DETERMINATION OF OXYCODONE AND A MAJOR METABOLITE IN URINE BY ELECTRON-CAPTURE GLC

This procedure uses naloxone as an internal standard. A major metabolite, tentatively identified as oxymorphone, was found to be excreted in conjugated form. From 33-61% of a single oxycodone dose was excreted in the 24-hr urine of 2 subjects as free (13-19%) and conjugated oxycodone (7-29%) and conjugated oxymorphone (13-14%). A second metabolite was observed by thin-layer chromatography, but was not identified. The purpose of this communication is to present an electron-capture gas chromatographic procedure for the determination of oxycodone in urine and to describe in quantitative terms the human urinary excretion of the drug and a previously unidentified major metabolite.