JPH0414084B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a new radioactive diagnostic agent useful for nuclear medicine applications for the purpose of depicting specific organs, detecting specific diseases, and testing the dynamics of physiologically active compounds. That is, the present invention relates to a composition for preparing a radioactive diagnostic agent containing the following polymer compounds (1) to (4) (hereinafter abbreviated as non-radioactive carrier). (1) A polymer compound obtained by condensing an amino group-containing bifunctional ligand compound and an amino group-containing physiologically active compound with the aldehyde group of polyacrolein. (2) A polymer compound obtained by condensing an amino group-containing bifunctional ligand compound and an amino group-containing physiologically active compound with the aldehyde group of polyacrolein, and further reducing the mixture. (3) A polymer compound obtained by condensing and reducing an amino group-containing bifunctional ligand compound to the aldehyde group of polyacrolein, and then condensing it with an amino group-containing physiologically active compound. (4) A polymer compound obtained by condensing and reducing an amino group-containing physiologically active compound to the aldehyde group of polyacrolein, and then condensing it with an amino group-containing bifunctional ligand compound. Another aspect of the present invention relates to a radiodiagnostic agent with a radioactive metal label, which is formed by contacting the composition with a solution containing a radioactive metal salt. For non-invasive nuclear medicine diagnosis for the purpose of depicting specific organs, detecting specific diseases, and testing dynamics,
Conventionally, bioactive compounds labeled with iodine-131 have been widely used. For example, iodine-131-labeled human serum albumin is used for visualization and dynamic testing of the blood circulation system, and iodine-131-labeled human serum albumin is used for the detection of blood clots.
Examples include 131-labeled fibrinogen. However, iodine-131 has a long half-life of about 8 days and emits beta rays in addition to gamma rays, which are useful for nuclear medicine diagnosis, so it has the disadvantage of subjecting the patient to a large amount of radiation exposure. has been pointed out. Attempts continue to be made to obtain useful radiodiagnostic agents by introducing radioactive metals with physical properties more suitable for nuclear medicine diagnosis into physiologically active compounds by other methods. That is, this is a labeling method in which a radioactive metal salt is directly applied to a physiologically active compound in the hope of forming a chelate bond. for example,
A method for obtaining technetium-99m-labeled human serum albumin by reacting an aqueous solution containing technetium-99m in the form of pertechnetate with human serum albumin in the presence of a suitable reducing agent; This includes a method of obtaining indium-111-labeled bleomycin by reacting with an aqueous solution containing indium-111. However, the chelate-forming properties of these physiologically active compounds to be labeled are not necessarily large;
Even in the case of technetium-99m-labeled human serum albumin and indium-111-labeled bleomycin, the stability after in vivo administration is low, and the behavior of radioactivity in the body does not match that of physiologically active compounds, making nuclear medicine diagnosis difficult. It has been pointed out that it is not satisfactory in its intended use. The physiologically active compound referred to here refers to a compound that exhibits a specific accumulation in a specific organ or a specific disease site, or
It refers to a compound that behaves in a unique manner in response to various physiological conditions in the body, and by tracking its behavior in the body, it is expected to provide useful information for various diagnoses. It is a compound. If radioactive metals with excellent physical properties can be stably introduced into such bioactive compounds without impairing the bioactivity of the compounds, extremely useful applications are expected in nuclear medicine diagnosis. In the field of nuclear medicine, there has been a strong desire for the appearance of such a radioactive diagnostic agent. Recently, in order to meet the above demands, diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetriacetic acid (EDTA), 3-oxobutyral bis(N
-methylthiosemicarbazone) carboxylic acid, deferoxamine, 3-aminomethylene-2,4-pentanedione bis(thiosemicarbazone) derivative and 1-(p-aminoalkyl)phenylpropane-1,2-dione-bis We focused on the strong chelate-forming ability of difunctional ligand compounds such as (N-methylthiosemicarbazone) derivatives with various metals, and the reactivity of the amino groups and carboxyl groups at the chain ends of these compounds with various physiologically active compounds. ,
A technique for binding radioactive metals and physiologically active compounds via these bifunctional ligand compounds was proposed (GEKrejcarek, Biochemical &
Biophysical Research Communication 77 2.
581−585 1977, CSHLeung.Int.Appl.
Radiation & Isotopes 29 687−692 1978, Tokukai Sho
56-34634, JP-A-56-125317, JP-A-57-
102820, patent application No. 57-157372). The radioactive diagnostic agent obtained by these methods is a stable labeled compound that retains the activity of the physiologically active compound, and is a drug of great interest for the purpose of nuclear medicine diagnosis. However, the biggest drawback of these known methods and the radioactive diagnostic agents obtained by them is that
Physiologically active compounds with large molecular weights (e.g. fibrinogen with a molecular weight of approximately 340,000 used for blood clot diagnosis and IgG with a molecular weight of approximately 160,000 used in cancer diagnosis)
etc.), the high specific radioactivity required for diagnosis cannot be obtained. This quick solution is based on the bioactive compound 1
This is a method of obtaining a compound with high specific radioactivity by bonding many bifunctional ligands per molecule and coordinating a radioactive metal to the bifunctional ligands in this compound. However, this method is not preferable because it results in denaturation of the physiologically active compound, or a reduction or disappearance of its activity. Furthermore, when a physiologically active compound with a large molecular weight is administered to humans, it is generally desirable to keep the dose as small as possible when considering its antigenicity. For this purpose, a material with high specific radioactivity is required. The present inventors conducted studies from various viewpoints in order to solve the above problems, and found that the method disclosed herein allows bioactive compounds to have high specific radioactivity without denaturing or reducing their activity. It was discovered that a radioactive diagnostic agent can be obtained. The non-radioactive carriers mentioned in (1) to (4) above are compounds with a large number of ligands per molecule. It is characterized by a significantly higher number of molecules compared to compounds into which a ligand compound has been introduced. Moreover, since there are very few sites in which the physiologically active compound is involved in the formation of this non-radioactive carrier, it is possible to provide the desired radiodiagnostic agent with high specific radioactivity without causing denaturation or activity reduction of the physiologically active compound. It is characterized by That is, by an extremely simple method of bringing an aqueous solution containing a radioactive metal ion into contact with a composition for preparing a radioactive diagnostic agent containing this non-radioactive carrier, it is possible to obtain high specific radioactivity and the physiological activity of the original physiologically active compound. We have discovered that it is possible to produce a radioactive diagnostic agent that is a physiologically active compound with a radioactive metal label that retains the following properties. The polyacrolein involved in the present invention is
Schulz et al. (Makromol.Chem., 24, 141 1957)
It is a chain polymer having one aldehyde group as a functional group in the unit molecule produced by the redox polymerization method of acrolein reported by et al. When used in the present invention, the number of structural units is preferably 3 to 4000, preferably 10 to 500. Further, examples of the physiologically active compounds according to the present invention include human serum albumin, fibrinogen, urokinase, proteins such as IgG which is an immune antibody, antibiotics such as bleomycin and kanamycin, hormones, saccharides, fatty acids and their derivatives. It will be done. However, this is not limited to the above, and by tracking the in-vivo behavior, it is possible to develop various types of If the compound is expected to provide useful information for the diagnosis of
It can be used as a physiologically active compound related to the present invention. However, when considering the practicality of the present invention, physiologically active compounds with a molecular weight of about 100,000 or more suitably exhibit their usefulness. Furthermore, in the case of a physiologically active compound that does not have an amino group, it can be used as a physiologically active compound according to the present invention by preparing a physiologically active compound derivative into which an amino group is introduced by an appropriate method as a precursor. The number of molecules of polyacrolein bound to the physiologically active compound may be an amount that does not cause denaturation or activity reduction of the physiologically active compound due to binding, and usually, per molecule of the physiologically active compound,
It should be at least 10 or less, preferably 3 or less. Next, the bifunctional ligand compound that can be used in the present invention is a compound having an amino group that has a strong ability to form chelates with various radioactive metals and an ability to bond to an aldehyde group under moderate conditions. good. Also,
Even in compounds with carboxyl groups that have a strong chelate-forming ability with various radioactive metals and the ability to bond with amino groups, the carboxyl group can be converted to an amino group using hexanediamine, etc., and bonded to an aldehyde group under mild conditions. By providing this ability, it can be used in the present invention. For example, deferoxamine, 3-aminomethylene-
Amino-terminated bifunctional moieties such as 2,4-pentanedione-bis(thiosemicarbazone) derivatives and 1-(p-aminoalkyl)phenylpropane-1,2-dione-bis(thiosemicarbazone) derivatives. difunctional coordination that can be induced into ligated compounds and amino-terminated compounds such as diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetriacetic acid (EDTA), and 3-oxobutyral bis(N-methylthiosemicarbazone)carboxylic acid. child compounds. The number of molecules of these bifunctional ligand compounds bonded per molecule of polyacrolein is arbitrary, but the usefulness of the present invention can be suitably exhibited when it is 5 or more, preferably 10 or more. Finally, the radioactive metal related to the present invention may be any radioactive metal that has physical properties suitable for nuclear medical diagnosis and that forms a stable chelate with a difunctional ligand compound, such as gallium-67, Examples of radioactive metals currently commonly used in the field of nuclear medicine include gallium-68, indium-111, thallium-201, and technetium-99m. However, technetium-99m, which is commercially available in the form of pertechnetate, which is commonly used in nuclear medicine diagnosis,
When a radioactive metal ion, such as a radioactive metal ion such as The present invention can be carried out if a reducing agent such as a stannous salt, which is commonly used for reducing the radioactive diagnostic agent, is previously included in the composition for preparing a radiodiagnostic agent according to the present invention. The implementation of the present invention will be specifically explained. First, regarding the method for producing a non-radioactive carrier that can be used in the present invention, as shown below, the aldehyde group of polyacrolein is reacted with a bifunctional ligand compound and the amino group of a physiologically active compound to form a non-radioactive carrier. Obtain (1). Further, the non-radioactive carrier (2) is obtained by reducing this non-radioactive carrier with a reducing agent such as sodium borohydride. The reaction order of the bifunctional ligand compound and the physiologically active compound with which polyacrolein is reacted is arbitrary, and a reduction operation may be performed in the middle of the reaction. If you want to create a more stepwise reaction,
Isolation and purification operations of intermediates can also be added at the end of each stage reaction. After the reaction, the desired non-radioactive carrier is purified by a conventional method such as column chromatography, gel filtration, or dialysis, which is selected based on the chemical and physical properties of the physiologically active compound. can get. Below, one step-by-step reaction is provided for understanding the present invention.
An example is illustrated very schematically. (In the formula, X and Y represent a bifunctional ligand compound and an amino group-reactive residue of a physiologically active compound, respectively. p, k, l, m, and n represent the number of structural units,
k is 2-4000, l is 1-4000, m is 0-4000, n
is an integer from 0 to 4000. However, p and k+l+
m+n is an integer from 3 to 4000. Also, R is -
_CH2OH , -CH=N-( _CH2 )g-OH and _-CH2
Represents a substituent selected from the group consisting of -NH-( _CH2 )g-OH. In addition, g is an integer of 1-5. ) The non-radioactive carrier shown here is only a linear one, but if the physiologically active compound has two or more terminal amino groups, a crosslinked polymer compound in which the physiologically active compound acts as a crosslinking substance can also be used as a secondary carrier. live. This crosslinked polymer compound also does not interfere with the implementation of the present invention. However, as mentioned above, the number of polyacrolein molecules bound to the physiologically active compound should be at least 10 or less, preferably 3 or less, per molecule of the physiologically active compound. Next, a method for preparing a composition for preparing a radioactive diagnostic agent will be described. The present composition is prepared by dissolving the non-radioactive carrier obtained by the above method in sterile water, physiological saline, or various buffer solutions. Additionally, as necessary, addition of an organic solvent to increase the solubility of the non-radioactive carrier, acid or base to adjust the pH, and addition of a reducing agent or oxidizing agent to adjust the valence state of the radioactive metal ion. , and stabilizers, tonicity agents, and preservatives may be added. As the reducing agent referred to herein, a pharmaceutically acceptable water-soluble reducing agent is used, preferably stannous salt. The stannous salts useful in the practice of the present invention are salts formed by divalent tin, and specifically include, for example, halogen anions such as chloride ions and fluoride ions, sulfate ions, nitrate ions, etc. Refers to salts formed with organic acid residue ions such as heteroinorganic acid residue ions, acetate ions, and citrate ions. The amount of the non-radioactive carrier should be such that the labeling rate of the radioactive diagnostic agent to be finally produced is high enough to cause no practical problems, and it should be within a pharmaceutically acceptable range. Needless to say, this is desirable. Further, the reducing agent such as a stannous salt that may be added as needed may be added in an amount sufficient to reduce the radioactive metal ion to an appropriate valence state and within a pharmaceutically acceptable range. The non-radioactive composition obtained in this way may be subjected to labeling with a radioactive metal in the form of a solution as it is, or in the form of a dry product from which the solvent is removed by a method such as freeze-drying or low-temperature vacuum evaporation. After that, it may be labeled with a radioactive metal. Finally, regarding the method for producing a radioactive diagnostic agent, a radioactive diagnostic agent labeled with a radioactive metal can be prepared extremely simply by simply bringing the composition for preparing a radioactive diagnostic agent into contact with a solution containing a radioactive metal. . The radioactivity of the radioactive metal to be contacted is arbitrary, but when carrying out the intended nuclear medicine diagnosis,
Needless to say, it is desirable that the radioactivity range be such that sufficient information can be obtained, and that the radiation exposure of the subject be as low as possible. As for the administration method, intravenous administration is generally performed, but any other administration method may be used as long as it is advantageous for the physiologically active compound to be labeled to exhibit its activity after administration, and other administration methods may also be used. The present invention will be described in more detail below with reference to Examples. Example 1 Production of a composition containing a non-radioactive carrier in which deferoxamine as a bifunctional ligand compound and human fibrinogen as a physiologically active compound are bound to polyacrolein (1) 125 mg of polyacrolein (hereinafter abbreviated as PA) was added.
It was dissolved in 2.5 ml of dimethyl sulfoxide (hereinafter abbreviated as DMSO). 25 DMSO solution containing 105 mg of deferoxamine (hereinafter abbreviated as DFO) in this solution
ml and then stirred at room temperature for 3 hours. This solution will be referred to as Solution A. In particular, human fibrinogen
200 mg was dissolved in 0.01 phosphate-0.15 saline buffer (hereinafter abbreviated as PBS) of pH 8.4. This solution is B
Make it into a liquid. 5 ml of solution A was added to solution B at 0 to 4°C, and the mixture was stirred and reacted at the same temperature for about 3 hours. After the reaction is complete, in order to remove unreacted reagents, etc. by desalting, the solution is heated to 0 to 4°C against a 0.01 glucose-0.35 sodium citrate solution (hereinafter abbreviated as GLC solution).
After dialysis for 24 hours, Sepharose 4B (4.4φ x 50cm column) was added using GLC solution as eluent.
The desired non-radioactive carrier was obtained. This solution was diluted with GLC solution so that the fibrinogen concentration was 1 mg/ml, and sodium ascorbate was further added to give a fibrinogen concentration of 30 m. After dispensing 3 ml into a vial, it was freeze-dried to prepare a radioactive diagnostic agent. A composition for use was obtained. All of the above operations were performed aseptically. The composition for preparing a radioactive diagnostic agent obtained in this example is a cotton-like freeze-dried product. Example 2 Production of a composition containing a non-radioactive carrier in which deferoxamine as a bifunctional ligand compound and human fibrinogen as a physiologically active compound were bound to PA (2) 125 mg of PA was dissolved in 2.5 ml of DMSO. After adding 2.5 ml of a DMSO solution containing 105 mg of DFO to this solution, the mixture was stirred at room temperature for 3 hours. This solution is A
Make it into a liquid. Separately 200mg of human fibrinogen
Dissolved in PBS at pH 8.4. This solution will be referred to as Solution B.
5 ml of solution A was added to solution B at 0 to 4°C, and the mixture was stirred and reacted at the same temperature for about 3 hours. Furthermore, to the above reaction solution,
7.0 mg of sodium borohydride was added, and reduction was carried out with stirring at 0 to 4°C for about 1 hour. After the reaction, the GLC solution was dialyzed at 0 to 4°C for 24 hours in order to desalt unreacted reagents, etc., and then applied to a Sepharose 4B (4.4φ x 50cm column) using the GLC solution as an eluent. , the desired non-radioactive carrier was obtained. Adjust the fibrinogen concentration of this solution to 1 mg/ml.
The mixture was diluted with a GLC solution, sodium ascorbate was added to the solution to a total volume of 30 ml, and 3 ml of the solution was dispensed into vials, followed by freeze-drying to obtain a composition for preparing a radioactive diagnostic agent. All of the above operations were performed aseptically. The composition for preparing a radioactive diagnostic agent obtained in this example is a cotton-like freeze-dried product. Example 3 Preparation of condensate of 3-oxobutyral bis(N-methylthiosemicarbazone)carboxylic acid-hexanediamine 3-oxobutyralbis(N-methylthiosemicarbazone)carboxylic acid (hereinafter abbreviated as KTS)
After dissolving 132 mg in 5 ml of anhydrous dioxane and cooling to around 10℃, 0.12 mg of tri-n-butylamine was dissolved in 5 ml of anhydrous dioxane.
ml, and 64μ of isobutyl chloroformate were added thereto and stirred at the same temperature for about 50 minutes to obtain a mixed acid anhydride solution. Separately N-tert-butyloxycarbonyl-1.6-
A solution of 104 mg of hexanediamine dissolved in 2 ml of anhydrous dioxane was prepared, and this solution was added to the mixed acid anhydride solution, stirred at around 10°C for about 15 hours, and KTS
A -N-tert-butyloxycarbonyl-1,6-hexanediamine condensate was obtained. By adding 1 to 2 drops of concentrated hydrochloric acid to this condensate solution to lower the pH to 2,
The N-tert-butyloxycarbonyl group, which is a protecting group for the amino group, was removed to obtain the desired KTS-hexanediamine condensate. This condensate was used in the next reaction without being isolated. Example 4 Production of a composition containing a non-radioactive carrier in which KTS is used as a bifunctional ligand compound, human fibrinogen is used as a physiologically active compound, and these are bonded to PA. 200 mg of PA was dissolved in 5 ml of dimethyl sulfoxide, and the KTS-hexanediamine condensate solution obtained in Example 3 was added to this solution, and the mixture was reacted at room temperature for about 3 hours to obtain a PA-hexanediamine-KTS condensate solution. Add 5 ml of this solution to human fibrinogen.
It was added to 50 ml of PBS (PH=8.4) in which 250 mg was dissolved, and the mixture was stirred at room temperature for about 3 hours to react. Thereafter, 12.9 mg of sodium borohydride was added to reduce the Schiff base formed, and stirring was continued for about 1 hour. After the reaction was completed, the reaction solution was placed in a regular dialysis tube and dialyzed against the GLC solution overnight to remove unreacted reagents and the like by desalting. After dialysis, for further purification, GLC solution was used as the eluent, and Sepharose 4B (4.4φ x 50cm
column) to obtain a non-radioactive carrier. Furthermore, flocculent crystals were obtained by freeze-drying this solution. 100 mg of the crystals were dissolved in 160 ml of water to which dissolved oxygen had been removed by blowing nitrogen gas, and 10 ml of a 1 m aqueous stannous chloride solution and 0.6 g of sodium ascorbate were added and completely dissolved. Pass this solution through a filter with a pore size of 0.45 μm.
1.5 ml each was filled into vials whose insides were purged with nitrogen to obtain the desired composition for preparing a radioactive diagnostic agent. All of the above operations were performed aseptically. The composition for preparing a radioactive diagnostic agent obtained in this example is a very pale pale yellow and clear liquid. Example 5 Quantification of bifunctional ligands in non-radioactive carriers DFO forms a 1:1 complex with Fe() and 420 nm
It has maximum absorption in . 420n of DFO−Fe() complex
εmax at m was 2.63×10 ³ . The composition for preparing a radioactive diagnostic agent produced in Example 2 was dissolved in distilled water for injection (hereinafter abbreviated as SPF water) to give a fibrinogen concentration of 1 mg/ml. To this solution was added enough ferric chloride solution to form a 1:1 complex of DFO and Fe(). After leaving this mixed solution for 1 hour, use the same method separately.
The composition dissolved in SPF water was used as a control solution,
Absorbance was measured at 420 nm. Using this method, the amount of DFO per fibrinogen molecule was determined to be 14.8. Example 6 Quantification of fibrinogen in a non-radioactive carrier An attempt was made to quantify fibrinogen in a non-radioactive carrier by high performance liquid chromatography. The column was run using TSK-3000SW, using 0.05 Tris-0.15 saline/hydrochloric acid buffer PH7.4 as the solvent, at a pressure of 100 Kg/cm ² , and at a flow rate of 1.0 ml/min. Gallium-67 was added as gallium citrate to the reaction solution containing side reactants before the purification step in Example 2.
A solution containing 1 mCi was added for labeling. This gallium-67 labeled solution was added under the above conditions.
Analyzed by HPLC. Detection was based on the radioactivity of gallium-67. As a result, the elution pattern of gallium-67 labeled fibrinogen and gallium-67
In addition to -PA-DFO, there were three peaks attributed to gallium-67-DFO. Gallium-67-PA
Based on the area ratio of −DFO peak and gallium −67−DFO peak, there are 18.9 DFO per molecule of PA.
It was confirmed that they were connected. Further, as shown in Example 5, the amount of DFO contained in the non-radioactive carrier produced in Example 2 was 14.8 per fibrinogen molecule. Therefore, HPLC
The number of DFO in PA determined by the method is 18.9 and the content per fibrinogen molecule.
When comparing the number of DFOs (14.8), the number of fibrinogen bound per PA molecule was calculated to be approximately 0.8. Example 7 Production of radioactive diagnostic agent labeled with gallium-67. 2 ml of a solution containing 2 mCi of gallium-67 as gallium citrate was added to the composition for preparing a radiodiagnostic agent produced by the method of Example 2 to obtain a radiodiagnostic agent labeled with gallium-67. The gallium-67 labeled radiodiagnosis obtained in this example was as follows:
It is a very pale yellow clear solution with a pH of approximately 7.8.
It is. Example 8 Production of radiodiagnostic agent labeled with technetium-99m To 1.5 ml of the composition for preparing a radiodiagnostic agent containing stannous chloride produced by the method of Example 4,
1.5 ml of physiological saline containing 3.3 mCi of technetium-99m in the form of sodium pertechnetate was added to obtain a radiodiagnostic agent labeled with technetium-99m. All of the above operations were performed aseptically. The technetium-99m-labeled radiodiagnostic agent obtained in this example is a very pale pale yellow clear liquid. Example 9 Properties of gallium-67-labeled radiodiagnostic agent The gallium-67-labeled radiodiagnostic agent produced in Example 7 was treated with veronal buffer (PH
After electrophoresis (1.7 mA/cm, 15 minutes) using cellulose acetate as a developing solution and a cellulose acetate electrophoresis membrane, scanning was performed using a radiochromato scanner. The position of the radioactivity was recognized as a single peak at a location 0.5 cm on the negative side from the original line, and the position of this radioactivity peak coincided with the color band of human fibrinogen produced by Ponceau 3R. From the above results, the labeling rate of the gallium-67 labeled radiodiagnostic agent produced by the method of the present invention was approximately 100%, and no difference was observed in its charge state from that of human fibrinogen. Example 10 Clotability of radiodiagnostic agent labeled with gallium-67 The radiodiagnostic agent labeled with gallium-67 produced by the method of Example 7 contains 0.05% calcium chloride.
A 0.1 sodium diethyl barbiturate hydrochloride buffer (PH7.3) was added to adjust the fibrinogen concentration to 1 mg/ml. Furthermore, 0.1 ml of 100 unit/ml thrombin was added to this solution, and the mixture was left in an ice bath for 30 minutes. After completely removing the generated fibrin clots, the clotting ability of this drug was measured by counting the fibrin clots and the radioactivity in the liquid from which the fibrin clots had been removed. The clotting ability was 86%. Example 11 Behavior of gallium-67-labeled radiodiagnostic agent in rat bodies 0.2 ml of gallium-67-labeled radiodiagnostic agent produced by the method of Example 7 was taken and intravenously administered to multiple SD female rats. Changes in blood concentration over time and distribution behavior in the body were investigated. Table 1 shows the uptake rate at each measurement time immediately after administration. The extremely high concentration in the blood of the gallium-67-labeled radiodiagnostic agent of the present invention over a long period of time and its distribution to other organs were almost the same as the distribution of conventional iodine-131-labeled fibrinogen in the body.

[Table] Example 12 Behavior of gallium-67-labeled radiodiagnostic agent in the body of a rabbit with a blood clot.
A thrombus was generated, and 0.5 ml of the gallium-67-labeled radiodiagnostic agent produced by the method of Example 7 was administered to the rabbit through the ear vein. Twenty-four hours after administration, a certain amount of blood was collected and the thrombus site was immediately removed. The collected blood and the thrombus site were used as samples, and the radioactivity of both was measured. Radioactivity ratio contained in the same weight of both (thrombus site/blood)
was 7.44±3.41 (mean value±SD value of 10 animals). From the results of this example, example 8, and example 11,
This radioactive diagnostic agent retains almost all of the physiological activity of fibrinogen, and is considered to be extremely useful in nuclear medicine diagnosis for the purpose of detecting blood clots. Example 13 Properties of radiodiagnostic agent labeled with technetium-99m When the labeling rate of the radiodiagnostic agent labeled with technetium-99m obtained in Example 8 was measured in the same manner as in Example 9, it was found to be approximately 100%. , and no difference was observed in its charge state from that of human fibrinogen. Example 14 Clotting ability of radiodiagnostic agent labeled with technetium-99m When the clotting ability of the radiodiagnostic agent labeled with technetium-99m obtained in Example 8 was measured in the same manner as in Example 10, it was found that the starting material It showed a clotting ability of 93% for human fibrinogen. Example 15 Labeling ability of radiodiagnostic agent labeled with gallium-67 SPF water was added to the composition for preparing the radiodiagnostic agent prepared in Example 2 and dissolved, and the amount of fibrinogen was 0.5, 0.75, 1.0, 1.5, and 2.0, respectively. ,3.0mg
To each vial, 1 ml of gallium citrate containing 1 mCi was added as gallium-67. These samples were incubated at room temperature for 1
After standing for a period of time, the labeling rate was measured by the method of Example 7. Furthermore, the labeling rate of gallium-67-labeled fibrinogen obtained using a conventional compound in which DFO was directly bound to fibrinogen was measured by the same method as in this example.
The results are shown in Table 2.

[Table] As shown in Table 2, when using 1 mg of fibrinogen, the non-radioactive carrier of the compound of the present invention can label 97.8% of 1 mCi of gallium-67 in 1 hour, which is a practical labeling time. In contrast, with the conventional method, not only could only 17.0% be labeled under similar conditions, but even if 25.1 mg was used,
Only 83.5% of 1 mCi of gallium-67 can be labeled.
From the above results, by using the compound of the present invention, it is possible to produce a gallium-67-labeled fibrinogen derivative with high specific radioactivity, and this labeled substance can be used for nuclear medicine diagnosis for the purpose of detecting blood clots. It was shown to be extremely suitable for the application. Example 16 Toxicity of radiodiagnostic agent labeled with gallium-67 After appropriately attenuating the radioactivity of the radiodiagnostic agent labeled with gallium-67 obtained by the method shown in Example 7, it was administered to five male and female SD rats. 1 ml per 100 g of body weight (equivalent to 600 times the planned human dose), and 0.5 ml per 1.0 g of body weight for each group of 5 male and female ICR mice (scheduled). (3000 times the human dose), both were administered intravenously. Separately, the same volume of physiological saline was intravenously administered to each group of animals of the same number as a control group. Each of the above animals was kept for 10 days, and body weight changes were recorded every day. No significant difference in body weight change was observed between the radiodiagnostic agent administered group and the control group. After 10 days of observation, all animals were dissected and each organ was observed for abnormalities, but no abnormalities were found in any of the animals. That is, the formulation of the present invention has a dosage of 600 to 3000 of the intended human dose.
No abnormalities were observed when the same amount was administered to two types of experimental animals. Although the present invention has been described with reference to the above examples, those skilled in the art will appreciate that these examples are intended to illustrate the invention and are not intended to limit its scope in any way. You should understand.

Claims (1)

[Scope of Claims] 1. A radiodiagnostic agent preparation comprising a polymer compound obtained by condensing an amino group-containing bifunctional ligand compound and an amino group-containing physiologically active compound with an aldehyde group of polyacrolein. Composition. 2. A composition for preparing a radioactive diagnostic agent characterized by containing a polymer compound obtained by condensing an amino group-containing bifunctional ligand compound and an amino group-containing physiologically active compound with the aldehyde group of polyacrolein and further reducing the same. . 3 Preparation of a radioactive diagnostic agent characterized by containing a polymer compound obtained by condensing and reducing an amino group-containing bifunctional ligand compound to the aldehyde group of polyacrolein, and then condensing the amino group-containing physiologically active compound. Composition for use. 4 After condensing and reducing the aldehyde group of polyacrolein with an amino group-containing physiologically active compound,
A composition for preparing a radioactive diagnostic agent, comprising a polymer compound obtained by condensing an amino group-containing bifunctional ligand compound. 5. The composition for preparing a radioactive diagnostic agent according to claims 1 to 4, wherein the number of constituent units of polyacrolein is 3 to 4,000. 6 Claims 1 to 5, characterized in that the number of molecules of the amino group-containing bifunctional ligand compound is 2 or more per molecule of the amino group-containing physiologically active compound introduced into polyacrolein. A composition for preparing a radioactive diagnostic agent. 7. The radioactive diagnostic agent according to claims 1 to 6, characterized in that the number of polyacrolein bound to the amino group-containing physiologically active compound is 10 or less molecules per molecule of the amino group-containing physiologically active compound. Preparative composition. 8. A radiodiagnostic agent with a radioactive metal label, which comprises bringing the composition for preparing a radiodiagnostic agent according to claims 1 to 7 into contact with a solution containing a radioactive metal ion. 9 Claim 1 further contains a reducing agent in an amount sufficient to reduce the radioactive metal ion to a low valence state that binds to the polymer compound according to Claims 1 to 7. A composition for preparing a radioactive diagnostic agent according to items 7 to 7. 10. A radiodiagnostic agent with a radioactive metal label, which comprises bringing the composition for preparing a radiodiagnostic agent according to claim 9 into contact with a solution containing a radioactive metal ion.