Metabolism of an Antidepressant, Lofepramine (DB-2182) in Human

Blood Concentration and Urinary Excretion

Abstract

The concentrations of Lofepramine (DB-2182) and its metabolites in human blood and urine were studied by using gas chromatographic-massfragmentography. When administered orally, Lofepramine was well absorbed and rapidly metabolised to the active metabolite: Desipramine. In the case of 50 mg single dose, the maximum blood concentrations of Lofepramine and Desipramine were 13.0-43.0 ng/ml at 1-2 hrs and 2.3-2.9 ng/ml at 1.5-3 hrs, respectively. In 24 hrs, 0.01-0.04% of Lofepramine, 0.1-0.35% of Desipramine and 1-6% of 2-Hydroxydesipramine against initial doses were excreted in urine.
In the chronic treatment, the blood concentration of Desipramine was gradually raised until the steady-state level.
After the final dose, the urinary excretion of Desipramine was continued for 3days.