TABLE 4

Percentage of radioactivity of casopitant and its relevant metabolites in male and female rat brain after a single-dose oral administration of 15 mg/kg [14C]casopitant

Observed metabolite radioactivity was determined by 96-well fraction collection with scintillation counting for 5 min after a chromatographic separation was performed by HPLC. Percentages obtained from the radiochromatogram were adjusted for the extraction recovery. The percentage of radioactivity per time point does not equal 100% because only distinct radioactive peaks were assigned values and a few minor metabolites were not reported.

PeakBrain Radioactivity
MaleFemale
2 h8 h2 h8 h24 h
%
Casopitant66.550.781.675.450.0
M39.1BQLN.D.N.D.N.D.
M12 + M69BQLBQL2.13.15.3
M1311.9BQL9.411.523.8
M31aBQL2.0N.D.
Total μg Eq/g in brain0.6290.2622.052.500.620
  • BQL, below quantification limit, set to 25 cpm as peak area; N.D., not detected.

  • a ✓, observed by HPLC-mass spectrometry only.