A modified HPLC method for rapid detection of moclobemide and its N-oxide metabolite in human urine

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.