phase extraction process described herein may use a reversed-phase stationary phase. As used herein, the term “reversed-phase” with respect to the stationary phase refers to a stationary phase that is substantially hydrophobic such that it has an affinity for hydrophobic or uncharged molecules. Examples of reversed-phase stationary phases may include Waters Sep-Pak cartridges such as C8, C18, light C18, light CN, light tC2, or HLB cartridges. Before filling with a solution containing the complex of formula (I), the cartridge is prepared by washing with ethanol, drying with air, and equilibrating with water. In one embodiment, the solid-phase extraction cartridge is a Waters C18 cartridge. In another embodiment, the solid-phase extraction cartridge is a Waters tC2 cartridge. In another embodiment, the solid-phase extraction cartridge is a Waters CN cartridge. In another embodiment, the solid-phase extraction cartridge is a Waters HLB cartridge.

[0051] Subsequently, a purified solution containing the complex of formula (I) and a Cu radioisotope can be used to produce a formulation containing the complex. For example, one or more pharmaceutically acceptable diluents, auxiliaries, and / or excipients may be added to the solution containing the complex of formula (I) and a Cu radioisotope. The diluents, auxiliaries, and excipients must be "acceptable" in that they are compatible with the other components of the composition and must not be harmful to the recipient. Pharmaceutical carriers for preparing pharmaceutical compositions are known in the art, as described in textbooks such as Remington's Pharmaceutical Sciences, 20th Edition, Williams & Wilkins, Pennsylvania, USA. The carriers depend on the route of administration, and those skilled in the art can easily determine the most appropriate formulation for each particular case.

[0052] Any reference in this specification to prior art (or information derived from prior art) or any publicly known information shall not be construed as an acknowledgment, acceptance, or proposal in any form that such prior art (or information derived from prior art) or publicly known information constitutes part of the general knowledge within the scope of the endeavor relating to this specification. Throughout this specification and the appended claims, unless the context requires otherwise interpretation, the word “comprise,” and variations such as “comprises” and “comprising,” shall be understood to mean the inclusion of the described whole or part (integer or step) or group of wholes or parts, but not the exclusion of any other whole or part, or group of wholes or parts. [Examples]

[0053] Overall experimental details Sodium acetate buffer for radiolabeling was prepared using sodium acetate (TraceSELECT, Fluka, batch number BCBM4793V), acetic acid (TraceSELECT, Fluka, batch number BCBM5177V), and Milli-Q water in acid-washed glass bottles and stored in acid-washed plastic bottles. All buffers were stored at 2-4°C when not in use. The phosphate buffer for radiolabeling was prepared using disodium hydrogen phosphate (anhydrous), sodium dihydrogen phosphate, and TraceSELECT water. All buffers were stored at room temperature when not in use. Copper-64( 64 Cu) was obtained from SAHMRI, SA, Australia, in 450 μL of 0.02 M HCl with a starting radioactivity of 2.39 GBq @ 08:39. 64 It was obtained as Cu]CuCl2 under batch number 19-0075-902R. SPE purification of the radiolabeled product was performed using a Waters Sep-Pak cartridge light C8 (lot number: 002836047A). The cartridge was washed with EtOH (10 mL), then conditioned with an air bolus (3 × 10 mL), followed by equilibration with MilliQ H2O (10 mL) and air (3 × 10 mL).

[0054] HPLC-grade MeCN (Honeywell, lot number: S1RA1H), HPLC-grade trifluoroacetic acid (TFA, ReagentPlus, 99%, Sigma Aldrich, lot number: SHBG2783V), (+)-L-sodium ascorbate (Sigma Aldrich, >99%, lot number: BCBV4424), L-methionine (Sigma Aldrich, >99.5%, lot number: BCBS2107V), and sodium gentisate hydrate (Sigma Aldrich, >99%, lot number: MKCC2280) were used as received. All HPLC mobile phases were prepared before use, filtered (using a 0.45 μm aqueous or organic filter), and degassed by sonication under vacuum for 10 minutes. All EtOH used was 100% ethyl alcohol (molecular biology grade). All syringes used were "B Braun Injekt-F". The elution buffer was prepared as 1:1 EtOH:H2O + 0.9% NaCl. All reaction vials were acid-washed before use. Plastic microcentrifuge tubes were filled with 4M HCl and allowed to stand overnight to remove the 4M HCl. The vials were then thoroughly washed with MilliQ H2O and dried in an oven at 50°C. After drying, the vials were sealed to prevent further contamination. Glassware was acid-washed by immersion in 4M HNO3 for at least 12 hours. After decanting the 4M HNO3 into a suitable waste container, the glassware was thoroughly washed with MilliQ H2O and dried in an oven at 50°C. After drying, the glassware was sealed to prevent further contamination. A stock solution of Sar-bis(PSMA), i.e., the compound of formula (Ia), was prepared in EtOH:H2O (1:1), and a solution containing the compound of formula (Ia) at a concentration of 1 nmol / μL was obtained.

[0055] Radioactive labeling of formula (I) using Cu radioisotopes (Example 1) To a 500 μL microcentrifuge tube washed with acid, labeled buffer (acetic acid buffer, 50 μL, 1 M, pH 5.0) was added, followed by 10 μL of stock solution of formula I. In the buffer solution, [ 0.02 M HCl 64 Cu]CuCl2 (25 μL, 116 MBq) was added. The microcentrifuge tube was sealed, and the radioactivity present in the reactant was measured using a dose calibrator. The tube was transferred to an Eppendorf thermomixer C and heated at 40°C for 20 minutes. After 20 minutes, the reactant was removed from the thermomixer, a sample (5 μL) was taken from the reactant, diluted with 1:1 EtOH:H2O (5 μL), and injected into a radio-HPLC system (QC1, 5 μL). The reaction mixture was left at room temperature while a final analysis was performed at 7 minutes to determine if the radiochemical yield was greater than 95%.

[0056] (Example 2) To a 500 μL microcentrifuge tube washed with acid, labeled buffer (acetic acid buffer, 50 μL, 1 M, pH 5.0) was added, followed by 5 μL of stock solution of formula I. In the buffer solution, [ 64 Cu]CuCl2 (25 μL, 109 MBq) was added. The microcentrifuge tube was sealed, and the radioactivity present in the reactant was measured using a dose calibrator. The tube was transferred to an Eppendorf thermomixer C and heated at 40°C for 20 minutes. After 20 minutes, the reactant was removed from the thermomixer, a sample (5 μL) was taken from the reactant, diluted with 1:1 EtOH:H2O (5 μL), and injected into a radio-HPLC system (QC1, 5 μL). The reaction mixture was left at room temperature while a final analysis was performed at 7 minutes to determine if the radiochemical yield was greater than 95%. (Example 3) Labeled buffer (acetic acid buffer, 600 μL, 1 M, pH 5.0) was added to an acid-washed 1500 μL microcentrifuge tube, followed by the addition of 20 μL of stock solution of formula I. In the buffer solution, [ 0.02 M HCl 64Cu]CuCl2 (300 μL, 1136 MBq) was added. The microcentrifuge tube was sealed, and the radioactivity present in the reactant was measured using a dose calibrator. The tube was transferred to an Eppendorf thermomixer C and heated at 40°C for 20 minutes. After 20 minutes, the reactant was removed from the thermomixer, a sample (5 μL) was taken from the reactant, diluted with 1:1 EtOH:H2O (5 μL), and injected into a radio-HPLC system (QC1, 5 μL). The reaction mixture was left at room temperature while a final analysis was performed at 7 minutes to determine if the radiochemical yield was greater than 95%.

[0057] (Example 4) To a 500 μL microcentrifuge tube washed with acid, labeled buffer (20% EtOH in acetate buffer, 100 μL, 1 M, pH 5.0) was added, followed by 10 μL of stock solution of formula I. To the buffer solution, [ 64 Cu]CuCl2 (50 μL, 183 MBq) was added. The microcentrifuge tube was sealed, and the radioactivity present in the reactant was measured using a dose calibrator. The tube was transferred to an Eppendorf thermomixer C and heated at 40°C for 20 minutes. After 20 minutes, the reactant was removed from the thermomixer, a sample (5 μL) was taken from the reactant, diluted with 1:1 EtOH:H2O (5 μL), and injected into a radio-HPLC system (QC1, 5 μL). The reaction mixture was left at room temperature while a final analysis was performed at 7 minutes to determine if the radiochemical yield was greater than 95%. (Example 5) To a 500 μL microcentrifuge tube washed with acid, labeled buffer (acetic acid buffer, 100 μL, 1 M, pH 5.0) was added, followed by 5 μL of stock solution of formula I. In the buffer solution, [ 0.02 M HCl 64Cu]CuCl2 (50 μL, 174 MBq) was added. The microcentrifuge tube was sealed, and the radioactivity present in the reactant was measured using a dose calibrator. The tube was transferred to an Eppendorf thermomixer C and heated at 21°C for 20 minutes. Aliquots (5 μL) were taken at 5 and 15 minutes for analysis to determine if the reaction was complete. These samples were diluted with 1:1 EtOH:H2O (5 μL) and injected into a radioHPLC system (QC1, 5 μL). The reaction mixture was placed back in the thermomixer while a final analysis was performed at 7 minutes to determine if the radiochemical yield was greater than 95%.

[0058] (Example 6) A solution of Sar-bis(PSMA) (50 μg, 24.8 nmol) in 0.1 M Na / Na phosphate buffer (5 mL) containing sodium gentisate (5 mg, 0.03 mmol) is prepared by adding [ 0.02 M ~ 0.05 M HCl 64 Cu]CuCl2 (500 μL NMT, 5000 MBq NMT) was added at room temperature. The resulting mixture was reacted at room temperature for up to 25 minutes. Upon completion, the reaction mixture was quenched with 15 mL of 50 mg / mL sodium ascorbate solution. The resulting mixture was then transferred to a sterile vial through a 0.22 μm vent filter. 64 A compound of formula (I) is obtained by forming a complex with a Cu radioactive isotope.

[0059] (Example 7) A solution of Sar-bis(PSMA) (50 μg, 24.8 nmol) in 0.1 M Na / Na phosphate buffer (4.5 mL) containing sodium gentisate (5 mg, 0.03 mmol) and ethanol (neat, 0.5 mL) is prepared by adding [ 0.02 M ~ 0.05 M HCl 64 Cu]CuCl2 (500 μL NMT, 5000 MBq NMT) was added at room temperature. The resulting mixture was reacted at room temperature for up to 25 minutes. Upon completion, the reaction mixture was quenched with 15 mL of 50 mg / mL sodium ascorbate solution. The resulting mixture was then transferred to a sterile vial through a 0.22 μm vent filter. 64A compound of formula (I) is obtained by forming a complex with a Cu radioactive isotope. Purification procedure (Example 8) The solution obtained in Example 1 was purified using a C8 SPE cartridge, and the product was eluted with 0.5 mL of 1:1 EtOH:H2O + 0.9% NaCl. 62% of the product eluted from the SPE, and it was shown to have a high radiochemical purity of 94.3% with zero "free copper". 4% was lost in the dilution / filling syringe, 12% remained in the reaction vial, and 9% was lost in the SPE. Less than 1% was lost in the SPE filling and washing steps.

[0060] (Example 9) The solution obtained in Example 2 was purified using a C8 SPE cartridge, and the product was eluted with 0.5 mL of 1:1 EtOH:H2O + 0.9% NaCl. 73% of the product eluted from the SPE, and with 0.2% "free copper", it was shown to have a high radiochemical purity of 94.3%. 7% was lost in the dilution / filling syringe, 1% did not detach from the reaction vial, and 14% was lost in the SPE. Less than 1% was lost in the SPE filling and washing steps. (Example 10) The solution obtained in Example 3 was purified using a C8 SPE cartridge, and the product was eluted with 0.5 mL of 1:1 EtOH:H2O + 0.9% NaCl. 64% of the product eluted from the SPE, and with 0.1% "free copper", it demonstrated a high radiochemical purity of 96.6%. 4% was lost in the dilution / filling syringe, and 1.5% remained in the reaction vial.

[0061] (Example 11) The solution obtained in Example 4 was purified using a C8 SPE cartridge, and the product was eluted with 0.5 mL of 1:1 EtOH:H2O + 0.9% NaCl. 71% of the product eluted from the SPE, and it was shown to have a high radiochemical purity of 96.3% with zero "free copper". 6% was lost in the dilution / filling syringe, 3% did not detach from the reaction vial, and 15% was lost in the SPE. Less than 1% was lost in the SPE filling and washing steps. (Example 12) The solution obtained in Example 5 was purified using a C8 SPE cartridge, and the product was eluted with 0.5 mL of 1:1 EtOH:H2O + 0.9% NaCl. 59% of the product was eluted from the SPE, and with 0.1% "free copper", it was shown to have a high radiochemical purity of 96.9%. 11% was lost in the dilution / filling syringe, 7% remained in the reaction vial, and 20% was lost in the SPE. Less than 1% was lost in the SPE filling and washing steps.

[0062] Preparation of pharmaceutical products (Example 13) Aliquotes of the purified solution from Example 10 were taken and diluted with a mixture of ethanol in saline to obtain a solution with a final concentration of approximately 10% ethanol in saline. One of the following was added: gentisic acid (0.63 mg / mL), ascorbic acid (10 mg / mL), or L-methionine (3 mg / mL), and the radiochemical purity of each sample was monitored for 48 hours.

Claims

1. A method for preparing a formulation containing a compound of formula (I) that has formed a complex with a Cu radioactive isotope, i) A step of adding a certain amount of the compound of formula (I) to an acetate buffer solution, ii) A step of adding a hydrochloric acid solution of a Cu radioactive isotope to the compound of formula (I) and an acetate buffer solution. iii) A step of heating the mixture from step ii) for a time and under conditions necessary to form a complex of formula (I) and a Cu radioisotope, and iv) A step of adding a sodium ascorbate solution to a mixture of the compound of formula (I) and a Cu radioisotope. The method, including the method described above. 【Chemistry 4】 Equation (I)

2. A method for preparing a formulation containing a compound of formula (I) that has formed a complex with a Cu radioactive isotope, i) A step of adding a certain amount of the compound of formula (I) to a phosphate buffer solution, ii) A step of adding a hydrochloric acid solution of a Cu radioisotope to the compound of formula (I) and a phosphate buffer solution. iii) A step of reacting the mixture from step ii) with formula (I) and a Cu radioisotope for a time and under conditions necessary to form a complex, and iv) A step of adding a sodium ascorbate solution to a mixture of the compound of formula (I) and a Cu radioisotope. The method, including the method described above. 【Transformation 5】 Equation (I)

3. The method according to claim 1 or 2, wherein the compound of formula (I) has the structure of formula (Ia). 【Transformation 6】 Equation (Ia)

4. Cu radioactive isotopes 64 The method according to any one of claims 1 to 3, wherein the material is Cu.

5. Cu radioactive isotopes 61 The method according to any one of claims 1 to 3, wherein the material is Cu.

6. Cu radioactive isotopes 67 The method according to any one of claims 1 to 3, wherein the material is Cu.

7. The radioactive isotope of Cu is [ 64 Cu] CuCl 2 The method according to any one of claims 1 to 3, provided as such.

8. The method according to any one of claims 1 to 7, wherein the pH of the formulation is maintained in the range of 4 to 8.

9. A method for purifying a compound of formula (I) that has formed a complex with a Cu radioactive isotope, i) A step of filling a solid-phase extraction cartridge with a solution of the compound of formula (I) that has formed a complex with a Cu radioactive isotope. ii) A step of eluting the compound of formula (I) that has formed a complex with a Cu radioisotope using an eluent containing water, ethanol, and sodium chloride. The method, including the method described above. 【Transformation 7】 Equation (I)

10. The method according to claim 9, wherein the compound of formula (I) has the structure of formula (Ia). 【Transformation 8】 Equation (Ia)

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