Enzyme-Linked Immunosorbent Assay (ELISA) for the Detection of Use of the Synthetic Cannabinoid Agonists UR-144 and XLR-11 in Human Urine

Amanda L.A. Mohr1, Bill Ofsa2, Alyssa Marie Keil2, John R. Simon3, Matthew McMullin2 and Barry K. Logan1,2

1The Center for Forensic Science Research and Education, Willow Grove, PA, USA, 2NMS Labs, Willow Grove, PA and 3Tulip Biolabs, Inc., West Point, PA

The article Enzyme-Linked Immunosorbent Assay (ELISA) for the Detection of Use of the Synthetic Cannabinoid Agonists UR-144 and XLR-11 in Human Urine appears in the Journal of Analytical Toxicology 2014; 1-5 doi:10.1093/jat/bku049. Abstract is included below.

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ABSTRACT: Ongoing changes in the synthetic cannabinoid drug market create the need for relevant targeted immunoassays for rapid screening of biological samples. We describe the validation and erformance characteristics of an enzyme-linked immunosorbent assay designed to detect use of one of the most prevalent synthetic cannabinoids in urine, UR-144, by targeting its pentanoic acid metabolite. Fluorinated UR-144 (XLR-11) has been demonstrated to metabolize to this common product. The assay has significant cross-reactivity with UR-144-5-OH, UR-144-4-OH and XLR-11-4-OH metabolites, but <10% cross-reactivity with the parent compounds, and no measurable cross-reactivity with other synthetic cannabinoids and their metabolites at concentrations of <1,000 ng/mL. The assay’s cutoff is 5 ng/mL relative to the pentanoic acid metabolite of UR-144, which is used as the calibrator. The method was validated with 90 positive and negative control urine samples for UR-144, XLR-11 and its metabolites tested versus liquid chromatography–tandem mass spectrometry. The accuracy, sensitivity and specificity were determined to be 100% for the assay at the specified cutoff.

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