6β-Naltrexol-d3 (Item No. 18350) is an analytical reference material intended for use as an internal standard for the quantification of 6β-naltrexol by GC- or LC-MS. 6β-Naltrexol is the major metabolite of naltrexone (Item Nos. ISO60192 | 15520). It is a neutral μ-opioid receptor antagonist (Ki = 94 pM). This product is intended for research and forensic applications.