Determination of Oxycodone, Noroxycodone and Oxymorphone by High-Performance Liquid ChromatographyElectrospray Ionization-Tandem Mass Spectrometry in Human Matrices: In vivo and In vitro Applications

• NCJ Number: 307077
• Journal: Journal of Analytical Toxicology Volume: 3 Issue: 37 Dated: 2013 Pages: 337-344
• Author(s): Wenfang B. Fang; Michelle R. Lofwall; Sharon L. Walsh; David E. Moody
• Date Published: 2013
• Length: 8 pages
• Grant Number(s): 2011-DN-BX-K532
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical)
• Award: Prediction of drug interactions with methadone, buprenorphine and oxycodone from in vitro inhibition of metabolism

Annotation

The authors of this paper report on their efforts to develop a simple, quick HPLC–MS-MS method suitable for multiple matrices that could detect oxycodone and its major metabolites, noroxycodone and oxymorphone; the authors describe their validation of the novel oxycodone detection method, and present the application of this method for in vivo and in vitro metabolism studies of oxycodone to noroxycodone and oxymorphone in humans.

Abstract

The opioid analgesic oxycodone is widely abused and increasingly associated with overdose deaths. A sensitive analytical method was developed for oxycodone and its metabolites, noroxycodone and oxymorphone, in human plasma, urine (±enzymatic hydrolysis at 50°C for 16 h) and liver microsomes (HLMs). Liquid–liquid extraction was followed by high-performance liquid chromatography–electrospray ionization-tandem mass spectrometry. The calibration range was 0.2–250 ng/mL for plasma and HLM and 10–5000 ng/mL for urine. Intra- and interrun accuracies were within 13.3 percent of target; precisions were within 12.8 percent for all matrices. Recoveries from plasma were: oxycodone, 75.6 percent; noroxycodone, 37.4 percent and oxymorphone, 18.2 percent. Analytes exhibited room temperature stability in plasma and urine up to 24 h, and freeze–thaw stability in plasma up to three cycles. In 24-h hydrolyzed urine from subjects administered intranasal oxycodone (30 mg/70 kg, n = 5), mean concentrations (ng/mL) and % daily doses excreted were: oxycodone, 1150, 6.53 percent; noroxycodone, 1330, 7.81 percent; and oxymorphone, 3000, 17.1 percent. Oxycodone incubated with HLM produced more noroxycodone than oxymorphone. With a panel of recombinant human cytochrome P450s (CYPs), CYP2C18 and CYP3A4 produced the most noroxycodone, whereas CYP2D6 produced the most oxymorphone. These results demonstrate a new method suitable for both in vivo and in vitro metabolism and pharmacokinetic studies of oxycodone. (Publisher Abstract Provided)