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In vivo pharmacokinetics of [ 14 C]‐etanidazole
Author(s) -
Breccia Alberto,
Gattavecchia Enrico,
Feroci Giorgio,
Fini Adamo,
Busutti Luciano
Publication year - 1994
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580340502
Subject(s) - chemistry , in vivo , pharmacokinetics , urine , polarography , nitro , imidazole , radiochemistry , pharmacology , stereochemistry , chromatography , organic chemistry , biochemistry , medicine , inorganic chemistry , alkyl , microbiology and biotechnology , biology
Etanidazole, like other nitroaromatic radio sensitizers, displays its biological activity mostly through two molecular groups: the nitro group and the side‐chain attached to the nitrogen in the imidazole ring in position 1. To monitor the behaviour of the two moieties in vivo, labelled Etanidazole, containing a 14 C atom in position 2 of the side‐chain was prepared and administered to four patients at a 2 gm −2 dose: the concentration of Etanidazole in different fluids and tissues was followed either by titrating the NO 2 group by polarography or determining the total radioactivity, carried by the side‐chain. Two different profiles of Etanidazole concentration were found, in blood and urine, as determined by the two methods. The concentration was found to be higher when measured as total radioactivity than when measured by polarography; this difference was greater in blood (49%) than in urine (27%). Since the two methods involve determination of different portions of the Etanidazole molecule, we hypothesized a degradation of the drug to explain these differences.