Determination of Oxycodone and a Major Metabolite in Urine by Electron-Capture GLC

An electron-capture gas chromatographic procedure has been developed for the analysis of oxycodone In human urine, using naloxone as Internal standard. A major metabollte, tentatively identified as oxymorphone, was found to be excreted in conjugated form. From 33-61% of a single oxycodone dose was excreted in the 2n-hour urine of two 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.