Bioavailability of opipramol from a film-coated tablet, a sugar-coated tablet and an aqueous solution in healthy volunteers.

Opipramol (4-[3-(5H-dibenz[b,f]-azepine-5-yl)-propyl]-1-piperazine-ethanol dihydrochloride, CAS 315-72-0) is regarded as an anxiolytic compound with antidepressant properties, and it is one of the most frequently prescribed psychotropic drugs in Germany. In two open, randomized cross-over studies in 20 (study 1) and 18 (study II) healthy volunteers, the relative bioavailability of 50 mg opipramol-2HCl from a sugar-coated tablet was compared with an aqueous solution, and of 100 mg opipramol-2HCl from a newly developed film-coated tablet was compared with the sugar-coated tablet. The concentrations of opipramol were determined in plasma by high-performance liquid chromatography (HPLC) with photometric detection. The mean dose corrected kinetic parameters of opipramol were similar after administration of all formulations. The peak concentrations of opipramol were 13-15 ng ml-1 (study I) and 28 ng ml-1 (study II). They were achieved after 3 h. The area under the plasma concentration-time curve was about 170 ng ml-1 h (study I) and about 320 ng ml-1 h (study II). The terminal plasma half-life was 11 h. Bioequivalence was proven between sugar-coated tablet and aqueous solution, and between film-coated tablet and sugar-coated tablet, respectively. In addition, in study II the plasma concentrations and pharmacokinetic parameters of the metabolites opipramol N-oxide and deshydroxyethyl opipramol were determined.

Determination of opipramol in human plasma by high-performance liquid chromatography with photometric detection using a cyanopropyl column.

A high-performance liquid chromatographic method is described for the determination of opipramol in human plasma. Opipramol was extracted into tert.-butylmethyl ether, separated on a cyanopropyl silica column and detected at 254 nm. Imipramine was used as internal standard. The limit of quantitation was 250 pg/ml using 1.5 ml plasma. Precision was better than 9%, inaccuracy less than 8%. The assay is more sensitive than previously published methods, and it has been applied to the analysis of plasma samples from a pharmacokinetic study.

Fatal poisoning with the antidepressive agent opipramol.

An ingestion of an unknown quantity ( < or = 3000 mg) of opipramol dihydrochloride in a suicide case is described. Quantitation of opipramol and its deshydroxyethyl metabolite was performed simultaneously after liquid-liquid extraction from alkalinized samples prior to HPLC analysis. Postmortem concentrations of opipramol and of the metabolite in body fluids and organs are given. The distribution pattern of opipramol in tissue was comparable to findings from animal studies. The results showed the high uptake of opipramol in parenchymal tissues resulting in a low blood concentration. A possibly low contribution of deshydroxyethyl opipramol to the antidepressive effect may be concluded as the concentration was considerably lower in brain compared to other organs.