Determination of risperidone and 9-hydroxyrisperidone in plasma, urine and animal tissues by high-performance liquid chromatography.

A high-performance liquid chromatographic method has been developed for the simultaneous determination of the new antipsychotic risperidone and its major metabolite 9-hydroxyrisperidone in plasma, urine and animal tissues. The alkalinized plasma samples were extracted with ethyl acetate and further purified prior to reversed-phase chromatography with ultraviolet detection at 280 nm. The method could also be applied to urine samples and animal tissue homogenates. Quantification limits were 2 ng/ml for plasma and urine and 10 ng/g for animal tissue. The method was applied to pharmacokinetic studies in experimental animals, human volunteers and patients.