title: Magnetic resonance of a dextran-coated magnetic fluid intravenously administered in mice.
abstract: Magnetic resonance was used to investigate the kinetic disposition of magnetite nanoparticles (9.4 nm core diameter) from the blood circulation after intravenous injection of magnetite-based dextran-coated magnetic fluid in female Swiss mice. In the first 60 min the time-decay of the nanoparticle concentration in the blood circulation follows the one-exponential (one-compartment) model with a half-life of (6.9 +/- 0.7) min. The X-band spectra show a broad single line at g approximately 2, typical of nanomagnetic particles suspended in a nonmagnetic matrix. The resonance field shifts toward higher values as the particle concentration reduces, following two distinct regimes. At the higher concentration regime (above 10(14) cm(-3)) the particle-particle interaction responds for the nonlinear behavior, while at the lower concentration regime (below 10(14) cm(-3)) the particle-particle interaction is ruled out and the system recovers the linearity due to the demagnetizing field effect alone.
authors.affiliation: Instituto de Biologia, Universidade de Brasília, 70910-900 Brasília (DF), Brazil.
authors.forename: L M
authors.initials: LM
authors.lastname: Lacava
authors.forename: Z G
authors.initials: ZG
authors.lastname: Lacava
authors.forename: M F
authors.initials: MF
authors.lastname: Da Silva
authors.forename: O
authors.initials: O
authors.lastname: Silva
authors.forename: S B
authors.initials: SB
authors.lastname: Chaves
authors.forename: R B
authors.initials: RB
authors.lastname: Azevedo
authors.forename: F
authors.initials: F
authors.lastname: Pelegrini
authors.forename: C
authors.initials: C
authors.lastname: Gansau
authors.forename: N
authors.initials: N
authors.lastname: Buske
authors.forename: D
authors.initials: D
authors.lastname: Sabolovic
authors.forename: P C
authors.initials: PC
authors.lastname: Morais
mesh_terms: D000818:Animals; D001775:Blood Circulation; D003287:Contrast Media / Q000493:pharmacokinetics*; D003911:Dextrans / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D005260:Female; D052203:Ferrosoferric Oxide; D007501:Iron / Q000493:pharmacokinetics*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008280:Magnetics; D051379:Mice; D010087:Oxides / Q000493:pharmacokinetics*; D013997:Time Factors
chemical_list: D003287:Contrast Media; D003911:Dextrans; D010087:Oxides; D007501:Iron; D052203:Ferrosoferric Oxide