title: Biodistribution and excretion of 153Gd-labeled gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid following repeated intravenous administration to rats.
abstract: OBJECTIVE
  We investigated the distribution of radioactivity in tissues and organs and its disappearance following repeated intravenous (i.v.) administration of 153Gd-labeled gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) to rats.
  
  
  METHODS
  A high total dose of 250 mumol/kg of 153Gd-labeled Gd-EOB-DTPA (a daily injection of 50 mumol/kg is equivalent to 92.5 kBq per animal on 5 consecutive days) was given to conscious rats by fast i.v. injection via a tail vein. The organ distribution and the body elimination into urine and feces were investigated at time points 3, 7, 14, and 21 days following the last injection; five animals were used at each time point. All samples were measured by gamma counting of 153Gd over a 10-min period.
  
  
  RESULTS
  The radioactivity quickly disappeared from the body, mostly through feces. In the liver, no radioactivity could be detected at 3 days postinjection. At 21 days postinjection, only 0.002% of the gadolinium injected was detected, the vast majority (approximately 95%) of which was found in the kidneys.
  
  
  CONCLUSIONS
  After repeated i.v. administration of a total dose of 250 mumol/kg of 153Gd-labeled Gd-EOB-DTPA, the elimination from the body was found to be 99.998% complete. Only negligible long-term retention of radioactive gadolinium was observed despite the relatively high dose injected. No perceptible evidence for decomplexation of Gd-EOB-DTPA could be found.
authors.affiliation: Research Laboratories of Schering AG, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Mühler
authors.forename: H J
authors.initials: HJ
authors.lastname: Weinmann
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000493:pharmacokinetics*; D005682:Gadolinium / Q000493:pharmacokinetics; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D007262:Infusions, Intravenous; D008099:Liver / Q000378:metabolism*; D008297:Male; D011868:Radioisotopes / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
chemical_list: D003287:Contrast Media; D011868:Radioisotopes; C073590:gadolinium ethoxybenzyl DTPA; D005682:Gadolinium; D019786:Gadolinium DTPA