National reflection on organs-on-chip for drug development: New regulatory challenges.

Organs-on-chip (OoC) are innovative and promising in vitro models, particularly in the process of developing new drugs, to improve predictivity of preclinical studies in humans. However, a lack of regulatory consensus on acceptance criteria and standards around these technologies currently hinders their adoption and implementation by end-users. A reflection has been conducted at the National Agency for Medicines and Health products safety (ANSM) in order to address this issue, which has gained momentum at the international level in recent years. If the subject of OoC is of international interest, France is also in the process of structuring an OoC network, in order to best support the emergence of this new technological innovation. Focusing on liver-on-a-chip, the authors drafted a first list of regulatory requirements to help standardize these devices and their use. Technological and biological relevance of liver-on-a-chip was also evaluated, in comparison with current in vitro and in vivo models, based on the available literature. The authors offer an analysis of the current scientific and regulatory situation, highlighting the key regulatory issues for the future.

[Use of synthetic substances in France and in Europe]. / Usages de substances de synthèse en France et en Europe.

This paper aims to present the main information presented at the 9th Meeting about addictovigilance in 2016 by four healthcare professionals and addiction experts on the issue of new psychoactive substance use. A new psychoactive substance (NPS) is defined as a narcotic or psychotropic drug, in pure form or in preparation, that is not controlled by the United Nations drug conventions, but which may pose a public health threat comparable to that posed by substances listed in these conventions. The emergence of NPS consumption is a worldwide concern. Although NPS are less consumed than established drugs, there has been a sharp increase in their use over the last few years, notably of synthetic cathinones, synthetic cannabinoids and, more recently, synthetic opioids. The latter in particular are involved in deaths in Europe. However, "established" drugs (MDMA [methylenedioxymethamphetamine], amphetamines, LSD, methamphetamine) are far from being dethroned by the more recent substances: they are considered "a safe bet" already "tried and tested" by many consumers over the years. MDMA, in particular, also known as ecstasy, which has been used as a recreational drug since the 1990s, saw its consumption decrease until 2010, and then increase again, especially in higher amounts; inexpensive and easily accessible, it is increasingly associated with emergency admissions or deaths in France. The perpetual appearance of new substances on the drug market is obligating to improve knowledge on these products, particularly by focusing on their analytical identification, and also by monitoring their use and harms.

Pharmacokinetics of 300 mg/d Intraperitoneal Daptomycin: New Insight from the DaptoDP Study.

The DaptoDP (NCT 2012-005699-33) study aimed to evaluate the pharmacokinetic parameters of daptomycin (DAP) in peritoneal dialysis-related peritonitis (PDRP) patients following intraperitoneal (IP) administration. The authors have already reported the findings on the 200-mg dosing and present here the follow-up results of the 300-mg dosing. The primary endpoint was a dialysate concentration of DAP above the effective concentration in situ during 6 hours of dwell time i.e., 16 mg/L. Secondary endpoints were to avoid the toxic threshold of 120 mg/L DAP and to be above 16 mg/L DAP for 2 hours in plasma. Pharmacokinetic parameters were evaluated on days 1 and 5. Safety data were evaluated on days 1 to 14 based on clinical and biological parameters. Daptomycin was administered in Nutrineal during 6 hours of dwell time for 14 days plus the usual antibiotic therapy in a separate dwell. Because the 200-mg dosing objectives were not reached, a higher DAP dose of 300 mg was tested in the next 3 patients. Effective dialysate and plasma concentrations were achieved at the 300-mg DAP dose with the plasma concentration well below the toxic threshold, even at steady state, during which the accumulation factor never exceeded 3. The optimal DAP dose of 300 mg daily by the IP route, as determined by the pharmacokinetic data, needs to be clinically confirmed prior to routine use. The peritoneal bioavailability of DAP supports using the IP route as an alternative to the intravenous route for peritonitis and systemic infections.

Pharmacokinetics of Intraperitoneal Daptomycin in Patients with Peritoneal Dialysis-Related Peritonitis.

♦ BACKGROUND: Antibiotics are preferentially delivered via the peritoneal route to treat peritoneal dialysis-related peritonitis (PDRP) to ensure that maximal concentrations are delivered to the site of infection. Our study focused on the pharmacokinetics of daptomycin (DAP) administered via the intraperitoneal (IP) route in patients with PDRP. ♦ METHODS: According to the DaptoDP protocol (Clinical Trial No. 2012-005699-33), IP DAP was administered daily, i.e., during the 6-h Nutrineal (Baxter Healthcare Corporation, Deerfield, IL, USA) dwell time period, for 14 days, in addition to administration of the antibiotics used for the usual care of patients with PDRP. The plasma and IP levels of DAP were measured on days 1 and 5. The tested dose was 200 mg/day. The principal endpoint was the dialysate concentration after 6 hours of dwell time > 16 mg/L (corresponding to 4 x minimum inhibitory concentration [MIC] for E. faecalis). ♦ RESULTS: Three participants were evaluated. On day 5, the IP concentrations after 6 hours of dwell time were between 6.3 and 23.4 mg/L, and the peak plasma concentrations were between 13.0 and 15.3 mg/L. ♦ CONCLUSION: The results suggest that 200 mg/day is very likely sufficient for the treatment of PDRP by Staphylococci or Streptococci whereas it could be insufficient to treat PRDP by Enterococci. The good peritoneal bioavailability of DAP was quantitatively established, suggesting that IP administration could also be used as an alternate route for patients with damaged venous access. No DAP accumulation that could lead to toxic concentrations after repeated administration is expected, even in anuric patients. The protocol will further continue to assess whether a higher dose achieves the pharmacokinetic objectives.

[The current aspects of the use of ecstasy/MDMA in France]. / Les aspects actuels de l'usage de l'ecstasy/MDMA en France.

Methylenedioxymethamphetamine (MDMA), the active compound of ecstasy, has been used for several years, especially by young adults to benefit of psychostimulant properties. By raising the level of neuromodulators in the synapsis, MDMA can cause psychiatric and physical injuries. After reduced supplies in 2009 (number of ecstasy seizures equal to 10 percent of those recorded in 2002), judicial authorities now observed an increased availability (a half more part of seizures in 2012 than 2010). From its "Spontaneous Notifications" data base and "deaths in connection with the abuse of medicine and substances (DRAMES)", "observation of illegal drugs and misuse of psychotropic medications" (OPPIDUM), and "observation of drug dependencies in ambulatory medicine" (OPEMA) national inquiries, the French Addictovigilance network (CEIP-A) highlighted the increasing consumption of MDMA. The way of use appeared quite unchanged: users were mainly young men between 25 and 30 years; they favored an occasional use but mainly combined other products such as alcohol, cannabis and other stimulants. Severity of the clinical cases, based on hospital care and forensic data, could be consistent with the higher amounts of MDMA measured in pills.

Pharmacokinetics and pharmacodynamics of MD1003 (high-dose biotin) in the treatment of progressive multiple sclerosis.

INTRODUCTION: Multiple sclerosis (MS) is a chronic, potentially highly disabling neurological disorder. No disease-modifying treatments are approved in the progressive and not active forms of the disease. AREAS COVERED: High doses of biotin were tested in an open-label pilot study involving 23 patients with progressive MS and reported positive results. A randomized, double-blind, placebo-controlled trial in 154 progressive MS patients confirmed the beneficial effect of MD1003 (high-dose biotin) on reversing or stabilizing disability progression, with a good safety profile. It is proposed that MD1003 in progressive MS 1) increases energy production in demyelinated axons and/or 2) enhances myelin synthesis in oligodendrocytes. Biotin is highly bioavailable; absorption and excretion are rapid. The major route of elimination is urinary excretion. EXPERT OPINION: A high oral dose of biotin seems generally well tolerated but a few important safety concerns were identified: 1) teratogenicity in one species and 2) interference with some biotin-based laboratory immunoassays. The animal toxicity data are limited at such high doses. Further preclinical studies would be useful to address the mechanism of action of MD1003. Assessment of clinical benefit duration in responders will be also very important to set. Results of randomized, placebo-controlled trial are reassuring and provide hope for the treatment of progressive MS.

Emerging drugs of abuse: current perspectives on synthetic cannabinoids.

New psychoactive drugs that have appeared over the last decade are typically dominated by cathinones and synthetic cannabinoids (SCs). SCs have been emerging as recreational drugs because they mimic the euphoria effect of cannabis while still being legal. Sprayed on natural herb mixtures, SCs have been primarily sold as "herbal smoking blends" or "herbal incense" under brand names like "Spice" or "K2". Currently, SCs pure compounds are available from websites for the combination with herbal materials or for the use in e-cigarettes. For the past 5 years, an ever increasing number of compounds, representative of different chemical classes, have been promoted and now represent a large assortment of new popular drugs of abuse, which are difficult to properly identify. Their legal status varies by country with many government institutions currently pushing for their control. The in vitro binding to CB1/CB2 receptors is usually well-known and considerable differences have been found in the CB1 versus CB2 selectivity and potency within the different SCs, with several structure-activity relations being evident. Desired effects by CB1 agonist users are relaxation/recreative, however, cardiovascular, gastrointestinal, or psychiatric/neurological side effects are commonly reported. At present there is no specific antidote existing if an overdose of designer drugs was to occur, and no curative treatment has been approved by health authorities. Management of acute toxic effects is mainly symptomatic and extrapolated from experience with cannabis.

New synthetic drugs in addictovigilance.

New substances, also known as "designer drugs" or "legal highs" are increasingly available to drug users. Two hundred and fifteen hitherto unlisted substances have been notified by European Union member states since 2005. These synthetic drugs, which have been developed to side-step the legislation on drugs, are analogues or derivatives of existing drugs and medications. The availability of these "legal highs", sold on Internet under various denominations such as bath salt, plant fertilizer, chemical not intended for human use, or spice, is unlimited. The effects felt by users vary, and the substances may be stimulant, entactogenic, hallucinogenic, psychedelic or dissociative. The pharmacological targets also vary, and may be either the increase of extracellular levels of neurotransmitters via different mechanisms (reuptake inhibition, stimulation of intracellular release) or else fixation on specific receptors. Several chemical classes, themselves divided into sub-classes, are involved: phenethylamines, tryptamines, piperazines, cathinones, cannabinoids etc. The toxicity of the main members of these categories is increasingly well known, the most deleterious being behavioural effects, physical manifestations, and cardiovascular consequences. However, small variations in their chemical structure can generate effects that are quantitatively different, thus enhancing their toxicity or addictive potential, and much remains to be achieved in terms of knowledge about these new drugs. These substances are indeed present on the French territory, as shown by data provided by the Observatoire Français des Drogues et Toxicomanies, and notifications by the French Addictovigilance network. Screening in clinical toxicology laboratories is not widespread, since these molecules are not detected by the standard screening tests, so that there is probably an under-estimation of the use of these new drugs. The legislation on these substances changes regularly, with more and more countries classifying them as "narcotics" or illegal psychotropic drugs so as to restrict their use, applying a generic classification when possible.

Emerging drugs of abuse: current perspectives on substituted cathinones.

Substituted cathinones are synthetic analogs of cathinone that can be considered as derivatives of phenethylamines with a beta-keto group on the side chain. They appeared in the recreational drug market in the mid-2000s and now represent a large class of new popular drugs of abuse. Initially considered as legal highs, their legal status is variable by country and is rapidly changing, with government institutions encouraging their control. Some cathinones (such as diethylpropion or pyrovalerone) have been used in a medical setting and bupropion is actually indicated for smoking cessation. Substituted cathinones are widely available from internet websites, retail shops, and street dealers. They can be sold under chemical, evocative or generic names, making their identification difficult. Fortunately, analytical methods have been developed in recent years to solve this problem. Available as powders, substituted cathinones are self-administered by snorting, oral injestion, or intravenous injection. They act as central nervous system stimulants by causing the release of catecholamines (dopamine, noradrenaline, and serotonin) and blocking their reuptake in the central and peripheral nervous system. They may also decrease dopamine and serotonin transporter function as nonselective substrates or potent blockers and may inhibit monoamine oxidase effects. Nevertheless, considerable differences have been found in the potencies of the different substituted cathinones in vitro. Desired effects reported by users include increased energy, empathy, and improved libido. Cardiovascular (tachycardia, hypertension) and psychiatric/neurological signs/symptoms (agitation, seizures, paranoia, and hallucinations) are the most common adverse effects reported. Severe toxicity signs compatible with excessive serotonin activity, such as hyperthermia, metabolic acidosis, and prolonged rhabdomyolysis, have also been observed. Reinforcing potential observed in animals predicts a high potential for addiction and abuse in users. In case of overdose, no specific antidote exists and no curative treatment has been approved by health authorities. Therefore, management of acute toxic effects is mainly extrapolated from experience with cocaine/amphetamines.

Argon prevents the development of locomotor sensitization to amphetamine and amphetamine-induced changes in mu opioid receptor in the nucleus accumbens.

Systemic administration of γ-amino-butyric acid type A (GABA-A) and benzodiazepine receptor agonists has been reported to block the development of locomotor sensitization to amphetamine. Here, we investigated whether the non-anesthetic noble gas argon, shown to possess agonistic properties at these receptors, may block the acquisition of amphetamine-induced locomotor sensitization and mu opioid receptor activation in the nucleus accumbens. Rats were pretreated with saline solution or amphetamine (1 mg/kg) from day 1 to day 3 and then exposed, immediately after injection of amphetamine, to medicinal air or argon at 75 vol% (with the remainder being oxygen). After a 3-day period of withdrawal, rats were challenged with amphetamine on day 7. Rats pretreated with amphetamine and argon had lower locomotor activity (U = 5, P < 0.005) and mu opioid receptor activity in the nucleus accumbens (U = 0, P < 0.001) than rats pretreated with amphetamine and air. In contrast, argon had effect on locomotor and mu receptor activity neither in rats pretreated with saline and challenged with amphetamine (acute amphetamine) nor in rats pretreated and challenged with saline solution (controls). These results indicate that argon inhibits the development of both locomotor sensitization and mu opioid receptor activation induced by repeated administration of amphetamine.

Toxicity and death following recreational use of 2-pyrrolidino valerophenone.

BACKGROUND: Consumption of substituted cathinones, frequently called 'legal highs' or 'designer drugs', is increasing in the European Union. In July 2012, the French Medicine Agency listed the substituted cathinone's chemical family as narcotic and psychotropic substances, to restrict their use and distribution. We present, here, the first documented cases of recreational use of 2-pyrrolidino valerophenone (PVP) associated with death for one patient, with post-mortem toxicological analysis. CASE REPORTS: Two men purchased the legal high Energy-3 (NRG-3). It can be sold as laboratory reagent and is available from Internet. The oldest died of sudden cardiac arrest. The other experienced visual hallucinations and psychotic symptoms for 24 h. He also presented bilateral mydriasis, sinus tachycardia and rhabdomyolysis. He reported an occasional intranasal use of NRG-3. Analysis of the powder and blood and urine from both men revealed the presence of PVP. DISCUSSION AND CONCLUSION: PVP belongs to the substituted cathinones chemical family. These cases highlight the need for emergency physicians, toxicologists and networks of toxicovigilance to control the use of these substances and their dangers, quickly identify cases of severe poisoning associated with the use of new drugs and to develop detection methods.

Radiolabelling of 1,4-disubstituted 3-[18F]fluoropiperidines and its application to new radiotracers for NR2B NMDA receptor visualization.

In order to develop a novel and useful building block for the development of radiotracers for positron emission tomography (PET), we studied the radiolabelling of 1,4-disubstituted 3-[(18)F]fluoropiperidines. Indeed, 3-fluoropiperidine became a useful building block in medicinal chemistry for the pharmacomodulation of piperidine-containing compounds. The radiofluorination was studied on substituted piperidines with electron-donating and electron-withdrawing N-substituents. In the instance of electron-donating N-substituents such as benzyl or butyl, configuration retention and satisfactory fluoride-18 incorporation yields up to 80% were observed. In the case of electron-withdrawing N-substituents leading to carbamate or amide functions, the incorporation yields depend on the 4-susbtitutent (2 to 63%). The radiolabelling of this building block was applied to the automated radiosynthesis of NR2B NMDA receptor antagonists and effected by a commercially available radiochemistry module. The in vivo evaluation of three radiotracers demonstrated minimal brain uptakes incompatible with the imaging of NR2B NMDA receptors in the living brain. Nevertheless, moderate radiometabolism was observed and, in particular, no radiodefluorination was observed which demonstrates the stability of the 3-position of the fluorine-18 atom. In conclusion, the 1,4-disubstituted 3-[(18)F]fluoropiperidine moiety could be of value in the development of other radiotracers for PET even if the evaluation of the NR2B NMDA receptor antagonists failed to demonstrate satisfactory properties for PET imaging of this receptor.

Synthesis and in vitro characterization of trans- and cis-[(18)F]-4-methylbenzyl 4-[(pyrimidin-2-ylamino)methyl]-3-fluoropiperidine-1-carboxylates as new potential PET radiotracer candidates for the NR2B subtype N-methyl-D-aspartate receptor.

Diastereoisomeric compounds [(18)F]cis- and [(18)F]trans-4-methylbenzyl 4-[(pyrimidin-2-ylamino)methyl]-3-fluoro-piperidine-1-carboxylates were successfully synthesized as new subtype-selective PET radiotracers for imaging the NR2B subunit containing NMDA receptors. Rat brain section autoradiographies demonstrated a high specific binding in NR2B/NMDA receptor rich regions for both radioligands. The measured logD(7.4) values as well as B(max)/K(d) ratios indicated that both radiotracers possess the adequate properties required for PET radiotracers.

Synthesis, evaluation and metabolic studies of radiotracers containing a 4-(4-[18F]-fluorobenzyl)piperidin-1-yl moiety for the PET imaging of NR2B NMDA receptors.

In this study, novel specific PET radioligands containing the 4-(4-fluorobenzyl)piperidine moiety and selectively antagonistic for the NR2B subunit containing NMDA receptors were developed. Two antagonists, RGH-896 (1a) and 4-(4-fluorobenzyl)piperidinyl-1-methyl-2-benzimidazol-5-ol (2a), belonging to two different structural families, were radiolabeled by an aromatic nucleophilic radiofluorination followed by a reduction of the para-position carbonyl function. Radiotracers [18F]1a, [18F]2a or the pattern 4-(4-[18F]-fluorobenzyl)piperidine ([18F]6) demonstrated an identical in vivo behavior with high accumulation of radioactivity in bone and cartilage which would suggest a radiodefluorination of the radiotracers. The identification of metabolites from 6 by LC-MS-MS confirmed the significant degree of defluorination as a result of the in vivo hydroxylation in the benzyl ring. In conclusion, [18F]1a or [18F]2a are not suitable for imaging the NR2B NMDA receptors due to their poor brain penetration. We also argue for a cautious use of the radiolabeled pattern, 4-(4-[18F]-fluorobenzyl)piperidine, to develop PET radiotracers.