Simplified determination of lorazepam and oxazepam in biological fluids by gas chromatography-mass spectrometry.
Lorazepam and oxazepam in plasma and urine were measured by gas chromatography-mass spectrometry. Oxazepam was used as an internal standard in the assay of lorazepam and vice versa. After removal of interfering substances with n-hexane, the drugs were extracted with benzene and converted to N1,O3-bistrimethylsilyl derivatives. Glucuronide forms of the drugs were extracted after hydrolysis with beta-glucuronidase. A common fragment ion at m/e 429 was used to monitor the two drugs. The sensitivity was 2 ng/ml for both drugs, which was sufficient to determine plasma and urine concentrations after therapeutic doses to humans.
D014151:Anti-Anxiety Agents / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008140:Lorazepam / Q000097:blood* / Q000627:therapeutic use / Q000652:urine; D010076:Oxazepam / Q000097:blood* / Q000627:therapeutic use / Q000652:urine
D014151:Anti-Anxiety Agents; D010076:Oxazepam; D008140:Lorazepam