Automated determination of amisulpride by liquid chromatography with column switching and spectrophotometric detection.

A fully automated chromatographic method including on-line blood serum or plasma clean-up, isocratic high-performance liquid chromatography (HPLC) and spectrophotometric detection was developed for quantitative analysis of the new antipsychotic drug amisulpride. After injection of serum or plasma onto the HPLC system and clean-up on a pre-column (10x4.0 mm I.D.) filled with Silica CN 20 micrometer (pore size 10 nm) by an eluent consisting of 8% acetonitrile in deionized water, the chromatographic separation was performed on Lichrospher CN (5 micrometer; 250x4.6 mm I.D.) by an eluent consisting of 50% acetonitrile and 50% aqueous potassium phosphate buffer (0.008 M, pH 6.4). The UV detector was set at 254 nm. The limit of quantification was about 10 microgram/l. The method revealed linearity between 10 and 600 microgram/l (correlation coefficients R(2)>0.9996). The inter-assay reproducibility (coefficient of variation) of quality control samples was between 2.8 and 11.3%. Inaccuracy was between -0.6 and +9.1%. The performance of daily calibration standards revealed an imprecision always below 15% and maximum inaccuracy of 7.7%. The method can be applied to therapeutic drug monitoring as well as pharmacokinetic studies of amisulpride.