Synthesis and renal excretion of technetium-99m-labeled organic cations.
Organic cations are excreted more efficiently than organic anions in uremia suggesting superiority as renal imaging agents. In this study, three 99mTc-labeled cationic cyclam complexes were synthesized and their renal clearance quantified in rats. The complexes are cleared at a rate of about 2.5-3 times that of inulin and about 60% that of p-amino-hipurate. Inhibition of 99Tc-cyclam excretion by quinine indicates transport by the organic cation process. Comparative in vivo imaging experiments demonstrated that in normal rats 99mTc-cyclam reached peak renal activity 1.8 +/- 0.6 min after injection, a value intermediate between that for [131I]OIH (1.0 +/- 0) and 99mTc-MAG3 (2.8 +/- 0.6). In rats injected with the acute nephrotoxin cisplatin, the times to peak were lengthened with the relative order being 99mTc-cyclam > 99mTc-MAG3 > [131I]OIH. The results demonstrate that cationic complexes may be useful for renal imaging diagnostic applications.
Herzog
K M
KM
College of Pharmacy, Department of Chemistry, University of Cincinnati, OH 45267-0004.
Deutsch
E
E
Deutsch
K
K
Silberstein
E B
EB
Sarangarajan
R
R
Cacini
W
W
D000818:Animals; D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D006573:Heterocyclic Compounds, 1-Ring; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D015609:Organotechnetium Compounds / Q000138:chemical synthesis*; D011073:Polyamines / Q000138:chemical synthesis*; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley
D006571:Heterocyclic Compounds; D006573:Heterocyclic Compounds, 1-Ring; D015609:Organotechnetium Compounds; D011073:Polyamines; C045774:technetium Tc 99m 1,4,8,11-tetraazaundecane; C045773:technetium Tc 99m cyclam