[Determination of dextromethorphan and its major metabolite dextrorphan by gas chromatography]

A gas chromatography assay has been developed for the determination of dextromethorphan and dextrorphan in human fluids. Drugs are extracted with chloroform-isopropanol-n-heptane (50/17/33, v/v) form alkalinized samples using cyclizine as an internal standard, analysed using a 3 p. cent OV-17 column, and detected by selective nitrogen detection. The lower detection limits are 0.4 and 0.7 micrograms/l for dextromethorphan and dextrorphan, respectively.