Simultaneous determination of topiramate, carbamazepine, phenytoin and phenobarbital in plasma by gas chromatography with nitrogen phosphorus detector

摘要

Topiramate and the other frequently co-administered antiepileptic drugs carbamazepine, phenytoin and phenobarbital were determined in 100 μL plasma samples by gas chromatography with nitrogen phosphorus detection (GC-NPD), after a one-step liquid-liquid extraction with ethyl acetate, followed by flash methylation with trimethylphenylammonium hydroxide. Total chromatographic run time was 12.5 min. Intra-assay and inter-assay precision was 2.5-7.3% and 1.6-5.2%, respectively. Accuracy was 100.1-104.2%. The limit of quantitation was 1 μg mL-1 for all analytes, proving suitable for routine application in therapeutic drug monitoring of antiepileptic drugs.