Simultaneous quantification of citalopram, clozapine, fluoxetine, norfluoxetine, maprotiline, desmethylmaprotiline and trazodone in human serum by HPLC analysis

We describe an analytical procedure for the simultaneous quantification of citalopram (seropram), clozapine (leponex), fluoxetine (fluctine), norfluoxetine, maprotiline (ludiomil), desmethylmaprotiline and trazodone (trittico) in human serum within a period of 11.5 minutes using reversed phase HPLC. After 2 liquid/liquid extractions in the sample preparation phase, the drugs and metabolites were separated on a C 18 column using a mobile phase consisting of acetonitrile/buffer (30/70, v: v) at 70 °C, a flow rate of 1.5 ml/min and haloperidol as internal standard. Absorption and native fluorescence signals of the eluted compounds were detected simultaneously at 260 nm and 227/300 nm (excitation/emission), respectively. The calibration ranges for citalopram, clozapine, fluoxetine, norfluoxetine, maprotiline, and desmethylmaprotiline ranged from 50 - 400 μg/l and for trazodone from 50 - 3,200 μg/l. The CVs varied between 0.6% and 5.5% (within-run) and between 3.2% and 7.1% (between-run). Recoveries were >90% for all pharmaceuticals. We noticed no interferences from several commonly used drugs.