In Vitro Conversion of Morphine to 6-Acetylmorphine in Urine Samples during Enzymatic Hydrolysis

[摘要] To the Editor:Heroin is an illegal drug and monitoring heroin use is important in rehabilitation, pain management services, and workplace employment testing. In humans, heroin is rapidly converted to 6-acetylmorphine (6AM),1 which is quickly hydrolyzed to morphine. Morphine glucuronide is the major metabolite of heroin in urine (1). However, 6AM is a unique metabolite of heroin and is considered the definitive indicator of heroin intake. 6AM in urine is measured by GC-MS, LC-MS, immunoassay, or thin-layer chromatography methods. For measuring opioids in urine, hydrolysis using β-glucuronidase is frequently employed to improve consistency because of large variable glucuronide conjugation rates between and within individuals. Acetate buffer is the primary choice for preparing enzymatic hydrolysis solution due to the favorable pH (4.5–5.0). In our routine LC-MS analysis (2, 3), a number of low-concentration 6AM results were observed in patient urine samples with high concentrations of morphine. A Medical Review Officers' advisory cites possible in vitro synthesis of 6AM in high-morphine samples during derivatization in GC-MS analyses (4). To the best of our knowledge, there are no reports …

[学科分类] 过敏症与临床免疫学