AUTOMATED-DETERMINATION OF TRIMIPRAMINE AND N-DESMETHYLTRIMIPRAMINE IN HUMAN PLASMA OR SERUM BY HPLC WITH ONLINE SOLID-PHASE EXTRACTION

A fully automated method including column-switching and isocratic high performance liquid chromatography (HPLC) was developed for determination of the tricyclic antidepressant trimipramine (T) and its N-demethylated metabolite N-desmethyltrimipramine (DT). The limit of quantification was below 10 ng/ml For T and DT. The assay revealed linearity between detector response and drug concentration in a therapeutically relevant range of 10 to 500 ng/ml. The mean intra- and interassay variabilities were 6.2 and 12.3%, respectively, for T and 4.7 and 8.7%,respectively, for DT. The method can be applied to therapeutic drug monitoring of patients under T therapy and may be useful for pharmacokinetic studies.