CMR 2005: 13.03: Relaxivity of gadopentetate dimeglumine, gadobutrol and gadobenate dimeglumine in human blood plasma at 0.2, 1.5 and 3 T

Abstract

of gadolinium complex derivatized carriers (lipid, protein or polymer vesicles, liposomes, dendrimers, micelles or nanoparticles engineered from oil-in-water microemulsion templates). Among the various strategies that were explored, previous use of gadolinium oxide (Gd 2 O 3 ) nanoparticles was not found. As shown in a previous paper (1), these particles are very promising because they can be doped with luminescent rare earth ions. Such particles were obtained by applying with modifications the polyol route, which allows the direct precipitation of oxide nanoparticles in a polyalcohol medium. The oxide core is embedded in a functionalized polysiloxane shell prepared by hydrolysis condensation of a mixture of APTES and TEOS. This protective layer allows the dispersion of the particles in aqueous solution. Thanks to the presence of amino groups, organic dyes and biotargeting groups (nucleic acid, biotin, streptavidin) were covalently linked to the polysiloxane network. These particles are efficient for the detection of biomolecules whose presence is revealed by the high fluorescence of organic dyes and/or by luminescence of the photostable Tb 3þ ions. The influence of Gd 3þ in an oxide matrix on the relaxation time of protons of water was investigated by doping an inactive Y 2 O 3 with various amount of gadolinium. The reduction was more pronounced when the gadolinium content increased. Compared with gadoliniumdiethylenetriaminepentaacetic acid, gadolinium oxide nanoparticles doped with terbium and encapsulated in a thin organic fluorophore functionalized polysiloxane layer exert, for the same amount of gadolinium, a greater influence on the relaxation times of protons of water. These multifunctional nanoparticles therefore appear very attractive since they are doubly luminescent, efficient as contrast agents for MRI and able to be functionalized by biotargeting groups. The next step of our work will consist of biodistribution and in vivo imaging studies.

Characterization of MRI contrast agent‐loaded polymeric nanocapsules as versatile vehicle for targeted imaging

“…In comparison to the gadopentetate chelate structure of Magnevist 1 , the gadobenate chelate of Multihance 1 is characterized by the presence of a (bulky) hydrophobic benzyloxymethyl substituent. This imparts Multihance 1 a markedly higher T 1 relaxivity in plasma among gadoliniumbased contrast agents, due to the weak, transient interaction with serum albumin (30,31). Gadovist 1 possesses a cyclic structure and is non-ionic in nature and is the only available contrast agent with 1.0 M formulation, having a viscosity of 4.96 CP at 378C (31-33), while Magnevist 1 and Multihance 1 are available in 0.5 M formulation having a viscosity of 2.9 and 5.3 CP at 378C, respectively.…”