Intriguing Cytotoxicity of the Street Dissociative Anesthetic Methoxphenidine: Unexpected Impurities Spotted.

The black market for new psychoactive substances has been constantly evolving and the substances that appear on this market cause a considerable number of issues, in extreme cases leading to human deaths. While monitoring the drug black market, we detected a sample of a dissociative anesthetic methoxphenidine, the salt of which contained an unusual anion in the form of bromo- and chloro-zincate complex. Concerning the unknown and potentially hazardous properties of this sample, we performed an in vitro cytotoxicity screening in cell lines of various origins (e.g., kidney, liver, bladder) which was compared with the toxicity results of the methoxphenidine standard prepared for this purpose. The street methoxphenidine sample exhibited markedly higher toxicity than the standard, which was probably caused by the anion impurity. Since it is not usual to analyze anions in salts of novel psychoactive substances, but such samples may be commonly available at the drug black market, we have developed a method for their identification with X-ray powder diffraction (XRPD), which also enabled us to distinguish between different polymorphs/solvates of methoxphenidine that were crystallized in the laboratory. XRPD offers additional data about samples, which may not be discovered by routine techniques, and in some cases, they may help to find out essential information.

Guilty by dissociation-development of gas chromatography-mass spectrometry (GC-MS) and other rapid screening methods for the analysis of 13 diphenidine-derived new psychoactive substances (NPSs).

The prevalence of new psychoactive substances (NPSs) in forensic casework has increased prominently in recent years. This has given rise to significant legal and analytical challenges in the identification of these substances. The requirement for validated, robust and rapid testing methodologies for these compounds is obvious. This study details the analysis of 13 synthesised diphenidine derivatives encountered in casework using presumptive testing, thin layer chromatography and gas chromatography-mass spectrometry (GC-MS). Specifically, the validated GC-MS method provides, for the first time, both a general screening method and quantification of the active components for seized solid samples, both in their pure form and in the presence of common adulterants. Graphical Abstract Chemical synthesis and forensic analysis of 13 diphenidine-derived new psychoactive substance(s).

"Word of mouse": indigenous harm reduction and online consumerism of the synthetic compound methoxphenidine.

Methoxphenidine (MXP) was one of several NMDA antagonists marketed in 2013 to replace the recently controlled compound Methoxetamine (MXE). A steep rise in user interest was recorded, despite vendor cautioning of limited user feedback. The study presented a phenomenological analysis of MXP experiences amongst recreational drug users as posted on public Internet fora. Internet searches were carried out using specific key words; "methoxphenidine," "MXP" and in combination with "experience," "report," "forum," and "trip." Seven self-reported experiences and 28 thread discussions relating sole use of MXP were analyzed using the Empirical Phenomenological Psychological method. Five themes and 61 categories emerged. MXP is marketed as a legal replacement for MXE, diphenidine, and ketamine, with a dissociative and stimulant wave outcome often lasting for days. Harm reduction tactics, awareness of prior tolerance to dissociative and optimal settings for use are discussed. Acute side-effects relate to hypertension and seizures. Chronic long-term memory loss and limb numbness is reported. Sense of empowerment occurs in the afterglow experience. Internet drug fora fuel information exchange and informed consumerism of synthetic compounds, and offer viable mechanisms for pre- and post-purchase decision making and indigenous harm reduction. Continued surveillance of synthetic market entries and user trends is warranted.

Methoxphenidine (MXP) induced abnormalities: Addictive and schizophrenia-related behaviours based on an imbalance of neurochemicals in the brain.

BACKGROUND AND PURPOSE: Methoxphenidine is a dissociative-based novel psychoactive designer drug. Although fatal accidents from methoxphenidine abuse have been reported, recreational use of the drug continues. We aim to provide scientific supportfor legal regulation of recreational abuse of methoxphenidine by demonstrating its the pharmacological action. EXPERIMENTAL APPROACH: Addictive potential of methoxphenidine was examined using intravenous self-administration test with rats and conditioned place preference test with mice. Further, a series of behavioural tests (open field test, elevated plus maze test, novel object recognition test, social interaction test and tail suspension test) performed to assess whether methoxphenidine caused schizophrenia-related symptoms in mice. Additionally, neurotransmitter enzyme-linked immunosorbent assay and western blot were used to confirm methoxphenidine-induced neurochemical changes in specific brain regions related to abnormal behaviours. KEY RESULTS: Methoxphenidine caused addictive behaviours via reinforcing and rewarding effects. Consistently, methoxphenidine induced over-activation of dopamine pathways in the nuclear accumbens, indicating activation of the brain reward circuit. Also, methoxphenidine caused all categories of schizophrenia-related symptoms, including positive symptoms (hyperactivity, impulsivity), negative symptoms (anxiety, social withdrawal, depression) and cognitive impairment. Consistently, methoxphenidine led to the disruption of the hippocampal-prefrontal cortex pathway that is considered to be pathological involved in schizophrenia. CONCLUSIONS AND IMPLICATIONS: We demonastrate that methoxphenidine causes addictive and schizophrenia-like behaviours and induces neurochemical changes in brain regions associated with these behaviours. We propose that methoxphenidine could be used in developing useful animal disease models and that it also requires legal restrictions on its recreational use.

Effects of the new psychoactive substances diclofensine, diphenidine, and methoxphenidine on monoaminergic systems.

Diclofensine, diphenidine, and methoxphenidine are new psychoactive substances (NPSs) that recently appeared on the illicit drug market. Pharmacological profiling of such newly emerged drugs is crucial for a better understanding of their psychotropic effects and toxicity. We therefore investigated the potential of these NPSs to inhibit the norepinephrine, dopamine, and serotonin transporters in human embryonic kidney cells stably transfected with the respective transporters. In addition, we determined monoamine transporter and receptor affinities for the substances. Diclofensine potently bound to the monoamine transporters in the submicromolar range and had similar inhibition potential for all three transporters in the range of 2.5-4.8µM. Moreover, diclofensine bound to adrenergic, dopamine, serotonin, and trace amine-associated receptors. Diphenidine was an equipotent inhibitor of the norepinephrine and dopamine transporters in the low micromolar range and a very weak inhibitor of the serotonin transporter. Besides binding to transporters, diphenidine bound to adrenergic α1A and α2A receptors and serotonin 5-hydroxytryptamine 1A (5-HT1A) and 5-HT2A receptors in the range of 4-11µM. Methoxphenidine bound to all transporters, but considerable inhibition (IC50 < 10µM) was observed only for the norepinephrine transporter. Moreover, methoxphenidine bound to adrenergic α2A and serotonin 5-HT2A and 5-HT2C receptors in the range of 2.5-8.2µM. None of the test drugs mediated substrate-type efflux of monoamines. These data demonstrate that the monoamine transporter inhibition and receptor interactions most likely mediate the psychoactive effects of diclofensine and possibly play a contributory role for diphenidine and methoxphenidine.

Ephenidine, diphenidine, and methoxphenidine complications reported to the French Addictovigilance Network.

Ephenidine, diphenidine, and methoxphenidine belong to the family of diarylethylamines that are psychoactive substances derived from lefetamine (N, N-di-methyl-1,2-diphenylethylamine, also called L-SPA). These dissociative anesthetic compounds act as potent and selective N-methyl-d-aspartate receptor antagonists and were recently classified as narcotic drugs in France. The available data suggest a significant risk of psychic and somatic complications. To obtain more information, this retrospective study analyzed all spontaneous notifications of serious cases of ephenidine, diphenidine, and methoxphenidine abuse collected by the French Addictovigilance Network from 2012 to 2016 and classified them as proven, probable, and possible. For each case, age, sex, concomitantly ingested substances, pattern of abuse of psychoactive drugs, and related complications (scored using the poisoning severity score) were collected. Eighteen cases were identified (one in 2013, five in 2015, and 12 in 2016) in 16 men (median age: 31.5 years [IQR 25-75% 27-34]). Ephenidine, diphenidine, and methoxphenidine were involved in four, seven, and 11 cases, respectively. No case was considered proven, 16 cases were considered possible, and two probable due to polysubstance abuse (co-ingestion of other new psychoactive substances). The reported clinical complications were minor in five cases, moderate in six cases, and serious in four cases, and included psychiatric, neurologic, and cardiovascular problems. This analysis indicates that the number of reported cases progressively increased from 2012 to 2016 and mainly concerned methoxphenidine. The addictive potential of these substances seems highly probable; but further investigations are needed to limit their harmful effects.

Intoxications by the dissociative new psychoactive substances diphenidine and methoxphenidine.

BACKGROUND: Diphenidine (1-(1,2-diphenylethyl)piperidine) and its 2-methoxylated derivative methoxphenidine (MXP, 2-MeO-diphenidine) are substances with dissociative effects that were recently introduced for "recreational" purpose through the online-based sale of new psychoactive substances (NPS). A number of analytically confirmed non-fatal intoxications associated with diphenidine or MXP have occurred in Sweden and were included in the STRIDA project. STUDY DESIGN: Observational case series of consecutive patients with admitted or suspected intake of NPS and requiring intensive treatment in an emergency room and hospitalization in Sweden. PATIENTS AND METHODS: Blood and urine samples were collected from intoxicated patients presenting at emergency departments all over the country. NPS analysis was performed by multi-component liquid chromatography-mass spectrometry methods. Data on clinical features were collected during telephone consultations with the Poisons Information Centre and retrieved from medical records. Information was also obtained from online drug discussion forums. CASE SERIES: Over a 12-month period from January to December 2014, 750 cases of suspected NPS intoxication originating from emergency departments were enrolled in the STRIDA project of which 14 (1.9%) tested positive for diphenidine and 3 (0.4%) tested positive for MXP. Co-exposure to several other NPS (e.g., 5-/6-(2-aminopropyl)benzofuran, 2-4-bromomethcathinone, butylone, 3,4-dichloromethylphenidate, 5-methoxy-N-isopropyltryptamine, methiopropamine, and α-pyrrolidinopentiothiophenone), also including other dissociative substances (3-/4-methoxyphencyclidine), and classical drugs of abuse (e.g., cannabis and ethanol) was documented in 87% of these cases. The 17 patients were aged 20-48 (median: 32) years, and 13 (76%) were men. They commonly presented with hypertension (76%), tachycardia (47%), anxiety (65%), and altered mental status (65%) including confusion, disorientation, dissociation, and/or hallucinations. Eight patients (47%) displayed severe intoxication (Poisoning Severity Score 3). The diphenidine- or MXP-positive patients required hospitalization for 1-3 (median: 2) days. In addition to standard supportive therapy, half of the cases were treated with benzodiazepines and/or propofol. CONCLUSION: The adverse effects noted in analytically confirmed cases of NPS intoxication involving diphenidine or MXP were similar to those reported for other dissociative substances such as ketamine and methoxetamine. However, the high proportion of polysubstance use might have played a role in the intoxication and clinical features in some cases.