New designer drugs N-(1-phenylcyclohexyl)-2-ethoxyethanamine (PCEEA) and N-(1-phenylcyclohexyl)-2-methoxyethanamine (PCMEA): Studies on their metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric techniques

Hair-based rapid UPLC-MS/MS analysis of 36 phencyclidine-type substances in forensic cases

Phencyclidine (PCP) is a frequently abused dissociative agent. It causes confusion, increased tendencies toward violence, and concentration-dependent cytotoxicity after entry into the body. The parent nucleus of phencyclidine-type substances is arylcyclohexylamine, which is easy to modify; therefore, abusers and dealers can readily synthesize substitutes beyond the drug control catalog. An urgent need exists to establish screening methods for phencyclidine-type substances to provide technical support for abuse monitoring. In this study, 20 mg of hair was pulverized in 500 mL of methanol containing 0.5 ng/mL PCP-d5. After ultrasonication, centrifugation, and filtration, the supernatant was analyzed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) operating in the multiple reaction monitoring mode. Phencyclidine-type substances were separated in 13 min on a biphenyl column using a mobile phase gradient composed of A (water, formic acid 0.1%, acetonitrile 5%, 20 mmol/L ammonium acetate) and B (acetonitrile). The developed and validated method showed good selectivity, sensitivity (limit of detection: 0.25-2 pg/mg and lower limit of quantitation: 0.5-4 pg/mg), linearity (R2 > 0.994), accuracy, and precision (< 20%), and a dilution effect. The method also showed good recovery and acceptable matrix effects for most of the targeted compounds. This analytical approach was successfully applied for the identification and quantification of phencyclidine-type substances in hair from 87 authentic forensic cases. Nine analytes were detected: ketamine (10.3-26211.3 pg/mg), 2-F-2-oxo-PCE (11.5-4034.9 pg/mg), 2-FDCK (14.0-43290.2 pg/mg), 2-BrDCK (10.6-21170.0 pg/mg), nor2-FDCK (10.1-16767.4 pg/mg), tiletamine (10.1-3250.8 pg/mg), O-PCE (43.3-166.1 pg/mg), DCK (10.2-90.4 pg/mg), and norDCK (24.9-103.0 pg/mg).

New Psychoactive Substances 3-Methoxyphencyclidine (3-MeO-PCP) and 3-Methoxyrolicyclidine (3-MeO-PCPy): Metabolic Fate Elucidated with Rat Urine and Human Liver Preparations and their Detectability in Urine by GC-MS, "LC-(High Resolution)-MSn" and "LC-(High Resolution)-MS/MS"

Background:

3-Methoxyphencyclidine (3-MeO-PCP) and 3-methoxyrolicyclidine (3-MeO-PCPy) are two new psychoactive substances (NPS). The aims of the present study were the elucidation of their metabolic fate in rat and pooled human liver microsomes (pHLM) the identification of the cytochrome P450 (CYP) isoenzymes involved and the detectability using standard urine screening approaches (SUSA) after intake of common users’ doses using gas chromatography-mass spectrometry (GC-MS) liquid chromatography-multi-stage mass spectrometry (LC-MSn) and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS)

Methods:

For metabolism studies rat urine samples were treated by solid phase extraction or simple precipitation with or without previous enzymatic conjugate cleavage. After analyses via LC-HR-MSn the phase I and II metabolites were identified

Results:

Both drugs showed multiple aliphatic hydroxylations at the cyclohexyl ring and the heterocyclic ring single aromatic hydroxylation carboxylation after ring opening O-demethylation and glucuronidation. The transferability from rat to human was investigated by pHLM incubations where O-demethylation and hydroxylation were observed. The involvement of the individual CYP enzymes in the initial metabolic steps was investigated after single CYP incubations. For 3-MeO-PCP CYP 2B6 was responsible for aliphatic hydroxylations and CYP 2C19 and CYP 2D6 for O-demethylation. For 3-MeO-PCPy aliphatic hydroxylation was again catalyzed by CYP 2B6 and O-demethylation by CYP 2C9 and CYP 2D6

Conclusions:

As only polymorphically expressed enzymes were involved pharmacogenomic variations might occur but clinical data are needed to confirm the relevance. The detectability studies showed that the authors’ SUSAs were suitable for monitoring the intake of both drugs using the identified metabolites

Toxicity evaluation of α-pyrrolidinovalerophenone (α-PVP): results from intoxication cases within the STRIDA project

CONTEXT

An increasing number of new psychoactive substances (NPS) of different chemical classes have become available through marketing and sale over the Internet. This report from the Swedish STRIDA project presents the prevalence, laboratory results, and clinical features in a series of intoxications involving the stimulant NPS α-pyrrolidinovalerophenone (α-PVP), a potent dopamine re-uptake inhibitor, over a 4-year period.

STUDY DESIGN

Observational case series of consecutive patients with admitted or suspected intake of NPS presenting to hospitals in Sweden from 2012 to 2015.

PATIENTS AND METHODS

In the STRIDA project, blood and urine samples are collected from intoxicated patients with admitted or suspected intake of NPS or unknown drugs presenting to hospitals over the country. Analysis of NPS is performed by mass spectrometry multicomponent methods. Clinical data are collected when caregivers consult the Swedish Poisons Information Centre (PIC), and retrieved from medical records. The severity of poisoning is graded retrospectively using the Poisoning Severity Score (PSS). The inclusion criteria for this study included absence of other stimulants than α-PVP.

RESULTS

During the 4-year study period, 23 intoxications were originally coded as "α-PVP related" out of a total 3743 NPS-related inquiries (0.6%) at the PIC. The present study covered 42 analytically confirmed cases in which α-PVP was the only stimulant detected. The age range of patients was 20-58 (median 32) years, of which 79% were males. The α-PVP concentration in serum was 4.0-606 (median 64; n = 42) ng/mL and 2.0-41,294 (median 1782; n = 25) ng/mL in urine. There was no statistically significant association between the serum α-PVP concentration and urinary α-PVP/creatinine ratio in 25 cases, where both sets of data were available. In 14/42 (33%) cases, α-PVP was the only psychoactive substance identified. In the remaining cases, additional substances comprised opioids, benzodiazepines, and ethanol. The main clinical manifestations were tachycardia (80%), agitation (70%), hypertension (33%), hallucinations (20%), and delirium (18%). Classification of poisoning severity yielded 25 (60%) moderate (PSS 2), 7 (17%) severe (PSS 3), and 2 fatal cases (PSS 4).

CONCLUSIONS

In analytically confirmed α-PVP intoxication cases involving no other stimulant drugs, the urine and serum concentrations showed high variability. The clinical features were consistent with a severe sympathomimetic toxidrome. The results further demonstrated that α-PVP prevailed as a drug of abuse after being classified as a narcotic substance, and despite a high incidence of severe poisonings and fatalities. However, the low prevalence of α-PVP cases registered at the PIC suggested that many were unaware of the actual substance they had taken.

Biotechnological synthesis of drug metabolites using human cytochrome P450 isozymes heterologously expressed in fission yeast

Cytochrome P450 mono-oxygenases (CYPs) are the major enzymes involved in the metabolism of drugs and poisons in humans. The variation of their activity - due to genetic polymorphisms or enzyme inhibition/induction - potentially increases the risk of side effects or toxicity. Studies on CYP-dependent metabolism are important in drug-development or toxicity studies. Reference standards of drug metabolites required for such studies, especially in the context of metabolites in safety testing (MIST), are often not commercially available and their classical chemical synthesis can be cumbersome. Recently, a biotechnological approach using human CYP isozymes heterologously expressed in fission yeast was developed for the synthesis of drug metabolites. Among other aspects, this approach has the distinct advantages that the reactions run under mild conditions and that only the final product must be isolated and characterized. This review overviews the first practical applications of this new approach and discusses the selection of substrates, metabolites and fission yeast strains as well as important aspects of incubation, product isolation and clean-up.

Bioanalysis of new designer drugs

Since the late 1990s the illicit drug market has undergone considerable change: along with the traditional drugs of abuse that still dominate, more than 100 psychotropic substances designed to bypass controlled substances legislation have appeared and led to intoxications and fatalities. Starting from the huge class of phenylalkylamines, containing many subgroups, the spectrum of structures has grown from tryptamines, piperazines, phenylcyclohexyl derivates and pyrrolidinophenones to synthetic cannabinoids and the first synthetic cocaine. Due to the small prevalence and high number of unknown substances, the detection of new designer drugs is a challenge for clinical and forensic toxicologists. Standard screening procedures might fail because a recently discovered or yet unknown substance has not been incorporated in the library used. Nevertheless, many metabolism studies, case reports, screening methods and substance-profiling papers concentrating on single compounds have been published. This review provides an overview of the developed bioanalytical and analytical methods, the matrices used, sample-preparation procedures, concentration of analytes in case of intoxication and also gives a résumé of immunoassay experiences. Additionally, six screening methods for biological matrices with a larger spectrum of analytes are described in more detail.

Absorption, distribution, metabolism and excretion pharmacogenomics of drugs of abuse

Pharmacologic and toxic effects of xenobiotics, such as drugs of abuse, depend on the genotype and phenotype of an individual, and conversely on the isoenzymes involved in their metabolism and transport. The current knowledge of such isoenzymes of frequently abused therapeutics such as opioids (oxycodone, hydrocodone, methadone, fentanyl, buprenorphine, tramadol, heroin, morphine and codeine), anesthetics (γ-hydroxybutyric acid, propofol, ketamine and phencyclidine) and cognitive enhancers (methylphenidate and modafinil), and some important plant-derived hallucinogens (lysergide, salvinorin A, psilocybin and psilocin), as well as of nicotine in humans are summarized in this article. The isoenzymes (e.g., cytochrome P450, glucuronyltransferases, esterases and reductases) involved in the metabolism of drugs and some pharmacokinetic data are discussed. The relevance of such data is discussed for predicting possible interactions with other xenobiotics, understanding pharmacokinetic behavior and pharmacogenomic variations, assessing toxic risks, developing suitable toxicological analysis procedures, and finally for interpretating drug testing results.

Chemistry, pharmacology, and metabolism of emerging drugs of abuse

In recent years, besides the classic designer drugs of the amphetamine type, a series of new drug classes appeared on the illicit drugs market. The chemistry, pharmacology, toxicology, metabolism, and toxicokinetics is discussed of 2,5-dimethoxy amphetamines, 2,5-dimethoxy phenethylamines, beta-keto-amphetamines, phencyclidine derivatives as well as of herbal drugs, ie, Kratom. They have gained popularity and notoriety as rave drugs. The metabolic pathways, the involvement of cytochrome P450 isoenzymes in the main pathways, and their roles in hepatic clearance are also summarized.

Microwave-assisted derivatization procedures for gas chromatography/mass spectrometry analysis

In this review, published applications of microwave-assisted derivatization procedures for gas chromatography/mass spectrometry (GC/MS) are summarized. Among the broad range of analytical techniques available, GC/MS is still the method of choice for most high-throughput screening procedures in forensic/clinical toxicology, doping control and food and environmental analysis. Despite the many advantages of the GC/MS method, time-consuming derivatization steps are often required in order to obtain desirable chromatographic characteristics or to improve the stability and detectability of the target analytes. These derivatization processes typically require reaction times from 30 min up to several hours at elevated temperature. In contrast, microwave protocols have demonstrated to be able to reduce the time required for derivatization to a few minutes, and can thus very effectively shorten the overall analysis time, in particular when carried out in a high-throughput format. Herein, the literature in this field is summarized and recent experimental techniques for performing parallel GC/MS derivatization protocols are discussed.