Cardella D S, Levtzow C B, Rifai N, Cross R E, Howlett C M, Parker N C
Department of Pathology, University of North Carolina School of Medicine, Chapel Hill.
Clin Biochem. 1988 Dec;21(6):329-31. doi: 10.1016/s0009-9120(88)80012-2.
A method for the determination of the anti-epileptic drug methsuximide (MSM) and its active metabolite N-desmethylmethsuximide (NDM) is presented. 5-Methyl-5-phenylhydantoin is used as the internal standard. A simple solid-phase extraction procedure utilizing disposable reversed-phase C18 columns is described. Samples are analyzed by gas chromatography with flame ionization detection using a wide-bore capillary column with a permanently bonded, non-polar stationary phase. The MSM assay possesses linearity to 6.0 micrograms/mL, sensitivity to 0.5 microgram/mL, recovery ranging from 93 to 110%, and precision reflected by a SD of +/- 0.37 microgram/mL. The NDM assay displays linearity up to 80.0 micrograms/mL, sensitivity to 5.0 micrograms/mL, recovery of 90 to 100%, and precision reflected by a SD +/- 0.90 microgram/dL. Lack interference is documented for 6 commonly prescribed anti-epileptic drugs and 4 drugs with similar retention times on this stationary phase; only guaifenesin was found to potentially interfere with the determination of methsuximide. We conclude that the method reported here is ideally suited for monitoring therapeutic and toxic levels of this anti-epileptic drug.
本文介绍了一种测定抗癫痫药物甲琥胺（MSM）及其活性代谢物N-去甲基甲琥胺（NDM）的方法。以5-甲基-5-苯基海因作为内标。描述了一种使用一次性反相C18柱的简单固相萃取程序。采用带有永久键合非极性固定相的宽口径毛细管柱，通过气相色谱-火焰离子化检测对样品进行分析。MSM测定的线性范围为6.0微克/毫升，灵敏度为0.5微克/毫升，回收率为93%至110%，精密度以±0.37微克/毫升的标准差表示。NDM测定的线性范围高达80.0微克/毫升，灵敏度为5.0微克/毫升，回收率为90%至100%，精密度以±0.90微克/分升的标准差表示。已证明6种常用抗癫痫药物和4种在该固定相上保留时间相似的药物无干扰；仅发现愈创甘油醚可能干扰甲琥胺的测定。我们得出结论，本文报道的方法非常适合监测这种抗癫痫药物的治疗和中毒水平。
