Simultaneous determination of chlorpromazine and levomepromazine in human plasma and urine by high-performance liquid chromatography using electrochemical detection.

A rapid, selective and sensitive method for the simultaneous determination of chlorpromazine and levomepromazine in human plasma and urine has been developed using high-performance liquid chromatography with electrochemical detection. The unchanged drugs and internal standard extracted from plasma and urine were separated by reversed-phase high-performance liquid chromatography. The influence of acetonitrile concentration and of the pH of the mobile phase were investigated. The detection limits were 100 pg for chlorpromazine and for levomepromazine. In comparison with three other detection systems this was found to be the most sensitive method. This method was successfully applied to the simultaneous determination of chlorpromazine and levomepromazine in human plasma and urine for pharmacokinetic studies.