Determination of pipamperone in human plasma by high performance liquid chromatography

A sensitive and reproducible high performance liquid chromatographic method was developed for the determination of pipamperone (1'-[4-(4-fluorophenyl)-4-oxobutyl]-[1,4'-bipiperidine]-4'- carboxamide, Dipiperon, CAS 1893-33-0) in plasma samples. Pipamperone and its internal standard (piritramide or 1'-(3-cyano-3,3-diphenylpropyl)-[1,4'-bipiperidine]-4'-carbo xamide) were extracted from alkalinized plasma by liquid-liquid extraction and analysed on a reversed-phase (C18) column. In order to reduce analysis time, a gradient elution technique was applied. Chromatographic peaks were quantified by UV detection at two wavelengths. The method has a detection limit of 2 ng/ml, it proved to have good accuracy and precision, and was linear in the range of 2 to 400 ng/ml. The assay was extensively applied to study the pharmacokinetics in man after oral administration of the drug.