WO2018168643A1

WO2018168643A1 - Method for producing ioflupane

Info

Publication number: WO2018168643A1
Application number: PCT/JP2018/008984
Authority: WO
Inventors: 正人外山; 恵美梅原; 友博木野; 森田　武; 伸介大畑
Original assignee: 日本メジフィジックス株式会社
Priority date: 2017-03-17
Filing date: 2018-03-08
Publication date: 2018-09-20
Also published as: JP7241013B2; JPWO2018168643A1; CN110582494A

Abstract

Provided is a method for producing [123I] ioflupane in a large quantity without deteriorating the quality thereof. The method is a method for producing radioactive-iodine-labeled ioflupane, comprising the steps of (a) reacting a labeling precursor compound with a radioactive iodide ion to produce a radioactive-iodine-labeled compound and (b) purifying the radioactive-iodine-labeled compound produced in step (a) by a high performance liquid chromatography (HPLC) method, wherein the amount of the radioactivity of the radioactive iodide ion used in step (a) is 200 GBq or more at the start time of step (a) and step (b) is carried out using a reverse phase column having a diameter of 7 mm or more and using an aqueous ethanol solution as an eluent.

Description

Ioflupan production method

The present invention relates to a method for producing ioflupan.

[ ¹²³ I] ioflupan ( ¹²³ I) has a high affinity for the dopamine transporter (DAT) in the synapse of striatal dopaminergic neurons, and therefore, a line of ataxia disorder in which nigrostriatal dopamine neurons degenerate. The DAT distribution density in the striatum can be visualized by single photon emission tomography (SPECT), and is used for the diagnosis of Parkinson's disease and other Parkinson's syndrome, which are the above-mentioned ataxia, and dementia with Lewy bodies.

As a method for producing [ ¹²³ I] ioflupan, for example, a trimethyltin body, which is a radiolabeled precursor of [ ¹²³ I] ioflupan, was reacted with radioiodide and then eluted using a 4.6 mm × 300 mm C18 column. It is known in the art to obtain a labeled compound [ ¹²³ I] ioflupan by HPLC purification of the resulting reaction solution with a retention time of 10 minutes using a methanol / water / triethylamine mixture as the solution (Non-patent Documents 1 and 2).

On the other hand, the tropane compound described in Patent Document 1 is known as a tropane compound that is a similar compound to [ ¹²³ I] ioflupan. For example, for [ ¹²³ I] β-CIT, the synthesis time is shortened and the prescription time is simplified. Therefore, after the radioactive iodine labeling reaction, it has been reported that the reaction solution is purified by HPLC using a compact column and an aqueous ethanol solution with a retention time of 5 to 6 minutes (Non-patent Document 3).

International Publication WO95 / 01184

However, the methods described in Non-Patent Documents 1 and 2 have a problem in that methanol having low safety is used in consideration of application to humans. Therefore, by adopting a method that uses safer ethanol as an eluent, it has been approved as a pharmaceutical in 34 countries or regions (as of July 2013), and it has been filed in Japan since 2014. It is sold by people.

However, it is clear from the knowledge of the present inventors that if the amount of radioactivity used for production is increased to improve productivity, the stability of [ ^123I ] ioflupan may be reduced and the standard approved by the Pharmaceutical Affairs may not be satisfied. became. Note that Non-Patent Document 3 and Patent Document 1 do not disclose or suggest any problems relating to the mass production of [ ^123I ] ioflupan.

The present invention has been made in view of the above circumstances, without reducing the quality, and to provide a process for producing a large amount ^{[123 I]} Iofurupan.

As a result of intensive studies to solve the above-mentioned problems, the present inventors obtained [ ¹²³ I] ioflupan by using a high-performance liquid chromatography (HPLC) method using a reaction column obtained by radiolabeling reaction with a column having a large diameter. In addition, it was found that the radiochemical purity standard of [ ¹²³ I] ioflupan can be ensured even when 200 GBq or more of radioactivity is used at the start of production, by suppressing the concentration of radioactivity in the column, The present invention has been completed.

Thus, according to one aspect of the invention,
(A) reacting a labeled precursor compound represented by the following general formula (1) with a radioiodide ion to obtain a radioactive iodine labeled compound represented by the following general formula (2);
(B) purifying the radioactive iodine-labeled compound obtained in the step (a) by a high performance liquid chromatography (HPLC) method,
The radioactive iodide ion used in the step (a) has a radioactivity of 200 GBq or more at the start of the step (a),
The method (b) provides a method for producing radioiodine-labeled ioflupan, wherein a reverse phase column having a diameter of 7 mm or more is used and an aqueous ethanol solution is used as an eluent.

(In the above general formula (1), R is a trialkylstannyl substituent having 1 to 6 carbon atoms in the alkyl chain or a triphenylstannyl substituent.)

(In the general formula (2), X is a radioactive isotope of iodine.)

According to the present invention, since the reaction solution obtained by the radiolabeling reaction is purified by HPLC using a column having a large diameter, the concentration of radioactivity in the column is suppressed and the productivity is improved. Can do.

In this specification, the term “ioflupan” refers to methyl (1R, 2S, 3S, 5S) -8- (3-fluorophenyl) -3- (4-iodophenyl) -8-azabicyclo [3. 2.1] A compound called octane-2-carboxylate or N-ω-fluoropropyl-2β-carbomethoxy-3β- (4-iodophenyl) nortropane.

[(A) Radioiodination step]
In the radioiodination step (a) of the present invention, the labeling precursor compound represented by the general formula (1) is reacted with a radioiodide ion to perform a radioiodination reaction, whereby the general formula (2) To obtain a radioactive iodine-labeled compound represented by the formula:

In the labeling precursor compound represented by the above general formula (1), R is preferably a trialkylstannyl substituent having 1 to 6 carbon atoms in the alkyl chain, and is a trimethylstannyl substituent or triethylstannyl substituent. More preferred are groups, tripropylstannyl groups and tributylstannyl groups.

The labeling precursor compound can be synthesized using, for example, the methods described in Non-Patent Documents 1 and 2 above.

The reaction between the labeled precursor compound and the radioactive iodide ion is preferably performed in a suitable solvent in the presence of an oxidizing agent. Examples of radioactive iodide ions include ions such as ¹²³ I, ¹²⁴ I, ¹²⁵ I, and ¹³¹ I. Of these, ¹²³ I is preferable. The radioiodide ion has a radioactivity of 200 GBq or more at the start of the radioiodination step (a), but the method of the present invention provides high yield even when the radioiodination step (a) is started at 400 GBq or more. Radioiodine labeled ioflupan can be produced at a high rate. Although the upper limit of the radioactivity amount of radioactive iodide ions is not particularly limited, for example, it is 3500 GBq or less, and 2000 GBq or less is practical.

Further, the radioactive iodide ion may be a salt having a counter ion. Examples of the counter ion include an alkali metal ion and an alkaline earth metal. Examples of the salt containing an iodide ion include sodium iodide (NaI), potassium iodide (KI), and ammonium iodide (NH ₄ I ), Iodates of amines such as cesium iodide (CsI), lithium iodide (LiI), triethylamine hydroiodide (Et ₃ N HI), quaternary such as tetrabutylammonium iodide (Bu ₄ NI) An ammonium salt can be exemplified, and among these, radioactive sodium iodide is preferable.

As the solvent, any solvent conventionally used for radioiodination reaction may be used. Acidic solutions such as hydrochloric acid, trifluoroacetic acid, sulfuric acid and acetic acid, alcohol solvents such as ethanol; ether solvents such as tetrahydrofuran (THF); Examples include polar solvents selected from acetonitrile and the like, halogen solvents such as methylene chloride, and nonpolar solvents selected from toluene and the like. These acidic liquids, polar solvents and nonpolar solvents can be used singly or in combination of two or more. When using a polar solvent and a nonpolar solvent, it is preferable to add and use the acidic liquid illustrated above, and the acidic buffer of phosphoric acid and phosphoric acid.

Examples of the oxidizing agent include N-chlorosuccinimide and hydrogen peroxide.

The concentration of the labeled precursor compound in the solvent is not particularly limited, but is preferably 0.3 mg / mL or more from the viewpoint of improving the yield of radioactive iodine-labeled ioflupan, 0.3 to 0.8 mg / mL It is more preferable that

The reaction between the labeled precursor compound and radioactive iodide ions is preferably performed in the presence of non-radioactive iodide ions. In this case, the concentration of non-radioactive iodide ions is not limited, but from the viewpoint of improving the yield of radioactive iodine-labeled ioflupan, it is preferably 0.015 mg / mL or more, and 0.015-0.04 mg / mL. It is more preferable that

The amount of the reaction solution in the radioiodination reaction is not particularly limited, but is, for example, 1 to 5 mL.

The temperature at the time of the reaction between the labeling precursor compound and iodide ion is not particularly limited, but is preferably 10 to 120 ° C, more preferably 15 to 40 ° C.

The reaction time between the labeling precursor compound and the radioactive iodide ion is not particularly limited, but is preferably 5 to 30 minutes.

As a reaction vessel for performing the radioactive iodine labeling reaction, a glass vessel or a plastic vessel resistant to a solvent can be used. Although it does not specifically limit as a heater, For example, a block heater and an air heater are used.

[Purification step (b)]
The purification step (b) of the present invention is a step of purifying the radioactive iodine-labeled compound represented by the general formula (2) from the reaction solution obtained in the step (a) by the HPLC (high performance liquid chromatography) method. Specifically, the reaction solution is packed in a reverse-phase column with an appropriate eluent and then eluted from the reverse-phase column, and the eluate having a retention time at which the radioactive iodine-labeled compound is eluted is collected. And isolating the radioactive iodine-labeled compound.

In the purification step (b), the present invention uses a reverse phase column having a diameter of 7 mm or more as the column and an ethanol aqueous solution as the eluent, thereby eluting the radioactive iodine-labeled compound with a retention time of 12 minutes or less. It is characterized in that it makes it possible. The column temperature during HPLC is preferably 10 to 30 ° C.

In the present invention, from the viewpoint of suppressing the concentration of radioactivity in the column, a reverse phase column having an inner diameter of 7 mm or more is used as the reverse phase column, and a reverse phase column having an inner diameter of 7 to 30 mm is more preferably used. . The length of the reverse phase column is preferably 50 to 200 mm, more preferably 60 to 170 mm from the viewpoint of shortening the holding time and reducing the pressure loss. As a specific example of this reverse phase column, the silyl group is selected from n-ethyl group, n-butyl group, n-octyl group, n-octadecylsilyl group, phenyl group, cyanopropyl group, trimethylsilyl group, and triacontyl group. And a filler using a filler modified with a functional group selected from n-octyl group, n-octadecylsilyl group, and phenyl group. Such reverse phase columns are commercially available from, for example, Waters, Phenomenex, Nomura Chemical, Tosoh, Shiseido, YMC. One column may be used alone, or two or more columns may be linked and used. For example, when two or more are connected and used, the first column is shorter than the subsequent columns, and after removing non-radioactive inorganic substances from the reaction solution and concentrating, eluting and purifying You may make it function as a pretreatment column for introducing into a column. The length of the pretreatment column is preferably 10 to 50 mm, more preferably 10 to 20 mm, from the viewpoint of efficiency of concentration. The second column preferably functions as a purification column and is longer than the pretreatment column. The length of the purification column is preferably 50 to 150 mm, more preferably 100 to 150 mm.

The eluent used in the present invention contains ethanol and water, and a mixture of ethanol and a buffered aqueous solution or an aqueous solution of an alkali metal salt of a weak acid is preferable. As the buffer aqueous solution, phosphate buffer, acetate buffer, citrate buffer, tartaric acid buffer, borate buffer and the like can be used, and among these, acetate buffer is preferable. These buffers can be prepared from a conjugate acid and a conjugate base. For example, an acetate buffer can be prepared from an aqueous solution in which acetic acid and sodium acetate are mixed. Moreover, as the aqueous solution of the alkali metal salt of the weak acid, an aqueous solution of an alkali metal salt of a weak acid such as phosphoric acid, acetic acid, citric acid, tartaric acid, boric acid (for example, sodium salt or potassium salt) is used. A sodium acetate aqueous solution is preferred. Further, the pH of the buffered aqueous solution or the aqueous solution of the alkali metal salt of the weak acid is preferably set so that the elution peak of the radioactive iodine-labeled ioflupan is shortened and the reproducibility is improved. It is more preferable because the degree of separation between iodine-labeled ioflupan and impurities is improved. Moreover, since it can reduce the damage of a reverse phase column by setting it as pH12 or less, it is more preferable. More preferably, the pH is 4.5 to 8.6. The ethanol concentration in the eluent is preferably 30 to 75% by volume, more preferably 50 to 70% by volume, based on 100% by volume of ethanol and the buffered aqueous solution.

Regarding preparation of a sample of radioiodine labeled ioflupan at the time of HPLC execution, it is preferable to prepare a solution containing ethanol from the viewpoint of further reducing the radiolysis of radioiodine labeled ioflupan. More preferably, by preparing the ethanol concentration to be 20% by volume or less and performing HPLC, radiolysis of radioactive iodine-labeled ioflupan can be suppressed without affecting the separation conditions.

Since the eluate eluted in the step (b) is usually a high concentration as it is, from the viewpoint of further reducing the radiolysis of radioactive iodine-labeled ioflupan, an appropriate concentration can be obtained with an appropriate diluent at the time of recovery to the recovery container. It is preferable to dilute to a concentration of 10 GBq / mL or less at the time of elution. Examples of the diluent include a diluent containing ethanol and / or a buffered aqueous solution. As this buffer aqueous solution, what was mentioned above as what can be used for an eluent can be used. The diluent is preferably a mixed solution of ethanol and acetate buffer, and more preferably the same as the eluent. Dilution may be performed by directly storing the eluate containing the iodine-labeled compound eluted from the reverse phase column in a collection container in which the dilute solution is previously stored.

The radioiodine labeled ioflupan obtained in the present invention is finally prepared in various dosage forms such as injections and provided as a preparation. Such a preparation is generally provided in the form of an aqueous solution containing the radioiodine-labeled compound of the above general formula (2), and the aqueous solution diluted with the diluent may be further diluted as necessary, physiologically or pharmaceutically It is prepared by adding various additives that are chemically or chemically acceptable. For example, when preparing an injection, examples of additives that can be included include stabilizers, pH adjusters, physiological saline, and solubilizers. Such an additive may be added in advance to the diluent.

When preparing the radioiodine-labeled ioflupan obtained in the present invention as an injection, the pH range generally used is pH 2 to 10, preferably pH 4 to 8, particularly preferably pH 4 to 6.

When the radioiodine labeled ioflupan obtained in the present invention is prepared as an injection, it can be used as an imaging agent used for various diagnoses in the brain, specifically, in ataxia diseases in which striatal dopamine neurons degenerate. It can be suitably used as an imaging agent for diagnosis by SPECT such as certain Parkinson's disease and other Parkinson's syndrome and dementia with Lewy bodies.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these contents.

(Examples 1 to 6, Comparative Example 1)
(A) Labeling step ^{124 A} 0.1 mol / L sodium hydroxide aqueous solution was added to ¹²³ I obtained by Xe (p, 2p) ¹²³ I reaction to prepare a [ ¹²³ I] sodium iodide solution. To the obtained [ ¹²³ I] sodium iodide solution, an aqueous solution of non-radioactive sodium iodide (NaI in Table 1 shown later) was added. In Examples 1 to 3 and Comparative Example 1, before addition of the non-radioactive sodium iodide aqueous solution, in Examples 4 to 6, after addition of the non-radioactive sodium iodide aqueous solution, the solution was concentrated at 120 ° C. did. Next, an absolute ethanol solution of N-ω-fluoropropyl-2β-carbomethoxy-3β- (4-trimethylstannylphenyl) nortropane (hereinafter SnFP-CT), 50% of 30% hydrogen peroxide, 40 μL of 25% sulfuric acid, and After adding 50 μL of 0.2 mol / L sodium acetate aqueous solution and stirring at room temperature for 10 minutes or more, 150 μL of 30% sodium pyrosulfite aqueous solution and 250 μL of 0.2 mol / L sodium acetate aqueous solution were added to quench the reaction. In Examples 4 to 6, ethanol was added so that the ethanol concentration was 18% by volume.

(B) Purification step Examples 1 to 6 were subjected to high performance liquid chromatography under conditions A below and Comparative Example 1 was under conditions B below to separate and purify ioflupan ( ¹²³ I). Examples 1 to 3 In Comparative Example 1, a recovery container containing 5 mL of acetic acid / sodium acetate buffer solution, and in Examples 4 to 6, 75 mL of acetic acid / sodium acetate buffer solution and 5 mL of ethanol were maintained so as to be maintained at 10 GBq / mL or less at the time of elution. Was eluted into a collection container containing ioflupan to obtain an ioflupan ( ¹²³ I) fraction.
<Condition A>
Precolumn: XBridge BEH Prep C18 (manufactured by Waters), 5 μm, φ10 × 10 mm
Column: XBridge BEH Prep C18 (manufactured by Waters), 5 μm, φ10 × 100 mm
Mobile phase: 0.2 mol / L sodium acetate aqueous solution (pH 8.2) / ethanol = 33: 67
Flow rate: 2.0 mL / min Detector: UV 230 nm
Column temperature: 25 ° C
Retention time: 9 to 11 minutes <Condition B>
Precolumn: Spherisorb ODS2 (manufactured by Waters), 5 μm, φ4.6 × 30 mm
Column: Spherisorb ODS2 (manufactured by Waters), 5 μm, φ4.6 × 250 mm
Mobile phase: 0.2 mol / L sodium acetate aqueous solution (pH 8.2) / ethanol = 33: 67
Flow rate: 0.6 mL / min Detector: UV 230 nm
Column temperature: 25 ° C
Retention time: 14-17 minutes

(C) Formulation step To the fractionated solution obtained in the above step (b), absolute ethanol and acetic acid / sodium acetate buffer solution are added, and the radioactivity concentration of ioflupan ( ¹²³ I) is determined from the date of assay (from the start of production). (After 27 hours), the mixture was adjusted to 74 MBq / mL and 5.0% by volume of absolute ethanol, filtered through a polyethersulfone membrane filter having a pore diameter of 0.22 μm, and washed and sterilized colorless glass syringe-type vial ( The volume was filled with 2 mL) and plugged with a cleaned and sterilized rubber gasket.

[Purity test and radiochemical contamination evaluation]
40 mL of ioflupan, 2.3 mL of 99.5% ethanol, 7.3 mL of 0.1 mol / L acetic acid / sodium acetate aqueous solution and sodium iodide aqueous solution (1 g of sodium iodide dissolved in water to make 100 mL)) 0.4 mL In addition, it was dissolved to prepare an ioflupan standard solution. Then, Iofurupan ^{(123 I)} and Iofurupan standard solution 1: Take appropriate amount of mixed sample solution in 1, ethyl acetate / acetone / triethylamine mixture (57: 43: 1) as the developing solvent, to about the lower end of the thin layer plate In addition to the position of 30 mm height as the original line, the general test method for the drug base was tested by thin layer chromatography, developed about 10 cm from the original line, and then the radioactivity on the thin layer was measured using a chromatogram scanner. It was measured. The results of measuring the radioactivity on the thin layer to determine the percentage of radioactivity Iofurupan to the total radioactivity on the thin layer ^{(123 I) (Rf = 0.5} ~ 0.7) (%). The thin layer plate was prepared using silica gel for thin layer chromatography (with fluorescent agent).

The results are shown in Table 1. In Table 1, SOS is the production start time of Ioflupan ( ¹²³ I). In this example, the production start time is the time when the preparation of [ ¹²³ I] iodide ion was completed in the above (a) labeling step and the concentration was started at 120 ° C. Further, the yield is obtained by attenuation correction. Immediately after the production is immediately after the completion of the above (c) formulation step, the expiration date is 34 to 35 hours after the start of the production. ND indicates that data is not acquired.

From Table 1, in the case of Comparative Example 1 using a column having a diameter of less than 7 mm when the radioactive amount of [ ¹²³ I] iodide ion used is 200 GBq or more at the production start time, the radiation of the obtained Ioflupan ( ¹²³ I) Whereas the chemical purity may not meet the specifications before the expiration date, in Examples 1 to 6 using a column having a diameter of 7 mm or more, the purity of the obtained ioflupan ( ¹²³ I) is 95% or more. Could be maintained. In addition, from the results of Examples 3 to 6, by using a labeled precursor compound of 0.3 mg / mL or more, when the amount of radioactivity of [ ¹²³ I] iodide ion used is 400 GBq or more at the production start time In addition, the yield of ioflupan ( ¹²³ I) could be increased to about 50% or more. Therefore, it was shown that high purity ioflupan can be produced in large quantities by the method of the present invention.

This application claims priority based on Japanese Patent Application No. 2017-052700 filed on Mar. 17, 2017, the entire disclosure of which is incorporated herein.

Claims

(A) reacting a labeled precursor compound represented by the following general formula (1) with a radioiodide ion to obtain a radioactive iodine labeled compound represented by the following general formula (2);
(B) purifying the radioactive iodine-labeled compound obtained in the step (a) by high performance liquid chromatography,
The radioactive iodide ion used in the step (a) has a radioactivity of 200 GBq or more at the start of the step (a),
The step (b) is a method for producing radioactive iodine-labeled ioflupan, which is performed using a reverse phase column having a diameter of 7 mm or more and using an aqueous ethanol solution as an eluent.

(In the above general formula (1), R is a trialkylstannyl substituent having 1 to 6 carbon atoms in the alkyl chain or a triphenylstannyl substituent.)

(In the general formula (2), X is a radioactive isotope of iodine.)
The method for producing radioactive iodine-labeled ioflupan according to claim 1, wherein the eluent is a mixed solution of ethanol and an aqueous solution containing sodium acetate.
The eluent in the step (b) is a mixture of ethanol and a buffered aqueous solution or an aqueous solution containing a weak acid alkali salt, and the pH of the buffered aqueous solution or the aqueous solution containing the weak acid alkali salt is 4 to 12. Item 3. The method according to Item 1 or 2.
The production method according to any one of claims 1 to 3, wherein in the step (a), 0.3 mg / mL or more of the labeled precursor compound and the radioactive iodide ion are reacted in the presence of a solvent. .
The manufacturing method according to claim 4, wherein in the step (a), the labeled precursor compound and the radioactive iodide ion are reacted in the presence of 0.015 mg / mL or more of non-radioactive iodide ion.
The production method according to claim 4 or 5, wherein the radioactive iodide ion used in the step (a) has a radioactivity amount of 400 GBq or more at the start of the step (a).
The eluate containing the radioactive iodine-labeled compound eluted in the step (b) is received in a collection container, and the radioactive iodine-labeled compound is diluted to a concentration of 10 GBq / mL or less. The production method according to item.
The recovery container contains a diluent for diluting the radioactive iodine labeled compound in advance, and the radioactive iodine labeled compound is received by receiving the eluate eluted from the reverse phase column. Is diluted to a concentration of 10 GBq / mL or less.
In the step (b), after preparing the radioactive iodine-labeled compound obtained in the step (a) so that the ethanol concentration is 20% by volume or less, purification by the high performance liquid chromatography method is performed. The manufacturing method according to any one of 1 to 8.