High-pressure liquid chromatographic analysis of diazepam, oxazepam and N-desmethyldiazepam in human blood.
We describe a rapid method for precisely measuring concentrations of diazepam, oxazepam and N-desmethyldiazepam in blood by high-pressure liquid chromatography. The drugs, together with an internal standard, prazepam, are extracted from 2 ml of blood and analyzed isocratically on a reversed-phase column with a mobile phase consisting of acetonitrile-0.01 M sodium acetate buffer (35:65 v/v). The eluted drugs are detected by their absorption at 240 nm. The sensitivity of this method is 30 microgram/l for oxazepam and N-desmethyldiazepam, 40 microgram/l for diazapam, for 2-ml blood samples. Relative recovery of added drugs to blood varies from 91 to 110%. The day-to-day precision (coefficient of variation) established by 10 replicate analyses was 2.8 to 9.6%.
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003975:Diazepam / Q000097:blood*; D006801:Humans; D003708:Nordazepam / Q000097:blood; D010076:Oxazepam / Q000097:blood*
D003708:Nordazepam; D010076:Oxazepam; D003975:Diazepam