Rapid determination of diazepam and nordiazepam in plasma by electron capture gas--liquid chromatography. Application in clinical pharmacokinetic studies.
A rapid method was developed for the determination of diazepam and nordiazepam (N-desmethyldiazepam) in human plasma using electron capture gas--liquid chromatography (GLC--ECE). The concentration of diazepam and nordiazepam is determined using 0.5 ml of plasma extracted with 1.0 ml of benzene containing 25 ng/ml of methylnitrazepam as the internal standard. The benzene extract is removed and an aliquot is subjected to automated GLC-ECD analysis. The method has a sensitivity limit of 5 ng diazepam and 10ng nordiazepam per milliliter of plasma. The method was used to determine the plasma levels in man following the first 5-mg diazepam dose, as well as during chronic oral administration of 5 mg diazepam three times daily and 15 mg diazepam once a day.
D001322:Autoanalysis; D002849:Chromatography, Gas; D002853:Chromatography, Liquid; D003975:Diazepam / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood*; D006801:Humans; D003708:Nordazepam / Q000008:administration & dosage / Q000097:blood*
D003708:Nordazepam; D003975:Diazepam