JP3301115B2 - Novel chelating agent, complex compound of the chelating agent and metal atom, and diagnostic agent containing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chelating agent, a complex compound of the chelating agent and a metal atom, and a diagnostic agent containing the same. More specifically, the present invention relates to a novel metal chelating agent capable of forming a complex with a metal atom, a complex compound comprising the chelating agent and a metal atom useful for medical diagnosis, and a diagnostic agent comprising the complex compound About.

[0002]

2. Description of the Related Art Information about a lesion is described as an image,
Diagnostic imaging is an indispensable test method for clinical diagnosis. At present, X-ray CT is one of the widely used diagnostic imaging methods.
New and outstanding image diagnostic technologies such as netic resonance imaging (MRI) have been developed, and these new technologies have greatly contributed to the development of the image diagnostic field.

[0003] MRI has recently been introduced into the medical field, and has since rapidly advanced and spread. Unlike conventional X-ray CT, MRI is characterized by no radiation exposure, no problem of exposure, imaging of any cross section, and no bone obstruction. MRI is a nuclear magnetic resonance phenomenon of a substance in the body [normally, the relaxation time (T ₁ ,
T ₂ ) is imaged as a difference in signal strength.
The paramagnetic substance has a relaxation effect of promoting the relaxation phenomenon of protons (protons of water), and serves as a contrast agent for enhancing the contrast of an image. Among them, Gd (trivalent) of rare earth metal is 4
Since it has seven unpaired electrons in the f orbital and has a large number of coordination sites (9 or 10), it has a strong relaxation effect and is a powerful contrast material [RB Lauffer, Chem. Rev., 87,901 (198
7)]. However, Gd (trivalent) is not excreted from the body and toxicity is a problem. For this reason, actually, a known chelating agent, DTPA (diethylenetriamine-pentaacetic acid)
(Gd-DTPA).

[0004]

The utility of Gd-DTPA in clinical diagnosis has been confirmed. However, the drug itself has short blood half-lives, poor tissue selectivity, and high osmotic pressure due to its existence as a divalent anion complex under physiological conditions. are doing. Various approaches to chelating agents have been made to solve these problems (Japanese Patent Application Laid-Open No.
No. 93758, JP-A-1-1395, etc.), a sufficiently satisfactory result has not been obtained. Therefore, the development of new complex compounds, especially the development of chelating agents, is of great significance.

An object of the present invention is to provide a novel compound capable of forming a complex compound having excellent contrast enhancing ability, tissue selection performance, stability, persistence in blood, and high osmotic pressure. It is to provide a chelating agent, a complex compound of the chelating agent and a metal atom, and a diagnostic agent containing the complex compound.

[0006]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted various studies on chelating agents and the like, and found that a compound represented by the following formula [I] and a metal atom are used. The present inventors have found that a complex compound having excellent contrast enhancing ability, tissue selection performance, stability, persistence in blood, and not exhibiting a high osmotic pressure, and have completed the present invention. That is, the present invention is a compound (chelating agent) represented by the following general formula [I], a complex compound comprising the chelating agent and a metal atom, and a diagnostic agent containing the complex compound.

[0007] [Wherein, m is an integer of 1 to 3, R ₁ and R ₂ are the same or different and are each a hydrogen atom or a lower alkyl group, R ₃ ,
R ₄ , R ₅ and R ₆ are the same or different and each is a hydroxyl group or a group: (Wherein A and B are the same or different and each have 6 to 2 carbon atoms)
It means a fatty acid residue of 2 or an alkyl group having 6 to 18 carbon atoms . X and Y are the same or different and represent O or NH. n is an integer from 0 to 6, and when n = 0, Y
Shall not exist. ). However, R ₃ , R ₄ , R ₅
And R ₆ have 2 or 3 hydroxyl groups. When there are two hydroxyl groups, those having both R ₃ and R ₅ are hydroxyl groups and those having both R ₄ and R ₆ being hydroxyl groups are excluded. ]

In the compound represented by the general formula [I], the lower alkyl group may be linear or branched, and has 1 to 4 carbon atoms, specifically, methyl, ethyl,
Examples include propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl and the like. A and B are fatty acid residues (acyl groups) having 6 to 22 carbon atoms. Examples of such fatty acids include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and araquine. Saturated or unsaturated higher fatty acids such as acids, behenic acid, oleic acid, elaidic acid, erucic acid, linoleic acid, linolenic acid and arachidonic acid are exemplified.
The alkyl group having 6 to 18 carbon atoms may be linear or branched, and may be saturated or unsaturated. For example, hexyl, octyl, decyl, dodecyl,
Examples include tetradecyl, hexadecyl, octadecyl and the like.

The compound of the present invention can be produced by various methods, for example, by the method shown in the following reaction scheme. (Wherein, m, n, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , Y,
A and B are as defined above, X ₁ is shows a -NH ₂ or -OH. )

In the above reaction step, the compound [III], which is an acid anhydride, can be converted from the compound [II] by a known dehydration reaction using, for example, acetic anhydride, dicyclohexylcarbodiimide, 1,1'-carbonyldiimidazole and the like. Can be obtained by attaching This reaction can be carried out in a solvent that does not adversely affect the reaction, at about 50 to 100 ° C. for about 3 hours to 3 days. Compound [I] is a compound
It is obtained by reacting [III] with compound [IV]. Compound [IV] can be prepared by a conventional method. For example,
If n is 0, see LD Bergelson's "Lipid Biochemic
al Preparations "1980 ELSEVIER / NORTH-HOLLAND BIOME
What is necessary is just to follow the method of DICAL PRESS p115-122.
When n is not 0, the compound is obtained by reacting the compound [IV] prepared in the case of n = 0 with an alkylating agent having a hydroxyl group or an amino group at a terminal by a conventional method. The reaction between the compound [III] and the compound [IV] can be carried out according to a conventional method for reacting an acid anhydride with an amino compound or a hydroxy compound. For example, the compound [III]
Is dissolved in an organic solvent such as N, N-dimethylformamide (DMF), and the compound [IV] is dissolved in an organic solvent such as methylene chloride and chloroform if necessary, and added at room temperature to about 90 ° C. for 30 minutes. The reaction can be performed for about 5 days. In this reaction, a basic compound such as pyridine, triethylamine, N, N-dimethylaniline and the like may be added.

In this reaction, R _{3 to} R ₆ of compound [I]
In preparing a compound having two hydroxyl groups, compound [IV]
Is used in an amount of 2.0 to 2.3 equivalents based on compound [III]. Also,
When preparing a compound having three hydroxyl groups, compound [IV] is used in an amount of 1.0 to 1.3 equivalents based on compound [III]. When the number of hydroxyl groups is 3, after the reaction, about 1.0 equivalent of water is added, and the reaction is carried out under the above-mentioned reaction conditions, whereby water is added to the unreacted carboxylic anhydride portion to lead to the compound [I]. The addition reaction of water to the carboxylic anhydride moiety is carried out by the compounds [III] and [I
Prior to the reaction of V], the reaction may be performed on compound [III]. The salt of compound [I] can be prepared according to a conventional method. Compound [I] and a salt thereof thus obtained are
For example, it can be isolated and purified by a conventional method such as recrystallization, reprecipitation, and column chromatography. When the chelating agent of the present invention has an asymmetric carbon in the molecule,
All the optical isomers based on the asymmetric carbon and mixtures thereof are included in the present invention.

The complex compound of the present invention comprises the above compound [I] and a metal atom, and the complex compound can be prepared by a method known in the art. For example, a metal oxide or halide compound may be added to water and treated with an equimolar amount of compound [I] or a salt thereof. The compound [I] and a salt thereof can be added in an aqueous solution. However, if the solubility in water is concerned, an organic solvent such as methanol, ethanol, acetone, or dimethyl sulfoxide may be added. Further, the pH can be controlled by adding a dilute acid or a dilute base as needed. Heating and cooling at the time of preparing the complex compound may be appropriately performed. The pharmaceutically acceptable salts of the complex compounds of the present invention may be prepared in the manner described above, while the complex compound is still in solution, while an acid (eg, an organic acid, an inorganic acid, etc.) or a base (eg, an alkali metal hydroxide). object,
Basic amino acids, etc.) to neutralize the complex compound.

The diagnostic agent of the present invention comprises the above-mentioned complex compound or a salt thereof. By appropriately selecting a metal atom of the complex compound, an MRI diagnostic agent, an X-ray diagnostic agent, a nuclear medicine diagnostic agent, an ultrasonic diagnostic agent, etc. Can be used as Among them, M
As an RI diagnostic agent. In this case, preferred as the metal atom for the complex compound are atomic numbers 21 to 29,
42, 44, and 57 to 70. The central metal ion of the complex compound needs to be paramagnetic, and divalent and trivalent ions of the metal atom are suitable. Suitable ions include, for example, chromium (III), manganese (II), iron (II
(I), cobalt (II), nickel (II), copper (II), praseodymium (III), neodymium (III), samarium (III), terbium (III), dysprosium (III), holmium (III), erbium ( III) and ytterbium (III) ions. Especially gadolinium (III), terbium (III), dysprosium (III), holmium (III), erbium (III)
And iron (III) ions.

When used as a nuclear medicine diagnostic agent, the metal atom of the complex compound must be radioactive, and for example, radioisotopes of elements such as gallium, technesium, indium, and yttrium are used. When used as an X-ray diagnostic agent, the metal atom of the complex compound must absorb X-rays. For example, lanthanide series metals, tantalum and the like are used. These complex compounds can also be used as an ultrasonic diagnostic agent.

[0015] Diagnostic agents of the present invention, aqueous solutions, liposome formulations, are provided in the form of such these lyophilized preparations, these preparations using the above complex compound solution, prepared by conventional means on formulation be able to. The lyophilized preparation is used after being dissolved and dispersed in an appropriate diluent at the time of use. To the diagnostic agent of the present invention, a physiologically acceptable buffer (eg, tris (hydroxymethyl) aminomethane or the like) or other physiologically acceptable additives (eg, stabilizers such as parabens) are added. May be. The diagnostic agent of the present invention can be used in the same manner as a conventional diagnostic agent. For example, a solution is orally or parenterally administered to mammals including human beings. The dose is substantially the same as that of a conventional diagnostic agent, and is administered at about 0.001 to 5 mmol / Kg, usually about 0.005 to 0.5 mmol / Kg.

[0016]

The complex compound of the compound of the present invention and a metal atom has properties such as excellent contrast enhancing ability, tissue selection performance, stability, persistence in blood, and no high osmotic pressure. It is useful in medical diagnosis, especially in MRI diagnosis.
The complex compound of the present invention includes various organs such as liver and spleen, tumor sites,
This is advantageous for contrast enhancement of blood vessels and the like. In addition, the compound of the present invention has a suitable fat-solubility and therefore has an affinity for lipid. Therefore, the complex compound of the present invention can be easily converted into a fat emulsion and a liposome by a known method, and the tissue selectivity can be further improved.

[0017]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. Reference Example 1 Synthesis of 1,3-O-distearoylglycerol 1,3-O-di (stearoyloxy) acetone 1,3-dihydroxyacetone dimer 4.64 g
(25 mmol) and 28.4 g of stearic acid (100
(mmol) was dissolved in 150 ml of pyridine, and a solution of 25.0 g (120 mmol) of dicyclohexylcarbodiimide dissolved in 150 ml of chloroform was added thereto, followed by stirring at room temperature for 91 hours. 15.6 g (yield 50%) of the target compound was obtained by acetone recrystallization. 1,3-O-distearoyl glycerol 1,3-di (stearoyloxy) acetone 12.5 g
(20 mmol) was suspended in 200 ml of tetrahydrofuran, and 25.5 ml (26 mmol) of a 1 M solution of BH ₃ in tetrahydrofuran was added dropwise under ice-cooling.
Stir for 2 hours. 8.5 g (67% yield) of the target compound as colorless needle crystals was obtained by acetone recrystallization.

Reference Example 2 2-O- (2-aminoethyl) -1,3-O-dilauri
Synthesis of luglycerol 1,3-O-dilaurylglycerol lauryl alcohol 27.0 ml (118.8 mmol
l) and 5.27 g of sodium hydride (131.6 mm
ol) in 60 ml of anhydrous dioxane,
After stirring for 0 minutes, 3.1 m of epichlorohydrin was added under ice cooling.
1 (39.6 mmol) and heated under reflux for 4 hours.
1,3-O-dilauryl glycerol and 1,2-O-
A mixture of dilauryl glycerol was obtained. 2-O-carbamoylmethyl-1,3-O-dilaurylglycerol 0.79 g (6.9 mmol) of potassium hydride is suspended in 50 ml of anhydrous tetrahydrofuran, and 1,3-O- and 1,2-O-dilauryl are suspended. Mixture of glycerol 2.15
g (5.0 mmol) in anhydrous tetrahydrofuran 12m
and heated under reflux for 1 hour, and then at room temperature, 2.82 g (15.3 mmol) of iodoacetamide.
Was dissolved in 10 ml of anhydrous tetrahydrofuran, and the mixture was heated under reflux for 2 hours. Purification was performed by column chromatography (eluent: hexane-ethyl acetate) to obtain 2-O-carbamoylmethyl-1,3-O-dilaurylglycerol as white crystals. 2-O- (2-aminoethyl) -1,3-O-dilaurylglycerol 3.34 g (7.0 mmol) of 2-O-carbamoylmethyl-1,3-O-dilaurylglycerol are dissolved in 14 ml of anhydrous tetrahydrofuran. And 10M under ice-cooling
3.5 ml (35.0 mmol) of BH ₃ .Me ₂ S complex
Was added and heated under reflux for 3 hours. Purification was performed by column chromatography (eluent: dichloromethane-methanol), and 2.16 g of the target compound was obtained as a colorless oil (yield: 6).
4.3%).

Embodiment 1N- [2- (1,3-distearoyloxy) propoxy
[Cicarbonylmethyl] diethylenetriamine-N,
N ′, N ″, N ″ -tetraacetic acid (hereinafter referred to as compound 1)
U) synthesis Diethylenetriaminepentaacetic acid dianhydride at 75 ° C
3.00 g (8.4 mmol) in 45 ml of anhydrous DMF
It melt | dissolved and 0.15 ml (8.3 mmol) of water was dripped.
Then, the mixture was stirred at the above temperature for 1 hour,
Produces pentaacetic anhydride. Add 1,3-
5.25 g of O-distearoyl glycerol (8.4 m
mol), and the mixture is further stirred at the above temperature for 16 hours.
Purification by recrystallization (chloroform-methanol)
The target compound (colorless amorphous, mp 188.0-190.0 ° C)
4.16 g (50.0% yield) was obtained.¹ H-NMR (CD_ThreeOD + CF_ThreeCOOD) δ: 0.88 (6
H, t, J = 6.7Hz), 1.1-1.5 (56H, m), 1.5-1.8 (4H,
m), 2.41 (4H, t, J = 7.6Hz), 3.2-3.6 (4H, m), 3.6
-4 (6H, m), 4-4.5 (10H, m), 4.5-4.6 (2H, m), 5.
2-5.4 (1H, m) IR (KBr): 3400, 1730, 1620cm^-1

Example 2 N- [2- (1,3-dilauroyloxy) propoxy
Carbonylmethyl] diethylenetriamine-N, N ′,
The combination of N ″, N ″ -tetraacetic acid (hereinafter, referred to as compound 2)
At 75 ° C., 3.00 g (8.4 mmol) of diethylenetriaminepentaacetic dianhydride was dissolved in 45 ml of anhydrous DMF, and 0.15 ml (8.3 mmol) of water was added dropwise. The mixture was stirred at the above temperature for 1 hour and stirred at the same temperature for 1 hour. Generate acetic monoanhydride. Add 1,3-
3.84 g (8.4 mmol) of O-dilauroylglycerol (synthesized according to Reference Example 1) is added, and the mixture is further stirred at the above temperature for 18 hours. Purification was performed by column chromatography (eluent: methanol) and recrystallization (chloroform-methanol), and 2.47 g of the target compound (colorless amorphous, mp 182.0 to 184.0 ° C) (yield: 35.0).
%)Obtained. ¹ H-NMR (CD ₃ OD + CF ₃ COOD) δ: 0.87 (6
H, t, J = 6.3Hz), 1.1-1.5 (32H, m), 1.5-1.8 (4H,
m), 2.38 (4H, t, J = 7.3Hz), 3-3.5 (4H, m), 3.5-4
(6H, m), 4-4.8 (12H, m), 5.2-5.4 (1H, m) IR (KBr): 3400, 1720, 1620 cm ^-1

Example 3 N, N "-bis [2- (1,3-dilauroyloxy)
Propoxycarbonylmethyl] diethylenetriamine-
N, N ′, N ″ -triacetic acid (hereinafter referred to as compound 3)
1.00 g of synthetic diethylenetriaminepentaacetic acid dianhydride
(2.8 mmol) is dissolved in 25 ml of anhydrous DMF.
To this solution was added 2.56 g (5.6 mmol) of 1,3-O-dilauroylglycerol,
Stir for hours. Produced by flash column chromatogram method (eluent: chloroform-methanol) and chromatogram method (eluent: methanol), 1.30 g of the target compound (yellow amorphous, mp 55.0-56.0 ° C)
(36.0% yield). ¹ H-NMR (CDCl ₃ ) δ: 0.88 (12H, t, J = 6H
z), 1.1-1.5 (64H, m), 1.5-1.9 (8H, m), 2.32 (8
H, t, J = 7Hz), 3-3.4 (4H, m), 3.4-3.9 (12H, m),
4-4.6 (10H, m), 5.1-5.4 (2H, m) IR (CHCl ₃ ): 3450, 1735, 1630 cm ^-1

Embodiment 4N- [2- (1,3-dilauryloxypropane) -2
-Yloxy) ethylcarbamoylethyl] diethylene
Triamine-N, N ', N ", N" -tetraacetic acid
Below, referred to as compound 4) Diethylenetriaminepentaacetic acid dianhydride at 80 ° C
0.30 g (0.8 mmol) in 60 ml of anhydrous DMF
Dissolve and add 0.015 ml (0.8 mmol) of water dropwise
After stirring at the above temperature for 1.5 hours,
Produces minpentaacetic acid monoanhydride. In this solution,
-O- (2-aminoethyl) -1,3-O-dilauryl
Glycerol (synthesized according to Reference Example 2) 0.40 g
(0.8 mmol), and the temperature was further increased for 1.5 hours.
Stir with. Column chromatogram method (eluent: meta
And purified with the desired compound (white amorpha).
Mp 180-184.0 ° C) in an amount of 0.31 g (58.5 yield).
%)Obtained.¹ H-NMR (MeOH-d_Four) Δ: 0.90 (6H, t, J = 6.4)
Hz), 1.2-1.4 (36H, m), 1.5-1.7 (4H, m), 3.10-3.
35 (8H, m), 3.35 to 3.55 (12H, m), 3.55-3.75 (11H,
m) IR (KBr): 3400, 1720, 1630cm^-1

Example 5 Preparation of Gd · Compound 2 Complex Compound To a solution of 8.4 g of Compound 2 dissolved in 800 ml of distilled water, 200 ml of a 0.05 M GdCl ₃ solution was gradually added, and an aqueous 0.1N NaOH solution was added. By p
The mixture was stirred while keeping H at around 7.0, and reacted at room temperature for about 1 hour. After the reaction, the reaction solution was lyophilized to obtain 11.2.
g of Gd · Compound 2 complex compound was obtained.

Example 6 Preparation of Gd · Compound 3 Complex Compound The desired complex compound was obtained in the same manner as in Example 5, except that Compound 3 was used instead of Compound 2.

Example 7 Preparation of Fat Emulsified Complex Compound To 10 g of purified soybean oil, 6 g of purified egg yolk phospholipid and 4 g of Gd · Compound 2 complex compound were added, mixed, and added to 175 g.
Then, ml of distilled water and 2.0 g of glycerin were added, and homogenized by a homomixer. Next, high-pressure emulsification was performed using a Manton-Gaurin-type high-pressure homogenizer to obtain a homogenized and extremely fine Gd · Compound 2 fat emulsion having an average particle diameter of 1 μm or less. The osmotic pressure ratio of the obtained Gd · Compound 2 fat emulsion to physiological saline was about 1.0.

Test Example 1 Measurement of Distribution in Rat Organs The aqueous solution of Gd · Compound 2 obtained in Example 5 was administered by bolus injection via the tail vein (dose: 0.02 mmol / k).
g). Thirty minutes, 1, 2, 4 and 6 hours after the administration, the animals were sacrificed with CO ₂ gas, then bled, and each organ (liver, kidney and spleen) was removed. After homogenizing each organ,
Ethanol was added thereto, and the mixture was centrifuged to obtain a supernatant. The amount of the complex compound was measured by a high performance liquid chromatographic method (65% methanol, 1% triethylamine, pH 7.0, C18 column), and the ratio to the dose (% ). As a result, excellent accumulation in the liver (60 to 2 hours after administration)
% Integration rate).

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masakazu Shindome 2-25-1 Odaiya, Hirakata-shi Inside the Central Research Laboratory of Midori Cross Corporation (72) Inventor Hiromichi Mukai 2-25-1 Odaiya, Hirakata-shi Midori Cross Central Research Institute Co., Ltd. (72) Inventor Ikuko Miyagi 2-25-1, Invitation Otani, Hirakata City Incorporated Midori Cross Central Research Institute Co., Ltd. (72) Inventor Takashi Imagawa 2-2-1, Omotani Otani, Hirakata City (72) Inventor Kim Naomoto 18-1-301 Kita, Mayugaoka, Suita-shi (72) Inventor Futa Marukawa 3-1 Pier 3C-4, Hiroji Honcho, Showa-ku, Nagoya-shi 72) Inventor Takashi Kozuka 2-3-15 Sekimori-cho, Suma-ku, Kobe (56) References JP-A-5-186372 (JP, A) JP-A-4-66540 (JP, A) JP 61-204137 (JP, A) JP-A-58-167524 (JP, A) JP-A-63-93758 (JP, A) JP-A-60-36452 (JP, A) (58) Fields investigated (Int. Cl. ^7, DB name) C07C A61K REGISTRY (STN) CA (STN)

Claims (2)

(57) [Claims] 1. The following general formula: [In the formula, m is an integer of 1 to 3, R ₁ and R ₂ are the same or different, and a hydrogen atom or a lower alkyl group, R ₃ , R ₄ , R ₅ and R ₆ are the same or different and are a hydroxyl group. Or group: (Wherein A and B are the same or different and each have 6 to 2 carbon atoms)
It means a fatty acid residue of 2 or an alkyl group having 6 to 18 carbon atoms. X and Y are the same or different and represent O or NH. n is an integer from 0 to 6, and when n = 0, Y
Shall not exist. ). However, R ₃ , R ₄ , R ₅
And R ₆ have 2 or 3 hydroxyl groups. When there are two hydroxyl groups, those having both R ₃ and R ₅ are hydroxyl groups and those having both R ₄ and R ₆ being hydroxyl groups are excluded. Or a salt thereof. 2. A complex compound of the compound according to claim 1 with a metal atom or a salt thereof.