title: Magnetic starch microspheres, biodistribution and biotransformation. A new organ-specific contrast agent for magnetic resonance imaging.
abstract: The biodistribution and elimination of magnetic starch microspheres (MSM) were studied qualitatively and quantitatively by radioiron tracer studies and relaxation time measurements. One hour after injection of MSM (1 mg/kg of Fe), 85% +/- 5% of the dose was accumulated in the liver and 6.5% +/- 1.3% [corrected] in the spleen. The hepatic clearance led to 50% reduction in the T2 relaxation time of liver tissue. This T2 effect was halved after 24 hours and T2 reversed to baseline value within 5 days after injection. The radioiron was gradually cleared from the liver with a t1/2 of 4 to 5 days. Six weeks after injection of MSM, 72% +/- 7% of the radioiron dose was detected in the circulation in a nonsuperparamagnetic form associated with the erythrocytes. The results indicate a redistribution of iron from the liver and spleen via the erythroid bone marrow to the erythrocytes after injection of MSM.
authors: Department of Pharmacology, University of Oslo, Norway.
authors: A K
authors: AK
authors: Fahlvik
authors: E
authors: E
authors: Holtz
authors: U
authors: U
authors: Schrøder
authors: J
authors: J
authors: Klaveness
mesh_terms: D000818:Animals; D001711:Biotransformation; D003287:Contrast Media / Q000493:pharmacokinetics*; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D008297:Male; D008863:Microspheres; D051381:Rats; D011919:Rats, Inbred Strains; D013213:Starch / Q000493:pharmacokinetics*; D014018:Tissue Distribution
chemical_list: D003287:Contrast Media; D013213:Starch