Chromatographic Identification of a Novel Nitazene Opioid in Nasal Spray

Testing drugs in non-body samples (such as powders or pills) helps experts spot new drug trends and improve how they analyze substances. One group, called nitazenes, has been linked to poisonings. A specific drug in this group—N-pyrrolidino fluetonitazene (fluetonitazepyne)—is a new synthetic opioid that could add to global drug-related problems.

A recent article published in Drug Testing and Analysis¹ describes the identification and characterization of N-pyrrolidino fluetonitazene in a rarely reported medium for opioids: nasal spray. The sample investigated by researchers from University of Halle-Wittenberg and the University of Applied Sciences Merseburg (Germany) was collected from a patient treated at the University Medicine Halle following first-time recreational use of a nasal spray and was submitted in an amber plastic bottle containing a small volume of a yellowish viscous liquid. The analytical techniques used for identifying this compound included gas chromatography-mass spectrometry (GC-MS), liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), nuclear magnetic resonance (NMR) spectroscopy, and Fourier transform infrared spectroscopy (FTIR).

What Are Nitazines and Why Are They Dangerous?

During the last decade, synthetic opioids, as well as other new psychoactive substances, have entered the drug market over the last decade.² A unique group of these compounds are 2-benzyl benzimidazoles, also known as nitazenes. These compounds are characterized by a benzimidazole ring with an ethylamine and a benzyl group, although further structural modifications are possible and have already been reported.^2-5 Although these substances were initially synthesized in the 1950s and investigated for their analgesic properties, their therapeutic use has never been approved.⁶

Despite the risks associated with their illegitimate use, the current data indicates an increasing prevalence of use of nitazines.² Their effects are similar to other opioids, but also accompanied by not only a much higher but also a substitution-dependent potency; for example, the nitazine etonitazene was found to be 10 times more potent than fentanyl.^7,8 “As nitazenes pose a significant risk to public health with new derivatives emerging persistently,” write the authors of the paper,¹ “the continuous adaptation of analytical methods to detect them is a necessity.

Why Are These Techniques Important?

The sample for the analysis was obtained from a patient after their presenting at the emergency department with a severe right arm paresis (partial or slight paralysis). He had perceived the paresis when waking up two days before and had since hoped in vain for a spontaneous resolution. He disclosed first-time recreational use of the nasal spray three days prior to symptom onset. N-pyrrolidino fluetonitazene was identified in nasal spray, which, according to past studies, has been recently detected in post-mortem samples.^1,9

“Given the steadily increasing number of substances entering the illegal drug market,” write the authors of the study¹, “this is relevant information as new synthetic opioids have already been a serious problem for public health due to their potency and risk of fatal intoxications. The data collected here also highlight that forensic toxicology laboratories need to keep their methods up to date in order to respond quickly to new trends and serve as a point of contact for answering subject-related questions from law enforcement agencies, drug treatment services and healthcare professionals in hospitals.”

The researchers point out, however, that their analysis was conducted on a single nasal spray product, which may limit the generalizability of the findings due to the small sample size.¹

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References

1. Picht, F.; Cepus, V.; Hohlfeld, R. et al. Identification and Characterization of the Designer Opioid N-Pyrrolidino Fluetonitazene in Nasal Spray. Drug Test Anal. 2026. DOI: 10.1002/dta.70074
2. European Drug Report 2024: Trends and Developments. European Union Drugs Agency (EUDA) website 2024. https://www.euda.europa.eu/publications/european-drug-report/2024_en
3. De Vrieze, L. M.; Stove, C. P.; Vandeputte, M. M. Nitazene Test Strips: A Laboratory Evaluation. Harm Reduct J. 2024, 21 (1), 159. DOI: 10.1186/s12954-024-01078-8
4. Schüller, M.; Lucic, I.; Øiestad, Å. M. L. et al. High-Throughput Quantification of Emerging "Nitazene" Benzimidazole Opioid Analogs by Microextraction and UHPLC-MS-MS. J Anal Toxicol. 2023, 47 (9), 787-796. DOI: 10.1093/jat/bkad071
5. Killoran, S.; McNamara, S.; Kavanagh, P. et al. Identification of N-pyrrolidino Protonitazene in Powders Sold as Heroin and Associated with Overdose Clusters in Dublin and Cork, Ireland. Drug Test Anal. 2025, 17 (3), 350-357. DOI: 10.1002/dta.3707
6. Gross, F.; Turrian, H. Uber Benzimidazolderivate mit starker analgetischer Wirkung [Benzimidazole Derivatives with Strong Analgesic Effects]. Experientia 1957, 13 (10), 401-403. German. DOI: 10.1007/BF02161117
7. Vandeputte, M. M.; Van Uytfanghe, K.; Layle, N. K. et al. Synthesis, Chemical Characterization, and μ-Opioid Receptor Activity Assessment of the Emerging Group of "Nitazene" 2-Benzylbenzimidazole Synthetic Opioids. ACS Chem Neurosci. 2021, 12 (7), 1241-1251. DOI: 10.1021/acschemneuro.1c00064
8. Glatfelter, G. C.; Vandeputte, M. M.; Chen, L. et al. Alkoxy Chain Length Governs the Potency of 2-benzylbenzimidazole 'Nitazene' Opioids Associated with Human Overdose. Psychopharmacology (Berl). 2023, 240 (12), 2573-2584. DOI: 10.1007/s00213-023-06451-2
9. Kriikku, P.; Pelander, A.; Jylhä, A. et al. Post-Mortem Identification and Toxicological Findings of Fluetonitazepyne and Isotonitazepyne. Drug Test Anal. 2025, 17 (11), 2164-2169. DOI: 10.1002/dta.3928