Polymorphic acetylation of 7-amino-clonazepam in human liver cytosol.

The N-acetylation of the reduced metabolite of clonazepam 7-amino-clonazepam was studied in cytosolic preparation from human fetal and adult livers. The metabolite formed 7-acetamido-clonazepam was measured with high performance liquid chromatography. A bimodal distribution of the N-acetyltransferase activities was observed in cytosols from human adult livers. These activities were 117 +/- 11 and 27 +/- 16 pmoles X mg-1 X min-1 for rapid and slow acetylators, respectively. The data observed in the fetal specimens did not allow any conclusion about bimodality because of a low number of samples.