Morphine-3-D glucuronide stability in postmortem specimens exposed to bacterial enzymatic hydrolysis

Area of Science:

• Forensic Toxicology
• Postmortem Specimen Analysis
• Pharmacokinetics

Background:

• Medical examiners use free morphine detection in postmortem specimens to confirm narcotic-related deaths.
• Morphine-3-D glucuronide (M3DG) is a common metabolite of morphine.
• In vitro hydrolysis of M3DG to free morphine is a potential confounding factor in postmortem toxicology.

Purpose of the Study:

• To investigate the in vitro hydrolysis of M3DG to free morphine under various postmortem conditions.
• To evaluate the impact of specimen pH, putrefaction, storage temperature, and time on M3DG hydrolysis.
• To assess the effectiveness of sodium fluoride (NaF) as a preservative against M3DG hydrolysis.

Main Methods:

• Reagent M3DG was added to opiate-free fresh blood and urine, and autopsy-derived blood specimens.
• Specimens were subjected to varying pH, degrees of putrefaction, storage temperatures, and durations.
• The influence of reagent bovine glucuronidase and NaF preservation was examined.

Main Results:

• Freshly collected, refrigerated NaF-preserved blood showed minimal free morphine generation.
• Four out of five autopsy blood specimens produced free morphine from M3DG.
• Increased storage time, temperature, and putrefaction significantly enhanced free morphine generation, even without viable bacteria.

Conclusions:

• Hydrolysis of M3DG to free morphine can occur during specimen storage, independent of bacterial activity.
• Factors like storage duration, temperature, and specimen putrefaction influence the rate of hydrolysis.
• This endogenous hydrolysis may lead to misinterpretation of results and erroneous conclusions in narcotic death investigations.