WO1995031220A1 - Contrast medium for magnetic resonance imaging - Google Patents

Contrast medium for magnetic resonance imaging Download PDF

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Publication number
WO1995031220A1
WO1995031220A1 PCT/JP1995/000894 JP9500894W WO9531220A1 WO 1995031220 A1 WO1995031220 A1 WO 1995031220A1 JP 9500894 W JP9500894 W JP 9500894W WO 9531220 A1 WO9531220 A1 WO 9531220A1
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Prior art keywords
iron oxide
magnetic
group
magnetic resonance
mr
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PCT/JP1995/000894
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French (fr)
Japanese (ja)
Inventor
Kazuo Yagi
Junji Nakamura
Original Assignee
Otsuka Pharmaceutical Co., Ltd.
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Priority to JP6/98735 priority Critical
Priority to JP9873594 priority
Application filed by Otsuka Pharmaceutical Co., Ltd. filed Critical Otsuka Pharmaceutical Co., Ltd.
Publication of WO1995031220A1 publication Critical patent/WO1995031220A1/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y5/00Nanobiotechnology or nanomedicine, e.g. protein engineering or drug delivery
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61KPREPARATIONS FOR MEDICAL, DENTAL, OR TOILET PURPOSES
    • A61K49/00Preparations for testing in vivo
    • A61K49/06Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations
    • A61K49/18Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations characterised by a special physical form, e.g. emulsions, microcapsules, liposomes
    • A61K49/1818Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations characterised by a special physical form, e.g. emulsions, microcapsules, liposomes particles, e.g. uncoated or non-functionalised microparticles or nanoparticles
    • A61K49/1821Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations characterised by a special physical form, e.g. emulsions, microcapsules, liposomes particles, e.g. uncoated or non-functionalised microparticles or nanoparticles coated or functionalised microparticles or nanoparticles
    • A61K49/1824Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations characterised by a special physical form, e.g. emulsions, microcapsules, liposomes particles, e.g. uncoated or non-functionalised microparticles or nanoparticles coated or functionalised microparticles or nanoparticles coated or functionalised nanoparticles
    • A61K49/1827Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations characterised by a special physical form, e.g. emulsions, microcapsules, liposomes particles, e.g. uncoated or non-functionalised microparticles or nanoparticles coated or functionalised microparticles or nanoparticles coated or functionalised nanoparticles having a (super)(para)magnetic core, being a solid MRI-active material, e.g. magnetite, or composed of a plurality of MRI-active, organic agents, e.g. Gd-chelates, or nuclei, e.g. Eu3+, encapsulated or entrapped in the core of the coated or functionalised nanoparticle
    • A61K49/1851Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations characterised by a special physical form, e.g. emulsions, microcapsules, liposomes particles, e.g. uncoated or non-functionalised microparticles or nanoparticles coated or functionalised microparticles or nanoparticles coated or functionalised nanoparticles having a (super)(para)magnetic core, being a solid MRI-active material, e.g. magnetite, or composed of a plurality of MRI-active, organic agents, e.g. Gd-chelates, or nuclei, e.g. Eu3+, encapsulated or entrapped in the core of the coated or functionalised nanoparticle having a (super)(para)magnetic core coated or functionalised with an organic macromolecular compound, i.e. oligomeric, polymeric, dendrimeric organic molecule
    • A61K49/1863Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations characterised by a special physical form, e.g. emulsions, microcapsules, liposomes particles, e.g. uncoated or non-functionalised microparticles or nanoparticles coated or functionalised microparticles or nanoparticles coated or functionalised nanoparticles having a (super)(para)magnetic core, being a solid MRI-active material, e.g. magnetite, or composed of a plurality of MRI-active, organic agents, e.g. Gd-chelates, or nuclei, e.g. Eu3+, encapsulated or entrapped in the core of the coated or functionalised nanoparticle having a (super)(para)magnetic core coated or functionalised with an organic macromolecular compound, i.e. oligomeric, polymeric, dendrimeric organic molecule the organic macromolecular compound being a polysaccharide or derivative thereof, e.g. chitosan, chitin, cellulose, pectin, starch

Abstract

A contrast medium for magnetic resonance imaging (MRI contrast medium) comprising fine magnetic iron oxide particles having an average particle diameter of 2-20 nm and the properties of a single magnetic domain as the core, with its surface being coated with a polysaccharide having functional groups selected from the group consisting of sulfone, ketone, amino, carboxyl and alkyl groups. When injected into the blood vessel in magnetic resonance angiography, this medium enhances the signal intensity of the blood vessel to thereby give a white image. It can be used also in the liver as the MRI contrast medium, because it can lower the signal intensity of the liver after the lapse of a given time from the injection. The medium is easy to inject and has high stability and safety as a pharmaceutical preparation. In addition, it can reside in the blood vessel for long and does not exude therefrom, so that it enables contrast enhancement in the blood vessel and facilitates the setting of a proper inspection time.

Description

Specification

Magnetic resonance contrast agent

Technical field

The present invention, biological magnetic resonance imaging (MR I) and its by improving the utility of the diagnostic magnetic resonance imaging agent (hereinafter, referred to as MR I contrast agents) relates, particularly useful MR I contrast as MR angiographic agent agent on.

BACKGROUND

Magnetic iron oxide particles having magnetism such as ferrite has attracted attention as a fit, MR I contrast agent having the properties of superparamagnetic.

However, conventional magnetic iron oxide fine particles, spins in MR I - lattice relaxation time (hereinafter, referred to as T 1) in comparison with the spin - spin relaxation time (hereinafter, referred to as T 2) is very Umate large, the convergence of relaxation it takes time, signal strength is reduced by disrupting the station plant field area iron oxide particles are present, an image of a peripheral organ or going missing image is black, there is the diagnosis difficult.

Further, the magnetic iron oxide fine particles are intact, poorly soluble, and has an extremely strong contact Keru toxic for intravenous administration, could not be used in vivo as a medical. Therefore, MRI contrast agents have been known that the magnetic iron oxide coated with dextran or dextran derivatives. For example Adobansudo-magnetic Tex Co. "AM 1 - 2 5" magnetic iron oxide contrast agents, such as is for effective superparamagnetic, it is known that toxicity is reduced by coating with dextran there.

However, the conventional dextran-based magnetic iron oxide contrast agents can not be retained longer in the body circulation (vascular system), it is rapidly taken up into the liver or spleen. Further, since the particle size is as large as 1 5 0~3 0 0 m, hypotension shock, there are side effects such as allergic reactions. For example, intravenous administration at infusion, when performing MR I photographing of liver after 1 hour, it is confirmed that the blood pressure decrease during shock, pulsation reduction occurs, sometimes death. Also, conventional contrast agents, since merely had a magnetic iron oxide coated with dextran ', rather weak binding to the iron oxide and dextran, therefore easily dissociate in the blood, Ya stability during heat sterilization long-term stability was also poor. Further, the conventional magnetic iron oxide based contrast agents from the blood liver, are rapidly absorbed into the organs, such as spleen, can not stay long in the vessel, be used as a MR I angiography agent is very difficult there were.

The main object of the present invention, originally by enhancing the signal intensity of intravascular blood flow is no signal on the MR image, by imaging blood flow, blood, heart, brain vasculature, abdominal vasculature, cardiovascular, such as lymphatics, der possible to enable imaging of organs, along with enable easy diagnosis by connexion lesions, providing MR I contrast agents having high safety and stability.

Another object of the present invention has a long residence time in the vessel, there is no bleeding from the blood vessel into the tissue as in conventional G d-DTPA contrast agent, blood vessels that the contrast between the blood vessels and tissue 鲜明to provide a MR I contrast agents for imaging (angiography).

Disclosure of the Invention

The present inventors have made intensive studies to solve the above problems, the magnetic iron oxide fine particles as a core, which by coating with a polysaccharide comprising an outer shell, heart, vasculature MRI, cine MR increasing the T 1 in I, it was found surprising fact T 1 weighted images which has the effect of reducing the T 2 is obtained. Further Upon formulation, by using a polysaccharide having a specific functional group as a coating agent for magnetic iron oxide fine 拉子, affinity for water of the iron oxide particles is increased, which increases the in vivo affinity , together with the adverse effects of long-term residence in the blood vessel is alleviated, the load of the living body is reduced, it becomes a high safety, moreover magnetic certain functional groups of the polysaccharide to be a shell of iron oxide particles to firmly bond by reacting with, connexion high Les cotton long term, indicating the stability.

In particular, the present inventors have found that by combining the magnetic iron oxide particles having an ultimate single domain structure, the manufacture of MR I contrast agents that can use fine particles having the properties of superparamagnetic material as a strong paramagnetic material succeeded in. The magnetism in the existing area of ​​the iron oxide particles NMR signal intensity is enhanced, such as the heart, brain vasculature, can be white contrast abdominal vasculature such. Thus, MR I contrast agents of the invention, usable der Ru as T 1 relaxation time by shortening T 1 signal strength emphasizing T 1 enhancement agent of the hydrogen atoms in the body. Iron oxide particles having a structure of single magnetic domain does not exist conventionally, but it is first created by the current MR I contrast agents.

That, MR I contrast agents of the present invention has an average particle size of the core of magnetic iron oxide fine particles having a single domain structure in 2 to 2 0 nm, the surface of the core, a sulfone group (sulfuric acid group), a ketone group, amino group, that is coated with a polysaccharide having a functional group is Ru selected from the group consisting of carboxyl group and an alkyl group and Toku徵.

That, MR I contrast agents of the invention, because not cover the single domain fine iron oxide particles with a polysaccharide, less likely to occur with time changes in the particle with the superparamagnetic effect, the heart with blood flow imaging of the organ's vasculature That leaves at suitably used as MR I contrast agents for angiography.

Further, since the oxide-coated iron particles with polysaccharides, biological reactions and toxicity problems are solved, further improves the affinity, such as blood. And power, also, MR I contrast agents of the invention, liver, by absorption into an organ such as the spleen is delayed, there is an advantage cormorants have to be able to stay longer in the blood vessel. Furthermore, since the average particle diameter of the magnetic iron oxide fine particles used in the present invention is very fine and 2 to 2 0 nm, even staying longer in the blood vessel, hypotension, no problems such as shock, safety to a living body high sex.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an explanatory diagram showing an MR I contrast agents of the present invention coated with magnetic iron oxide fine particles polysaccharide,

2 is a magnetization curve of Kondoroichin sulfate one magnetic iron oxide complex obtained in Production Example 1 a view to graph,

Figure 3 is a transmission electron micrograph (T EM, magnification: 1 0 0 0 times) of chondroitin sulfate one magnetic iron oxide complex obtained in Production Example 1 was,

Figure 4 is a photograph showing the MR angiography image near the heart and the aorta of the rabbit was imaged under the same conditions using different contrast agents, photo right the angiography Ichizo by MR I contrast agents of the present invention, the left There is shown an angiography Ichizo by conventional G d-DT PA respectively.

BEST MODE FOR CARRYING OUT THE INVENTION

The magnetic iron oxide particles in the present invention, for example, the general formula:

(MO) m · F e 23 (wherein, M represents a divalent metal atom, m is a number of 0 m 1.)

In ferrite represented, and the like. Examples of the divalent metal atom, for example magnesium © 厶, calcium, manganese, iron, nickel, cobalt, copper, zinc, Sutoronchi © beam, barium and the like. Especially M is a divalent magnetic iron oxide in the case of iron (e.g. magnetite F e 3 4, 7 - F e 2 0 3 , etc.) are preferably used in the present invention. Incidentally, the magnetic iron oxide particles in the present invention is also wrapped including those containing water of crystallization.

Magnetic iron oxide particles in the present invention has an average particle size. 2 to 2 0 nm, preferably. 3 to 8 nm.

The single domain structure in which the magnetic iron oxide particles have, no magnetic wall such as a conventional magnetic, refers to a structure with only one magnetic domain. The reason no domain walls as is because the average particle diameter of the magnetic iron oxide as described above is very small to a molecular level. In such a single magnetic domain structure, the domain wall does not appear residual magnetization found in a typical magnetic hysteresis curve can by moving when subjected to external magnetic fields as a normal magnetic (to be described later Example Referring to Figure 2 in). Thus, magnetic iron oxide particles having such a single magnetic domain structure because they act as super as paramagnetic or strong paramagnetic, can be suitably used as T 1 enhancement agent.

The polysaccharide having a specific functional group in the present invention, Roh rather preferably is water-soluble, for example, chondroitin 4 monosulfate, chondroitin 6-sulfate, hyaluronic acid, chitin, to,. Phosphorus, sialic acid, Noirami phosphate, to Asechiru Kisosamin, Inurin, Agarosu, dextran sulfonic acid, polysaccharide or 厶Ko polysaccharides such as N- Ryo cetyl glycolate Sa amine derivatives. Furthermore, a sulfone group substituted, amino Moto置conversion, an alkyl group substituted or ketone group (e.g., - CH 2 -C0-CH 2 CH 3,

Dextrins such as -CH 2 -0C0-N 2) was substituted also be preferably used.

Examples of the alkyl group include a methyl group, Echiru group, propyl group, isopropyl group, n- butyl group, t- butyl group, an alkyl group having a carbon 1 to 6, such as a pentyl group, a hexyl group.

These polysaccharides have a number average molecular weight of from about 5 0 0-3 00 000, preferably about 1 0 0 0-50000, more preferably about 1 5 0 0 is suitably lies within 30,000 range is there. Moreover, polysaccharides various oligosaccharides (glucose, maltose Ichisu, lactose, cellobiose, maltotriose, etc. melibiose), it may be used as a mixture such as pullulan 0

Furthermore, the polysaccharides, function as a therapeutic agent contain a variety of receptors one with integrated specificity for abnormal cells such as tumor cancers can be imparted. The receptions As evening scratch, examples Ebashuju monoclonal antibodies of various proteins, immune-related agents (immune cell activation, activation materials) and the like. Thus, for example, diagnosis of tumors, other therapeutically valuable, there killer cell induction effect.

The production of MR I contrast agents of the invention, a first method is first reacted with magnetic aqueous zone le consisting only of iron oxide particles prepared then polysaccharides, first synthesized in one step in the presence of the polysaccharide there is a second method.

In the first method, to prepare an aqueous Bull comprising only magnetic iron oxide particles. The preparation of the water soluble sol leaving in be exemplified a Al force Li coprecipitation Ya Ion exchange resin method.

The alkali coprecipitation method, for example, the first iron salt and a second iron salt at a molar ratio of 1: 3

To 2:. About 0 includes in the order of one ratio and the 1-2 moles of aqueous, N a OH, then mixed as KOH, NH 4 〇 ^ 1 like base and a 11 is about 7 to 1 2, aged pressurized heat if necessary, then separated and the resulting magnetic iron oxide, washed with water, redispersed in water by adding a mineral acid such as hydrochloric acid to p H of the solution is from about 1 to 3 it is possible to obtain magnetic iron oxide aqueous Bull.

On the other hand, the ion exchange resin method, for example, ferrous salt and ferric salt and about i:. About 0 containing 2 molar ratio 1 to 2 moles of an aqueous solution, stirring strongly basic exchange resin slurry one after addition while maintaining the p H of about 8-9, a mineral acid such as hydrochloric acid added until p H is about 1 to 3 and then obtain a magnetic iron oxide aqueous Bull by the resin is filtered off it can.

These aqueous sol, optionally dialyzed, ultrafiltration, may be purified or ^ reduced by centrifugal separation.

The reaction between the magnetic iron oxide aqueous Bull polysaccharide is usually carried out by mixing them in a predetermined ratio and heated. Ratio of the magnetic iron oxide aqueous sol and polysaccharide approximately in a weight ratio 1: 1 to 1: may be about 6. The reaction may be carried 1 0 minute to about one 0 hours at a temperature of room temperature to about 1 2 0 ° C, usually it is sufficient for about 1 hour or so heated to reflux. The concentration of magnetic iron oxide in the reaction solution is usually about 0. 1~1 O wZ v% as iron, and preferably from in the range of about 1~5 w / v%.

After the reaction, using a known method such as ultrafiltration, subjected to purification procedures to separate the polysaccharides or a low molecular compound unreacted obtain an aqueous Bull having a predetermined purity and concentration. In which this was added methanol, ethanol, a solvent such as acetone, magnetic iron oxide fine particles - polysaccharide complexes is preferentially precipitate deposited, which was separated and then the precipitate was redissolved in water, running water dialyzed, and concentrated under reduced pressure to optionally obtain an aqueous Bull of the complex. Then, if necessary, centrifugation, filtration, or the like may be performed p H adjusting. MR I contrast agents of the present invention obtained in furniture, an average particle size of about 3 0 to 2 0 0 nm, the magnetic iron oxide fine particles are core has an average particle size of from about. 2 to 2 0 nm. These particle size is measured by dynamic light scattering method. In addition, you Keru magnetization in 1 tesla of MR I contrast agent is in the normal range of about 2 0~1 5 0 emu per iron 1 g.

A second method for preparing the MR I contrast agents of the invention, the presence of a polysaccharide having a specific functional group, the mixed iron salt solution of divalent iron salts and trivalent iron salts and the aqueous base mixed and in which the reaction. Polysaccharides, order of addition of the mixed iron salt solution and the aqueous base is not limited particularly.

The mixed iron salt solution is about a ferrous salt and a ferric salt in a molar ratio of 1: 4 to 3: 1, preferably from about 1: 3 to 1: dissolving in an aqueous medium at a ratio of 1 it can be obtained by. The concentration of the iron salt solution is generally about 0. 3 mol, preferably about 0. Suitably, 5 is 2 moles.

The iron salts, such as hydrochloric acid, Ru can be mentioned salts of sulfuric acid, mineral acids such as nitric acid. As the base, N A_〇_H, alkali metal hydroxides such as K_〇_H, ammonium NiRyo, Toryechiruamin, raised and amines such as Torimechiruamin, a mixture of two or more if necessary using good record, even if the.

The amount of the polysaccharide to be used is about 1 to 1 5 times by weight based on the weight of the iron salt used, rather preferably is preferably set to 3 to 1 0-fold.

Addition and mixing of the aqueous solution, the row with heating from room temperature to about 1 0 0 ° C under stirring - i-

Ukoto can, after adjusting the p H was added base or acid as required, about 6 0 to 1 2 0 ° temperature for about 〖0 minutes to 5 hours and C, the heating is preferably about 1 hour instead It reacted by Rukoto flow. The resulting reaction mixture was purified as in the first method, if necessary p H adjusting, for concentrating, further filtration.

In these methods, 2 of the particle size of the magnetic iron oxide particles described above to be generated

In order to adjust in the range of 2 0 nm, it is necessary following synthesis conditions are satisfied.

(1) a high temperature is reacted with ferric chloride and ferrous chloride under high p H is an aqueous solution.

(2) polysaccharide was added under high p H, rapidly lowering while p H maintaining the high temperature.

(3) The reaction for oxidation performed under an atmosphere of an inert gas (such as argon). (4) it is removed by centrifugation coarse particles.

(5) adjusting the particle size membrane filter.

(6) perform dialysis in pure water at least 2 0 hours.

The particle size of the complex formed is more controllable to adjust the reaction time and the reaction temperature.

The ratio of the polysaccharide and the magnetic iron oxide particles but is not limited particularly, generally iron 1 parts by weight per polysaccharide in the magnetic iron oxide is approximately 0.1 to 5 parts by weight, rather preferably 0 . it can contain in the range of 2-3 parts by weight.

Even when by any method of the first and second methods, 5 0 molar% divalent metal salt below other ferrous salt, such as magnesium, calcium, manganese, Stevenage gel, cobalt, copper, leaving at be replaced with one or more salts such as zinc.

Wherein the polysaccharide and the magnetic iron oxide particles, reacting by the above method, the compound bound to each other. More specifically, the core of magnetic iron oxide particles has the form of the surface polysaccharide was firmly coated. This can, for example, fractionating the reaction product by gel column, than the elution position of the polysaccharide elution peak was observed on the polymer side, the force, both the sugar and the iron is detected by partial folding peak Tsuso ing.

T 1 relaxation ability of the MR I contrast agents of the invention, one crotch about 2~5 0 (sec - mM) 1 , is good Mashiku is about 3~3 O (sec 'mM) _ 1. Further, T 2 relaxation ability is generally from about 3 to

3 0 O (sec - m) is preferably about 6~3 0 (sec · mM). MR I contrast agents of the present invention are preferably used in the form of an aqueous sol. Since the concentration of magnetic iron oxide fine particles one polysaccharide conjugates in the aqueous sol to exhibit paramagnetic effect in very small amount as the force which will be described later can be appropriately set in consideration of the dosage to the living body, typically iron conversion calculated at about 9 0 ax mol / ^ ~ Ryo 2 0 ^ mol (9 0 nmol / ~ 7 2 0 nmol / m ヽ preferably sufficiently about 1 8 0 / ^ ~3 6 0 mol / ^ in. the , in the preparation of aqueous sols, for example an inorganic salt such as sodium chloride, monosaccharides such as dextrose, Man'ni' DOO, sugar alcohols such as sorbitol, acetate, lactate, Kuen salts, organic acid salts such as tartrate , it can be added phosphate buffer, tris buffer and the like as appropriate.

MR I contrast agents of the present invention is to use a magnetic iron oxide ultrafine particles by polysaccharides comprising an outer shell having a specific functional group, the superficial effect of a superparamagnetic material with it, it is possible to use as strong paramagnetic T 1 contrast agent.

Further, according to electron microscopy, a polysaccharide as the outer shell has an elastic structure in which a hair ball-shaped or coil-like mass, has a very long molecular structure if Hikinobase this and forces, et al, rather difficulty is decomposed in vivo, Ru can exist long as dragees in blood. That, MR I contrast agents of the present invention, as shown in FIG. 1, the magnetic iron oxide fine particles 1 and the core, firmly in a number of the polysaccharide chains 2 of the magnetic iron oxide fine particles 1 surface so as to cover the surface It is bound to. Therefore, the iron oxide particles 1 and polysaccharide chains 2 hardly dissociated even blood fluid can be present longer in the blood.

Accordingly, poles in the administration of trace amounts are expressed paramagnetic effect, as a vascular contrast medium, there have can be suitably used as T 1 tissue relaxation contrast agent. Therefore, the amount of the MR I contrast agents of the present invention, when the iron concentration in terms of 1 8 0 mol Bruno ^ ~ 3 6 0 mol ^ the aqueous sol is about 1 to 2 cc Zk g intravenously it is appropriate. The dose of General of iron terms of about 5 ^ moI ~ 4 0 \ / i iron terms, preferably about 1 0 mol Z ^ ~2 0 mol Z.

Methods of administration include, intravenous, intraarterial, intravesical, intramuscular, subcutaneous injection to such, but such Note entry is preferred, oral administration, etc. can be enteral administration.

MR I contrast agents of the present invention, there is characteristic that staying longer in the bloodstream liver, no longer difficulty absorbed into organs such 陴 can stay longer in the vascular system, which is a feature of the dragee. At that time, polysaccharide surface sulfonic group is an outer shell (single S 0 3 H, sulfate group), by a particular functional group, such as a ketone group present, the saccharification coalesce recognition of biological defense mechanisms It was recognized, delaying the decomposition absorption of the magnetic iron oxide. Further, by polysaccharide shell structure by reaction with the magnetic iron oxide, the side in relation to the enzyme in the polysaccharide relatively shall be subject to a long time to be estimated (e.g. bind to degraded and absorbed in vivo chain is less likely to be cut). Therefore, the can suitably perform shooting MR I against organ takes a relatively long time to reach of the contrast agent, there is an advantage that it becomes easy setting of inspection time. Name your, as the shooting target organs, blood vessels is the main target. Unlike conventional G d-chelating contrast agents, there is no transmission from the vessel, it is suitable for contrast enhancement of blood vessels and surrounding tissue. In addition, liver, lymph vessels, brain, spleen, Oh is also possible contrast for, such as the digestive tract

At that time, MR I contrast agents of the invention, blood pressure lowering, it is rather name that causes such shocks, with the safety of such can bolus intravenous.

In particular, MR I contrast agents of the invention by extremely fine particles to the particle diameter of the magnetic iron oxide in the ultimate single magnetic domain particles Sa I's, the T 1 relaxation ability magnitude than the T 2 relaxation ability Kudekiru. As a result, in contrast, such as conventional in the magnetic iron oxide particles circulatory vessel or vascular its contrast is impossible, the present site of the magnetic iron oxide particles becomes a high signal, superior of the site white can be photographed with the nature. Therefore, MRI contrast agents of the present invention, in modern equipment, such as fast MR I imaging, have the effect thereof is great der is, myocardial infarction, cerebral infarction, cancer, greatly facilitates the diagnosis of lesions such as vascular lesions cormorants effect can be expected.

Industrial Applicability

MR I contrast agents of the invention, by being administered intravascularly, it is possible to contrast white enhance the signal intensity of the blood vessels in the MR Angiodara Fi scratch. Also it is used even if because of lowering hepatic signal, that over a certain time post given throw a liver MR I contrast agents.

Moreover, MR I contrast agents of the invention on can be easily administration, and. High safety have a high stability as a preparation. Further MR I contrast agents of the present invention has a long residence time in the vessel, may bleed of vascular since no contrast to the extravascular and it is easy to set the inspection time.

Example

Production Example 1

(Production of Kondoroichin sulfate one magnetic iron oxide complex)

29. 86 g0F e C a l 3 · 6Η 2 〇 was dissolved in distilled water 80 m 1, after A r substitution for 10 minutes, F under Ar eC l 2 · 4Η 2 〇 a 5. 49 g added dissolved completely, it was facilitated heated reaction 1:80 00 ° C. All iron content were charged 0. Is 1 to 3 mol, F e 2+ / F e 3+ was 1Z4.

- How, an aqueous solution prepared by dissolving chondroitin sulfate 43 g distilled water 1 2 Om l and heated to 80 ° C under Ar was added the iron chloride solution once.

While maintaining the temperature at 80 ± 5'C, under stirring, the pH was adjusted to 1 1 by the dropwise addition of 3 N sodium hydroxide. Then, was added dropwise 6N hydrochloric acid, the pH was adjusted to 6.9. In this state, the temperature of the solution was heated for 1 hour maintaining the 1 00 ° C, then 2 (after cooling to TC, and centrifuged 30 min at 3000 r pm, the resulting supernatant was collected.

This supernatant 4 1 4 ml of methanol were added 262m l, by centrifugation 1 1 minute at 3000 rpm, to obtain a precipitate of the complex. The precipitate was dissolved in water 1 50 ml, pH was adjusted to 8 with 3 N sodium hydroxide, was about 20 hours running water dialysis. The pH of the dialysate 3 N7] was adjusted to 8 with sodium oxide, and concentrated under reduced pressure, Kondoroichin sulfate - to obtain an aqueous sol of magnetic iron oxide complex.

A magnetic measurement results of the chondroitin sulfate one magnetic iron oxide complex. Toei Industry Co., Ltd. made a vibrating sample magnetometer to the measuring device: draw a hysteresis curve using (VMS Vibrating Sample agnetome ter), to determine the saturation magnetization from this curve. Measurement samples were used after packed into the measuring capsule samples (S 1 to S 5) sampled at random from the powder particles obtained was dried the aqueous Bull, results converted into a value per sample 1 g did. Also compared performs similarly measured for the iron oxide particles uncoated with chondroitin sulfate (S 6). The magnetization curve of the sample S 1 to S 5 shown in FIG. Also shows the saturation magnetization of the sample S 1 to S 6 in Table 1. table 1

2, the resulting complex is clearly shown to be superparamagnetic. Chi words, the magnetization curve by drawing the same trajectory with respect to the external magnetic field inversion, iron oxide fine particles obtained are shown to have a single domain structure. Specifically, initial magnetization curve, a demagnetization curve and the magnetization curve of iron oxide particles are the same, hold be superparamagnetic, magnetic anisotropy not considered, the coercive force no residual magnetization also not recognized at all, chondroitin sulfate - the particle size of the magnetic iron oxide complex, was measured using a dynamic light scattering method using a dynamic light scattering photometer system to determine the particle size distribution by the histogram method analysis. The results are shown in Table 2.

Table 2

Also, transmission electron micrographs (TEM, magnification: 1 000-fold) of chondroitin sulfate one magnetic iron oxide complex shows the Figure 3. In the figure, a black mass of Hitotsuhitotsugako chondroitin sulfate - shows a magnetic iron oxide complex.

It is shown below the results of an analysis of the aqueous Bull.

Iron concentration: 3 1. 6mg / m 1

The concentration of chondroitin sulfate: 43. 5mg / m 1

pH: 7. 0

The average particle size of the core: 4. 1 nm

Magnetization in 1 tesla (1 0K) 2 1. 3 emu / 1 g iron

T 1 relaxation ability: 3. 3 (sec · πιΜ)

Τ2 relaxation ability: 6. 0 (sec - mM) "

Overall Average particle diameter: 42 nm

Production Example 2

(Production of Kondoroichin sulfate one magnetic iron oxide complex) 29. 86 g F eC 13 - 6H 2 〇 soluble _ construed in distilled water 8 OML a, after the A r substituted 10 minutes, FeC under Ar the 1 2 · 4Η 2 0 5. dissolved in 49 g added completely. All iron content were charged is 0.1 to 3 mol, Fe 2+ ZFe 3 + was 1Z 4.

- How, an aqueous solution prepared by dissolving chondroitin sulfate 43 g of distilled water 120ml and heated to 80 ° C under Ar was added the iron chloride solution once.

While maintaining the temperature at 80 ± 5 ° C, under stirring, pH was adjusted to l 1 by the dropwise addition of 3 N sodium hydroxide. Then, was added dropwise 6 N hydrochloric acid, the pH was adjusted to 6.9. In this state, the temperature of the solution 1. was heated for 5 hours maintained at 100, then after cooling to 14 hands and centrifuged 30 minutes at 3000 r pm, the resulting supernatant was collected. This supernatant 400ml of acetone were added 310 ml, performs centrifugal separation at 2000 rpm, to obtain a precipitate of the complex. The precipitate was dissolved in water 120 ml, pH was adjusted to 8 with 3 N sodium hydroxide, was about 1 5 hours running water dialysis. The pH was adjusted to 8 permeable 析液 in 3 N sodium hydroxide, bore size is filtered through a membrane filter of 0. 45 m, further aqueous sol was concentrated under reduced pressure, and the chondroitin sulfate one magnetic iron oxide complex It was obtained. Iron concentration The analytical results of the aqueous sol in the following: 56. 5mg / m 1

The concentration of chondroitin sulfate: 71. 2mg / m 1

pH: 6. 9

The average particle size of the core: 6. 3 nm

Magnetization in 1 tesla (1 OK): 32. 6 emuZl g iron

T 1 relaxation ability: 4. 4 (s ec - mM) one '

T 2 relaxation ability: 9. 8 (sec · mM) one 1

Overall Average particle diameter: 69 nm

Test Example 1 (in vivo MR imaging)

Rats (Wistar, 3 weeks old, weight 300 g) after anesthesia was injected ip into Nembutal 0. 25 cc of, prior to contrast injection liver, 肾臓 and with muscle site spin echo (Spin Echo) method use axial (body axis cross) direction in a slice thickness 3 mm T 1 -weighted images (repetition time: 6 0 Oms, echo time: 1 5 ms), T2 weighted images (repetition time: 20 0 Oms, echo time: 9 Oms) and pro colonization City (PD) images (repetition time: 20 0 Oms, echo time: 1 5 ms) captured were to as control images.

Then, after administration complex obtained in Production Example 1 (contrast medium) 0. 3 cc (concentration 1 3. 0 M) into the tail vein, about 1 5 to 3 in 0-minute time, the same spin echo and the same cross-section at the law, the same slice thickness by T 1 -weighted images (repetition time: 60 0ms, echo time between: 1 5 ms) and proton density (PD) images (repetition time: 20 0 0 ms, echo time: 1 5 ms ) imaged and compared the change in signal intensity between the control image before contrast administration. The value of the signal intensity of the image sets the CRT (display) screen of the mouth I (region of interest), the average value was calculated. The results shown in Table 3, 4. Incidentally, clinical MR device as an imaging device (Siemens (SIE ENS)'s trade name "Magnetom" static magnetic field strength: 1. 5 T) was used.

Table 3 a T 1 weighted image, Table 4 shows the signal strength for each concentration upon imaging each proton density weighted images.

Table 3 s ^ (τ ι:. 6oo / i5 6 o min after administration) Control Π- le 10 mol / g 20 mol / Kg 40 Sir 1 / g 80 / zmol / Kg Blood 462 ± 34 686 ± 40 876 ± 37 1340 ± 51 1301 ± 52 liver 646 ± 38 418 ± 46 375 ± 41 242 ± 50 215 ± 68

575 ± 66 637 ± 55 667 ± 65 718 ± 74 719 ± 81

516 ± 48 624 ± 46 597 ± 49 π9 ± 68 786 ± 51 Spleen 5 ± 63 345 ± 38 50 is 37 316 ± 62 269 ± 89 skeletal muscle 394 ± 54 431 ± 35 380 ± 33 413 ± 38 427 ± 40 heart muscle 470 ± 45 577 ± 71 667 ± 54 578 ± 28 58 16 table 4 ^ sm ^. (proton density:. 2500/15 6 o min after administration)

Table 3 and Table 4, abundant renal cortex and signal strength of the renal medulla of blood flow and blood is increased in 1 -weighted and proton density T, it is observed a signal to decrease in liver reversed. That signal strength of the blood vessel portion is enhanced. Similar effects were obtained when the complexes obtained in Production Example 2 (contrast medium) 0. 4 CC (concentration 8. 8 Micromax) were administered the same manner as described above to rats Bok tail vein.

Test Example 2 (in vivo MR imaging)

The MR angiography Ichizo near the heart and the aorta of rabbits 4, in comparison with MRI contrast agents and Gd-DTP A of the present invention. Photo right MR I contrast agents of the present invention (imaging agent obtained in Production Example 1), an image in which the left is obtained using conventional Gd-DTPA (the shea We one ring Ltd. trade name Magunepisuto).

The test conditions are as follows.

3D - FLASH se qu ence,

Use models: Siemens of Ma gn et om 1. 5

TR:. 4 0ms e c TE: 1 0ms e c.

flipang 1 e: 20 degr ees

As apparent from FIG. 4, the vessel near the heart and the aorta of rabbits are clearly contrast. Thus, MR I contrast agents of the invention, it is possible to project clearly blood vessel image not be able be viewed on conventional contrast agents, such immense contribution to future medical les.

Claims

The scope of the claims .
The magnetic iron oxide particles having one-average particle size of the single magnetic domain structure. 2 to 2 0 nm as a core, the surface of the core, consisting of a sulfonic group, a ketone group, an amino group, a carboxyl group and an alkyl group magnetic resonance imaging agent to FEATURE: that is coated with a polysaccharide having a functional group selected from the group.
2. The magnetic resonance Concrete Kagezai of claim 1, wherein the magnetic iron oxide fine particles are ferrite particles.
3. The polysaccharide is chondroitin 4-sulfate, chondroitin 6-sulfate, hyaluronan, chitin, heparin, sialic acid, Noirami phosphate, Kisosami down to Asechiru, Inurin, Agarosu, dextran sulfonate and N- Asechirugurikosa Min magnetic resonance imaging agent of claim 1 selected from the group consisting of derivatives.
4. The magnetic resonance contrast agent according to claim 1, wherein an average particle diameter of 3 0~ 2 0 0 nm.
PCT/JP1995/000894 1994-05-12 1995-05-10 Contrast medium for magnetic resonance imaging WO1995031220A1 (en)

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US6123920A (en) * 1996-01-10 2000-09-26 Nycomed Imaging As Superparamagnetic contrast media coated with starch and polyalkylene oxides
US6423296B1 (en) 1996-01-10 2002-07-23 Amersham Health As Constrast media
WO2005087367A1 (en) * 2004-03-15 2005-09-22 Hitachi Maxell, Ltd. Magnetic composite particle and process for producing the same
JP2005296942A (en) * 2004-03-15 2005-10-27 Hitachi Maxell Ltd Magnetic composite particle and method for producing it
AU2001294068B2 (en) * 2000-10-16 2005-12-22 Consejo Superior De Investigaciones Cientificas Nanoparticles
JP2008037856A (en) * 2006-07-10 2008-02-21 Keio Gijuku Mri probe
EP1952919A2 (en) 2007-02-02 2008-08-06 Fujifilm Corporation Magnetic nanoparticles and aqueous colloid composition containing the same
KR100949465B1 (en) 2008-02-20 2010-03-29 전남대학교산학협력단 Superparamagnetic iron oxide nanoparticles coated with mannan, preparation method thereof and contrast agent for diagnosing liver diseases
WO2011062217A1 (en) 2009-11-20 2011-05-26 戸田工業株式会社 Magnetic iron oxide microparticle powder, aqueous dispersion containing magnetic particles, and process for production of same
JP2011241194A (en) * 2010-05-20 2011-12-01 Cota Co Ltd Hair growth promoter
KR101303567B1 (en) 2011-03-08 2013-09-23 주식회사 인트론바이오테크놀로지 MRI contrast agent coated with carboxylated mannan and method for producing the same

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WO1989003675A1 (en) * 1987-10-26 1989-05-05 Carbomatrix Ab Superparamagnetic particles, a way of producing said particles and their use
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US6423296B1 (en) 1996-01-10 2002-07-23 Amersham Health As Constrast media
US6123920A (en) * 1996-01-10 2000-09-26 Nycomed Imaging As Superparamagnetic contrast media coated with starch and polyalkylene oxides
US8080431B2 (en) 2000-10-16 2011-12-20 Midatech Limited Nanoparticles
US8790934B2 (en) 2000-10-16 2014-07-29 Consejo Superior De Investigaciones Cientificas Nanoparticles
AU2001294068B2 (en) * 2000-10-16 2005-12-22 Consejo Superior De Investigaciones Cientificas Nanoparticles
US7364919B2 (en) 2000-10-16 2008-04-29 Midatech Limited Nanoparticles
WO2005087367A1 (en) * 2004-03-15 2005-09-22 Hitachi Maxell, Ltd. Magnetic composite particle and process for producing the same
JP2005296942A (en) * 2004-03-15 2005-10-27 Hitachi Maxell Ltd Magnetic composite particle and method for producing it
JP2008037856A (en) * 2006-07-10 2008-02-21 Keio Gijuku Mri probe
EP1952919A2 (en) 2007-02-02 2008-08-06 Fujifilm Corporation Magnetic nanoparticles and aqueous colloid composition containing the same
KR100949465B1 (en) 2008-02-20 2010-03-29 전남대학교산학협력단 Superparamagnetic iron oxide nanoparticles coated with mannan, preparation method thereof and contrast agent for diagnosing liver diseases
JP2011126876A (en) * 2009-11-20 2011-06-30 Toda Kogyo Corp Magnetic iron oxide microparticle powder, aqueous dispersion containing magnetic particles, and process for production of same
WO2011062217A1 (en) 2009-11-20 2011-05-26 戸田工業株式会社 Magnetic iron oxide microparticle powder, aqueous dispersion containing magnetic particles, and process for production of same
US9127168B2 (en) 2009-11-20 2015-09-08 Toda Kogyo Corporation Magnetic iron oxide fine particles, and magnetic particle-containing water dispersion and process for producing the same
JP2011241194A (en) * 2010-05-20 2011-12-01 Cota Co Ltd Hair growth promoter
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