Urinary elimination of nitrazepam and its main metabolites.
Nitrazepam and its main metabolites, 7-aminonitrazepam and 7-acetamidonitrazepam, free and conjugated, were determined in the human urine after a single oral dose of 5 mg. The determinations were performed by GLC method using 63Ni-EC-detector for unchanged nitrazepam and nitrogen selective detector for the metabolites. Unchanged nitrazepam was poorly eliminated through the kidneys (about 1% of the dose). The interindividual variation of total excreted urinary metabolites was large ranging between 848-4933 microgram (17-99% of the dose during 7 days). Of this amount conjugated metabolites made up 57%. The urinary half-lives of free and conjugated-7-aminonitrazepam were (mean and ranges) 44 (23-65) and 46 (25-69) hrs, and of 7-acetamidonitrazepam 12 (5-31) and 18 (5-46) hrs, respectively. The half-lives of the excreted amounts of the metabolites did not correlate with any pharmacokinetic parameter of unchanged nitrazepam in serum.
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D006207:Half-Life; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008297:Male; D009567:Nitrazepam / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*
D009567:Nitrazepam