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Stability of 3,4-methylenedioxymethampetamine (MDMA), 4-methylmethcathinone (mephedrone) and
Peter D Maskell1, L Nitin Seetohul, Alison C Livingstone
1Centre for Forensic and Legal Medicine, University of Dundee, UK. p.d.maskell@dundee.ac.uk
Abstract:
Occasionally, the only postmortem samples available for analysis are contaminated with formaldehyde, either due to embalming prior to sampling or because analysis is carried out only when formalin-fixed tissues retained for histological study are available. Formaldehyde reacts with several drugs of forensic interest that contain either a primary or a secondary amine group to form their N-methyl derivatives. We investigated the stability of 3,4-methylenedioxymethampetamine (MDMA), 4-methylmethcathinone (mephedrone) and 3-trifluromethylphenylpiperazine (3-TFMPP) in formalin solutions using three different formaldehyde concentrations (5, 10 and 20%) and three different pHs (3.0, 7.0 and 9.5). Analysis was performed using high-performance liquid chromatography with diode array detection to determine the percentage degradation of each drug over time, up to 60 days. MDMA, mephedrone and 3-TFMPP are unstable in formalin solutions, with the degradation rate increasing with increasing pH. After 28 days in 20% formalin, pH 9.5, there remained 57% of the initial 3-TFMPP concentration, 11% of the initial MDMA concentration and 4% of the initial mephedrone concentration. Forensic toxicologists should be aware that, when analyzing for these drugs in an embalmed body or in tissues stored in formalin solutions, the methylated form of the secondary amine-containing drug could be a more useful analyte than the parent drug.
Insights
Formaldehyde in formalin solutions degrades drugs like MDMA, mephedrone, and 3-TFMPP, especially at higher pH levels. Forensic toxicologists should consider analyzing for N-methyl derivatives in embalmed samples.
Area of Science:
- Forensic Chemistry
- Analytical Toxicology
Background:
- Formaldehyde contamination is common in postmortem samples due to embalming or histological storage.
- Formaldehyde can react with amine-containing drugs, forming N-methyl derivatives.
Purpose of the Study:
- To investigate the stability of 3,4-methylenedioxymethampetamine (MDMA), 4-methylmethcathinone (mephedrone), and 3-trifluromethylphenylpiperazine (3-TFMPP) in formalin solutions.
- To determine the influence of formaldehyde concentration and pH on drug degradation rates.
Main Methods:
- Drugs were incubated in formalin solutions with varying formaldehyde concentrations (5-20%) and pH levels (3.0-9.5).
- High-performance liquid chromatography with diode array detection was used to quantify drug concentrations over 60 days.
Main Results:
- MDMA, mephedrone, and 3-TFMPP showed instability in formalin, with degradation increasing at higher pH.
- After 28 days in 20% formalin at pH 9.5, remaining drug concentrations were 57% for 3-TFMPP, 11% for MDMA, and 4% for mephedrone.
Conclusions:
- Forensic toxicologists must account for drug degradation in formalin-fixed samples.
- Analyzing for N-methyl derivatives may be more reliable than parent drug analysis in embalmed specimens.
