Gadolinium-labeled liposomes containing amphiphilic Gd-DTPA derivatives of varying chain length: Targeted MRI contrast enhancement agents for the liver

Kabalka, George W.; Davis, M.A.F.; Holmberg, Eric G.; Maruyama, Kazuo; Huang, Leaf

doi:10.1016/0730-725x(91)90425-l

Cited by 45 publications

(20 citation statements)

References 18 publications

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“…The amphiphiles used can consist of Gd-DTPA as the hydrophilic part attached to a hydrophobic part. DTPA-stearate (131,132) or DTPA attached to alkyl chains via amide linkers are examples of such molecules (133,134). Phosphatidylethanolamine (PE) has been linked to DTPA to obtain PE-DTPA, which can form vesicles when mixed with natural phospholipids (135).…”

Section: Lipid-based Mri Contrast Agents: Applications Liposomal Contmentioning

confidence: 99%

Lipid-based nanoparticles for contrast-enhanced MRI and molecular imaging

et al. 2006

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In the field of MR imaging and especially in the emerging field of cellular and molecular MR imaging, flexible strategies to synthesize contrast agents that can be manipulated in terms of size and composition and that can be easily conjugated with targeting ligands are required. Furthermore, the relaxivity of the contrast agents, especially for molecular imaging applications, should be very high to deal with the low sensitivity of MRI. Lipid-based nanoparticles, such as liposomes or micelles, have been used extensively in recent decades as drug carrier vehicles. A relatively new and promising application of lipidic nanoparticles is their use as multimodal MR contrast agents. Lipids are amphiphilic molecules with both a hydrophobic and a hydrophilic part, which spontaneously assemble into aggregates in an aqueous environment. In these aggregates, the amphiphiles are arranged such that the hydrophobic parts cluster together and the hydrophilic parts face the water. In the low concentration regime, a wide variety of structures can be formed, ranging from spherical micelles to disks or liposomes. Furthermore, a monolayer of lipids can serve as a shell to enclose a hydrophobic core. Hydrophobic iron oxide particles, quantum dots or perfluorocarbon emulsions can be solubilized using this approach. MR-detectable and fluorescent amphiphilic molecules can easily be incorporated in lipidic nanoparticles. Furthermore, targeting ligands can be conjugated to lipidic particles by incorporating lipids with a functional moiety to allow a specific interaction with molecular markers and to achieve accumulation of the particles at disease sites. In this review, an overview of different lipidic nanoparticles for use in MRI is given, with the main emphasis on Gd-based contrast agents. The mechanisms of particle formation, conjugation strategies and applications in the field of contrast-enhanced, cellular and molecular MRI are discussed.

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Section: Lipid-based Mri Contrast Agents: Applications Liposomal Contmentioning

confidence: 99%

Lipid-based nanoparticles for contrast-enhanced MRI and molecular imaging

et al. 2006

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“…These liposomes, containing paramagnetic amphiphilic agents, significantly enhanced the proton relaxivity and were shown to be especially suitable for contrast enhancement in the liver, where the highly soluble parent GdϪDTPA complex does not accumulate efficiently. [22] Other attempts to slow down the rotational motion of gadolinium-based contrast agents, and thus to improve their relaxation efficiency, have included the synthesis of macromolecular gadolinium() chelates such as dendrimers, [23] linear polymers [24Ϫ26] or proteins.…”

Section: Introductionmentioning

confidence: 99%

Potential MRI Contrast Agents Based on Micellar Incorporation of Amphiphilic Bis(alkylamide) Derivatives of [(Gd−DTPA)(H₂O)]²⁻

et al. 2003

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Keywords:Imaging agents / Contrast agents / Lanthanides / Micelles / N,O ligands / NMR spectroscopy DTPA-bisamide derivatives with alkyl chains containing 14, 16 and 18 carbon atoms were synthesized and complexes of various trivalent lanthanide ions (Ln = Gd, La, Pr, Eu) were formed. Variable temperature proton NMR spectroscopy of paramagnetic praseodymium(III) and europium(III) complexes revealed that long aliphatic substituents considerably increase the energy barrier for the intramolecular rearrangement around the lanthanide ion. The gadolinium(III) complexes were incorporated into mixed micelles, and photon correlation spectroscopy showed that the mean sizes of all the micelles were within the same range. The NMRD curves of all three DTPA-bisamide-gadolinium complexes incorpor-

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“…[157][158][159][160][161][162][163][164] In the case of MR imaging, for a better MR signal, all reporter atoms should be freely exposed for interaction with water. Membranotropic chelating agents -such as DTPA-stearylamine (DTPA-SA) 159 or DTPA-phosphatidyl ethanolamine (DTPA-PE) 156 -consist of the polar head containing a chelated paramagnetic atom, and the lipid moiety that anchors the metal-chelate complex in the liposome membrane. Liposomes with membrane-bound paramagnetic ion demonstrate also a reduced risk of leakage of potentially toxic metals in the body.…”

Section: Targeting Tumors For Diagnostic Visualizationmentioning

confidence: 99%

“…155 Alternatively, DTPA or a similar chelating compound may be chemically derivatized by the incorporation of a hydrophobic group, which can anchor the chelating moiety onto the liposome surface during or after liposome preparation. 156 Different chelators and different hydrophobic anchors were tried for the preparation of 111 In, 99m Tc, Mn-, and Gd-liposomes. [157][158][159][160][161][162][163][164] In the case of MR imaging, for a better MR signal, all reporter atoms should be freely exposed for interaction with water.…”

Section: Targeting Tumors For Diagnostic Visualizationmentioning

confidence: 99%

Targeted pharmaceutical nanocarriers for cancer therapy and imaging

Torchilin

2007

AAPS J

670

428

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Gadolinium-labeled liposomes containing amphiphilic Gd-DTPA derivatives of varying chain length: Targeted MRI contrast enhancement agents for the liver

Cited by 45 publications

References 18 publications

Lipid-based nanoparticles for contrast-enhanced MRI and molecular imaging

Lipid-based nanoparticles for contrast-enhanced MRI and molecular imaging

Potential MRI Contrast Agents Based on Micellar Incorporation of Amphiphilic Bis(alkylamide) Derivatives of [(Gd−DTPA)(H₂O)]²⁻

Targeted pharmaceutical nanocarriers for cancer therapy and imaging

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Gadolinium-labeled liposomes containing amphiphilic Gd-DTPA derivatives of varying chain length: Targeted MRI contrast enhancement agents for the liver

Cited by 45 publications

References 18 publications

Lipid-based nanoparticles for contrast-enhanced MRI and molecular imaging

Lipid-based nanoparticles for contrast-enhanced MRI and molecular imaging

Potential MRI Contrast Agents Based on Micellar Incorporation of Amphiphilic Bis(alkylamide) Derivatives of [(Gd−DTPA)(H2O)]2−

Targeted pharmaceutical nanocarriers for cancer therapy and imaging

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Potential MRI Contrast Agents Based on Micellar Incorporation of Amphiphilic Bis(alkylamide) Derivatives of [(Gd−DTPA)(H₂O)]²⁻