The identification of N-isopropyl butylone in postmortem cases in Northern Virginia.

The emergence of synthetic cathinones in the illicit drug market over the past two decades has posed significant challenges for forensic laboratories. Marketed initially as "legal highs," these stimulants rose in popularity around 2009, prompting the United States government to pass the Synthetic Drug Abuse Prevention Act in 2012. Despite regulatory measures, novel cathinones continue to surface in forensic casework. One such compound is N-isopropyl butylone, a structural isomer of N, N-dimethylpentylone-the most frequently identified synthetic cathinone in 2023 in the United States. Detected by the Virginia Department of Forensic Science in March 2024, N-isopropyl butylone has since appeared in items including solid material, powders, tablets, crystalline material, and residues in 170 Controlled Substances cases across the Commonwealth through July 2025. From July to September 2024, the Northern Laboratory's Toxicology Section presumptively identified the compound in six postmortem blood specimens with detection in an additional blood specimen in August 2025. This study investigates the seven toxicology cases, with three being selected for further research analysis. Cases were assessed for case history, additional toxicology findings, and cause/manner of death. Presumptive positive identifications were made using full-scan gas chromatography-mass spectrometry. Confirmation and semi-quantitative analysis utilized an adapted stimulant-targeted extraction with liquid chromatography-tandem mass spectrometry. N-Isopropyl butylone was confirmed in three cases at semi-quantitative values of 20, 200, and 1700 ng/mL. All seven cases involved poly-drug use with four deaths being attributed to drug intoxication and three to fatal gunshot wounds. Although N-isopropyl butylone has only been observed in seven postmortem Toxicology cases, its increased prevalence in Controlled Substances cases could indicate broader circulation. These findings highlight the growing concern over novel psychoactive substances and the need for continued surveillance and research to assess their role in forensic casework.