Toxicological Determination of Benzodiazepines in Serum: Methods and Concentrations Associated with High-Dose Intravenous Therapy with Diazepam

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Abstract
A rapid and simple procedure for the determination of benzodiazepines in biological samples is described. Five common benzodiazepines (diazepam, oxazepam, clorazepate, flurazepam and chlordiazepoxide) and/or their major metabolites are extracted from a buffered serum sample at pH 9.2 by a mixture of toluene, hexane and isoamyl alcohol. The phases are separated by centrifugation and a small aliquot of the organic layer is injected into a gas chromatograph equipped with an electron-capture detector. The drugs are identified and quantitated by comparison with standards simultaneously and similarly processed. A sample can be analyzed in about 30 min. The technique is illustrated by its application to sequential samples from a patient being treated for delirium tremens with large i.v. doses of diazepam. Serum diazepam, N-desmethyldiazepam and oxazepam concentrations several times higher than usually encountered therapeutically were observed.