This article reports on a project In which 16 different ELISA reagents were evaluated to determine the cross-reactivity of 30 designer drugs, including 24 phenylethylamines (including 8 cathinone derivatives), 3 piperazines, and 3 tryptamines.
Since the introduction of synthetic heroin, designer drugs have been increasing in prevalence in the United States drug market over the past few decades. Recently, ‘legal highs’ sold as ‘bath salts’ have become a household term for one such class of designer drugs. Although a number of federal and state bans have been enacted, the abuse of these designer drugs still continues. Few assays have been developed for the comprehensive detection of such compounds, so it is important to investigate how they may or may not react in presumptive screens, i.e. pre-existing commercial immunoassays. In the current project, cross-reactivity towards most drugs was <4 percent in assays targeting amphetamine or methamphetamine. Compounds such as MDA, MDMA, ethylamphetamine, and α-methyltryptamine demonstrated cross-reactivities in the range of 30–250 percent, but data were consistent with both manufacturer's inserts and published literature. When tested against the Randox Mephedrone/Methcathinone kit, cathinone derivatives demonstrated cross-reactivity at concentrations as low as 150 ng/ml. Since this same reagent did not cross-react with other amphetamine-like compounds, it opens the possibility to screen postmortem specimens without the interference of putrefactive amines. All other assays demonstrated essentially no cross-reactivity towards any of the analytes evaluated. Given these results, there is a need for more broad-range screening techniques to be applied when analyzing biological specimens by immunoassays for drugs of abuse, specifically the more recent designer drugs. (publisher abstract modified)