The continuing emergence of designer drugs imposes high demands on the scope and sensitivity of toxicological drug screening procedures. An ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOFMS) method was developed for screening and simultaneous confirmation of both designer drugs and other drugs of abuse in urine samples in a single run. The method covered selected synthetic cannabinoids and cathinones, amphetamines, natural cannabinoids, opioids, cocaine and other important drugs of abuse, together with their main urinary metabolites. The database consisted of 277 compounds with molecular formula and exact monoisotopic mass; retention time was included for 192 compounds, and primary and secondary qualifier ion exact mass for 191 and 95 compounds, respectively. Following a solid-phase extraction, separation was performed by UHPLC and mass analysis by HR-TOFMS. MS, and broad-band collision-induced dissociation data were acquired at m/z range 50-700. Compound identification was based on a reverse database search with acceptance criteria for retention time, precursor ion mass accuracy, isotopic pattern and abundance of qualifier ions. Mass resolving power in spiked urine samples was on average FWHM 23,500 and mass accuracy 0.3 mDa. The mean and median cut-off concentrations determined for 75 compounds were 4.2 and 1 ng/mL, respectively. The range of cut-off concentrations for synthetic cannabinoids was 0.2-60 ng/mL and for cathinones 0.7-15 ng/mL. The method proved to combine high sensitivity and a wide scope in a manner not previously reported in drugs of abuse screening. The method's feasibility was demonstrated with 50 authentic urine samples.

Immunoassay is currently the most common approach for urine drug screening. However, the continuous emergence of new psychoactive substances (NPS) and their low urinary concentrations have challenged the scope and sensitivity of immunoassays. Consequently, specialized toxicology laboratories rely more and more on mass spectrometry (MS) based techniques. Ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOF-MS) is an especially attractive technique for comprehensive drug screening. The objective was to compare the performances of immunoassay and UHPLC-HR-TOF-MS in terms of scope, flexibility, sensitivity, and reliability of substance identification. A total of 279 post-mortem urine samples were analyzed using a method representative of each technique. The immunoassay method was an Emit II Plus enzyme immunoassay for the following drug groups: amphetamines, benzodiazepines, buprenorphine, cannabis, and opiates. The UHPLC-HR-TOF-MS method was a recently published method covering hundreds of drugs: conventional drugs of abuse, abused prescription drugs, and NPS of various classes. UHPLC-HR-TOF-MS produced a lower number of false positive (FP) results for the drug groups covered by immunoassay. Many of the false negative (FN, n = 40) and FP (n = 22) immunoassay results were obviously due to the higher cut-off concentrations and interfering matrix, respectively. Moreover, the wider scope of UHPLC-HR-TOF-MS allowed detection of NPS and prescription drugs. UHPLC-HR-TOF-MS gave FP results related to a few particular substances. The future option of adjusting all compound-specific reporting parameters individually would allow the method's sensitivity and specificity to be fully exploited.

A widespread occurrence of abused substances beyond the ordinary was revealed. Identifying these patients is essential as polydrug abuse is a safety risk to the patient and may cause attrition from OMT.

The β-keto amphetamine (cathinone, β-KA) designer drugs such as mephedrone (4-methylmethcathinone, 4-MMC) show a large degree of structural similarity to amphetamines like methamphetamine (METH). However, little is currently known about whether these substances also share the potential neurotoxic properties of their non-keto amphetamine counterparts, or what mechanisms could be involved. Here, we evaluate the cytotoxicity of β-KAs in SH-SY5Y cells using lactate dehydrogenase (LDH) assays, assess the redox potential of a range of β-KAs and non-keto amphetamines using the sensitive redox indicator 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST-1), and explore the effect of 4-MMC on the formation of protein adducts using ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOFMS) and on the mitochondrial respiratory chain using high-resolution respirometry. We show that treatment with β-KAs increases LDH release. Further, we demonstrate that even under physiological pH, β-KAs are effective and selective-as compared with their non-keto analogues-reductants in the presence of electron acceptors. Increased pH (range 7.6-8.0) greatly enhanced the reactivity up to sixfold. We found no evidence of protein adduct formation, suggesting the reactivity is due to direct electron transfer by the β-KAs. Finally, we show that 4-MMC and METH produce dissimilar effects on the respiratory chain. Our results indicate that β-KAs such as 4-MMC possess cytotoxic properties in vitro. Furthermore, in the presence of an electron-accepting redox partner, the ketone moiety of β-KAs is vital for pH-dependent redox reactivity. Further work is needed to establish the importance of β-KA redox properties and its potential toxicological importance in vivo.

The increased use of cathinone-type designer drugs, known as legal highs, has led to concerns about their potential neurotoxicity due to their similarity to methamphetamine (METH). Therefore, closer investigations of their toxic effects are needed. We investigated the effects of the cathinones 4-methylmethcathinone (4-MMC) and 3,4-methylenedioxymethcathinone (MDMC) and the amphetamine METH on cytotoxicity and mitochondrial respiration in SH-SY5Y neuroblastoma cells. We also investigated the contribution of reactive species, dopamine, Bcl-2 and tumor necrosis factor α (TNFα) on toxicity. Finally, we investigated the effect of cathinone breakdown products using ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry and studied their involvement in toxicity. We observed dose-dependent increases in cytotoxicity and decreases in mitochondrial respiration following treatment with all cathinones and amphetamines. Glutathione depletion increases amphetamine, but not cathinone toxicity. Bcl-2 and TNFα pathways are involved in toxicity but dopamine levels are not. We also show that cathinones, but not amphetamines, spontaneously produce reactive species and cytotoxic methylbenzamide breakdown products when in aqueous solution. These results provide an important first insight into the mechanisms of cathinone cytotoxicity and pave the way for further studies on cathinone toxicity in vivo.