Development of a rapid LC‐MS/MS method for direct urinalysis of designer drugs

Abstract

The current immunoassay screening methodologies used to detect sympathomimetic amines within the context of workplace drug testing may fail to detect a number of the emerging designer drugs, for example β-keto amphetamines and piperazine derivatives, commonly referred to as 'legal highs'. Therefore, a rapid multi-analyte qualitative screening method, using ultra-high-pressure liquid chromatography-tandem mass spectrometry (LC-MS/MS), was investigated for analysis of new designer drugs that have emerged from the former legal highs market. Eight analytes were targeted as model compounds: 4-methylmethcathinone (mephedrone), 3,4-methylenedioxymethcathinone (bk-MDMA, 'methylone'), 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one (bk-MBDB, 'butylone'), 4-methoxymethcathinone (bk-PMMA, 'methedrone'), 1-benzylpiperazine (BZP), 1-(3-trifluoromethyl phenyl)-piperazine (TFMPP), 1-(3-chloro phenyl)-piperazine (mCPP), and 3, 4-methylenedioxypyrovalerone (MDPV). The LC-MS/MS method developed encompassed direct analysis following a 1:4 dilution of urine with mobile phase to reduce matrix effects. Although not all compounds were completely resolved chromatographically, two product ions conferred sufficient specificity to allow target analyte identification. Although all target analytes were readily detected at 500 ng/ml, a cut-off of 1000 ng/ml was chosen to mirror the amphetamine screening cut-off commonly used for routine analysis of workplace drug testing samples. In conclusion, direct analysis using LC-MS/MS offers an attractive way forward for the development of a rapid routine screen for new psychoactive substances, particularly given the growing number of novel compounds.

A brief history of ‘new psychoactive substances’

“…[18] In forensic toxicology, emphasis is placed on low reporting thresholds, not least to improve retrospection of detection of drug administration, and sample extraction is therefore important to reduce matrix effects that can cause ion suppression and also to help concentrate the drugs targeted and also their metabolites. By contrast, in routine workplace drug testing programmes, the main aim is to deter drug misuse by focusing on detection of very recent drug administration and thus the reporting thresholds chosen are much higher, permitting direct analysis ('dilute and shoot') liquid chromatography-tandem mass spectrometry (LC-MS/MS) for rapid screening purposes, as presented by Bell et al [19] Sumnall et al [20] describe how the social factors determining use of a new generation of psychoactive compounds differ from the major historical trends in recreational drug use of the twentieth century. They note how manufacture, distribution, and access to a range of psychoactive and so-called lifestyle/well-being drugs firmly embeds these substances into a new consumer culture.…”

Identifying and Overcoming Matrix Effects in Drug Discovery and Development

“…xenobiotic glucuronides). Therefore, matrix effects are observed less frequently and simple sample dilution is sufficient to resolve observed matrix effects (Bell et al, 2011;Schreiber et al, 2007;Schreiber and Formal, 2007). However, it is important to note that, the composition and pH of urine is considerably more variable compared to plasma and is affected by age, gender, disease state, and dietary habits.…”

Selective solid phase extraction of JWH synthetic cannabinoids by using computationally designed peptides

“…The importance of this type of drugs is well described by different works reporting that these new substances with cannabis-like effects are more and more frequently observed in the drug scene [6][7][8][9]. A fast and cheap detection of drugs of abuse can be carried out with immunochemical methods but, regrettably, those methods are unsuitable for a systematic toxicological analysis requested by these new molecules that continuously appear on the illicit market [10,11]. To have a determination of psychoactive substances and their metabolites with high mass accuracy, liquid chromatography can be coupled with high resolution mass spectrometry (MS) [12,13].…”