Rapid extraction of oxazepam from greyhound urine for high performance liquid chromatography analysis.

A rapid and efficient procedure is described for the extraction and analysis of oxazepam, the major urinary metabolite of diazepam in greyhounds. Urine was extracted by passing through a bonded silica column (Bond Elut) following enzyme hydrolysis. The adsorbed drug was eluted and then detected and measured by high performance liquid chromatography (HPLC). Recoveries were in excess of 85% at 50 ng/ml concentrations. Detection was possible up to 30 h after a single oral dose of diazepam (5 mg).