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Title: Relaxometry, luminescence measurements, electrophoresis, and animal biodistribution of lanthanide(III) complexes of some polyaza macrocyclic acetates containing pyridine

Four Gd{sup 3+} complexes [Gd(BP2A){sup +}, Gd(PC2A){sup +}, Gd(PCTA){sup 0}, and Gd(BPO4A){sup {minus}}] with polyazamacrocyclic ligands that contain a pyridine moiety were prepared and examined for possible use as MRI contrast enhancement agents. The authors estimated the number of inner sphere water molecules (q{sub Gd}) for the Gd{sup 3+} complexes from the values of q found for the Tb{sup 3+} and/or Eu{sup 3+} complexes by luminescence lifetime measurements. It was estimated that q{sub Gd} = 3.5, 3.3, 2.4, and 0.2 for Gd(BP2A){sup +}, Gd(PC2A){sup +}, Gd(PCTA){sup 0}, and Gd(BPO4A){sup {minus}}, respectively. The inner sphere relaxivities (r{sub 1,inner}) of these tetraaza macrocyclic complexes were higher than that of Gd(DOTA){sup {minus}} [i.e. 6.79 for Gd(BP2A){sup +}, 6.21 for Gd(PC2A){sup +}, and 4.60 for Gd(PCTA){sup 0} mM{sup {minus}1}s{sup {minus}1} at 40 MHz and 25{degrees}C], but the normalized relaxivities per q{sub Gd} (1.94, 1.88, and 1.92 mM{sup {minus}1}s{sup {minus}1}, respectively) were comparable to that of Gd(DOTA){sup {minus}}. A quantitative treatment of the NMRD profiles based on Solomon-Bloembergen-Morgan theory, using the NMRD profile of Gd(BPO4A){sup {minus}} to correct for an outer sphere contribution, showed that the complexes exhibit characteristics similar to that of Gd(DOTA){sup {minus}} but with shorter electronic relaxation times. Tissue biodistribution results usingmore » radioactive {sup 153}Sm and {sup 159}Gd complexes in rats indicate that the cationic [{sup 153}Sm-(BP2A){sup +} and {sup 153}Sm(PC2A){sup +}] complexes accumulate preferably in the bone tissue while the neutral [{sup 153}Sm-(PCTA){sup 0}] and anionic [{sup 153}Sm(BPO4A){sup {minus}}] complexes appear to have renal clearances similar to those of other low molecular weight contrast agents [i.e. Gd(DTPA){sup 2{minus}} and Gd(DOTA){sup {minus}}].« less
Authors:
;  [1] ; ;  [2] ; ;  [3]
  1. Univ. of Texas, Dallas, Richardson, TX (United States)
  2. Dow Chemical Co., Freeport, TX (United States)
  3. Univ. of Mons-Hainault (Belgium)
Publication Date:
OSTI Identifier:
75715
Resource Type:
Journal Article
Resource Relation:
Journal Name: Inorganic Chemistry; Journal Volume: 34; Journal Issue: 8; Other Information: PBD: 12 Apr 1995
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; 40 CHEMISTRY; RARE EARTH COMPLEXES; UPTAKE; STRUCTURAL CHEMICAL ANALYSIS; LUMINESCENCE; ELECTROPHORESIS; ACETATES; PYRIDINES; SAMARIUM 135; GADOLINIUM 159; LABELLED COMPOUNDS; RATS; SKELETON