Differentiation of 2-, 3-, and 4-fluorofuranylfentanyl using high performance liquid chromatography-mass spectrometry...

Area of Science:

• Forensic Chemistry
• Analytical Chemistry
• Pharmacology

Background:

• Positional isomers of fentanyl analogs present significant forensic challenges due to structural similarities.
• Differentiating isomers like 2-, 3-, and 4-fluorofuranylfentanyl (FFF) is crucial for forensic analysis.

Purpose of the Study:

• To evaluate the differentiation of 2-, 3-, and 4-FFF positional isomers using HPLC-MS and human liver microsomes (HLMs).
• To identify metabolic pathways and products that can aid in distinguishing these isomers.

Main Methods:

• Analysis of synthesized FFF isomers using GC-MS and various HPLC-MS techniques.
• Incubation of FFF isomers with HLMs to generate Phase I metabolites.
• Characterization of metabolites using HPLC-MS/MS and HPLC-IT-TOF-MS.

Main Results:

• Parent FFF isomers showed similar retention times and product-ion spectra via HPLC-MS/MS.
• Three Phase I metabolite categories were identified: N-dealkylated (M1), monohydroxylated (M2a, M2b), and amide hydrolysis (M3).
• M3 exhibited distinct retention times, aiding differentiation, while M2a/M2b retained the FFF structure but lacked chromatographic separation.

Conclusions:

• HPLC-MS analysis combined with HLM metabolism provides valuable data for differentiating FFF positional isomers.
• Metabolite profiling, particularly of M3, offers a viable strategy for forensic identification.
• Observed differences in in vitro elimination half-lives suggest potential pharmacokinetic variations among FFF isomers.