© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com doi: 10.1093/jat/bkaa066 Article Report on a New Opioid NPS: Chemical and In Vitro Functional Characterization of a Structural Isomer of the MT-45 Derivative Diphenpipenol Annelies Cannaert 1,† , Fabian Hulpia 2,† , Martijn Risseeuw 2 , Katleen Van Uytfanghe 1 , Eric Deconinck 3 , Serge Van Calenbergh 2 , Peter Blanckaert 4 and Christophe Stove 1, * 1 Laboratory of Toxicology, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium, 2 Laboratory for Medicinal Chemistry, Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium, 3 Section of Medicines and Health Products, Scientific Direction Chemical and Physical Health Risks, Sciensano, Juliette Wytsmanstraat 14, 9050 Brussels, Belgium, and 4 Belgian Early Warning System Drugs, Substance Use and Related Disorders, Sciensano, Juliette Wytsmanstraat 14, 9050 Brussels, Belgium *Author to whom correspondence should be addressed. Email: christophe.stove@ugent.be † Equally contributed. Abstract In this paper, the identification and full characterization of a novel non-fentanyl opioid sourced online, which is a member of the 1-substituted-4-(1,2-diphenylethyl)piperazine deriva- tives related to MT-45, is reported. The sample was sold under the name “diphenpipenol,” (3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]-2-phenylethyl]phenol), although extensive NMR analy- sis showed that the product obtained was actually a diphenpipenol structural isomer, (2-[4-(2- methoxyphenyl)piperazin-1-yl]-1,2-diphenylethanol). Liquid chromatography time-of-flight mass spectrometry identified an exact mass for the protonated molecule of m/z 389.2264, with two prominent fragment ions (m/z 91.0567 and 150.0937), which were not reported in earlier literature describing MT-45 derivatives. The chemical characterization was finalized by gas chromatography– mass spectrometry, high-performance liquid chromatography diode array detector and Fourier- transform infrared spectroscopy analyses. This product is a clear example of the trend that new non-fentanyl opioids are reappearing on the recreational drug market to escape the recent changes in (inter)national legislation concerning fentanyl analogues. Although in this particular case, the product’s potency and efficacy were relatively low, other new non-fentanyl opioids might possess stronger potencies and therefore pose greater health risks for ignorant users. The fact that the product was sold under the wrong name further demonstrates the well-known problematic issue of a mismatch between the adverted and true identity, confirming the irregularities of the online new psychoactive substances market. Article Journal of Analytical Toxicology, 2021;45:134 Advance Access Publication Date: 6 June 2020 – 134 140 Downloaded from https://academic.oup.com/jat/article/45/2/134/5854565 by guest on 10 June 2022