[Plasma assay of haloperidol by high performance liquid chromatography].

Haloperidol is extracted with hexane-isoamyl alcohol in the presence of two internal standards, chlorohaloperidol and spiroperidol. For chromatographic separation, a C18 reversed-phase column and a mobile phase of acetonitrile/methanol/phosphate buffer are used. Detection is by UV absorption spectrophotometry at 245 nm, and the limit of detection was set to 1 ng/ml. To study hydroxyhaloperidol, a metabolite of haloperidol which has much less UV-absorption than haloperidol, detection must be seat 220 nm.