Simultaneous determination of imipramine and its metabolite desipramine in human plasma by capillary gas chromatography with mass-selective detection

An analytical method for the simultaneous determination of imipramine (IMI) and its N-desmethyl metabolite, desipramine (DIMI) in human plasma by capillary gas chromatography–mass selective detection (GC–MS), with D4-imipramine (D4-IMI) and D4-desipramine (D4-DIMI) as internal standards, was developed and validated. After addition of the internal standards, the compounds were extracted from plasma at basic pH into n-heptane–isoamyl alcohol (99:1, v/v), back-extracted into acidic aqueous solution and re-extracted at basic pH into toluene. Desipramine and D4-desipramine were converted into their pentafluoropropionyl derivatives. The compounds were determined by gas chromatography using a mass selective detector at m/z 234 for IMI, m/z 238 for D4-IMI, m/z 412 for DIMI and m/z 416 for D4-DIMI. The method was applied to clinical samples.     

Localisation of Tricyclic Antidepressant Binding Sites on Serotonin Nerve Terminals

Abstract: High-affinity specific [³H]imipramine binding has been demonstrated in the brain and platelets of various species including man. Electrolytic lesion of the rat dorsal raphe, which resulted in a significant decrease in the endogenous levels of serotonin produced a reduction in the density of [³H]imipramine binding sites in the hypothalamus and cortex. The affinity constants were unchanged. These results suggest that [³H]imipramine binding sites are located on serotonin nerve terminals.     

Sensitive and rapid method for the simultaneous quantification of five antidepressants with their respective metabolites in plasma using high-performance liquid chromatography with diode-array detection

A high-performance liquid chromatographic method with diode array detection (HPLC-DAD) has been developed for the simultaneous separation and quantification of imipramine, amitriptyline, maprotiline, fluoxetine, clomipramine and their respective metabolites using a 500-μl plasma sample and clovoxamine as the internal standard. The substances were eluted on a Symmetry C₁₈ 5-μm column (250×4.6 mm, I.D.). Full UV spectra from 200 to 450 nm were recorded on-line during the entire analysis and were automatically compared to spectra stored in a library. The quantification was performed at 226, 254, and 400 nm. Peak height ratios were linear over a concentration range of 10–3000 ng/ml: the correlation coefficient (r) was better than 0.998 for all substances at each wavelength. Acceptable coefficients of variation are demonstrated for both within-run and day-to-day assays. The method is simple, highly specific and currently being used for drug monitoring and toxicological studies in children and adult patients.