The formation of a large number of metabolites is a common finding, with the metabolic pathways usually involving hydroxylation and carboxylation, followed by glucuronidation. Several examples can be found in the mini-review by ElSohly, Gul, Wanas, & Radwan (2014). Several reports are also based on real samples from single cases, or more routine analyses. More often, metabolite patterns are studied using mice models or in vitro experiments with either human liver microsomes or human hepatocytes. In a few cases, volunteers had smoked or digested a SC and subsequent monitoring of urine allows the elucidation of different metabolites. In most of these papers, chromatographic methods based on GC-MS, LC-MS/MS, or LC-HR-MS, or combinations are utilized. Many papers addresses the metabolism of different SC, as knowledge of the metabolites formed is crucial for the detection of the SC since the mother substances are usually not excreted in urine. Neither the HEIA nor ELISA assays showed cross-reactivity with the newer SC, such as UR-144 or XLR-11, or metabolites. In total, 76 SC and metabolites were tested and of these 19 were classified as moderately to highly cross-reactive. (2014) and Kronstrand, Brinkhagen, Birath-Karlsson, Roman, & Josefsson (2014) presented sensitivity/specificity results of 92/98% and 87/82%, respectively. Using the same immunalysis homogeneous enzyme immunoassay (HEIA ) K2 Spice kit with JWH-018 N-pentanoic acid as calibrator, Barnes et al. Compared to a confirmation method using LC-MS/MS, the specificities and sensitivities for both methods were more than 95%. The JWH-250 assay had very limited cross-reactivity, with JWH-250-5-OH-pentyl and JWH-250-5-carboxypentyl metabolites at 50% being the only ones with a cross-reactivity >1%, compared to the JWH-250-4-OH calibrator. The JWH-018 assay had moderate to high cross-reactivity with 17 SC or SC metabolites. (2013) reported two enzyme-linked immunosorbent assays (ELISA) that were designed to detect the 5-OH metabolite of JWH-018 and the 4-OH metabolite of JWH-250 in urine. The antibodies can show cross-reactivity towards other structures than the targeted one, thus expanding the usefulness of the assays, and also enabling the detection of new SC.Īrntson et al. Commercial immunoassay kits have, however, become available for some SC metabolites. Chromatographic analysis is easier to adapt to this ever-changing regimen, and the majority of published urine methods are based on either GC-MS, LC-MS/MS, or LC-HR-MS. Methods for urine analysis that can easily be expanded with new compounds are advantageous as new SC appear on the market when others are scheduled. Screening has often been performed using immunoassays whereas, nowadays, chromatographic screening is also common. Urine is historically the most common medium for drugs of abuse screening.
Øiestad, in Handbook of Cannabis and Related Pathologies, 2017 Urine
0 kommentar(er)
