Degradation of Opioids and Opiates During Acid Hydrolysis Leads to Reduced Recovery Compared to Enzymatic Hydrolysis
Pongkwan Sitasuwan1, Cathleen Melendez1, Margarita Marinova1, Kaylee R. Mastrianni2, Alicia Darragh3, Emily Ryan3 and L. Andrew Lee1 (2016) Journal of Analytical Toxicology 40 (8): 601-607. doi: 10.1093/jat/bkw085.
Drug monitoring laboratories utilize a hydrolysis process to liberate the opiates from their glucuronide conjugates to facilitate their detection by tandem mass spectrometry (MS). Both acid and enzyme hydrolysis have been reported as viable methods, with the former as a more effective process for recovering codeine-6-glucuronide and morphine-6-glucuronide. Here, we report concerns with acid-catalyzed hydrolysis of opioids, including a significant loss of analytes and conversions of oxycodone to oxymorphone, hydrocodone to hydromorphone and codeine to morphine. The acid-catalyzed reaction was monitored in neat water and patient urine samples by liquid chromatography–time-of-flight and tandem MS. These side reactions with acid hydrolysis may limit accurate quantitation due to loss of analytes, possibly lead to false positives, and poorly correlate with pharmacogenetic profiles, as cytochrome P450 enzyme (CYP2D6) is often involved with oxycodone to oxymorphone, hydrocodone to hydromorphone and codeine to morphine conversions. Enzymatic hydrolysis process using the purified, genetically engineered β-glucuronidase (IMCSzyme®) addresses many of these concerns and demonstrates accurate quantitation and high recoveries for oxycodone, hydrocodone, oxymorphone and hydromorphone.