Simultaneous Determination of 5- and 6-APB in Blood, Other Body Fluids, Hair and Various Tissues by HPLC--MS-MS

Abstract

5-(2-aminopropyl)benzofuran (5-APB) and 6-(2-aminopropyl)benzofuran (6-APB) are benzofuran analogues of amphetamine and belong to the category of new psychoactive substances (NPS). Despite already published fatal 5- and 6-APB intoxication - in most cases, a combination of both substances - no sensitive method for the simultaneous detection and quantification of these new psychoactive compounds in human blood samples has yet been developed. Therefore, an easy and fast sample preparation-, as well as specific high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) method for the determination of both substances in blood, were established and validated. In a fatal intoxication in 2017 at the Institute of Forensic and Traffic Medicine in Heidelberg, Germany, concentrations of 850 ng/mL (5-APB) and 300 ng/mL (6-APB) were determined in peripheral blood. Besides, other body fluids (central blood, urine, bile), hair, and various tissues were examined to verify the presence of both compounds and to gain first insights into their distribution. In this publication, we show a method for the simultaneous determination of 5- and 6-APB in human samples by a chromatographic method and to investigate their distribution in the human body.

Fatal cases involving new psychoactive substances and trends in analytical techniques

“… Hofmann et al (2021) reported a fatal case in Germany involving two stereoisomers (5- and 6-(2-aminopropyl)benzofuran), which are substituted benzofuran phenethylamines. Concentrations ranged from 300 to 2,400 ng/ml in blood and from 2,100 ng/ml in bile to 65,000 ng/ml in stomach content.…”

Synthesis of 2-(5-(2-Aminopropyl)-2-hydroxyphenyl)acetic Acid, a Metabolite of the Drug 5-APB

“…These benzofurans have a similar chemical structure to MDMA (ecstasy) and MDA (Figure 1), two well-known illicit drugs [3,4]. Due to their popularity among users, reports of serious intoxication, including some fatalities, have emerged (there have been several fatal cases of the simultaneous consumption of 5-APB and 6-APB) [5][6][7][8][9][10]. Similar to MDMA and MDA, 5-APB and 6-APB are known for their entactogenic effects, which is a primary reason for their popularity among users.…”

“…This lack of information is compounded by the difficulty of developing reliable detection methods. However, a recent breakthrough has been made in this area with the development of a highly sensitive method for the simultaneous detection and quantification of both 5-APB and 6-APB in human blood samples [10]. In vitro studies in primary rat hepatocytes of the two benzofurans, 6-APB and 5-APB, showed that 5-APB Molbank 2023, 2023, M1629 2 of 7 displayed higher hepatotoxicity in these cellular models than its 6-isomer [12].…”

“…Molbank 2023, 2023, x FOR PEER REVIEW 2 of 7 blood samples [10]. In vitro studies in primary rat hepatocytes of the two benzofurans, 6-APB and 5-APB, showed that 5-APB displayed higher hepatotoxicity in these cellular models than its 6-isomer [12].…”

“…The most abundant metabolite found after the exposure of human hepatocytes to 5-APB was 2-(5-(2-aminopropyl)-2-hydroxyphenyl)acetic acid (1). Other identified metabolites were hydroxy-5-APB and hydroxy-dihydro 5-APB [10,[14][15][16]. Although metabolism is often referred to as a detoxification process, bioactivation is also a frequent metabolic process of xenobiotics that results in the formation of reactive metabolites.…”