Simultaneous determination of paroxetine, risperidone and 9-hydroxyrisperidone in human plasma by high-performance liquid chromatography with coulometric detection

A method for the simultaneous determination of paroxetine, risperidone and its main metabolite 9-hydroxyrisperidone in human plasma has been developed . The procedure involved a multistep solid-phase liquid extraction with an internal standard. The drugs were separated on a cyano column followed by c oulometric detection. This method described here has sufficient sensitivity to quantitate paroxetine accurately in the range 5-500 ng/ ml with a lower limit of detection of 1 ng/ml and risperidone and its main metabolite 9-hy droxyrisperidone in the range 2-100 ng/ml with a lower limit of detection o f 1 ng/ml when 1 ml of plasma was used for the analysis. The precision, acc uracy and specificity have been proven, and show that the method is reliabl e for clinical studies and routine drug monitoring. Copyright (C) 2000 S. K arger AG, Basel.