1989 Volume 4 Issue 4 Pages 411-418
Metabolite composition in rat plasma, tissues, urine and bile was studied by TLC radiochromatography after oral administration of [14C]zonisamide at 20 mg/kg. Metabolites excreted with dog and monkey urine were analyzed by TLC-radiochromatography and mass spectrometry.
Radioactivity in rat plasma, erythrocytes and preputial gland virtually consisted of unchanged zonisamide both after stngle and consecutive administration. More than 4 metabolites were detected in rat urine : the major component was unchanged zonisamide. The composition was not significantly different after intravenous administration. Unchanged zonisamide was detected as a major radioactive component also in the bile. Metabolite composition in dog and monkey urine was rather different from that in rat, however, major component in common was unchanged zonisamide. Besides zonisamide, N-O cleaved compound, hydroxylated zonisamide, acetylated zonisamide and carboxylic acid compound were identified by mass spectrometry.
