N,N-Dimethylpentylone (dipentylone)—A new synthetic cathinone identified in a postmortem forensic toxicology case series

Abstract

Synthetic cathinones emerged on the novel psychoactive substance (NPS) drug market as alternatives to controlled stimulants and entactogens such as methamphetamine and 3,4-methylenedioxymethamphetamine. The majority of synthetic cathinones can be subclassified into two groups: beta-keto amphetamines (i.e., NPS with the suffix “drone”) and beta-keto methylenedioxyamphetamines (i.e., NPS with the suffix “lone”). Although a significant number of beta-keto amphetamines have been identified, beta-keto methylenedioxyamphetamines have dominated the NPS market, including notable drugs like methylone, butylone, N-ethyl pentylone (ephylone), eutylone and now N,N-dimethylpentylone. N,N-Dimethylpentylone, also known as dipentylone or beta-keto-dimethylbenzodioxolylpentanamine, emerged into the illicit drug supply <2 months of the international control of eutylone (September 2021). A novel standard addition method was developed and validated for N,N-dimethylpentylone, pentylone and eutylone, and 18 postmortem cases were quantitated using the method described in this manuscript. The resulting blood concentration range for N,N-dimethylpentylone in this case series was 3.3 to 970 ng/mL (median: 145 ng/mL, mean: 277 ± 283 ng/mL). Pentylone, a metabolite of N,N-dimethylpentylone, was detected in all cases (range: 1.3–420 ng/mL, median: 31 ng/mL and mean: 88 ± 127 ng/mL). Due to the rise in identifications of N,N-dimethylpentylone in postmortem investigations as well as the potential misidentification of N,N-dimethylpentylone as N-ethyl pentylone, samples testing positive for pentylone should be additionally confirmed for the presence of N,N-dimethylpentylone. Based on prior trends of new synthetic cathinones, it can be theorized that N,N-dimethylpentylone may predominate the US synthetic stimulant market for the next 1–2 years; however, given the emergence of additional closely related isomeric compounds, it is important to utilize methodology capable of differentiating N,N-dimethylpentylone from its isomers (N-isopropylbutylone, N-ethyl pentylone, N-ethyl N-methyl butylone, hexylone, N-propylbutylone, diethylone and tertylone).