UCLA researchers find high levels of the industrial chemical BTMPS in fentanyl

A UCLA research team has found that drugs being sold as fentanyl contain high amounts of the industrial chemical bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, or BTMPS. This new substance of concern emerged in the illicit drug supply nearly simultaneously in multiple U.S. locations from coast-to-coast.

From June through October 2024, the team quantitatively tested samples of drugs sold as fentanyl that had high levels of the chemical, which belongs to a class of compounds called hindered amine light stabilizers and has a variety of applications including as a sealant, adhesive, and additive to plastics. 

The paper is published(Link is external) in the peer-reviewed journal JAMA.

“The emergence of BTMPS is much more sudden than previous changes in the illicit drug supply, and the geographic range where it was detected nearly simultaneously suggests it may be added at a high level in the supply chain,” said study lead Chelsea Shover(Link is external), an assistant professor-in-residence at the David Geffen School of Medicine at UCLA(Link is external). “This is concerning because BTMPS is not approved for human consumption, and animal studies have shown serious health effects such as cardiotoxicity and ocular damage, and sudden death at certain doses.” 

In drug product testing where the team was able to quantify different components by mass, samples contained an average of 7 times more BTMPS than fentanyl, with BTMPS sometimes accounting for more than 50% of a drug sold as “fentanyl.” 

BTMPS is not a controlled substance, and though studies in rats have shown action on nicotinic receptors, it has not been commonly understood as a “drug.” The reasons for its addition to fentanyl remain unknown, and traditional testing methods such as postmortem toxicology, criminal investigations, or clinical testing would be unlikely to detect it. The effects on human health are also unknown, but the researchers are concerned.

Testing was performed by the National Institute of Standards and Technology and included drug product samples from Los Angeles and Philadelphia and residue testing of samples from Delaware, Maryland, Nevada, Washington, and Puerto Rico, along with two other California sites.