Rapid emergence of UV stabilizer Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (BTMPS) in the illicit fentanyl supply across the United States in July-August 2024: Results from drug and drug paraphernalia testing

Background Changes to the US drug supply historically unfold slowly with predictable patterns of geographic diffusion. Here we draw on drug checking results from around the United States to report a rapid shift in the illicit drug supply with important implications for public health. Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, or “BTMPS” is a hindered amine light stabilizer with various industrial applications. Animal studies indicate multiple kinds of adverse health effects. Methods Drug samples collected by community-based drug checking programs in Los Angeles and Philadelphia, along with drug residue samples from other jurisdictions in California, Delaware, Maryland, and Washington, were submitted to the National Institute on Standards and Technology. Samples were qualitatively tested with Direct Analysis in Real Time mass spectrometry, with reflex to liquid chromatography mass spectrometry (LCMS) for confirmatory testing. Quantitation – percent by mass – was performed using LCMS. At both sites where drug samples were collected, participants were asked to respond to a survey that included questions about what the substance was sold as and any unexpected effects. Results Between June 1, 2024 and August 31, 2024, a total of 178 samples sold as fentanyl were tested. Of these, 43 (24%) contained BTMPS, with the proportion per month rising from 0% in June to more than a third in August. An additional 23 residue samples from sites doing residue testing contained BTMPS. Fentanyl samples with BTMPS also contained many other compounds, including local anesthetics and alpha-2 agonists. Average fentanyl purity was significantly lower in samples with BTMPS compared to samples without. Conclusions The introduction of an industrial chemical to the illicit drug supply at this speed and scale is unprecedented and concerning. Further research is urgently needed to determine why it is present in the fentanyl supply and characterize effects on human health.