A rapid and simple high performance liquid chromatographic (HPLC) method to
measure moclobemide and its N-oxide metabolite (Ro12-5637) in human urine
has been developed by modifying an existing HPLC technique. Sample preparat
ion involves mixing urine with water and internal standard (Roll-9900) foll
owed by centrifugation. Separation of the analytes in the supernatant was a
chieved using a reversed-phase Spherisorb C6 column (Phenomenex, 5 mum, 250
x 4.6 mm i.d.) eluted with methanol-triethylamine-phosphate buffer (pH7.0)
. Moclobemide and Ro12-5637 were detected by UV absorption at 240 nm.
The limits of quantification for moclobemide and Ro12-5637 were 0.5 and 2.0
mug/mL, respectively. This method has been used to measure the concentrati
ons of moclobemide and Ro12-5637 in urine samples from healthy Caucasians a
dministered a 300 mg oral dose of moclobemide.