EP1765162A1 - Agents de contrastes pour l"imagerie par résonance magnétique - Google Patents

Agents de contrastes pour l"imagerie par résonance magnétique

Info

Publication number
EP1765162A1
EP1765162A1 EP05749298A EP05749298A EP1765162A1 EP 1765162 A1 EP1765162 A1 EP 1765162A1 EP 05749298 A EP05749298 A EP 05749298A EP 05749298 A EP05749298 A EP 05749298A EP 1765162 A1 EP1765162 A1 EP 1765162A1
Authority
EP
European Patent Office
Prior art keywords
contrast agent
signal generating
generating core
nanoparticle
water soluble
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05749298A
Other languages
German (de)
English (en)
Other versions
EP1765162A4 (fr
Inventor
Havva Y. Acar
Faisal Syud
Rachel Garaas
Jr. Peter Bonitatebus
Amit Kulkarni
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Publication of EP1765162A1 publication Critical patent/EP1765162A1/fr
Publication of EP1765162A4 publication Critical patent/EP1765162A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K49/00—Preparations for testing in vivo
    • A61K49/06—Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations
    • A61K49/18—Nuclear magnetic resonance [NMR] contrast preparations; Magnetic resonance imaging [MRI] contrast preparations characterised by a special physical form, e.g. emulsions, microcapsules, liposomes
    • A61K49/1818—Nuclear 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
    • A61K49/1821—Nuclear 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
    • A61K49/1824—Nuclear 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
    • A61K49/1827—Nuclear 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
    • A61K49/1851—Nuclear 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
    • A61K49/1857—Nuclear 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 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. PLGA
    • A61K49/186—Nuclear 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 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. PLGA the organic macromolecular compound being polyethyleneglycol [PEG]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y5/00—Nanobiotechnology or nanomedicine, e.g. protein engineering or drug delivery

Definitions

  • the present invention relates generally to the field of magnetic resonance imaging (MRI) contrast agents comprising a plurality of magnetic nanoparticles. More particularly, the present invention relates to the design and synthesis of magnetic nanoparticles comprising a monocrystalline superparamagnetic core coated with an organic shell and decorated with targeting moieties.
  • MRI magnetic resonance imaging
  • Imaging procedures and contrast agents are used to study organs, tissues, and diseases in a body.
  • MRI is most effective at providing images of tissues and organs that contain water, such as the brain, internal organs, glands, blood vessels and joints.
  • Magnetic resonance imaging is based on the magnetic properties of atoms. When focused radio wave pulses are broadcast towards aligned hydrogen atoms in a tissue of interest, the hydrogen atoms return a signal as a result of proton relaxation. The subtle differences in the signal from various body tissues enable MRI to differentiate between organs, and potentially contrast benign and malignant tissue.
  • MRI is useful for detecting tumors, bleeding, aneurysms, lesions, blockage, infection, joint injuries, etc.
  • Contrast agents function by changing the relaxation time of a tissue that they occupy by enhancing the relaxation time of the water protons in a close range due to time-dependent magnetic dipolar interaction between the magnetic moments of the contrast agent and the water protons.
  • Contrast agent specificity is another desired property for enhancing contrast at a site of interest and providing functional information through imaging. Natural bio-distribution of contrast agents depends upon the size, charge, surface chemistry and administration route. Contrast agents may concentrate in either healthy tissue or at lesion sites and increase the contrast between the normal tissue and the lesion. In order to maximize contrast, it is necessary to concentrate as much of the contrast agent at the site of interest as possible.
  • Contrast agents comprising one or more crystalline superparamagnetic iron oxide nanoparticles embedded in an organic coating are currently known. These nanoparticles generally have sizes in the range of 50-400 nm and have been evaluated for magnetic separation, cell tracking, and imaging. Magnetic nanoparticles in the 20- 160 nm size range have been tested for clinical applications as MRI contrast agents for liver and spleen imaging, bowel contrast, and MR angiography. Most of these contrast agents are based upon dextran or dextran-based derivatives as coating materials.
  • Iron oxide nanoparticles are typically synthesized and precipitated in alkaline aqueous solutions, and tend to have a broad size distribution. Extensive manufacturing techniques, including multiple purification and size separation steps, are necessary to obtain the desired sizes and size distributions.
  • the size of the iron oxide nanoparticles directly relates to the superparamagnetism and the relaxivity of the contrast agent.
  • nanoparticles obtained using current methods also have a low level of crystallinity, which significantly impacts the sensitivity of the contrast agent.
  • nanoparticles tend to agglomerate due to strong interparticle interactions. Aggregation increases the size of the nanoparticle, resulting in rapid blood clearance as well as reducing targeting efficiency, and may result in a reduction in relaxivity.
  • Contrast agents have inherent problems that limit targeting efficiency, such as low sensititivity large sizes, quick blood clearances, low efficiency of ligand attachment, and the accessibility of ligands to the biomarkers targets. Therefore, what is needed is a contrast agent having a particle size that is sufficiently small to avoid rapid clearance from the blood. What is also needed is a contrast agent having a particle size that is capable of imaging organs other than those of the reticuloendothelial system (RES) and to achieve receptor-directed delivery of the contrast agent. What is further needed is a contrast agent that is able to detect the increased presence of chemical biomarkers and provide biochemical information on the early presence of a specific disease state.
  • RES reticuloendothelial system
  • the present invention meets these and other needs by contrast agents based on superparamagnetic iron oxide in a core-shell structure.
  • the contrast agents provide enhanced relaxivity, high signal-to-noise ratios, and targeting abilities.
  • the contrast agents possess resistance to agglomeration, controlled particle size, blood clearance rate, and biodistribution.
  • a nanoparticle having a signal generating core and a stabilizing coating is also disclosed. Methods of making such contrast agents and nanoparticles are also disclosed.
  • one aspect of the invention is to provide a contrast agent comprising a plurality of nanoparticles.
  • Each of the plurality of nanoparticles comprises: a signal generating core having a diameter of up to 10 nm; at least one organic layer comprising at least, one of a polymer, a monomer, a ligand, and a surfactant; and a water soluble outer shell comprising at least one of a polymer, a monomer, a ligand, and a surfactant.
  • the at least one organic layer is adsorbed upon and substantially surrounds the signal generating core, and stabilizes the signal generating core.
  • the water soluble outer shell solubihzes each of the plurality of nanoparticles and provides biocompatibility for each of the plurality of nanoparticles.
  • a second aspect of the invention is to provide a nanoparticle.
  • the nanoparticle comprises: a signal generating core having a diameter of up to 10 nm and a stabilizing coating disposed on and substantially covering the signal generating core.
  • the stabilizing coating comprises: an inner shell comprising at least one of a polymer, a monomer, a ligand, and a surfactant, wherein the inner shell is adsorbed upon and substantially surrounds the signal generating core and stabilizes the signal generating core; and a water soluble outer shell disposed on an outer surface of the inner shell and substantially surrounding the inner shell.
  • the water soluble outer shell comprises at least one of a second polymer, a second monomer, a second ligand, and a second surfactant.
  • a third aspect of the invention is to provide a contrast agent comprising a plurality of nanoparticles.
  • Each of the plurality of nanoparticles comprises: a signal generating core having a diameter of up to 10 nm, wherein the signal generating core is superparamagnetic; and a stabilizing coating disposed on and substantially covering the signal generating core.
  • the stabilizing coating comprises: an inner shell comprising at least one of a polymer, a monomer, a ligand, and a surfactant, wherein inner shell is adsorbed upon and substantially surrounds the signal generating core, and wherein inner shell stabilizes the signal generating core; and a water soluble outer shell.
  • the water soluble outer shell is disposed on an outer surface of the inner shell and substantially surrounds the inner shell.
  • the water soluble outer shell comprises at least one of a second polymer, a second monomer, a second ligand, and a second surfactant.
  • the water soluble outer shell solubihzes each of the plurality of nanoparticles and provides biocompatibility for each of the plurality of nanoparticles.
  • a fourth aspect of the invention is to provide a method of making a plurality of monodisperse nanoparticles, wherein each of the plurality of nanoparticles comprises a substantially crystalline signal generating core having a diameter of up to 10 nm and a stabilizing coating disposed on and substantially covering the signal generating core.
  • the stabilizing coating comprises: an inner shell comprising at least one of a polymer, a monomer, a ligand, and a surfactant, wherein the inner shell is adsorbed upon and substantially surrounds the signal generating core and stabilizes the signal generating core; and a water soluble outer shell disposed on an outer surface of the inner shell and substantially surrounding the inner shell.
  • the method comprises the steps of: providing the signal generating core and the at least one polymerizable layer, wherein the at least one polymerizable layer is adsorbed upon and substantially surrounds the signal generating core, and wherein the at least one polymerizable layer stabilizes the signal generating core; forming the water soluble shell on an outer surface of the at least one polymerizable layer, wherein the water soluble outer shell solubihzes and provides biocompatibility for each of the plurality of nanoparticles; and covalently bonding the at least one polymerizable layer to the water soluble shell.
  • FIGURE 1 is a schematic representation of a nanoparticle comprising the contrast agent of the present invention
  • FIGURE 2 is a schematic representation of a nanoparticle of the present invention
  • FIGURE 3 is a schematic representation of the linking of the inner and outer layer of the nanoparticle of the present invention.
  • FIGURE 4 is a table summarizing the properties of the contrast agent of the present invention.
  • FIGURE 5a, 5b, 5c, and 5d are magnetic resonance images of a mouse before injection and a specified time after injection of contrast agents of the present invention.
  • the present invention provides a contrast agent for the imaging of biological tissues.
  • the contrast agent comprises a plurality of nanoparticles.
  • Each of the plurality of nanoparticles is designed to enhance signal and contrast, and to provide prolonged blood circulation time and targeted delivery of the contrast to specific organs, tissues, disease states, and the like.
  • the contrast agents may be designed to maximize contrast with respect to physiological parameters of interest, such as pH and temperature, which are important indicators of abnormality and disease.
  • Nanoparticle 100 comprises a signal generating core 110, at least one organic layer 120 that is adsorbed upon and substantially surrounds signal generating core 110, and a water soluble outer shell 130, that solubihzes and provides biocompatibility for nanoparticle 100.
  • Contrast agents function by changing the relaxation time of a tissue that they occupy.
  • Contrast agents for MR are typically magnetic materials that enhance the relaxation time of water protons at close range due to time-dependent magnetic dipolar interaction between the magnetic moments of the contrast agent and the water protons.
  • the efficiency to shorten relaxation times of protons is defined as relaxivity R, which is inversely proportional to the relaxation time T.
  • MR contrast agents may be either positive agents (also referred to hereinafter as "Tl agents”) that illuminate or "light up" the tissue that they occupy, or negative agents (also referred to hereinafter as "T2 agents”) that make a tissue appear darker.
  • Tl agents include, but are not limited to, paramagnetic gadolinium species, such as Gd-DTPA and the like.
  • T2 agents include superparamagnetic iron oxide nanoparticles. Superparamagnetic agents provide higher relaxivities than paramagnetic agents, as they generally have magnetic moments that are about 100 times greater than those of paramagnetic agents.
  • Nanoparticle 100 has a diameter of up to about 100 nm. In one embodiment, nanoparticle 100 has a diameter of up to about 50 nm. In a preferred embodiment, nanoparticle 100 has a diameter in a range from about 10 nm to about 30 nm.
  • Signal generating core 110 has a diameter of up to 30 nm. In one embodiment, signal generating core 110 has a diameter of up to 10 nm. hi one particular embodiment, signal generating core 110 has a diameter in a range from about 4 nm to about 10 nm.
  • signal generating core 110 is a monodisperse superparamagnetic nanoparticle and comprises at least one of: an iron oxide, such as but not limited to, hematite (Fe 2 O 3 ), ferrite (Fe 3 O 4 ) or magnetite; a mixed spinel ferrite having the general formula MFe 2 O 4 , where M is a metal such as, but not limited to, manganese, cobalt, copper, nickel, gadolinium, zinc, and vanadium; and combinations thereof.
  • an iron oxide such as but not limited to, hematite (Fe 2 O 3 ), ferrite (Fe 3 O 4 ) or magnetite
  • a mixed spinel ferrite having the general formula MFe 2 O 4 , where M is a metal such as, but not limited to, manganese, cobalt, copper, nickel, gadolinium, zinc, and vanadium; and combinations thereof.
  • signal generating core 110 is substantially crystalline.
  • substantially crystalline is understood to mean that signal generating core 110 comprises at least 50 volume percent and, preferably, at least 75 volume percent crystalline material. Most preferably, signal generating core 110 is a single crystal.
  • the at least one organic layer 120 surrounds and entraps signal generating core 110 and prevents the aggregation of a plurality of signal generating cores 110 and enhances the stability of each signal generating core 110. Aggregation of the plurality of signal generating cores 110 adversely affects the relaxivity.
  • the at least one organic layer 120 comprises at least one of a polymer, a monomer, a ligand, and a surfactant and has a thickness in a range from about 0.1 nm to about 100 nm.
  • the at least one organic layer 120 may be chemisorbed onto an outer surface of signal generating core 110 during the synthesis of signal generating core 100.
  • the at least one organic layer 120 comprises a water soluble surface binding polymer and a hydrophobic polymer.
  • the at least one organic layer 120 comprises a copolymer of a monomer having a pendant group that has an affinity for, and adsorbs onto, the outer surface of signal generating core 110 and a hydrocarbon group, wherein the hydrocarbon group includes a carbon chain of at least three carbon atoms.
  • Non-limiting examples of such copolymers include copolymers of acrylic acid, undecenoic acid, lauryl acrylate, combinations thereof, and the like. Specific examples of such copolymers include polyacrylic acid, poly(undecenoic acid), and poly(lauryl acrylate).
  • the at least one organic layer 120 comprises a monomer having a surface binding head group and at least one polymerizable functionality, such as, but not limited to, undecenoic acid.
  • the surface binding head group is an ionic head group.
  • One non-limiting example of such a monomer is triakylsilyl undecylene.
  • the at least one organic layer 120 comprises a surfactant having a surface binding head group and at least one hydrocarbon tail.
  • the surfactant may be one of lauric acid and sodium dodecyl sulfate.
  • the water soluble polymer is polyethylene glycol (also referred to herein as "PEG”) and the hydrocarbon moiety is undecylene.
  • Water soluble outer shell 130 comprises at least one of a polymer, a monomer, a and ligand, and has a thickness in a range from about 0.1 nm to about 100 nm. Contrast agent 100 may be directed towards specific organs or sites by tailoring the size, polarity and charge of the water soluble outer shell 130. Water soluble outer shell 130 solubihzes nanoparticle 100 in an aqueous medium, provides biocompatibility for nanoparticle 100, and may, in some instances, affect the pharmokinetics.
  • Water soluble outer shell 130 enables the contrast agent to bind to a specific site through molecular recognition of a portion of water soluble outer shell 130 by a specific biomarker, also known as a "receptor.”
  • water soluble shell 130 further includes at least one targeting moiety such as, but not limited to, at least one of a peptide comprising, for, example LSIPKKA, an antibody, at least one sugar, at least one organic molecule such as folic acid, estradiol, and the like, and combinations thereof.
  • water soluble outer shell 130 comprises a copolymer of a carboxylic acid and a hydrocarbon, wherein the hydrocarbon includes a carbon chain of at least three carbon atoms.
  • copolymers include copolymers of acrylic acid, undecenoic acid, lauryl acrylate, combinations thereof, and the like.
  • Specific examples of such copolymers include polyacrylic acid, poly(undecenoic acid), and poly(lauryl acrylate).
  • water soluble outer shell 130 comprises a monomer having a surface binding head group and at least one polymerizable functionality.
  • a monomer is undecenoic acid.
  • water soluble outer shell 130 comprises at least one ligand.
  • water soluble outer shell includes a ligand comprising a water soluble polymer, such as PEG, attached to a polymerizable hydrocarbon moiety such as, for example, undecylene, wherein the hydrocarbon moiety comprises a chain of at least three carbon atoms.
  • the invention also provides a nanoparticle that may be used in imaging applications in addition to MRI contrast agents.
  • the nanoparticle 200 which is shown in Figure 2, comprises: a signal generating core 210 having a diameter of up to about 10 nm; a stabilizing coating 220 disposed on and substantially covering the signal generating core 210.
  • the stabilizing coating comprises an inner shell 230 and a water soluble outer shell 240.
  • the inner shell 230 is adsorbed upon and substantially surrounds and stabilizes the signal generating core 210.
  • the inner shell 230 comprises at least one of a polymer, a monomer, a ligand, and a surfactant.
  • the water soluble outer shell 240 is disposed on an outer surface of the inner shell 230 and substantially surrounds the inner shell 230.
  • the water soluble outer shell 240 solubihzes the nanoparticle in an aqueous medium.
  • water soluble outer shell 240 provides biocompatibility for the nanoparticle 220.
  • Water soluble outer shell 240 comprises at least one of a a second monomer and a second ligand.
  • Signal generating core 210 has a diameter of up to 30 nm. In one embodiment, signal generating core 210 has a diameter of up to 10 nm. In one particular embodiment, signal generating core 210 has a diameter in a range from about 4 nm to about 10 nm.
  • signal generating core 210 is superparamagnetic and comprises an iron oxide, as previously described hereinabove.
  • Signal generating core 210 may further comprise at least one of gadolinium, manganese, copper, nickel, cobalt, zinc, germanium, gold, silver, compounds comprising group II (A or B) and group VI elements (also referred to hereinafter as "II- VI compounds"), compounds comprising group IV and group VI elements (also referred to hereinafter as "IV- VI compounds”), combinations thereof, and the like.
  • signal generating core 210 is responsive to laser radiation and comprises at least one of gold, silver, combinations thereof, and the like.
  • signal generating core 210 is radio-opaque, and comprises at least one of gadolinium, barium, combinations thereof, and the like.
  • Inner shell 230 comprises at least one of a polymer, a monomer, and a surfactant and has a thickness in a range from about 0.1 nm to about 100 nm.
  • inner shell 230 comprises a water soluble surface binding polymer and a hydrophobic polymer.
  • inner shell 230 comprises a copolymer of a monomer, the monomer having a pendant group that has an affinity for, and adsorbs onto, the outer surface of signal generating core 210 and a hydrocarbon group, wherein the hydrocarbon group includes a carbon chain of at least three carbon atoms.
  • Non-limiting examples of such copolymers include copolymers of acrylic acid, undecenoic acid, lauryl acrylate, combinations thereof, and the like.
  • Inner shell 230 may comprise polyacrylic acid, poly(undecenoic acid), lauryl acrylate, and combinations thereof.
  • inner shell 230 comprises a monomer having a surface binding head group and at least one polymerizable functionality, such as, but not limited to, undecenoic acid.
  • inner shell 230 comprises a monomer having a surface binding functionality and at least one polymerizable functionality.
  • One non-limiting example of such a monomer is triakylsilyl undecylene.
  • inner shell 230 comprises a surfactant having a surface binding head group and at least one hydrocarbon tail.
  • the surfactant may be one of lauric acid and sodium dodecyl sulfate.
  • the at least one organic layer includes a ligand comprising a water soluble polymer attached to a polymerizable hydrocarbon moiety, wherein the hydrocarbon moiety comprises a chain of at least three carbon atoms.
  • the water soluble polymer is polyethylene glycol (also referred to herein as "PEG”) and the hydrocarbon moiety is undecylene.
  • Water soluble outer shell 240 comprises at least one of a polymer, a monomer, a ligand, and a surfactant and has a thickness in a range from about 0.1 nm to about 100 nm. Water soluble outer shell 240 solubihzes nanoparticle 200 and, in one embodiment, provides biocompatibility for nanoparticle 200. In one embodiment, water soluble outer shell 240 further includes at least one targeting moiety such as, but not limited to, at least one of a peptide, a protein, an antibody, a sugar, at least one molecule of biological significance such as, folic acid, estradiol, combinations thereof, and the like.
  • water soluble outer shell 240 comprises a copolymer of a carboxylic acid and a hydrocarbon, the hydrocarbon having a carbon chain of at least three carbon atoms.
  • Non-limiting examples of such copolymers include copolymers of acrylic acid, undecenoic acid, lauryl acrylate, combinations thereof, and the like. Specific examples of such copolymers include polyacrylic acid, poly(undecenoic acid), and lauryl acrylate.
  • water soluble outer shell 240 comprises a monomer, the monomer having a surface binding head group and at least one polymerizable functionality.
  • a monomer is undecenoic acid.
  • water soluble outer shell 240 comprises a ligand comprising a water soluble polymer, such as PEG, attached to a polymerizable hydrocarbon moiety such as, for example, undecylene, wherein the hydrocarbon moiety comprises a chain of at least three carbon atoms.
  • inner shell comprises a surface binding head group and at least one polymerizable functionality, such as undecenoic acid
  • water soluble outer shell 240 includes a ligand comprising a water soluble polymer, such as PEG, attached to a polymerizable hydrocarbon moiety, such as undecylene.
  • Particle 200 has a diameter of up to about 100 nm. In one embodiment, nanoparticle 200 has a diameter of up to about 50 nm and, in a preferred embodiment, has a diameter in a range from about 10 nm to about 30 nm.
  • Another aspect of the invention is to provide a method of making both the contrast agent and the monodisperse nanoparticle described hereinabove.
  • the method comprising the steps of: providing the signal generating core having at least one polymerizable layer disposed on its outer surface; forming a water soluble shell on an outer surface of the at least one polymerizable layer; and covalently bonding the at least one polymerizable layer to the water soluble shell.
  • the monodisperse signal generating core is formed by a non-aqueous synthetic route in which at least one organometallic compound is thermally decomposed at high temperatures in a solvent in the presence of a surfactant and an oxidant.
  • a non-aqueous synthetic route in which at least one organometallic compound is thermally decomposed at high temperatures in a solvent in the presence of a surfactant and an oxidant.
  • Such methods produce superparamagnetic nanoparticles coated with a surfactant monolayer.
  • a non-aqueous synthetic approach tends to produce more spherical nanoparticles.
  • One non-limiting example of such a synthetic route is disclosed in United States Patent Application 10/208,945, filed on July 31, 2002, by Peter John Bonitatebus and Hawa Acar, entitled “Method of Making Crystalline Nanoparticles," the contents of which are incorporated herein by reference in their entirety.
  • the method comprises first combining a nonpolar aprotic organic solvent, an oxidant, and a first polymerizable surfactant having a polarizable head group. At least one organometallic compound comprising a metal and at least one ligand is then added to the combined nonpolar aprotic organic solvent, oxidant, and first polymerizable surfactant. The combined nonpolar aprotic organic solvent, oxidant, first polymerizable surfactant, and the at least one organometallic compound are then heated under an inert gas atmosphere to a first temperature in a range from about 30°C to about 400°C for a first time interval to form the signal generating core surrounded by the first polymerizable surfactant.
  • the signal generating core surrounded by the first surfactant is then precipitated out of the nonpolar solvent.
  • the nanoparticles generated by the non-aqueous synthetic method described above signal generating core sizes in a range from about 5 nm to about 10 nm.
  • the nanoparticles sO formed have a size distribution of less than about 15 percent.
  • the plurality of signal generating cores coated with the first surfactant is precipitated out of solution by adding at least one of an alcohol or a ketone to the nonpolar aprotic solvent.
  • Alcohols such as, but not limited to, methanol and ethanol may be used. Alcohols having at least three carbon atoms, such as isopropanol, are preferred, as precipitation by the addition of such alcohols tends to produce the least degree of agglomeration of the plurality of nanoparticles.
  • Ketones such as, but not limited to, acetone may be used in conjunction with, or separate from, an alcohol in the precipitation step.
  • the first surfactant is undecenoic acid (UD)
  • the second surfactant is undecenoic polyethylene glycol (UDPEG)
  • the resulting bilayer is UD/UDPEG.
  • the present invention also provides an aqueous synthetic route for the synthesis of substantially monodisperse crystalline superparamagnetic iron oxide nanoparticles.
  • the aqueous synthesis of iron oxide in the presence of micelle forming, surface binding non-polymeric surfactants provides improved control over the size distribution of iron oxide nanoparticles relative to synthetic methods that do not use surface binding surfactants.
  • the method comprises forming a core-shell structure in which the shell comprises a bilayer of at least one surface binding surfactant.
  • the surfactants have a high affinity for the oxide surface of the iron oxide core. As the iron oxide crystal starts to form, the surfactants adsorb on the crystal surface and thus prevent further crystal growth at the surface.
  • the presence of the coating during crystal growth controls the size distribution of the crystals, limits agglomeration, and prevents formation of a thick non-magnetic oxidation layer on the crystal surface. Consequently, the nanoparticles formed by this aqueous route have a much higher magnetization than currently available superparamagnetic iron oxide contrast agents.
  • iron oxide nanoparticles coated with an undecenoic acid bilayer and having a diameter of about 8.4 nm have a Fe saturation magnetization of about 95.4 emu/g.
  • the nanoparticles generated by this method have superparamagnetic cores with sizes in a range from about 5 nm to about 10 nm.
  • the nanoparticles have a size distribution of less than about 20 percent and, in one embodiment, the size distribution is less than about 15 percent.
  • the colloidal suspension is then cooled slowly to room temperature with stirring to yield substantially monodisperse spinel-structured mixed iron oxide ( ⁇ -Fe O 3 ) 1-y (Fe O 4 ) y nanocrystals that are coated with an undecenoic acid bilayer.
  • a water soluble outer layer 130 is then deposited on the stabilized nanoparticles by mixing the material forming the water soluble outer layer 130 with the stabilized nanoparticles.
  • the water soluble outer layer 130 is then covalently bonded - or linked - to the at least one polymerizable layer 120 by at least one of cross-polymerization, irradiation, and heating, as schematically shown in Figure 3.
  • Covalent bonding fixes the stabilizing inner layer and water soluble outer layer around the core and provides stability for the nanoparticles, making them resistant to agglomeration.
  • Ligands may possess physiologically responsive entities, such as, but not limited to polymers that are sensitive to pH or temperature.
  • physiologically responsive entities such as, but not limited to polymers that are sensitive to pH or temperature.
  • Non-limiting examples of such polymers include poly(N-isopropyl acrylamide), pluronics, poly(hydroxyethyl methacrylate), and polyarylic acid.
  • the physiological MRI contrast agents of the present invention may be applied to cells or be administered to a body intravenously and allowed to circulate in the bloodstream.
  • the contrast agents may be used in the form of a suspension or solution in a solvent, such as physiological saline, sugar solution, and the like.
  • at least one pharmacologically acceptable additive such as a carrier or expedient, may be used.
  • the contrast agent is administered in the form of a stable aqueous solution.
  • Additives used vary depending on the mode of administration, administration route and the like. Examples of additives for intravenous injections include buffers, antibacterial agents, stabilizers, solubilizers, excipients that are either used alone or in combination with each other.
  • Iron oxide nanocrystals coated with surfactant and monomer, as described hereinabove, were synthesized according to the non-aqueous synthesis route referred to hereinabove.
  • Iron carbonyl (Fe(CO) 5 ) was then added to the reaction solution, which was at a temperature in a range from about 100°C to about 105°C, resulting in instantaneous and aggressive reaction.
  • the reaction mixture was then heated to a temperature in a range from about 120°C to about 130°C under nitrogen and maintained at temperature for about 1 hour while being vigorously stirred.
  • Additional iron carbonyl (Fe(CO) 5 ) was then added to the reaction mixture, and the temperature was rapidly increased to about 280°C to allow the reaction mixture to reflux. After 1 hour of refluxing and stirring at about 280°C, the color of the reaction mixture turned black.
  • Crystal structure, composition and particle size analysis of the powder was obtained by transmission electron microscopy (TEM) imaging, energy dispersive x-ray (EDX) elemental analysis, x-ray absorption spectroscopy (XAS), and selected area electron diffraction/x-ray diffraction (SAED- XRD) crystal symmetry pattern indexing.
  • TEM transmission electron microscopy
  • EDX energy dispersive x-ray
  • XAS x-ray absorption spectroscopy
  • SAED- XRD selected area electron diffraction/x-ray diffraction
  • the powder obtained was found to comprise monodisperse spinel-structured mixed iron oxide ( ⁇ -Fe 2 O 3 ) 1-y (Fe O 4 ) y nanocrystals, each having a particle size of about 10 nm ⁇ 1 nm.
  • the suspension was placed on a magnet for at least 1 hour, and then filtered to remove any insoluble material.
  • the material obtained was found to comprise monodisperse spinel-structured mixed iron oxide ( ⁇ - Fe 2 O 3 ) 1-y (Fe O 4 ) y nanocrystals.
  • the average particle size of the nanocrystals an about 8.5 ⁇ 1.2 nm, as determined TEM.
  • PEGylated ligands PEG and undecenoic acid
  • the PEGYlated ligands were first prepared using either PEGs, or alternatively, PEG monomethyl ethers with molecular weights between 300-5,000 g/mol as starting materials. In one instance, PEG (2,000Da) was dissolved in dry methylene chloride. Trimethyl amine (TEA), and dimethylamino pyridine (DMAP) were added to the solution and stirred under nitrogen in an ice bath.
  • TEA Trimethyl amine
  • DMAP dimethylamino pyridine
  • Iron oxide nanocrystalline cores obtained by either the non-aqueous synthesis route (Example 1) or the aqueous synthetic route (Example 2) described hereinabove were precipitated in isopropanol and then suspended in Milli-Q water by sonication at 60°C.
  • the suspension was placed on a magnet for about 1 hour.
  • a method isolating the signal generating core and depositing an outer layer comprising a PEGylated ligand is described.
  • a solution obtained from Example 2 was shaken with chloroform.
  • the organic phase was separated and the chloroform was evaporated under reduced pressure, leaving a residue.
  • the residue was dried further under vacuum at 60 °C for 2h.
  • the residue was then suspended in water by sonication at 60 °C and 4 mL of 0.4M UDPEG750 solution in milli-Q water was added dropwise to the suspension during continuous sonication until a stable solution was obtained.
  • the final suspension was placed on a magnet for lh to remove any precipitate from the stable suspension.
  • the particle size of the coated nanoparticles, as determined by DLS, was 35 nm.
  • a method isolating the signal generating core and depositing an outer layer comprising a PEGylated ligand is described.
  • a solution obtained from Example 2 was sonicated at 60 °C with toluene for 30 min.
  • the organic phase was separated and added to an aqueous solution of UDPEG750 in a centrifuge tube and centrifuged at 15,000 rpm for 1.5 h.
  • the organic layer was removed and the aqueous layer was sonicated for about 20 min.
  • Stable suspension was filtered from 20 nm filter and particle size was measured by DLS as 21nm. (0.27mM Fe)
  • Hydrodynamic size of the nanoparticles was determined by Dynamic Light Scattering (DLS).
  • DLS Dynamic Light Scattering
  • Dh hydrodynamic diameter in a range from about 20 nm to about 80 nm was measured.
  • Targeting moieties may be attached to PEGylated ligands through, for example, free -OH or -NH 2 chain ends, if either hydroxy- or amine-terminated PEG is used in either the at least one organic layer or the water soluble outer shell.
  • a free -OH chain end is converted to an activated carboxylic acid in order to achieve facile conjugation of the targeting moieties to the PEGylated surfactants.
  • the nanoparticles comprising the contrast agent of the present invention have a high magnetic moment in the presence of a magnetic field and a negligible magnetic moment in the absence of a magnetic field. Magnetization of the nanoparticles was measured using a vibrating sample magnetometer with fields up to 2,500 Gauss at 25°C. The nanoparticles have a saturation magnetization in the range of about 40 emu/g to about 105 emu/g of metal. The saturation magnetization values of nanoparticles having different hydrodynamic diameters (Dh) are listed in Figure 4.
  • Magnetic resonance (MR) contrast agents work by shortening the proton relaxation times and hence increasing the contrast and overall image quality.
  • the nanoparticles were found affect both the longitudinal relaxation (Tl) and transverse relaxation times (T2).
  • the relaxation times were measured by imaging nanoparticle suspensions at different concentrations in a 1.5 Tesla scanner at 25 C.
  • the nanoparticles exhibited a longitudinal relaxation rate (Rl) in a range from about 1 mM/s to about 10 mM/s, and a transverse relaxation rate (R2) in a range from about 90 mM/s to about 400 mM/s. Values of Rl and R2 that were obtained for nanoparticles are listed in Figure 4.
  • Nanoparticles having sizes in the range from 50 nm tolOO nm had R2 relaxivity values between 290 mM ' V 1 and 360 mM ' V 1 , which is three times greater than values exhibited by currently available contrast agents and R2/R1 ratios between 135 mM ' V 1 and 158 mM ' V 1 , which is about 10 times greater than which is three times greater than values exhibited by currently available contrast agents.
  • Nanoparticles of the present invention having sizes of less than 50 nm, and, in one embodiment, sizes of less than 35 nm, exhibit R2 relaxivities that are comparable to those of existing contrast agent systems having much greater particle sizes. This result indicates that the smaller nanoparticles of the present invention possess improved magnetics and coatings.
  • the application of the contrast agents of the present invention in MR applications was evaluated by performing in vivo studies on mice and rats. Solutions of nanoparticles described hereinabove were prepared in 0.9M NaCl at 0.2-0. mg/ml. The animals were injected with known quantities (20-40 micromol Fe/kg body weight) of the nanoparticles and imaged using a 1.5T scanner. In addition, the blood half-life of contrast agents of the present invention were measured by injecting known amounts of nanoparticles into rats and removing blood samples at known time intervals. The blood samples were analyzed using MR imaging to determine the metal concentration at different times after injection. MR images before and after injection were compared to determine the effect of nanoparticles on specific tissues or organs.
  • Figures 5a, 5b, 5c, and 5d are T2 weighted MR images of a mouse before ( Figures 5a and 5c) and a specified time after injection ( Figures 5b and 5d) for contrast agents having hydrodynamic diameters of 75 nm and 35 nm, respectively.
  • liver 510 had taken up a sufficient portion of the contrast agent having a hydrodynamic diameter of 70 nm, causing the MR image of liver 510 to noticeably darken ( Figure 5b).
  • the blood half-life of the contrast agent having a hydrodynamic diameter of 70 nm was about 16 min.
  • Contrast agents having sizes in the range from about 10 nm to about 50 nm may be used as Tl blood pool agents, and may be decorated for receptor-mediated delivery to target tissues. Entities such as peptides, antibodies, folic acid, estradiol can be attached to the ligand for this purpose.

Abstract

Un agent de contraste pour l’imagerie par résonance magnétique comportant une pluralité de nanoparticules (100, 200). Chacune des nanoparticules (100, 200) comporte : un noyau générant des signaux (110, 210) ayant un diamètre allant jusqu’à 10 nm ; au moins une couche organique (120, 230) d’au moins un parmi un polymère, un monomère (122), et un agent tensioactif ; et une enveloppe externe soluble dans l’eau d’au moins un parmi un polymère, un monomère (122), et un ligand. La couche organique (120, 230) est adsorbée sur et entoure sensiblement et stabilise le noyau générant les signaux. L’enveloppe externe soluble dans l’eau se solubilise et apporte une biocompatibilité à chacune des nanoparticules (100, 200). Les agents de contraste apportent une relaxivité améliorée, des rapports signal sur bruit élevés, et des aptitudes de ciblage. En outre, les agents de contraste possèdent une résistance à l’agglomération, une taille particulaire contrôlée, une vitesse d’épuration sanguine, et une biodistribution. Des procédés de fabrication de tels agents de contraste et de telles nanoparticules (100, 200) sont également décrits.
EP05749298A 2004-05-18 2005-05-18 Agents de contrastes pour l"imagerie par résonance magnétique Withdrawn EP1765162A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US57272604P 2004-05-18 2004-05-18
PCT/US2005/017341 WO2005112758A1 (fr) 2004-05-18 2005-05-18 Agents de contrastes pour l’imagerie par résonance magnétique

Publications (2)

Publication Number Publication Date
EP1765162A1 true EP1765162A1 (fr) 2007-03-28
EP1765162A4 EP1765162A4 (fr) 2008-10-01

Family

ID=35428219

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05749298A Withdrawn EP1765162A4 (fr) 2004-05-18 2005-05-18 Agents de contrastes pour l"imagerie par résonance magnétique

Country Status (2)

Country Link
EP (1) EP1765162A4 (fr)
WO (1) WO2005112758A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1810688A1 (fr) * 2004-11-10 2007-07-25 Konica Minolta Medical & Graphic, Inc. Préparation pharmaceutique contenant des particules magnétiques revêtues et procédé de fabrication idoine, et système de thérapie de diagnostic
US20070140974A1 (en) * 2005-12-15 2007-06-21 General Electric Company Targeted nanoparticles for magnetic resonance imaging
WO2007093451A2 (fr) * 2006-02-17 2007-08-23 Topass Gmbh Imagerie multimode utilisant une nanoparticule polymere a trois compartiments presentant une specificite cellulaire
ES2379915B1 (es) 2010-10-07 2013-03-20 Consejo Superior De Investigaciones Científicas (Csic) Procedimiento para el recubrimiento y funcionalización de nanopartículas mediante reacción de michael.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5492814A (en) * 1990-07-06 1996-02-20 The General Hospital Corporation Monocrystalline iron oxide particles for studying biological tissues
US20030185757A1 (en) * 2002-03-27 2003-10-02 Mayk Kresse Iron-containing nanoparticles with double coating and their use in diagnosis and therapy
US20040022937A1 (en) * 2002-07-31 2004-02-05 General Electric Company Method of making crystalline nanoparticles

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1031354A3 (fr) * 1999-01-19 2003-02-05 Rohm And Haas Company Agents de contraste polymère pour imagerie RMN

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5492814A (en) * 1990-07-06 1996-02-20 The General Hospital Corporation Monocrystalline iron oxide particles for studying biological tissues
US20030185757A1 (en) * 2002-03-27 2003-10-02 Mayk Kresse Iron-containing nanoparticles with double coating and their use in diagnosis and therapy
US20040022937A1 (en) * 2002-07-31 2004-02-05 General Electric Company Method of making crystalline nanoparticles

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
LIU XIANQIAO ET AL: "Surface modification and characterization of magnetic polymer nanospheres prepared by miniemulsion polymerization" LANGMUIR, ACS, WASHINGTON, DC, US, vol. 20, no. 23, 6 October 2004 (2004-10-06), pages 10278-10282, XP002391024 ISSN: 0743-7463 *
See also references of WO2005112758A1 *

Also Published As

Publication number Publication date
EP1765162A4 (fr) 2008-10-01
WO2005112758A1 (fr) 2005-12-01

Similar Documents

Publication Publication Date Title
US20050260137A1 (en) Contrast agents for magnetic resonance imaging
Xie et al. Iron oxide nanoparticle platform for biomedical applications
US5069216A (en) Silanized biodegradable super paramagnetic metal oxides as contrast agents for imaging the gastrointestinal tract
CA1301063C (fr) Materiaux superparamagnetiques biodegradables destines a des applications cliniques
Fang et al. Multifunctional magnetic nanoparticles for medical imaging applications
Patel et al. The cell labeling efficacy, cytotoxicity and relaxivity of copper-activated MRI/PET imaging contrast agents
US5219554A (en) Hydrated biodegradable superparamagnetic metal oxides
Dave et al. Monodisperse magnetic nanoparticles for biodetection, imaging, and drug delivery: a versatile and evolving technology
US9375495B2 (en) Magnetic resonance imaging contrast agents comprising zinc-containing magnetic metal oxide nanoparticles
Yan et al. Self-assembled magnetic fluorescent polymeric micelles for magnetic resonance and optical imaging
Dong et al. Controllable synthesis of exceptionally small-sized superparamagnetic magnetite nanoparticles for ultrasensitive MR imaging and angiography
Neoh et al. Surface modification of magnetic nanoparticles for stem cell labeling
JP2009519316A (ja) 磁気共鳴造影法用のターゲティングナノ粒子
US20120114564A1 (en) Mri t1 contrasting agent comprising manganese oxide nanoparticle
Lee et al. Amphiphilic hyaluronic acid-based nanoparticles for tumor-specific optical/MR dual imaging
WO1996002235A1 (fr) Particules inorganiques injectables evitant le sre
WO2012177039A2 (fr) Agent de contraste d'irm pour lymphographie à base de nanoparticules d'oxyde de fer et méthode pour l'imagerie d'un nœud lymphatique utilisant celui-ci
Tallury et al. Fluorescent and paramagnetic chitosan nanoparticles that exhibit high magnetic resonance relaxivity: synthesis, characterization and in vitro studies
Tian et al. Paclitaxel-loaded magnetic nanoparticles: synthesis, characterization, and application in targeting
KR100827292B1 (ko) 실리콘-포함 수용성 고분자로 코팅된 나노입자 및 그의조영제로서의 용도
WO2005112758A1 (fr) Agents de contrastes pour l’imagerie par résonance magnétique
CN111388668B (zh) 一种磁性复合纳米材料及其制备方法与应用
AU2019437331A1 (en) Ultrafine iron oxide nanoparticle-based magnetic resonance imaging T1 contrast agent
WO2019004297A1 (fr) Nanoparticule, agent de contraste pour imagerie par résonance magnétique la contenant, et composé ligand
WO2018217520A1 (fr) Agents de contraste pour irm à base d'hémine biogénique, et compositions et procédés associés

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20061213

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU MC NL PL PT RO SE SI SK TR

RIN1 Information on inventor provided before grant (corrected)

Inventor name: SYUD, FAISAL

Inventor name: ACAR, HAVVA, Y.

Inventor name: GARAAS, RACHEL

Inventor name: KULKARNI, AMIT

Inventor name: BONITATEBUS, JR., PETER

DAX Request for extension of the european patent (deleted)
RIN1 Information on inventor provided before grant (corrected)

Inventor name: BONITATEBUS, JR., PETER

Inventor name: ACAR, HAVVA, Y.

Inventor name: KULKARNI, AMIT

Inventor name: GARAAS, RACHEL

Inventor name: SYUD, FAISAL

A4 Supplementary search report drawn up and despatched

Effective date: 20080828

RIC1 Information provided on ipc code assigned before grant

Ipc: A61K 49/18 20060101AFI20080822BHEP

17Q First examination report despatched

Effective date: 20090219

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20090901