RU2788581C2 - Compositions for radiotherapy and diagnostic imaging - Google Patents

Abstract

FIELD: pharmaceutics.

SUBSTANCE: group of inventions relates to pharmaceutics, namely to aqueous compositions of MeCOSar-octreotate or its salt in a complex with copper ion, which can be used for radiation imaging, diagnostics of cancer, and treatment of cancer, as well as to a method for their production and a kit. The aqueous composition for radiation imaging for parenteral administration, containing MeCOSar-octreotate or its salt in a complex with Cu ion, additionally contains from 3 to 11% (vol./vol.) of ethanol, from 0.6 to 1.2% (wt./vol.) of sodium chloride, and from 0.1 to 0.55% (wt./vol.) of gentisic acid or its salt; at the same time, the composition has a pH value from 4 to 8 and contains acetate salt. An aqueous composition for diagnostics of cancer for parenteral administration is described. An aqueous composition for the treatment of cancer for parenteral administration is described. A method for the production of these aqueous compositions is described. A kit for the production of this aqueous composition is also described.

EFFECT: proposed group of inventions has higher stability and differs in reduced radiolysis.

19 cl, 12 dwg, 9 ex

Description

The present invention relates to formulations of radiolabeled compounds that can be used for radiotherapy and diagnostic imaging.

BACKGROUND OF THE INVENTION

Radiolabeled compounds, or ligands, can be used as radiopharmaceuticals in applications such as radiotherapy or diagnostic imaging. Especially useful are radiolabeled compounds that have the properties of selectively targeting a specific site in vivo (eg, a specific receptor), followed by delivery of the radioisotope to the desired site of its action. This requires that the ligand be a component that forms a complex with a radioisotope, and, in addition, a component that targets the desired site.

One of the known problems associated with such a ligand is the premature dissociation of the radioisotope before the ligand-radioisotope complex reaches the coverage area. This not only reduces the effectiveness of the complex, but, in addition, the ingress of a radioisotope into areas not intended for radiotherapeutic exposure can lead to adverse consequences.

Dissociation of a radioisotope from a ligand can occur through transchelation, where a radioisotope is transferred to another biological ligand in vivo . Again, this leads to a reduction in therapeutic effect, as well as delivery of the radioisotope to areas where treatment is not required.

The ligand to be radioactively labeled and the radioisotope are typically stored and transported to the patient in separate containers to minimize the above dissociation problems prior to administration. The ligand can be transported as a lyophilized powder at reduced temperatures to prolong the stability of the compound. The radioisotope can then be combined with a ligand to form a radiopharmaceutical immediately prior to administration, which can help minimize dissociation of the radioisotope before the complex reaches its region of action.

Another problem with radiolabeled compounds is that the use of a radioisotope can lead to radiolysis, or destruction, of the ligand. Since the radioisotope undergoes spontaneous decay, followed by the emission of radiation, this energy may be sufficient to induce bond cleavage and cause the subsequent destruction of the ligand. In addition to reducing the effectiveness of the radiopharmaceutical, a radioisotope is also released, resulting in the delivery of radiation to unwanted areas.

Because many radiopharmaceuticals are intended for parenteral administration, ie, not by the oral route and typically as a solution, the ligand itself must be soluble in a pharmaceutically acceptable solvent or carrier. As is known in the art, the solubility of a particular compound in any particular solvent can be unpredictable. Although the solubility of a particular compound in a particular solvent may be known, the solubility of a compound analog in a different solvent system may be completely different. This can create difficulties in formulating a compound, and especially a pharmaceutically acceptable injectable formulation.

Pharmaceutical formulations typically contain one or more excipients that affect the compound in some way, such as increasing the solubility of the compound or increasing the stability of the compound in solution. Alternatively, additional excipients may be used to impart other properties to the formulation, such as preservatives, buffers, and the like.

Although many thousands of formulations of ligand-radioisotope complexes are known, it is difficult to expect that the excipients used in such formulations will provide the necessary stability and bioavailability of the newly formed complex. In addition, it cannot be expected that a particular combination of excipients will also prevent or minimize the dissociation of the radioisotope, or minimize the likelihood of radiolysis.

Accordingly, it is necessary that the compositions of the ligand-radioisotope complexes be specifically adapted to exhibit the necessary stability with respect to radiolysis and dissociation of the radioisotope, while remaining pharmaceutically acceptable. The present invention is directed to solving these problems for a particular ligand complex.

SUMMARY OF THE INVENTION

In one aspect, the present invention relates to an aqueous parenteral formulation comprising a compound of formula (I), or a salt thereof, in complex with a Cu ion:

Formula (I),

additionally containing:

about 7 to about 13% (v/v) ethanol;

from about 0.3 to about 1.2% (w/v) sodium chloride;

from about 0.02 to about 0.1% (w/v) gentisic acid or a salt thereof;

wherein the composition has a pH value of from about 4 to about 8.

In another aspect, the present invention provides an aqueous parenteral formulation comprising a compound of formula (I), or a salt thereof, in complex with a Cu ion:

Formula (I),

additionally containing:

about 7 to about 13% (v/v) ethanol;

from about 0.3 to about 1.2% (w/v) sodium chloride;

from about 0.02 to about 0.1% (w/v) gentisic acid or a salt thereof; and

from about 1.0 to about 4.0 mg/ml of L-methionine or a salt thereof;

wherein the composition has a pH value of from about 4 to about 8.

In one embodiment, and in connection with the above two aspects, the compound of formula (I) is provided as an acetate salt.

In a further aspect, the present invention relates to a process for preparing an aqueous composition containing a compound of formula (I) complexed with a Cu ion, comprising the steps of:

i) preparing an acetate salt buffer solution, wherein the buffer solution further comprises ethanol and gentisic acid or a salt thereof;

ii) dissolving the compound of formula (I), or a salt thereof, in the buffer solution obtained in step i);

iii) adding the Cu ion solution to the solution obtained in step ii);

iv) filtering the solution obtained in step iii) on the stationary phase; and

v) washing the stationary phase from step iv) with ethanol and brine;

to obtain an aqueous composition containing a compound of formula (I), or a salt thereof, in complex with a Cu ion.

In a further aspect, the present invention relates to a process for preparing an aqueous composition containing a compound of formula (I) complexed with a Cu ion, comprising the steps of:

i) preparing an acetate salt buffer solution, wherein the buffer solution further comprises ethanol and gentisic acid or a salt thereof;

ii) dissolving the compound of formula (I), or a salt thereof, in the buffer solution obtained in step i);

iii) adding the Cu ion solution to the solution obtained in step ii);

iv) filtering the solution obtained in step iii) on the stationary phase; and

v) washing the stationary phase from step iv) with ethanol and saline into a vial containing a solution of L-methionine or its salt;

to obtain an aqueous composition containing a compound of formula (I), or a salt thereof, in complex with a Cu ion.

In the following aspect, the present invention relates to an aqueous composition obtained by the method indicated in the above aspect.

The aqueous composition of the present invention can also be obtained by providing certain components of the composition in the form of a set of parts, including at least a compound of formula (I), or a salt thereof, and a Cu ion, which should form a complex with a compound of formula (I), while the compound of formula (I), or a salt thereof, and the Cu ion are provided separately in a kit and may be combined to form the above complex prior to administration.

Accordingly, in another aspect, the present invention provides a kit for preparing an aqueous parenteral formulation comprising a compound of formula (I), or a salt thereof, complexed with a Cu ion, comprising:

a container containing a lyophilized compound of formula (I)

Formula (I)

or its salt;

a container containing a Cu ion solution; and

instructions for obtaining the aqueous composition specified in the above aspect, including the addition of a buffer solution of ethanol, sodium chloride and gentisic acid or its salt.

In another aspect, the present invention relates to a kit for preparing an aqueous composition for parenteral administration containing a compound of formula (I), or a salt thereof, in complex with a Cu ion, comprising:

a container containing a lyophilized compound of formula (I)

Formula (I)

or its salt;

a container containing a Cu ion solution; and

instructions for preparing an aqueous composition as defined in the above aspect comprising adding a buffer solution of ethanol, sodium chloride and gentisic acid or a salt thereof and L-methionine or a salt thereof.

In a further aspect, the present invention relates to a kit for preparing an aqueous formulation for parenteral administration as defined in the above aspect, comprising:

a container containing a lyophilized compound of formula (I) or a salt thereof;

Formula (I)

a container containing a Cu ion solution;

a container containing a buffer solution of ethanol, sodium chloride and gentisic acid or its salt; and

instructions for obtaining the aqueous composition specified in the above aspect.

In another aspect, the present invention relates to a kit for preparing the above aqueous formulation for parenteral administration, comprising:

a container containing a lyophilized compound of formula (I) or a salt thereof;

Formula (I)

a container containing a Cu ion solution;

a container containing a buffer solution of ethanol, sodium chloride, gentisic acid or a salt thereof, and L-methionine or a salt thereof; and

instructions for obtaining the aqueous composition specified in the above aspect.

In another aspect, the present invention relates to a method for imaging, diagnosing or treating cancer, comprising administering to a subject in need thereof an aqueous formulation as defined in the above aspect.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1: Determination of the area, in percent, using a gamma scintillation detector - Analysis by high performance liquid chromatography (HPLC) of the low-dose formulation ⁶⁴ Cu-SARTATE from Example 1 immediately after preparation (radiochemical yield = 606 MBq), showing that 97.3 % of detected ⁶⁴ Cu is present as ⁶⁴ Cu-SARTATE.

Figure 2 : Graph representing the results of periodic HPLC analyzes of the low dose formulation of ⁶⁴ Cu-SARTATE from Example 1 over 24 hours using a gamma scintillation detector showing that the radiochemical purity of ⁶⁴ Cu-SARTATE remains stable (>90%) over time time.

Figure 3 : Determination of the area, in percent, using a gamma scintillation detector - HPLC analysis of the high-dose formulation of ⁶⁴ Cu-SARTATE from Example 2 immediately after preparation (radiochemical yield=3500 MBq), showing that 98.2% of the detected ⁶⁴ Cu is present as ⁶⁴ Cu-SARTATE.

Figure 4 : Graph representing the results of periodic HPLC analyzes of the high dose formulation of ⁶⁴ Cu-SARTATE from Example 2 over 45 hours using a gamma scintillation detector showing that the radiochemical purity of ⁶⁴ Cu-SARTATE remains stable (>90%) over time time.

Figure 5: Determination of the area, in percent, using a gamma scintillation detector - HPLC analysis of the composition of ⁶⁷ Cu-SARTATE from Example 3 immediately after preparation (radiochemical yield = 3922 MBq), showing that 98.6% of the detected ⁶⁷ Cu is present in form ⁶⁷ Cu-SARTATE.

Figure 6 : Graph representing the results of periodic HPLC analyzes of the composition of ⁶⁷ Cu-SARTATE from Example 3 for 11 hours, using a gamma scintillation detector, showing that the radiochemical purity of ⁶⁷ Cu-SARTATE remains stable (> 90%) over time .

Figure 7: Graph representing the results of periodic HPLC analyzes of the ⁶⁴ Cu-SARTATE composition of Example 2 for 43 hours after incubation in fresh human serum.

Figure 8 : In vitro internalization of ⁶⁴ Cu-SARTATE in SSTR2 overexpressing A427-7 cells (shaded symbols) and overexpressing Tyr ³ -octreotate (open symbols), during increasing incubation periods.

Figure 9 : Cell surface binding of ⁶⁴ Cu-SARTATE in SSTR2 overexpressing A427-7 cells (shaded symbols) and overexpressing Tyr ³ -octreotate (open symbols), during increasing incubation periods.

Figure 10: Comparison of normalized uptake of ⁶⁴ Cu-SARTATE in A427-7 cell line and A427 parental line for 2 hours (p<0.0001).

Figure 11: In vivo biodistribution of ⁶⁴ Cu- ^SARTATE in selected tissues of A427-7 tumor-bearing Balb/c mice at 2 and 24 hours. injection of excess Tyr ³ -octreotate.

Figure 12: In vivo PET imaging of ⁶⁴ Cu-SARTATE using PET small animal projection images of maximum intensity tumor-bearing A427-7 Balb/c mice at 2 hours and 24 hours after ⁶⁴ Cu-SARTATE injection, co-administered , or without administration, by injection of excess Tyr ³ -octreotate.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to stable formulations of a particular radioisotope ligand complex. The present inventors have found that the complex compositions disclosed herein minimize dissociation of the radioisotope from the ligand and/or minimize radiolysis of the ligand caused by the radioisotope.

The radioisotope ligand complex formulations described herein are stable in solution and under physiological conditions for some time. The stability of the composition means the stability of the complex in the case where the radioisotope can dissociate or the complex can undergo radiolysis. The stability of the complex can be measured based on the radiochemical purity of the composition. Radiochemical purity is defined as the amount of radioisotope complexed with the sarcophagin ligand, expressed as a percentage of the total amount of radioisotope present in the formulation. The radioisotope may be present in the formulation as a complex with the sarcophagin ligand, as a free radioisotope, or as part of a radiolysis product.

It has previously been found that octreotate-containing ligands target somatostatin receptors, namely type 2 (SSTR2) and type 5 (SSTR5) receptors. An example of an octreotate-containing ligand is MeCOSar-octreotate, or MeCOSar-D-Phe-Cys-Tyr-D-Trp-Lys-Thr-Cys-Thr-OH, where MeCOSar is the macrocyclic ligand sarcophagin 5-[[8- amino-3,6,10,13,19-hexaazabicyclo[6.6.6]eico-1-yl)amino]-5-oxopentanyl and octreotate is D-Phe-Cys-Tyr-D-Trp-Lys-Thr- Cys-Thr-OH. The person skilled in the art understands that octreotate is a cyclic octapeptide and is derived from the corresponding linear peptide by formation of a Cys-Cys disulfide bond. The person skilled in the art also understands that sarcophagin (“sar”) is a nitrogen-containing hexadentate macrocyclic ligand that is capable of complexing with donor atoms such as transition metal ions, and in the context of the present invention, Cu ions.

MeCOSar-octreotate (herein also referred to as "SARTATE") is also represented by Formula (I):

Formula (I).

The compound of formula (I) can be prepared by a coupling reaction between a sarcophagin ligand and a cyclic octreotate peptide, wherein the macrocyclic sarcophagin and the octreotate moieties are synthesized separately prior to the coupling reaction. Sarcophagin of formula (I) is obtained from a macrocylic ligand with blocked amino groups associated with an aliphatic carboxylate group. The synthetic route to obtain the compound of formula (I) as well as the sarcophagin component and octreotate moieties have previously been described in Dalton Trans. , 2015, 43, 1386.

The present invention also relates to the use of pharmaceutically acceptable salts of the compounds of formula (I) as part of the claimed compositions. Examples of pharmaceutically acceptable salts of compounds of formula (I) may include the corresponding acetate salt, sodium salt, hydrochloride salt, potassium salt, magnesium salt, calcium salt or ammonium salt. In one embodiment, the compound of formula (I) is provided as an acetate salt.

Suitable formulations of the present invention comprise a complex of a compound of formula (I), or a salt thereof, and a radioisotope. A radioisotope, which may also be referred to as a radionuclide, may be a metal or a metal ion. The ligand of the present invention has been found to complex with copper ions, in particular Cu ²⁺ ions, particularly efficiently. A complex of a compound of formula (I) containing a copper ion radioisotope has previously been described in Dalton Trans. , 2015, 43, 1386. The person skilled in the art also understands that a complex of a compound of formula (I) and a radioisotope can be obtained by contacting a compound of formula (I), or a salt thereof, with the radioisotope to be included in the complex, resulting in the compound of formula (I), or a salt thereof, forms a complex with a radioisotope. This may include mixing a compound of formula (I), or a salt thereof, and a radioisotope in a suitable solvent system (such as that specifically described herein).

In one embodiment, the ligand is complexed with a Cu ion. The copper ion may be radioactive and therefore a radionuclide, or radioisotope, of copper. In one embodiment, the ligand is complexed with ⁶⁰ Cu. In another embodiment, the ligand is complexed with ⁶¹ Cu. In another embodiment, the ligand is complexed with ⁶⁴ Cu. In another embodiment, the ligand is complexed with ⁶⁷ Cu. In a preferred embodiment, the ligand is complexed with ⁶⁴ Cu. In another preferred embodiment, the ligand is complexed with ⁶⁷ Cu.

The compositions of the present invention contain ethanol as a component. The ethanol used in the formulation may be anhydrous ethanol. Alternatively, the ethanol used in the formulation may not have been dried and may be hydrated. The ethanol is preferably pharmaceutical grade ethanol. The ethanol present in the formulation can further help prevent radiolysis of the radiolabeled complex of the compound of formula (I).

In one embodiment, ethanol is present in the formulation in an amount of from about 7% to about 13% (v/v). In one embodiment, ethanol is present in the formulation at about 7% (v/v). In another embodiment, ethanol is present in the composition in an amount of about 8% (v/v). In another embodiment, ethanol is present in the formulation at about 9% (v/v). In another embodiment, ethanol is present in the composition in an amount of about 10% (v/v). In another embodiment, ethanol is present in the composition in an amount of about 11% (v/v). In another embodiment, ethanol is present in the formulation at about 12% (v/v). In another embodiment, ethanol is present in the formulation at about 13% (v/v). In a preferred embodiment, ethanol is present in the composition in an amount of about 10% (v/v). In other embodiments, implementation of the present invention also provides for the content of ethanol in the range of the above quantities.

The compositions of the present invention also contain sodium chloride as a component. In the compositions of the present invention, sodium chloride can be introduced in the form of a saline solution. Salt solution is an aqueous solution of sodium chloride. For example, a normal saline solution is an aqueous solution of sodium chloride at a concentration of 0.9% (w/v). In one of the embodiments of the present invention, sodium chloride is introduced into the composition in the form of a saline solution.

In one embodiment, sodium chloride is present in the composition in an amount of from about 0.6% to about 1.2% (w/v). In one embodiment, sodium chloride is present at about 0.6% (w/v). In another embodiment, sodium chloride is present in an amount of about 0.7% (w/v). In another embodiment, sodium chloride is present at about 0.8% (w/v). In another embodiment, sodium chloride is present at about 0.9% (w/v). In another embodiment, sodium chloride is present in an amount of about 1.0% (w/v). In another embodiment, sodium chloride is present at about 1.1% (w/v). In another embodiment, sodium chloride is present in an amount of about 1.2% (w/v). In a preferred embodiment, sodium chloride is present in the composition in an amount of about 0.9% (w/v). In other embodiments, implementation of the present invention also provides for the content of sodium chloride in the range of the above quantities.

The compositions of the present invention contain gentisic acid, or pharmaceutically acceptable salts and/or hydrates thereof, as a component. Gentisic acid is also known as 2,5-dihydroxybenzoic acid, 5-hydroxysalicylic acid, or hydroquinonecarboxylic acid. Salts of gentisic acid may include sodium salt and sodium salt hydrate. Any reference to gentisic acid may include reference to its salts where appropriate. The present inventors have found that gentisic acid, or a salt thereof, in the present formulations helps to prevent or minimize radiolysis of the radiolabeled complex of a compound of formula (I).

In one embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of from about 0.02% to about 0.1% (w/v). In one embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.02% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.025% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.03% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.035% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.04% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.045% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.05% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.055% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.6% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.065% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.07% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.075% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.08% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.085% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation at about 0.09% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.095% (w/v). In another embodiment, gentisic acid, or a salt thereof, is present in the formulation in an amount of about 0.1% (w/v). In other embodiments, implementation of the present invention also provides for the content of gentisic acid, or its salts, in the range of the above quantities. In a preferred embodiment, gentisic acid, or a salt thereof, is present in the composition in an amount of not more than 0.056% (w/v).

The compositions of the present invention have a pH value of from about 4 to about 8. One skilled in the art understands that the pH value of a composition is an inherent characteristic of the composition due to the combination of the compound of formula (I), or a complex thereof, and the remaining excipients of the composition. The authors of the present invention have found that this range of pH values provides optimal efficiency of radioactive labeling.

In one embodiment, the pH of the composition is from about 4 to about 8. In one embodiment, the pH of the composition is about 4. In another embodiment, the pH of the composition is about 4.5. In another embodiment, the pH of the formulation is about 5.0. In one embodiment, the pH of the formulation is about 5.5. In another embodiment, the pH of the formulation is about 5.6. In another embodiment, the pH of the formulation is about 5.7. In another embodiment, the pH of the formulation is about 5.8. In another embodiment, the pH of the formulation is about 5.9. In another embodiment, the pH of the formulation is about 6.0. In another embodiment, the pH of the formulation is about 6.1. In another embodiment, the pH of the formulation is about 6.2. In another embodiment, the pH of the formulation is about 6.3. In another embodiment, the pH of the formulation is about 6.4. In another embodiment, the pH of the formulation is about 6.5. In another embodiment, the pH of the formulation is about 7.0. In another embodiment, the pH of the formulation is about 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 a preferred embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, and about 0.06% gentisic acid, or a salt thereof, the composition having a pH value of about 6.0. In one embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, not more than 0.056% gentisic acid, or a salt thereof, the composition having a pH value of about 6.0. In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, and 0.056 % gentisic acid, or a salt thereof, wherein the composition has a pH value of about 6.0. One skilled in the art will appreciate that the amount of compound of formula (I)-Cu ion complex present in an aqueous formulation may be varied for different purposes.

In one embodiment, the aqueous formulation of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a ⁶⁴ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and about 0.06 % gentisic acid, or a salt thereof, wherein the composition has a pH value of about 6.0. In one embodiment, the aqueous formulation of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a ⁶⁴ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and not more than 0.056% gentisic acid, or a salt thereof, wherein the composition has a pH value of about 6.0. In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, in complex with a ⁶⁴ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, and 0.056% gentisic acid, or a salt thereof, the composition having a pH value of about 6.0.

In one embodiment, the aqueous formulation of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a ⁶⁷ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and about 0.06 % gentisic acid, or a salt thereof, wherein the composition has a pH value of about 6.0. In one embodiment, the aqueous formulation of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a ⁶⁷ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and not more than 0.056% gentisic acid, or a salt thereof, wherein the composition has a pH value of about 6.0. In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, in complex with a ⁶⁷ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, and 0.056% gentisic acid, or a salt thereof, the composition having a pH value of about 6.0.

In one embodiment, the aqueous formulation of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁴ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and about 0.06 % gentisic acid, or a salt thereof, wherein the composition has a pH value of about 6.0. In another embodiment, the aqueous formulation of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁴ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and about 0.056% gentisic acid. , or salts thereof, wherein the composition has a pH value of about 6.0. In another embodiment, the aqueous formulation of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁴ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and not more than 0.056% gentisinic acid. acid, or its salts, while the composition has a pH value of about 6.0.

In one embodiment, the aqueous formulation of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁷ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and about 0.06 % gentisic acid, or a salt thereof, wherein the composition has a pH value of about 6.0. In another embodiment, the aqueous formulation of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁷ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and about 0.056% gentisic acid. , or salts thereof, wherein the composition has a pH value of about 6.0. In another embodiment, the aqueous formulation of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁷ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, and not more than 0.056% gentisinic acid. acid, or its salts, while the composition has a pH value of about 6.0.

The aqueous composition of the present invention may also contain an acetate salt as a buffer salt. The acetate salt may be ammonium acetate or sodium acetate.

The present inventors have also found that the formulation can be further stabilized by adding L-methionine or a salt thereof. The addition of L-methionine to a formulation containing a compound of formula (I), ethanol, sodium chloride, and gentisic acid or a salt thereof results in a further increase in the stability of the formulation by preventing or minimizing radiolysis of the radiolabeled complex of the compound of formula (I). The present inventors have also found that the addition of L-methionine to a composition containing a compound of formula (I) and a Cu ion makes it possible to obtain a composition with a higher initial radioactivity in which the Cu ion is a Cu radioisotope.

Accordingly, the present invention also relates to an aqueous parenteral formulation comprising a compound of formula (I), or a salt thereof, in complex with a Cu ion:

Formula (I),

additionally containing:

about 7 to about 13% (v/v) ethanol;

from about 0.3 to about 1.2% (w/v) sodium chloride;

from about 0.02 to about 0.1% (w/v) gentisic acid or a salt thereof; and

about 1 to about 4 mg/ml of L-methionine or a salt thereof;

wherein the composition has a pH value of from about 4 to about 8.

In one embodiment, L-methionine, or a salt thereof, is present in the formulation in an amount of from about 1 mg/mL to about 4 mg/mL. In one embodiment, L-methionine, or a salt thereof, is present in the formulation at about 1.0 mg/mL. In another embodiment, L-methionine, or a salt thereof, is present in the formulation at about 1.5 mg/mL. In another embodiment, L-methionine, or a salt thereof, is present in the formulation at about 2.0 mg/mL. In another embodiment, L-methionine, or a salt thereof, is present in the formulation at about 2.5 mg/mL. In another embodiment, L-methionine, or a salt thereof, is present in the formulation at about 3.0 mg/mL. In another embodiment, L-methionine, or a salt thereof, is present in the formulation at about 3.5 mg/mL. In another embodiment, L-methionine, or a salt thereof, is present in the formulation at about 4.0 mg/mL.

In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, in complex with a Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.06% gentisic acid, or a salt thereof, and about 2.5 mg/ml L-methionine, or a salt thereof, the composition having a pH value of about 6.0. In another embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, in complex with a Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, not more than 0.056% gentisic acid, or a salt thereof, and about 2.5 mg/ml of L-methionine, or a salt thereof, the composition having a pH value of about 6.0. In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, 0.056 % gentisic acid, or a salt thereof, and about 2.5 mg/ml of L-methionine, or a salt thereof, the formulation having a pH of about 6.0. One skilled in the art will appreciate that the amount of compound of formula (I)-Cu ion complex present in an aqueous formulation may be varied for different purposes.

In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a ⁶⁴ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.06% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0. In one embodiment, the aqueous formulation of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a ⁶⁴ Cu ion, about 10% (v/v) ethanol, not more than 0.9% (w/v) chloride sodium, not more than 0.056% gentisic acid, or a salt thereof, and about 2.5 mg/ml of L-methionine, or a salt thereof, the composition having a pH value of about 6.0. In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, complexed with a ⁶⁴ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.056% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0.

In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, in complex with a ⁶⁷ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.06% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0. In one embodiment, the aqueous formulation of the present invention comprises a compound of formula (I), or a salt thereof, in complex with a ⁶⁷ Cu ion, about 10% (v/v) ethanol, not more than 0.9% (w/v) chloride sodium, not more than 0.056% gentisic acid, or a salt thereof, and about 2.5 mg/ml of L-methionine, or a salt thereof, the composition having a pH value of about 6.0. In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, in complex with a ⁶⁷ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.056% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0. In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I), or a salt thereof, in complex with a ⁶⁷ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.056% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0.

In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁴ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.06% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0. In another embodiment, the aqueous composition of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁴ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.056% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0. In another embodiment, the aqueous composition of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁴ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, not more than 0.056% gentisinic acid, or a salt thereof, and about 2.5 mg/ml of L-methionine, or a salt thereof, the composition having a pH value of about 6.0.

In a further embodiment, the aqueous composition of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁷ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.06% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0. In another embodiment, the aqueous composition of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁷ Cu ion, about 10% (v/v) ethanol, about 0.9% (w/v) sodium chloride, about 0.056% gentisic acid, or a salt thereof, and about 2.5 mg/mL L-methionine, or a salt thereof, the formulation having a pH of about 6.0. In another embodiment, the aqueous composition of the present invention comprises a compound of formula (I) as an acetate salt, complexed with a ⁶⁷ Cu ion, about 10% ethanol, about 0.9% (w/v) sodium chloride, not more than 0.056% gentisinic acid, or a salt thereof, and about 2.5 mg/ml of L-methionine, or a salt thereof, the composition having a pH value of about 6.0.

In accordance with the present invention, the composition of the complex ⁶⁴ Cu and compounds of formula (I) may have a radiochemical purity of at least about 90% for at least 45 hours. This means that at least about 90% of the ⁶⁴ Cu radioisotope present in the formulation is complexed with the compound of formula (I), or a salt thereof, for at least 45 hours after formulation is made. If the ⁶⁴ Cu radioisotope present in the formulation is not complexed with a compound of formula (I) or a salt thereof, the ⁶⁴ Cu radioisotope may be present as a free ⁶⁴ Cu ion or as part of a radiolysis product.

In one embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 90% at about 45 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a ⁶⁴ Cu complex and a compound of formula (I), or a salt thereof, is about 91% at about 45 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 92% at about 45 hours after manufacture of the composition.

In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 93% at about 45 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 94% at about 45 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 95% at about 45 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 96% at about 45 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 97% at about 45 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 98% at about 45 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 45 hours after the composition is made.

In one embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% immediately after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 1 hour after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 3 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 6 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a ⁶⁴ Cu complex and a compound of formula (I), or a salt thereof, is about 99% at about 9 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 12 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 15 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 18 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 21 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁴ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 24 hours after the composition is made.

In accordance with the present invention, the composition of the complex ⁶⁷ Cu and compounds of formula (I) can also have a radiochemical purity of at least 90% for at least 11 hours. This means that at least about 90% of the ⁶⁷ Cu radioisotope present in the formulation is complexed with the compound of formula (I), or a salt thereof, for at least 11 hours after the formulation is made. If the ⁶⁷ Cu radioisotope present in the formulation is not complexed with a compound of formula (I) or a salt thereof, the ⁶⁷ Cu radioisotope may be present as a free ⁶⁷ Cu ion or as part of a radiolysis product.

In one embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 90% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 91% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 92% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 93% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 94% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 95% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 96% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 97% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 98% at about 11 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 11 hours after the composition is made.

In one embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% immediately after preparation of the composition. In another embodiment, the radiochemical purity of a composition of the present invention containing a ⁶⁷ Cu complex and a compound of formula (I), or a salt thereof, is about 99% at about 1 hour after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 3 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 6 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a ⁶⁷ Cu complex and a compound of formula (I), or a salt thereof, is about 99% at about 9 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 12 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 15 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 18 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 21 hours after the composition is made. In another embodiment, the radiochemical purity of a composition of the present invention containing a complex of ⁶⁷ Cu and a compound of formula (I), or a salt thereof, is about 99% at about 24 hours after the composition is made.

Preparation of the aqueous composition of the present invention

A compound of formula (I), or a salt thereof, complexed with a Cu ion can be prepared by mixing a compound of formula (I), or a salt thereof, with a solution of the Cu ion in the presence of a buffer solution. The solution can then be filtered, followed by washing, to give a formulation containing a compound of formula (I), or a salt thereof, complexed with a Cu ion. Accordingly, the present invention relates to a process for preparing an aqueous composition containing a compound of formula (I) complexed with a Cu ion, comprising the steps of:

i) preparing an acetate salt buffer solution, wherein the buffer solution further comprises ethanol and gentisic acid or a salt thereof;

ii) dissolving the compound of formula (I), or a salt thereof, in the buffer solution obtained in step i);

iii) adding the Cu ion solution to the solution obtained in step ii);

iv) filtering the solution obtained in step iii) on the stationary phase; and

v) washing the stationary phase from step iv) with ethanol and brine;

to obtain an aqueous composition containing a compound of formula (I), or a salt thereof, in complex with a Cu ion.

The buffer solution may be an ammonium acetate solution. Alternatively, the buffer solution may be a sodium acetate solution. A buffer solution containing an acetate salt is used to maintain the pH in a range allowing maximum and rapid complexation of a compound of formula (I), or a salt thereof, with the Cu ion. The buffer solution may contain an aqueous solution of ammonium acetate at a concentration of from about 0.08 to about 0.12 mol/L. In one embodiment, the buffer solution contains an aqueous solution of ammonium acetate at a concentration of about 0.08 mol/L. In another embodiment, the buffer solution contains an aqueous solution of ammonium acetate at a concentration of about 0.09 mol/l. In another embodiment, the buffer solution contains an aqueous solution of ammonium acetate at a concentration of about 0.1 mol/L. In another embodiment, the buffer solution contains an aqueous solution of ammonium acetate at a concentration of about 0.11 mol/L. In another embodiment, the buffer solution contains an aqueous solution of ammonium acetate at a concentration of about 0.12 mol/L. In a preferred embodiment, the buffer solution contains an aqueous solution of ammonium acetate at a concentration of 0.1 mol/l.

The buffer solution also contains ethanol as a component. As previously described, the ethanol may be anhydrous or have been subjected to drying procedures known in the art. The buffer solution may contain ethanol at a concentration of from about 3 to about 11% (v/v). In one embodiment, the buffer solution contains ethanol at a concentration of about 3% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 3.5% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 4% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 4.5% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 5% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 6% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 7% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 8% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 9% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 10% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 10% (v/v). In another embodiment, the buffer solution contains ethanol at a concentration of about 11% (v/v). In a preferred embodiment, the buffer solution contains ethanol at a concentration of about 10% (v/v).

The buffer solution also contains gentisic acid, or a salt thereof, as a component. As previously described, salts of gentisic acid may include sodium salt or sodium salt hydrate. Other salts of gentisic acid are also contemplated. The buffer solution may contain sodium gentisate at a concentration of from about 0.1% to about 0.55% (w/v). In one embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.1% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.15% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.2% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.25% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.3% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.35% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.4% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.45% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.5% (w/v). In another embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.55% (w/v). In a preferred embodiment, the buffer solution contains sodium gentisate at a concentration of about 0.228% (w/v).

In one embodiment of the present invention, the buffer solution can be prepared by mixing ethanol and gentisic acid, or a salt thereof, with an aqueous solution of ammonium acetate. The buffer solution may be prepared by sequentially adding ethanol and gentisic acid or a salt thereof to an aqueous ammonium acetate solution, or alternatively ethanol and gentisic acid or a salt thereof may be added together to the ammonium acetate solution. In one embodiment of the present invention, the buffer solution contains ammonium acetate at a concentration of about 0.1 M, with ethanol at a concentration of about 4-11% (v/v) and gentisic acid, or a salt thereof, at a concentration of about 0.5% ( wt/rev).

In one embodiment of the present invention, a compound of formula (I), or a salt thereof, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. The compound of formula (I), or a salt thereof, may be obtained as a solid. In one embodiment, the compound of formula (I), or a salt thereof, is obtained as a lyophilized powder. In one embodiment, a compound of formula (I), or a salt thereof, obtained as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In one embodiment, about 15 µg to about 65 µg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 15 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 20 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 25 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 30 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 35 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 40 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 45 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 50 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 55 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 60 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof. In another embodiment, about 65 μg of a compound of formula (I), or a salt thereof, as a lyophilized powder, is mixed with an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof.

The Cu ion solution is added to a mixture of a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer solution containing ethanol and gentisic acid, or a salt thereof, and left to stand for some time.

In one embodiment, the Cu ion solution is a Cu salt solution. In another embodiment, the Cu ion solution is a chloride salt solution containing copper. In another embodiment, the Cu ion solution is a copper (II) chloride salt solution. In another embodiment, the Cu ion solution is a copper salt solution containing the ⁶⁰ Cu radioisotope. In another embodiment, the Cu ion solution is a chloride salt solution containing the ⁶¹ Cu radioisotope. In another embodiment, the Cu ion solution is a chloride salt solution containing the ⁶⁴ Cu radioisotope. In another embodiment, the Cu ion solution is a chloride salt solution containing the ⁶⁷ Cu radioisotope. In another embodiment, the Cu ion solution is a radioactive copper(II) chloride salt solution. In another embodiment, the Cu ion solution is a copper (II) chloride salt solution, wherein copper is the ⁶¹ Cu isotope. In another embodiment, the Cu ion solution is a copper(II) chloride salt solution, where copper is the ⁶⁴ Cu isotope. In another embodiment, the Cu ion solution is a copper (II) chloride salt solution, wherein copper is the ⁶⁷ Cu isotope. In another embodiment, the Cu ion solution is a [ ⁶¹ Cu]CuCl ₂ solution. In another embodiment, the Cu ion solution is a [ ⁶⁴ Cu]CuCl ₂ solution. In another embodiment, the Cu ion solution is a [ ⁶⁷ Cu]CuCl ₂ solution.

The Cu ion solution is used as an aqueous solution. The Cu ion can be provided in an aqueous solution of hydrochloric acid. In one embodiment, the Cu ion is provided in a hydrochloric acid solution at a concentration of about 0.01 to about 0.1 mol/L. In one embodiment, the Cu ion is provided in a hydrochloric acid solution at a concentration of about 0.01 mol/L. In another embodiment, the Cu ion is provided in a hydrochloric acid solution at a concentration of about 0.02 mol/L. In another embodiment, the Cu ion is provided in a hydrochloric acid solution at a concentration of about 0.05 mol/l. In another embodiment, the Cu ion is provided in a hydrochloric acid solution at a concentration of about 0.075 mol/L. In another embodiment, the Cu ion is provided in a hydrochloric acid solution at a concentration of about 0.1 mol/L. In a preferred embodiment, the Cu ion is used as [ ⁶⁴ Cu]CuCl ₂ in a hydrochloric acid solution at a concentration of about 0.05 mol/l. In another preferred embodiment, the Cu ion is used as [ ⁶⁷ Cu]CuCl ₂ in a hydrochloric acid solution at a concentration of about 0.05 mol/l.

The ⁶⁴ Cu radioisotope solution is used as an aqueous solution with radioactivity from about 750 to about 3500 MBq. In one embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 750 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 1000 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 1250 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 1500 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 1750 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 2000 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 2250 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 2500 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 2750 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 3000 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 3250 MBq. In another embodiment, the radioactivity of the ⁶⁴ Cu radioisotope solution is about 3500 MBq.

The ⁶⁷ Cu radioisotope solution is used as an aqueous solution with a radioactivity of about 1000 to about 5000 MBq. In one embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 1000 MBq. In another embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 1500 MBq. In another embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 2000 MBq. In another embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 2500 MBq. In another embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 3000 MBq. In another embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 3500 MBq. In another embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 4000 MBq. In another embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 4500 MBq. In another embodiment, the radioactivity of the ⁶⁷ Cu radioisotope is about 5000 MBq.

A mixture of a Cu ion, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof, can be left to stand at room temperature. The mixture can be left to stand with agitation, alternatively, the mixture is left to stand without agitation. The mixture can be left to stand for a period of time from about 5 to about 25 minutes. In one embodiment, a mixture of a Cu ion, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer solution containing ethanol and gentisic acid is allowed to stand without stirring for about 5 minutes. In another embodiment, a mixture of a Cu ion, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer solution containing ethanol and gentisic acid is allowed to stand without stirring for about 10 minutes. In another embodiment, a mixture of a Cu ion, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer solution containing ethanol and gentisic acid is allowed to stand without stirring for about 15 minutes. In another embodiment, a mixture of a Cu ion, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer containing ethanol and gentisic acid is allowed to stand without stirring for about 20 minutes. In another embodiment, a mixture of a Cu ion, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer solution containing ethanol and gentisic acid is allowed to stand without stirring for about 25 minutes. In a preferred embodiment, a mixture of a Cu ion, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer solution containing ethanol and gentisic acid is allowed to stand without stirring for about 15 minutes. In another preferred embodiment, the mixture of the ⁶⁴ Cu radioisotope, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer solution containing ethanol and gentisic acid is allowed to stand without stirring for about 20 minutes.

In another embodiment of the present invention, a mixture of a Cu ion, a compound of formula (I), or a salt thereof, and an aqueous ammonium acetate buffer containing ethanol and gentisic acid, or a salt thereof, is filtered. The mixture can be filtered to remove the acetate salt which may remain in solution. The mixture can be filtered by solid phase extraction. The mixture can be filtered by a solid phase extraction method, wherein the stationary phase of the solid phase extraction cartridge keeps the compound of formula (I), or its salt, in complex with a Cu ion, any compound of formula (I), or its salt, which is not complexed, and some amount of gentisic acid present in the form of a salt, such as sodium gentisate. As used herein, the term "stationary phase" refers to the resinous material that resides in the solid phase extraction cartridge and allows compounds to be separated based on their polarity.

The solid phase extraction method described herein may use a reversed phase stationary phase. As used herein, the term "reversed phase" in relation to the stationary phase means a stationary phase that is hydrophobic in nature, whereby the stationary phase has an affinity for hydrophobic or uncharged molecules. Examples of a reverse phase stationary phase may include reverse phase polymer Phenomenex Strata-X 33u, Waters tC18 or Waters C18. Other similar stationary phases can also be used. Because the solid phase extraction method uses a reverse phase stationary phase, ammonium acetate from a buffer solution, any free Cu ions and most of the remaining gentisic acid or salt thereof are not retained by the stationary phase and these components are discarded.

In one embodiment, the mixture of Cu ion, compound of formula (I), and aqueous ammonium acetate buffer is filtered through a solid phase extraction cartridge. In one embodiment, the mixture of Cu ion, compound of formula (I), and aqueous ammonium acetate buffer solution is filtered through a reverse phase stationary phase solid phase extraction cartridge. In one embodiment, ammonium acetate and gentisic acid are removed from the buffer solution using a reverse phase stationary phase solid phase extraction cartridge. In one embodiment, the compound of formula (I) complexed with a Cu ion is retained in a reverse phase stationary phase solid phase extraction cartridge. In a preferred embodiment, the mixture of ⁶⁴ Cu radioisotope, compound of formula (I) and aqueous ammonium acetate buffer solution is filtered through a reverse phase stationary phase solid phase extraction cartridge. In a preferred embodiment, the compound of formula (I) in complex with the ⁶⁴ Cu ion is retained in a reverse phase stationary phase solid phase extraction cartridge. In another preferred embodiment, the mixture of ⁶⁷ Cu radioisotope, compound of formula (I) and aqueous ammonium acetate buffer solution is filtered through a reverse phase stationary phase solid phase extraction cartridge. In another preferred embodiment, the compound of formula (I) complexed with the ⁶⁷ Cu ion is retained in a reverse phase stationary phase solid phase extraction cartridge.

The compound of formula (I) in complex with Cu ion is eluted from the solid phase extraction cartridge containing the stationary phase by washing with solvent. Since the solid phase extraction cartridge contains a reverse phase stationary phase, eluting the compound of formula (I) in complex with the Cu ion requires washing the stationary phase with ethanol, saline and/or other solvent. In one embodiment, the solid phase extraction cartridge is washed with ethanol to elute the compound of formula (I) complexed with the Cu ion. In another embodiment, the solid phase extraction cartridge is washed with saline to elute the compound of formula (I) complexed with Cu ion. In another embodiment, the solid phase extraction cartridge is washed with ethanol and saline to elute the compound of formula (I) complexed with Cu ion. In a preferred embodiment, the SPE cartridge is washed successively with ethanol and saline to elute the compound of formula (I) complexed with Cu ion. In a preferred embodiment, the solid phase extraction cartridge is washed successively with ethanol and saline to give the composition of the present invention. In a preferred embodiment, the SPE cartridge is washed successively with ethanol and saline to elute the compound of formula (I) complexed with Cu ion and any remaining components such as gentisic acid or a salt thereof.

As described above, the present inventors have found that formulations of the compound of formula (I) complexed with a Cu ion further containing L-methionine exhibit even greater resistance to radiolysis. In another preferred embodiment, the SPE cartridge is washed successively with ethanol and brine to elute the compound of formula (I) complexed with Cu ion and gentisic acid, or a salt thereof, into a solution of L-methionine in brine. In another preferred embodiment, the SPE cartridge is washed successively with ethanol and saline to elute the compound of formula (I) complexed with Cu ion, ammonium acetate and gentisic acid, or a salt thereof, into a solution of L-methionine in saline. In another preferred embodiment, the concentration of L-methionine in the saline into which the SPE cartridge is washed is about 2.5 mg/mL. In another preferred embodiment, the solid phase extraction cartridge is washed successively with ethanol and brine to give the composition of the present invention.

One skilled in the art will appreciate that formulation excipients include the solvent that is used to elute the compound of formula (I) in complex with the Cu ion from the stationary phase, and that the amount of each solvent used is related to the amount of each excipient in the formulations of the present invention.

The person skilled in the art understands that this document proposes a manual method for obtaining the composition of the present invention. The person skilled in the art understands that the steps described herein can be automated, using an appropriate automated module for radiation synthesis, to obtain the composition of the present invention.

The present inventors have found that the compositions disclosed herein are more stable and exhibit reduced radiolysis, given the higher initial radioactivity. This increased stability may be due to the higher radiochemical purity of the composition at a given level of radioactivity. The stability of the compositions of the present invention can be observed for periods of time up to 45 hours after production in the case of the composition ⁶⁴ Cu-SARTATE and up to 11 hours after production in the case of the composition ⁶⁷ Cu-SARTATE. If the compositions of the present invention are used for the purpose of treatment or therapy, then increased stability may mean that doses for many patients at many remote locations can be made at the same time in the same production center. This may mean that production resources are needed in one production center rather than in many production centers, and greater efficiency in the production of formulations can be achieved. If the compositions of the present invention are used for imaging purposes, there may be additional advantages since clinical imaging centers can receive a dosage form ready for injection. This can be particularly advantageous for clinical centers that do not have dedicated manufacturing facilities for the manufacture of a radiopharmaceutical.

The compositions of the present invention contain a ligand-radioisotope complex, wherein the ligand is a compound of formula (I) or a salt thereof. The compound of formula (I), or a salt thereof, and the radioisotope may be provided in separate containers. Alternatively, the compound of formula (I), or a salt thereof, and the radioisotope may be provided together as a ligand-radioisotope complex.

In a container containing a compound of formula (I) or a salt thereof, the compound of formula (I) or a salt thereof may be in the form of a lyophilized powder. The container can be kept at -20°C to 20°C.

The formulations may be provided as a kit including a radioisotope container and a separate ligand container, as well as instructions for preparing an aqueous formulation of the present invention. In one embodiment, the kit of the present invention includes a container containing a solution of the ⁶⁴ Cu radioisotope and a separate container containing a compound of formula (I) or a salt thereof. The container containing the radioisotope may contain a metal salt solution, wherein the metal is the radionuclide.

In one embodiment, the kit of the present invention includes a container with a solution of the ⁶⁴ Cu radioisotope. In a further embodiment, the kit of the present invention includes a container with a copper salt solution containing the ⁶⁴ Cu radioisotope. In another embodiment, the kit of the present invention includes a container with a chloride salt solution containing the ⁶⁴ Cu radioisotope. In another embodiment, the kit of the present invention includes a container with a solution of radioactive copper (II) chloride salt. In another embodiment, the kit of the present invention includes a container with a solution of copper(II) chloride salt, wherein the copper ion is the ⁶⁴ Cu isotope. In another embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁴ Cu]CuCl ₂ .

In one embodiment, the kit of the present invention includes a container with a solution of the ⁶⁷ Cu radioisotope. In another embodiment, the kit of the present invention includes a container with a copper salt solution containing the ⁶⁷ Cu radioisotope. In another embodiment, the kit of the present invention includes a container with a chloride salt solution containing the ⁶⁷ Cu radioisotope. In another embodiment, the kit of the present invention includes a container with a solution of radioactive copper (II) chloride salt. In another embodiment, the kit of the present invention includes a container with a solution of copper(II) chloride salt, wherein the copper ion is the ⁶⁷ Cu isotope. In another embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁷ Cu]CuCl ₂ .

The radioisotope solution is usually used in the form of an aqueous solution. In one embodiment, the kit of the present invention includes the radioisotope in the form of an aqueous solution. In a further embodiment, the kit of the present invention includes the radioisotope in the form of an acidic aqueous solution. In another embodiment, the kit of the present invention includes a radioisotope in the form of a solution in hydrochloric acid. The radioisotope can be used as a solution in hydrochloric acid at a concentration of from about 0.01 to about 0.1 mol/L.

In one embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁴ Cu]CuCl ₂ in hydrochloric acid. In one embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁴ Cu]CuCl ₂ in hydrochloric acid, the hydrochloric acid having a concentration of about 0.02 mol/L. In one embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁴ Cu]CuCl ₂ in hydrochloric acid, the hydrochloric acid having a concentration of about 0.05 mol/L. In one embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁴ Cu]CuCl ₂ in hydrochloric acid, the hydrochloric acid having a concentration of about 0.1 mol/L.

In one embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁷ Cu]CuCl ₂ in hydrochloric acid. In another embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁷ Cu]CuCl ₂ in hydrochloric acid, with hydrochloric acid having a concentration of about 0.02 mol/l. In another embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁷ Cu]CuCl ₂ in hydrochloric acid, with hydrochloric acid having a concentration of about 0.05 mol/L. In another embodiment, the kit of the present invention includes a container with a solution of [ ⁶⁷ Cu]CuCl ₂ in hydrochloric acid, with hydrochloric acid having a concentration of about 0.1 mol/l.

The kit may further include a container containing ethanol, sodium chloride and gentisic acid in a buffer solution. This container may contain ethanol, sodium chloride and gentisic acid in an aqueous solution or, alternatively, the container may contain only ethanol, sodium chloride and gentisic acid. In one embodiment, the kit includes a container containing ethanol, sodium chloride, and gentisic acid, or a salt thereof, in ammonium acetate buffer.

The kit may also include a container containing ethanol, sodium chloride, gentisic acid, or a salt thereof, and L-methionine, or a salt thereof, in a buffer solution. The container in the kit may contain ethanol, sodium chloride, gentisic acid, or a salt thereof, and L-methionine, or a salt thereof, in aqueous solution, or alternatively, the container may contain only ethanol, sodium chloride, gentisic acid, or a salt thereof, and L-methionine, or its salt. In one embodiment, the kit includes a container containing ethanol, sodium chloride, gentisic acid, or a salt thereof, and L-methionine, or a salt thereof. In one embodiment, the kit includes a container containing ethanol, sodium chloride, gentisic acid, or a salt thereof, and L-methionine, or a salt thereof, in ammonium acetate buffer.

Applications of the composition of the present invention

The compositions of the present invention may be particularly useful in the medical field for diagnosis and treatment. Ligand complexes bearing an appropriate targeting moiety can be used to target specific tissue types. For such complexes to be considered suitable for use in in vivo diagnosis and treatment, the complex must demonstrate certain kinetics, stability and clearance under physiological conditions, in addition to the necessary properties of solubility and stability of the complex in solution. As used herein, the term "complex" may refer to a ligand-metal ion complex, wherein the metal ion is a radioactive isotope or, alternatively, the metal ion is a non-radioactive isotope.

Accordingly, the present invention relates to a method for imaging, a method for diagnosing a disease in a subject, or a method for treating a disease in a subject, comprising administering to the subject an effective amount of the composition described herein. The inventors of the present invention have found that the compositions of the present invention can be used in a method for imaging, a method for diagnosing, or a method for treating cancer.

As used herein, the term "cancer" broadly encompasses a class of neoplastic diseases characterized by abnormal cell growth that has the potential to invade, or spread, to other parts of the body. These diseases are to be distinguished from benign tumors that do not spread to other parts of the body, and therefore the definition used herein includes all malignant (cancerous) disease states. Thus, the term refers to the treatment of tumors.

Accordingly, the term "tumor" is used generally to refer to any malignant cancerous or precancerous growth of cells, and may include leukemias, but is predominantly used to refer to solid tumors or carcinomas such as melanomas, colon, lung, ovarian, skin, breast, pancreas, pharynx, brain, prostate, central nervous system and kidney (as well as other forms of cancer).

Somatostatin receptors, in particular SSTR2, are highly expressed on the plasma membrane of several tumors and malignancies, including pancreatic tumors, neuroendocrine tumors (NETs) of the gastrointestinal tract and lungs, pituitary adenomas, breast carcinomas, meningiomas, neuroblastomas, medulloblastomas , pheochromocytomas and paragangliomas. The presence of somatostatin receptors on such tumors has led to the development and clinical use of stable somatostatin receptor ligands, for example compounds having an octreotate moiety. The present inventors have found that the complex of a compound of formula (I) and a Cu ion in the compositions of the present invention exhibits particular binding property to somatostatin receptors, and in particular subtype 2 and subtype 5 somatostatin receptors. In specific embodiments, the formulation can be used for radiation therapy. imaging, diagnosing, or treating cancer whose cells express or highly express the somatostatin receptor.

The compositions of the present invention contain a compound of formula (I) containing an octreotate moiety similar to octreotide, a somatostatin analog used in clinical practice. Somatostatin is secreted by neuroendocrine cells of the gastrointestinal tract and acts through 5 subtypes of somatostatin receptors (SSTR 1-5). Given the similar nature of the octreotate moiety and octreotide, the compounds of formula (I) can target and bind to specific sites in the body where somatostatin receptors are present. Likewise, a compound of formula (I) complexed with a Cu ion can also target and bind to such sites.

The radioisotope-ligand complex of the present invention may contain a radioisotope such as ⁶⁴ Cu. The ^64Cu isotope has a half-life of approximately 12.7 hours and decays by both positron emission and beta decay, making the ^64Cu -labeled complex suitable for use in various beam imaging applications. In particular, the decay characteristics and half-life of ⁶⁴ Cu make this radioisotope suitable for use in positron emission tomography (PET) and single photon emission computed tomography (SPECT) techniques. The radioisotope-ligand complex of the present invention may contain a radioisotope such as ⁶¹ Cu. The ^61Cu isotope has a half-life of approximately 3 hours and decays by the positron emission mechanism, making the ^61Cu -labeled complex suitable for use in various beam imaging applications. The radioisotope-ligand complex of the present invention may also contain a radioisotope such as ⁶⁷ Cu. The ⁶⁷ Cu isotope has a half-life of approximately 61.8 hours and decays by a beta emission mechanism, making the ⁶⁷ Cu-labeled complex suitable for use in SPECT imaging. The ⁶⁷ Cu-labeled complex may also be suitable for use in radiotherapy treatment.

Administration of an effective amount of a formulation containing a compound of formula (I) and a Cu radioisotope, such as ⁶⁰ Cu, ⁶¹ Cu, ⁶⁴ Cu or ⁶⁷ Cu, may result in complexing of the compound of formula (I) and the Cu radioisotope with somatostatin receptors. If somatostatin receptors are expressed on the surface of the tumor, the complex of the compound of formula (I) and the Cu ion can bind to the somatostatin receptors. In one embodiment, the present invention relates to a radiation imaging method comprising administering to a subject a composition comprising a compound of formula (I) and a Cu ion. In one embodiment, a composition containing a compound of formula (I) and a ⁶⁴ Cu or ⁶⁷ Cu ion can be used in a beam imaging method. Monitoring a subject to whom a composition containing a compound of formula (I) and a Cu radioisotope has been administered by PET or SPECT, for example, allows visualization and subsequent detection of tumor zones. The image obtained by the method of radiation imaging can provide information related to the localization of any such tumor areas. Monitoring a subject who has been injected with a radioactively labeled complex by SPECT, for example, allows visualization and subsequent detection of tumor areas. This allows obtaining information related to the localization of tumors, if present. Re-imaging at later time points allows control of the clearance of the radioisotope ligand complex, allowing dosimetric assessments to be made. One skilled in the art will appreciate that the amount administered to perform radiation imaging may vary and will depend on the characteristics of the subject and the intended imaging area.

In order for the complex to be used for radiation imaging purposes, the radioisotope-ligand complex must have sufficient metabolic stability, ie remain intact, with the radioisotope bound to the ligand for the required time. The present invention relates to a complex of compounds of formula (I) and ⁶⁴ Cu, which remains intact for up to 45 hours, as evidenced by the absence of radioisotope loss and metabolic decay.

The compositions of the present invention can be administered to a subject for the purpose of radiation imaging, diagnosis or therapy. Administration is by parenteral route, preferably by intravenous injection. Alternatively, the compositions of the present invention may be administered by intra-arterial or other routes of administration for delivery to the circulatory system. The subject to whom the composition is administered is then placed in a PET scanner and images are obtained demonstrating the localization of the radioisotope ligand complex and, as a result, the localization of any tumors. This allows the diagnosis and detection of tumors. Alternatively, a sample (e.g., a blood or tissue sample) that has been exposed to the composition of the present invention can be analyzed by gamma spectroscopy, using a gamma counter, liquid scintillation counter, autoradiography, or a beta probe to obtain radio images.

In one embodiment, the present invention relates to the use of a composition containing a compound of formula (I) in a method for imaging a tumor or cancer. One skilled in the art will appreciate that information obtained from a subject's imaging technique can be used in diagnosing a tumor or cancer in a subject. In one embodiment, the present invention relates to a method for diagnosing a tumor or cancer. In a further embodiment, the tumor or cancer may be a tumor or cancer with cells expressing the somatostatin receptor. In one embodiment, the tumor or cancer is a neuroendocrine tumor. In another embodiment, the tumor or cancer is a pituitary adenoma. In another embodiment, the tumor or cancer is a neuroblastoma. In another embodiment, the tumor or cancer is a meningioma. In another embodiment, the tumor or cancer is a medulloblastoma. In another embodiment, the tumor or cancer is a breast carcinoma. In another embodiment, the tumor or cancer is a pheochromocytoma. In another embodiment, the tumor or cancer is a paraganglioma. In another embodiment, the tumor is a pancreatic tumor. In another embodiment, the tumor is a tumor of the gastrointestinal tract.

Since the composition of the present invention contains a compound of formula (I) and a Cu radioisotope, the administration of the composition may contribute to the treatment of a tumor or cancer. As described above, the compound of formula (I) can bind to somatostatin receptors on the surface of tumor or cancer cells, and by binding the compound to sites having somatostatin receptors, the Cu radioisotope is also delivered to these sites. Since the Cu radioisotope undergoes radioactive decay in a decay mechanism dependent on the particular radioisotope chosen, the decay products may be useful for tumor or cancer treatment due to the proximity of the tumor or cancer to the compound of formula (I) and the Cu radioisotope.

In one embodiment, the present invention relates to the use of a composition comprising a compound of formula (I) and a Cu radioisotope in a method of treating a tumor or cancer. In one embodiment, the tumor or cancer is a neuroendocrine tumor. In another embodiment, the tumor or cancer is a pituitary adenoma. In another embodiment, the tumor or cancer is a neuroblastoma. In another embodiment, the tumor or cancer is a meningioma. In another embodiment, the tumor or cancer is a medulloblastoma. In another embodiment, the tumor or cancer is a breast carcinoma. In another embodiment, the tumor or cancer is a pheochromocytoma. In another embodiment, the tumor or cancer is a paraganglioma. In another embodiment, the tumor is a pancreatic tumor. In another embodiment, the tumor is a tumor of the gastrointestinal tract.

In this specification, reference to any earlier publication (or information derived from it) or to any fact that is known does not, and should not be taken as an endorsement or admission, or any form of suggestion, that this earlier publication (or information derived from it) or a known fact is part of the general knowledge in the field to which the present invention pertains.

In the text of this specification and the appended claims, unless the context clearly requires otherwise, the term "comprise" and its variations, such as "comprises" and "including", should be understood as implying the inclusion of a specified integer or step, or group of integers numbers or stages, but not to the exclusion of any other integers or stages, or a group of integers or stages.

EXAMPLES

Example 1 - Preparation of a low dose formulation ⁶⁴ Cu-SARTATE containing ethanol and sodium gentisate as excipients to reduce radiolysis

Prepare a buffer solution of 0.1 M ammonium acetate, also containing ethanol at a concentration of 4-10% (v/v). The buffer solution also contains sodium gentisate, with a 5 ml volume of the buffer solution containing 38 mg of sodium gentisate.

The compound of formula (I) is obtained as a lyophilized powder. 20 μg of the compound of formula (I) in a lyophilized state are dissolved in 5 ml of the prepared buffer solution.

Prepare a solution of [ ⁶⁴ Cu]CuCl ₂ in 0.05 M hydrochloric acid, while a 300-μl volume of this solution contains 1500 MBq of [ ⁶⁴ Cu]. 300 μl of this [ ⁶⁴ Cu]CuCl ₂ solution is added to a solution containing a compound of formula (I) and sodium gentisate in ammonium acetate buffer. This combined solution is allowed to stand with stirring at room temperature for 15 minutes.

The solution is then filtered through a solid phase extraction cartridge. The cartridge is eluted with 1.0 ml ethanol followed by 9.0 ml saline into a sterile formulation vial to give ⁶⁴ Cu-SARTATE in a volume of 10 ml ethanol/saline. The results of the HPLC analysis of the resulting solution are shown in Figure 1 and show a radiochemical purity of 97%. The results of additional HPLC analysis of the same solution of the composition, obtained at different points in time, are shown in Figure 2, they show that the radiochemical purity remains >90% for more than 11 hours.

Example 2 - Preparation of a high dose formulation ⁶⁴ Cu-SARTATE containing ethanol, sodium gentisate and L-methionine as excipients to reduce radiolysis

Prepare a buffer solution of 0.1 M ammonium acetate, also containing ethanol at a concentration of 4-10% (v/v). The buffer solution also contains sodium gentisate, with a 5 ml volume of buffer solution containing 114 mg of sodium gentisate.

The compound of formula (I) is obtained as a lyophilized powder. 20 μg of the compound of formula (I) in a lyophilized state are dissolved in 5 ml of the prepared buffer solution.

Prepare a solution of [ ⁶⁴ Cu]CuCl ₂ in 0.05 M hydrochloric acid, while a 300-μl volume of this solution contains 4650 MBq [ ⁶⁴ Cu]. 300 μl of this [ ⁶⁴ Cu]CuCl ₂ solution is added to a solution containing a compound of formula (I) and sodium gentisate in ammonium acetate buffer. This combined solution is allowed to stand with stirring at room temperature for 15 minutes.

The solution is then filtered through a solid phase extraction cartridge. The cartridge was eluted with 1.0 ml ethanol followed by 16.0 ml saline to give ⁶⁴ Cu-SARTATE in a volume of 20 ml ethanol/brine. The results of the HPLC analysis of the resulting solution are shown in Figure 3, they show a radiochemical purity of more than 98%. The results of additional HPLC analysis of the same composition solution, obtained at different time points, are shown in Figure 4, they show that the radiochemical purity remains >90% for more than 45 hours.

Example 3 - Getting the composition ⁶⁷ Cu-SARTATE containing ethanol, sodium gentisate and L-methionine as excipients to reduce radiolysis

Prepare a buffer solution of 0.1 M ammonium acetate, also containing ethanol at a concentration of 4-10% (v/v). The buffer solution also contains sodium gentisate, with a 5 ml volume of buffer solution containing 114 mg of sodium gentisate.

The compound of formula (I) is obtained as a lyophilized powder. 60 μg of the compound of formula (I) in a lyophilized state are dissolved in 5 ml of the prepared buffer solution.

Prepare a solution of [ ⁶⁷ Cu]CuCl ₂ in 0.05 M hydrochloric acid, while a 300-μl volume of this solution contains 4650 MBq [ ⁶⁴ Cu]. 300 μl of this [ ⁶⁷ Cu]CuCl ₂ solution is added to a solution containing a compound of formula (I) and sodium gentisate in ammonium acetate buffer. This combined solution is allowed to stand with stirring at room temperature for 15 minutes.

The solution is then filtered through a solid phase extraction cartridge. The cartridge is eluted with 1.0 ml ethanol followed by 16.0 ml saline into a sterile formulation vial containing L-methionine solution (50 mg in 3 ml saline) to give ⁶⁷ Cu-SARTATE in a volume of 20 ml ethanol/saline . The results of the HPLC analysis of the resulting solution are shown in Figure 5, they show a radiochemical purity of more than 98%. The results of additional HPLC analysis of the same composition solution, obtained at different time points, are shown in Figure 6, they show that the radiochemical purity remains >90% for more than 11 hours.

Example 4 - In vitro stability ⁶⁴ Serum Cu-SARTATE

Incubation of ⁶⁴ Cu-SARTATE (>99% radiochemical purity) with fresh human serum demonstrated high metabolic stability. The results of the HPLC analysis of the serum incubated with the resulting ⁶⁴ Cu-SARTATE are shown in Figure 7, they show that >90% of the radioactivity in the non-protein fraction after 3 hours, 20 hours, 23 hours, 26 hours and 34 hours was still bound with a chelator, which indicated the intact radioactive peptide and indicated no loss of copper or noticeable metabolic decay for up to 43 hours.

Example 5 - In vitro internalization and binding at the cell surface ⁶⁴ Cu-SARTATE

Internalization and cell surface binding studies of ⁶⁴ Cu-SARTATE were performed using A427-7 cells bearing somatostatin receptor 2. The percentage of total added radioactivity per mg protein (% DR/mg protein) that was internalized increased with time, reaching 23.9 ± 0.7 after 120 minutes (Figure 8). After 30 minutes, 40.2±0.7% DR/mg protein was bound to the cell surface (Figure 9). This value decreased to 31.2 ± 1.2 after 60 min and 35.2 ± 1.3 after 120 min. Both receptor-mediated internalization and cell surface binding were partially inhibited by the addition of cold Tyr ₃ -octreotate to the medium. The normalized uptake of ⁶⁴ Cu-SARTATE in parental A427 cells was markedly less than in SSTR2-expressing A427-7 cells, indicating the importance of specific receptor-associated accumulation (Figure 10).

Example 6 - in vivo biodistribution ⁶⁴ Cu-SARTATE

Biodistribution of Cu-SARTATE was studied using ⁶⁴ Cu-SARTATE in A427-7 tumor-bearing Balb/c nude mice (Figure 11). For ⁶⁴ Cu-SARTATE, an effective clearance from the blood was observed after 2 hours (0.4 ± 0.2% ID/g, where % ID/g is the percentage of injected dose per gram of tissue), with a further clearance after 24 hours (0 .1 ± 0.02% ID/g). Absorption of ⁶⁴ Cu-SARTATE by the liver (3.1 ± 1.3% ID/g) and kidneys (35.2 ± 5.4% ID/g) was maximal 2 hours after dosing. 24 hours after dosing, renal uptake of ⁶⁴ Cu-SARTATE was reduced by 71% to 10.1 ± 3.5% ID/g, indicating effective clearance of ⁶⁴ Cu-SARTATE in the kidneys. At 24 hours post dosing, the uptake of ⁶⁴ Cu-SARTATE in the lungs and spleen (i.e., non-target organs) was 0.6 ± 0.3% ID/g and 0.8 ± 0.2% ID/g, respectively, with muscle accumulation was 0.1 ± 0.01% ID/g after 24 hours. Tumor uptake of ⁶⁴ Cu-SARTATE 2 hours after administration was high at 31.2 ± 13.1% ID/g and remained high at 24 hours at 31.4 ± 14.0% ID/g. Co-administration of excess Tyr ³ -octreotate (excess Y ³ -TATE) to block receptors resulted in a significant decrease in tumor uptake of ⁶⁴ Cu-SARTATE after 2 hours, by 81% to a level of 5.9 ± 0.3% ID/g, while increased uptake by non-target tissues, as evidenced by a 135% increase in the kidneys to a level of 47.7 ± 6.3% ID/g.

Example 7 - in vivo visualization ⁶⁴ Cu-SARTATE by PET method

Images of Balb/c tumor-bearing A427-7 mice obtained on a small animal PET machine at 2 and 24 hours, with and without blocking by excess Tyr ₃ -octreotate, are shown in Figure 12. The tumor is clearly visible 2 hours after injection of ⁶⁴ Cu- SARTATE, with an average tumor/background ratio of 48. The tumor/background ratio after 24 hours remained constant at 45, indicating a high degree of binding specificity and stability of the complex. Co-administration of excess Tyr ³ -octreotate resulted in effective blocking of tumor uptake, with a tumor/background ratio of 3.1 at 2 hours and below the limit of quantitation at 24 hours. the level of non-specific binding ⁶⁴ Cu-SARTATE. Significant uptake in the kidneys and bladder occurred in all animals, indicating that clearance through the kidneys was the main route of excretion of the compound. The tumor/kidney ratio at 2 hours was 1.6 and increased to 2.8 at 24 hours.

Example 8 - in vivo toxicology studies SARTATE

A single-dose preclinical toxicology study was performed in Sprague Dawley rats to evaluate the potential toxicity of SARTATE when administered by intravenous injection. Solutions of the SARTATE-copper complex (SCC) and unlabeled SARTATE ligand (SL) were tested in a ratio of 1:1. The study was carried out in accordance with the principles of OECD GLP.

The test formulation was administered once to six groups of 10 rats (5 animals of each sex) at three doses of 50, 250 and 1000 μg/kg in vehicle, with an injection volume of 3 ml/kg. Two control groups of 10 rats (5 animals of each sex) were injected with only the solvent (10% ethanol in 0.9% sodium chloride solution and 0.056% gentisic acid) in the same dose volume.

Four groups of rats (one vehicle injection group and three test formulation groups at 50, 250, and 1000 μg/kg) from the main study were sacrificed on day 2. The remaining four groups of 10 rats (one vehicle injection group and three test formulation groups) at 50, 250, and 1000 µg/kg) from the recovery study was followed up for a 14-day no-treatment period and sacrificed on day 15 to assess the reversibility of any toxicity.

The following parameters were assessed: mortality, daily clinical examination results, weekly weighing results, weekly food intake results, hematology, biochemistry, urinalysis, organ weighing, and autopsy and macroscopic examination on the day of euthanasia. A large-scale histopathological study was performed for all animals.

There were no treatment-associated deaths in both the solvent administration group and the experimental groups, both during the treatment period and during the recovery period. The test formulation did not cause any treatment related clinical abnormalities in any of the animals during the 2 day and 15 day experimental periods. Comparable weight gain was observed in the treatment and vehicle control groups during the 2 day and 15 day experimental periods. Food intake was similar in the control and experimental groups during the 2 day and 15 day experimental periods. Hematology, blood biochemistry, and urinalysis showed no composition-related abnormalities. No macroscopic abnormalities were found at autopsy in any of the animals. There was no evidence of any test formulation related effect on organ weight and all tissues for which histopathological analysis was performed in this study.

Under study conditions, the test formulation administered intravenously at doses of 50, 250 and 1000 μg/kg to Sprague Dawley rats showed no toxic effect. Thus, the dose that causes no detectable adverse effects (NOAEL) is 1000 µg/kg (1 mg/kg).

NOAEL 1 mg/kg in rats corresponds to a human equivalent dose (HED) of 0.16 mg/kg, or a total dose of 11.2 mg for a 70 kg patient. The maximum allowable total dose in this clinical trial is 0.02 mg (20 micrograms) per patient. Thus, NOAEL represents a safe dose limit of 50 times the maximum human dose of SARTATE. Since the dose of ⁶⁴ Cu-SARTATE administered to patients is activity driven (200 MBq), it is expected that the actual dose of SARTATE administered will likely be a fraction of the total allowable dose, which greatly expands the margin of safety.

Example 9 - In vitro SARTATE genotoxicity

To assess the mutagenic potential of SARTATE, an Ames test was performed, in accordance with the principles of GLP, for solutions of SARTATE-copper complex (SCC) and unlabeled SARTATE ligand (SL) in a 1:1 ratio. The SL:SCC solution did not cause a corresponding fold increase in the average number of revertants per plate relative to the average number of revertants per plate with the corresponding control solvent. The SL:SCC solution showed no cytotoxic effect at the dose levels used with any of the 5 strains tested. The composition was found to be non-mutagenic.

Claims (58)

1. An aqueous formulation for parenteral radiation imaging containing a compound of formula (I), or a salt thereof, in complex with a Cu ion

Formula (I), additionally containing: 3 to 11% (v/v) ethanol; from 0.6 to 1.2% (w/v) sodium chloride and 0.1 to 0.55% (w/v) gentisic acid, or a salt thereof; wherein the composition has a pH value of 4 to 8; and wherein the composition contains an acetate salt. 2. An aqueous composition for diagnosing cancer for parenteral administration, containing a compound of formula (I), or a salt thereof, in complex with a Cu ion

Formula (I), additionally containing: 3 to 11% (v/v) ethanol; from 0.6 to 1.2% (w/v) sodium chloride and 0.1 to 0.55% (w/v) gentisic acid, or a salt thereof; wherein the composition has a pH value of 4 to 8; and wherein the composition contains an acetate salt. 3. An aqueous composition for the treatment of cancer for parenteral administration, containing a compound of formula (I), or a salt thereof, in complex with a Cu ion

Formula (I), additionally containing: 3 to 11% (v/v) ethanol; 0.6 to 1.2% (w/v) sodium chloride; and 0.1 to 0.55% (w/v) gentisic acid, or a salt thereof; wherein the composition has a pH value of 4 to 8; and wherein the composition contains an acetate salt. 4. An aqueous composition according to any one of claims 1 to 3, wherein the composition contains: 10% (v/v) ethanol; 0.9% (w/v) sodium chloride; 0.55% (w/v) gentisic acid, or a salt thereof; and 2.5 mg/ml L-methionine, or its salt; wherein the composition contains an acetate salt; and wherein the composition has a pH value of 6.0. 5. An aqueous composition according to any one of claims 1 to 4, wherein the compound of formula (I) is in the form of an acetate salt. 6. An aqueous formulation according to any one of claims 1 to 5, wherein the gentisic acid salt is sodium gentisate. 7. An aqueous composition according to any one of claims 1 to 6, wherein the Cu ion is a radioisotope of Cu. 8. The aqueous composition of claim 7 wherein the Cu radioisotope is selected from the group consisting of ⁶⁰ Cu, ⁶¹ Cu, ⁶⁴ Cu and ⁶⁷ Cu. 9. A method for obtaining an aqueous composition according to any one of claims 1 to 8, including the steps: i) preparing an acetate salt buffer solution, wherein the buffer solution further comprises ethanol and gentisic acid or a salt thereof; ii) dissolving the compound of formula (I), or a salt thereof, in the buffer solution obtained in step i); iii) adding the Cu ion solution to the solution obtained in step ii); iv) filtering the solution obtained in step iii) on the stationary phase; and v) washing the stationary phase from step iv) with ethanol and brine; to obtain an aqueous composition containing a compound of formula (I), or a salt thereof, in complex with a Cu ion. 10. The method of claim 9 wherein the acetate salt of the buffer solution is ammonium acetate. 11. The method according to claim 9 or 10, wherein the buffer solution contains sodium gentisate. 12. The method according to any one of claims 9 to 11, wherein the solution of the Cu ion is a solution in hydrochloric acid. 13. The method according to any one of claims 9 to 12, wherein the Cu ion is a Cu radioisotope selected from the group consisting of ⁶⁰ Cu, ⁶¹ Cu, ⁶⁴ Cu and ⁶⁷ Cu. 14. The method according to any one of claims 9 to 13, wherein the Cu ion is obtained from the chloride salt of the Cu ion. 15. Aqueous composition for radiation imaging, obtained by the method according to any one of claims 9-14. 16. An aqueous composition for diagnosing cancer, obtained by the method according to any one of claims 9-14. 17. Aqueous composition for the treatment of cancer, obtained by the method according to any one of claims 9-14. 18. A set for obtaining an aqueous composition according to any one of claims 1 to 8, including:

Formula (I) a container containing a lyophilized compound of formula (I) or a salt thereof; a container containing a Cu ion solution; a container containing a buffer solution of ethanol, sodium chloride and gentisic acid, or a salt thereof; and instructions for obtaining an aqueous composition according to any one of claims 1 to 8, including adding a buffer solution of ethanol, sodium chloride and gentisic acid, or a salt thereof. 19. The kit according to claim 18, wherein the container containing the buffer solution of ethanol, sodium chloride and gentisic acid further contains L-methionine, or a salt thereof.

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