The application of HPLC to the determination of some 1,4 benzodiazepines and their metabolites in plasma.

1 A high pressure liquid chromatographic (HPLC) assay has been developed for the measurement of chlordiazepoxide and its metabolites, N-desmethylchlordiazepoxide and demoxepam in microgram concentrations in human plasma. 2 Another metabolite was detected in appreciable amounts in the plasma from patients receiving high doses of chlordiazepoxide after the first 3 days of treatment. 3 Preliminary studies would indicate that this metabolite is N-desmethyldiazepam. 4 A modified HPLC system, using a microparticulate column was developed to separate N-desmethyldiazepam from chlordiazepoxide and its other metabolites in plasma.