Thin-layer chromatographic method for determination of diazepam and its major metabolite, N-desmethyldiazepam, in human serum

Rapid and simple chromatographic method for the determination of diazepam and its major metabolites in human plasma and urine

A simple, rapid, sensitive and selective HPLC method has been developed for the analysis of diazepam (DZP) and its major metabolites, N-desmethyldiazepam (DMDZP), temazepam (TZP) and oxazepam (OZP), in plasma and urine, using clonazepam (CZP) as the internal standard and chloroform as the extracting solvent, with a 10 ng/ml limit of quantitation for the four assayed drugs, and an average (+/-S.D.) recovery of 87.7+/-6.46%, 92.9+/-5.31%, 91.4+/-4.01% and 91.7+/-2.68% for DZP, DMDZP, TZP and OZP, respectively (from plasma), and 89.6+/-2.26%, 90+/-4.24%, 87.45+/-0.64% and 94.50+/-0.71% for DZP, DMDZP, TZP and OZP, respectively (from urine). The method has also proved to be selective and reproducible.

Analysis of the 1,4-benzodiazepines by methods based on hydrolysis

The analytical applications of the hydrolysis of 1,4-benzodiazepines to the corresponding benzophenone derivatives are reviewed according to the analytical methods used for their final determination. The scope and limitations of the individual methods for the hydrolysis products are discussed: Colour reactions, photometry, fluorimetry, thin-layer chromatography, gas chromatography and high-performance liquid chromatography. Published data on the kinetic parameters and mechanisms are summarized in an attempt to explain the problems involved in exploiting this reaction for analytical applications.

Determination of diazepam and its major metabolites in man and in the cat by high-performance liquid chromatography

A rapid, sensitive and specific high-performance liquid chromatography (HPLC) assay was developed for the determination of diazepam, and its major metabolites, oxazepam, temazepam and nordiazepam in plasma, blood, and urine of humans and cats. The assay for the compounds involves extraction into benzene--methylene chloride (90:10) from plasma, blood or urine buffered to pH 9.0. In both species the overall recovery of diazepam and its major metabolites from plasma or blood ranged from 60 +/- 3.2 to 89 +/- 13% (S.D.) and for urine from 79 +/- 7.9 to 93 +/- 10.5% (S.D.). The sensitivity limit of the assay using UV detection at 254 nm was 50 ng/ml of plasma and blood in both species except for human urine (post-Glusulase) which was 200 ng/ml. The HPLC assay was used to monitor the plasma concentration--time profile in humans following a 10-mg oral dose of diazepam and the blood concentration time profile of diazepam and nordiazepam in cats following a 10 mg/kg intravenous dose of either diazepam or nordiazepam. The HPLC assay data correlated well with data generated by an electron-capture--gas--liquid chromatography assay.