Paramagnetic liposomes as MRI contrast agents: influence of liposomal physicochemical properties on the in vitro relaxivity

Fossheim, Sigrid L.; Fahlvik, Anne K.; Klaveness, Jo; Müller, Robert N.

doi:10.1016/s0730-725x(98)00141-6

Cited by 147 publications

(123 citation statements)

References 19 publications

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“…Liposomes are vesicles which can carry paramagnetic complexes for magnetic resonance applications either by encapsulating them into the interior aqueous volume or by incorporating paramagnetic moieties into the membranes of liposomal vesicles (Fossheim et al 1999;Tilcock et al 1992). In the latter case the paramagnetic amphiphilic gadolinium(III) complex becomes an integral part of the liposomal lamella.…”

Section: Resultsmentioning

confidence: 99%

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

et al. 2005

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Three amphiphilic DTPA bisamide derivatives containing long-chain phenylalanine esters (with 14, 16 and 18 carbon atoms in the alkyl chain) were synthesized and their corresponding gadolinium(III) complexes were prepared. The attempts to form paramagnetic micelles carrying the gadolinium(III) complexes yielded unstable or polydisperse micelles implying that the presence of the bulky aromatic side groups in the amphiphilic Gd-DTPA bisamide complexes results in an inefficient packing of the paramagnetic complex into micelles. All complexes were efficiently incorporated into liposomes consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), yielding stable and monodisperse paramagnetic liposomes. All liposomes had a comparable size, typically between 120 and 160 nm. As a result of the reduced mobility of the gadolinium(III) complexes, solutions of these supramolecular structures show a higher relaxivity than solutions of Gd-DTPA. However, the relaxivity gain is lower compared to compounds consisting of purely aliphatic chains of the same length, most likely due to the less efficient packing or increased local mobility of the gadolinium(III) complex. In the case of the Gd-DTPA bisamide complex with 18 carbon atoms, the immobilization inside the liposomal structure is less effective, probably because the aliphatic chains of the complex are longer than the alkyl chains of the DPPC host, resulting in a relatively high local mobility. The paramagnetic liposomes containing the Gd-DTPA bisamide complexes with 14 carbon atoms showed the highest relaxivity because the optimal length match between the hydrophobic chains of the DPPC and the ligand allowed very efficient packing of the paramagnetic complex into the liposome.

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Section: Resultsmentioning

confidence: 99%

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

et al. 2005

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“…For visualization of temperature-induced release, the contrast agent has to be encapsulated inside the TSL. [91][92][93] Below the T m , the contrast agent interacts mainly with the water present inside the TSL, because water exchange with the exterior of the TSL is limited. As a result, the visibility of the contrast agent is reduced when compared with free contrast agents.…”

Section: Signal Mechanismmentioning

confidence: 99%

“…84 Around the T m , the contrast agent is released and the signal change is maximal and comparable with the signal change achieved with free contrast agent. 84,86,91,92 This makes it possible to strongly change an MRI signal by altering temperature. 92 The maximum achievable signal change depends on the type of contrast agent, 86 lipid composition, 86,91 vesicle size, 51,91 and concentration of the encapsulated contrast agent.…”

Section: Signal Mechanismmentioning

confidence: 99%

“…84,86,91,92 This makes it possible to strongly change an MRI signal by altering temperature. 92 The maximum achievable signal change depends on the type of contrast agent, 86 lipid composition, 86,91 vesicle size, 51,91 and concentration of the encapsulated contrast agent. 86,91 The heating method might also play a role, eg, focused ultrasound adds a mechanical release component to the signal mechanism.…”

Section: Signal Mechanismmentioning

confidence: 99%

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Thermosensitive liposomal drug delivery systems: state of the art review

Kneidl¹,

Peller²,

Winter³

et al. 2014

IJN

147

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Thermosensitive liposomes are a promising tool for external targeting of drugs to solid tumors when used in combination with local hyperthermia or high intensity focused ultrasound. In vivo results have demonstrated strong evidence that external targeting is superior over passive targeting achieved by highly stable long-circulating drug formulations like PEGylated liposomal doxorubicin. Up to March 2014, the Web of Science listed 371 original papers in this field, with 45 in 2013 alone. Several formulations have been developed since 1978, with lysolipid-containing, low temperature-sensitive liposomes currently under clinical investigation. This review summarizes the historical development and effects of particular phospholipids and surfactants on the biophysical properties and in vivo efficacy of thermosensitive liposome formulations. Further, treatment strategies for solid tumors are discussed. Here we focus on temperature-triggered intravascular and interstitial drug release. Drug delivery guided by magnetic resonance imaging further adds the possibility of performing online monitoring of a heating focus to calculate locally released drug concentrations and to externally control drug release by steering the heating volume and power. The combination of external targeting with thermosensitive liposomes and magnetic resonance-guided drug delivery will be the unique characteristic of this nanotechnology approach in medicine.

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“…The paramagnetic chelate, gadolinium diethylentriaminepentaacetic bis-methylamide (GdDTPA-BMA; Gadodiamide, Amersham Health AS, Olso, Norway), was encapsulated within thermosensitive liposomes, as previously described (8,12). The phospholipid composition was 95% (w/w) distearoylphosphatidylcholine and 5% (w/w) distearoylphosphatidylglycerol, and the total phospholipid concentration was 50 mg/mL.…”

Section: Paramagnetic Thermosensitive Liposomesmentioning

confidence: 99%

Local delivery of magnetic resonance (MR) contrast agent in kidney using thermosensitive liposomes and MR imaging‐guided local hyperthermia: A feasibility study in vivo

Salomir

Palussière

Fossheim³

et al. 2005

Magnetic Resonance Imaging

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Purpose:To investigate the feasibility of local delivery of a magnetic resonance (MR) contrast agent in vivo using paramagnetic thermosensitive liposomes and infrared (IR) laser-induced local hyperthermia under real-time MR thermometry on rabbit kidney. Materials and Methods:Respiratory gated, radio frequency (RF)-spoiled gradient-echo sequences were used for precise MR temperature mapping (SD ϭ 1°C). In vivo heating experiments confirmed local release of MR contrast agent from liposomes.Results: T 1 decreased from 800 msec to about 500 msec, as measured after tissue cooling, in those locations where the renal parenchyma was heated above the phase transition temperature of the liposome membrane. Conclusion:The release of MR contrast agent has been demonstrated in rabbit kidney in vivo. This may be used as a reporter for simultaneous release of therapeutic agents.

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Paramagnetic liposomes as MRI contrast agents: influence of liposomal physicochemical properties on the in vitro relaxivity

Cited by 147 publications

References 19 publications

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

Thermosensitive liposomal drug delivery systems: state of the art review

Local delivery of magnetic resonance (MR) contrast agent in kidney using thermosensitive liposomes and MR imaging‐guided local hyperthermia: A feasibility study in vivo

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