Screening of antipsychotic drugs by wide-bore capillary gas chromatography with nitrogen phosphorus detection--detection levels in plasma.

The detection levels of 12 antipsychotic drugs as ascertained from drug screening were examined in order to use the screening results effectively for treatment of patients or medico-legal examinations in cases of poisoning. Wide-bore capillary gas chromatography with nitrogen phosphorus detection was used for the analysis. The detection limits of drugs in plasma using 3 extraction procedures, single-solvent, 3-step solvent and solid-phase extractions were 50-100 ng/ml, 10-200 ng/ml and 5-50 ng/ml, respectively. The detection limits were compared with blood levels previously reported in the literature. Only 4 drugs were detected at the therapeutic level, thioridazine, floropipamide, sultopride and oxypertine using the single-solvent extraction procedure. Using the 3-step solvent extraction procedure, chlorpromazine, levomepromazine and zotepine in addition to the above 4 drugs were detected. Using the solid-phase extraction procedure, 8 of 12 drugs were able to be detected at the therapeutic level, with the exception of perphenazine, haloperidol, bromperidol and nemonapride. These data were proved to be useful for a rapid forensic diagnosis.