Sex differences in the effects of N-ethylpentylone in young CD1 mice: Insights on behaviour, thermoregulation and early gene expression.

BACKGROUND AND PURPOSE: New psychoactive substances such as N-ethylpentylone (NEP) are continuously emerging in the illicit drug market, and knowledge of their effects and risks, which may vary between sexes, is scarce. Our present study compares some key effects of NEP in male and female mice. EXPERIMENTAL APPROACH: Psychostimulant, rewarding and reinforcing effects were investigated by tracking locomotor activity, conditioned place preference (CPP) paradigm and through a self-administration (SA) procedure, respectively, in CD1 mice. Moreover, the expression of early genes (C-fos, Arc, Csnk1e, Pdyn, Pp1r1b and Bdnf in addiction-related brain areas) was assessed by qPCR. Finally, serum and brain levels of NEP were determined by UHPLC-MS/MS. KEY RESULTS: NEP-treated males experimented locomotor sensitisation and showed higher and longer increases in locomotion as well as higher hyperthermia after repeated administration than females. Moreover, while preference score in the CPP was similar in both sexes, extinction occurred later, and reinstatement was more easily established for males. Female mice self-administered more NEP than males at a higher dose. Differences in early gene expression (Arc, Bdnf, Csnk1e and Ppp1r1b) were found, but the serum and brain NEP levels did not differ between sexes. CONCLUSION AND IMPLICATIONS: Our results suggest that male mice are more sensitive to NEP psychostimulant and rewarding effects. These differences may be attributed to different early gene expression but not to pharmacokinetic factors. Moreover, males appear to be more vulnerable to the hyperthermic effects of NEP, while females might be more prone to NEP abuse.

3,4-Methylenedioxy methamphetamine, synthetic cathinones and psychedelics: From recreational to novel psychotherapeutic drugs.

The utility of classical drugs used to treat psychiatric disorders (e.g., antidepressants, anxiolytics) is often limited by issues of lack of efficacy, delayed onset of action or side effects. Psychoactive substances have a long history of being used as tools to alter consciousness and as a gateway to approach the unknown and the divinities. These substances were initially obtained from plants and animals and more recently by chemical synthesis, and its consumption evolved toward a more recreational use, leading to drug abuse-related disorders, trafficking, and subsequent banning by the authorities. However, these substances, by modulation of certain neurochemical pathways, have been proven to have a beneficial effect on some psychiatric disorders. This evidence obtained under medically controlled conditions and often associated with psychotherapy, makes these substances an alternative to conventional medicines, to which in many cases the patient does not respond properly. Such disorders include post-traumatic stress disease and treatment-resistant depression, for which classical drugs such as MDMA, ketamine, psilocybin and LSD, among others, have already been clinically tested, reporting successful outcomes. The irruption of new psychoactive substances (NPS), especially during the last decade and despite their recreational and illicit uses, has enlarged the library of substances with potential utility on these disorders. In fact, many of them were synthetized with therapeutic purposes and were withdrawn for concrete reasons (e.g., adverse effects, improper pharmacological profile). In this review we focus on the basis, existing evidence and possible use of synthetic cathinones and psychedelics (specially tryptamines) for the treatment of mental illnesses and the properties that should be found in NPS to obtain new therapeutic compounds.

Elimination profile of triamcinolone hexacetonide and its metabolites in human urine and plasma after a single intra-articular administration.

Triamcinolone hexacetonide (THA) is a synthetic glucocorticoid (GC) used by intra-articular (IA) administration. GCs are prohibited in sports competitions by systemic routes, and they are allowed by other routes considered of local action (IA administration, among others). The aim of the present work was to study the metabolic profile of THA in urine and plasma following IA administration. Eight patients (4 males and 4 females) with knee osteoarthritis received an IA dose of THA (40 mg) in the knee joint. Spot urine and plasma samples were collected before injection and at different time periods up to day 23 and 10 post-administration, respectively. The samples were analysed by liquid chromatography-tandem mass spectrometry. Neither THA nor specific THA metabolites were detected in urine. Triamcinolone acetonide (TA) and 6ß-hydroxy-triamcinolone acetonide were the main urinary metabolites. Maximum concentrations wereobtained between 24 and 48 h after administration. Using the reporting level of 30 ng/mL to distinguish allowed from forbidden administrations of GCs, a large number of false adverse analytical findings would be reported up to day 4. On the other hand, TA was detected in all plasma samples collected up to day 10 after administration. THA was also detected in plasma but at lower concentrations. The detection of plasma THA would be an unequivocal proof to demonstrate IA use of THA. A reversible decrease was observed in plasma concentrations of cortisol in some of the patients, indicating a systemic effect of the drug.

Dose-Response Pharmacological Study of Mephedrone and Its Metabolites: Pharmacokinetics, Serotoninergic Effects, and Impact of CYP2D6 Genetic Variation.

Mephedrone (MEPH), the most widely consumed synthetic cathinone, has been associated with acute toxicity episodes. The aim of this report was to study its metabolic disposition and the impact of genetic variation of CYP2D6 on MEPH metabolism, in a dose range compatible with its recreational use. A randomized, crossover, phase I clinical trial was performed. Subjects received 50 and 100 mg (n = 3) and 150 and 200 mg (n = 6) of mephedrone and were genetically and phenotypically characterized for the CYP2D6 allelic variation. Our results showed a linear kinetics of mephedrone at the dose range assayed: plasma concentrations, cardiovascular and subjective effects, and blood serotonin concentrations all correlated in a dose-dependent manner. Mephedrone metabolic disposition is mediated by CYP2D6. Mephedrone pharmacology presented a linear dose-dependence within the range of doses tested. The metabolism of mephedrone by CYP2D6 implies that recreational users with no or low CYP2D6 functionality are exposed to unwanted acute toxicity episodes.

Metabolomics predicts the pharmacological profile of new psychoactive substances.

BACKGROUND: The unprecedented proliferation of new psychoactive substances (NPS) threatens public health and challenges drug policy. Information on NPS pharmacology and toxicity is, in most cases, unavailable or very limited and, given the large number of new compounds released on the market each year, their timely evaluation by current standards is certainly challenging. AIMS: We present here a metabolomics-targeted approach to predict the pharmacological profile of NPS. METHODS: We have created a machine learning algorithm employing the quantification of monoamine neurotransmitters and steroid hormones in rats to predict the similarity of new drugs to classical ones of abuse (MDMA (3,4-methyl enedioxy methamphetamine), methamphetamine, cocaine, heroin and Δ9-tetrahydrocannabinol). RESULTS: We have characterized each classical drug of abuse and two examples of NPS (mephedrone and JWH-018) following alterations observed in the targeted metabolome profile (monoamine neurotransmitters and steroid hormones) in different brain areas, plasma and urine at 1 h and 4 h post drug/vehicle administration. As proof of concept, our model successfully predicted the pharmacological profile of a synthetic cannabinoid (JWH-018) as a cannabinoid-like drug and synthetic cathinone (mephedrone) as a MDMA-like psychostimulant. CONCLUSION: Our approach allows a fast NPS pharmacological classification which will benefit both drug risk evaluation policies and public health.

Concentrations of MDPV in rat striatum correlate with the psychostimulant effect.

3,4-methylenedioxypyrovalerone or MDPV is a synthetic cathinone with psychostimulant properties more potent than cocaine. We quantified this drug in the striatum after subcutaneous administration to rats. MDPV reached the brain around 5 min after its administration and peaked at 20-25 min later. The elimination half-life in the striatum (61 min) correlates with the decrease in the psychostimulant effect after 60 min. Around 11% of the administered dose reached the striatum and, considering a homogeneous brain distribution, we determined that around 86% of the plasma MDPV is distributed to the brain. MDPV induced a dose-dependent increase in locomotor activity, rearing behaviour and stereotypies, all prevented by haloperidol. A plot of locomotor activity or stereotypies versus MDPV striatal concentrations over time showed a direct relationship between factors. No free MDPV metabolites were detected in plasma, at any time, but hydrolysis with glucuronidase allowed us to identify mainly three metabolites, one of them for the first time in rat plasma. The present results contribute to evidence that MDPV induces hyperlocomotion mainly through a dopamine-dependent mechanism. Good correlation between behavioural effects and striatal levels of MDPV leads us to conclude that its psychostimulant effect is mainly due to a striatal distribution of the substance. The present research provides useful information on the pharmacokinetics of MDPV, and can help design new experiments with kinetics data as well as provide a better understanding of the effects of MDPV in humans and its potential interactions.

An integrated pharmacokinetic and pharmacodynamic study of a new drug of abuse, methylone, a synthetic cathinone sold as "bath salts".

INTRODUCTION: Methylone (3,4-methylenedioxymethcathinone) is a new psychoactive substance and an active ingredient of "legal highs" or "bath salts". We studied the pharmacokinetics and locomotor activity of methylone in rats at doses equivalent to those used in humans. MATERIAL AND METHODS: Methylone was administered to male Sprague-Dawley rats intravenously (10mg/kg) and orally (15 and 30 mg/kg). Plasma concentrations and metabolites were characterized by LC/MS and LC-MS/MS fragmentation patterns. Locomotor activity was monitored for 180-240 min. RESULTS: Oral administration of methylone induced a dose-dependent increase in locomotor activity in rats. The plasma concentrations after i.v. administration were described by a two-compartment model with distribution and terminal elimination phases of α=1.95 h(-1) and ß=0.72 h(-1). For oral administration, peak methylone concentrations were achieved between 0.5 and 1h and fitted to a flip-flop model. Absolute bioavailability was about 80% and the percentage of methylone protein binding was of 30%. A relationship between methylone brain levels and free plasma concentration yielded a ratio of 1.42 ± 0.06, indicating access to the central nervous system. We have identified four Phase I metabolites after oral administration. The major metabolic routes are N-demethylation, aliphatic hydroxylation and O-methylation of a demethylenate intermediate. DISCUSSION: Pharmacokinetic and pharmacodynamic analysis of methylone showed a correlation between plasma concentrations and enhancement of the locomotor activity. A contribution of metabolites in the activity of methylone after oral administration is suggested. Present results will be helpful to understand the time course of the effects of this drug of abuse in humans.

Clinical pharmacology of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy"): the influence of gender and genetics (CYP2D6, COMT, 5-HTT).

UNLABELLED: The synthetic psychostimulant MDMA (± 3,4-methylenedioxymethamphetamine, ecstasy) acts as an indirect serotonin, dopamine, and norepinephrine agonist and as a mechanism-based inhibitor of the cytochrome P-450 2D6 (CYP2D6). It has been suggested that women are more sensitive to MDMA effects than men but no clinical experimental studies have satisfactorily evaluated the factors contributing to such observations. There are no studies evaluating the influence of genetic polymorphism on the pharmacokinetics (CYP2D6; catechol-O-methyltransferase, COMT) and pharmacological effects of MDMA (serotonin transporter, 5-HTT; COMT). This clinical study was designed to evaluate the pharmacokinetics and physiological and subjective effects of MDMA considering gender and the genetic polymorphisms of CYP2D6, COMT, and 5-HTT. A total of 27 (12 women) healthy, recreational users of ecstasy were included (all extensive metabolizers for CYP2D6). A single oral weight-adjusted dose of MDMA was administered (1.4 mg/kg, range 75-100 mg) which was similar to recreational doses. None of the women were taking oral contraceptives and the experimental session was performed during the early follicular phase of their menstrual cycle. Principal findings show that subjects reached similar MDMA plasma concentrations, and experienced similar positive effects, irrespective of gender or CYP2D6 (not taking into consideration poor or ultra-rapid metabolizers) or COMT genotypes. However, HMMA plasma concentrations were linked to CYP2D6 genotype (higher with two functional alleles). Female subjects displayed more intense physiological (heart rate, and oral temperature) and negative effects (dizziness, sedation, depression, and psychotic symptoms). Genotypes of COMT val158met or 5-HTTLPR with high functionality (val/val or l/*) determined greater cardiovascular effects, and with low functionality (met/* or s/s) negative subjective effects (dizziness, anxiety, sedation). In conclusion, the contribution of MDMA pharmacokinetics following 1.4 mg/kg MDMA to the gender differences observed in drug effects appears to be negligible or even null. In contrast, 5-HTTLPR and COMT val158met genotypes play a major role. TRIAL REGISTRATION: ClinicalTrials.gov NCT01447472.

Changes in CYP1A2 activity in humans after 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) administration using caffeine as a probe drug.

3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is a ring-substituted amphetamine widely used for recreational purposes. MDMA is predominantly O-demethylenated in humans by cytochrome P450 (CYP) 2D6, and is also a potent mechanism-based inhibitor of the enzyme. After assessing the inhibition and recovery of CYP2D6 in a previous study, the aim of this work was to study in humans the activity of CYP1A2 in vivo after CYP2D6 had been inhibited by MDMA, using caffeine as a probe drug. Twelve male and nine female recreational MDMA users were included. In session 1, 100 mg of caffeine was given at 0 h. In session 2, a 1.5 mg/kg MDMA dose (range 75-100 mg) was given at 0 h followed by a 100 mg dose of caffeine 4 h later. Aliquots of plasma were assayed for caffeine (137X) and paraxanthine (17X) and statistically significant differences were assessed with a one-way ANOVA. There were significant gender differences at basal condition, which persisted after MDMA administration. CYP1A2 activity was higher in both genders after drug administration, with an increase in 40% in females and 20% in males. Results show an increase in CYP1A2 activity when CYP2D6 is inhibited by MDMA in both genders, being more pronounced in females.

Sex differences in 3,4-methylenedioxymethamphetamine (MDMA; ecstasy)-induced cytochrome P450 2D6 inhibition in humans.

BACKGROUND AND OBJECTIVE: 3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is a ring-substituted amphetamine widely used for recreational purposes. MDMA is predominantly O-demethylenated in humans by cytochrome P450 (CYP) 2D6 and is also a potent mechanism-based inhibitor of the enzyme. This study assessed the inhibition and recovery half-life of CYP2D6 and CYP3A4 activity in female subjects by administering the probe drug dextromethorphan before and repeatedly after MDMA administration. These data were compared with the data obtained from a previous study in male subjects. STUDY DESIGN: Twelve healthy female subjects who were CYP2D6 extensive metabolizers participated as outpatients in two experimental sessions. Session 1 was conducted over 2 days and session 2 over 10 days, with a minimum of 3 days between sessions. In session 1, subjects received a single oral dose of dextromethorphan 30 mg. In session 2, a 1.5 mg/kg MDMA dose was given at 0 hours, followed at 4 hours by repeated 30 mg doses of dextromethorphan over the next 10 days. METHODS: Plasma concentration-time profiles and urinary recoveries of dextromethorphan and its metabolites dextrorphan (DOR), 3-methoxymorphinan (MM) and hydroxymorphinan-3-ol (HM) were measured. RESULTS: MDMA given prior to dextromethorphan resulted in a 10-fold increase in the dextromethorphan maximum plasma concentration (C(max)) and area under the plasma concentration-time curve (AUC), with corresponding decreases in DOR and HM pharmacokinetic parameters. The mean ± SD C(max) of MDMA was 188.8 ± 16.7 ng/mL, with a time to reach C(max) (t(max)) of 2.0 ± 0.4 hours and an AUC from 0 to 25 hours of 2645.2 ± 170.9 mg · h/mL. The urinary recovery of the dextromethorphan dose as dextromethorphan and its main metabolites was 25.4 ± 8.9% with no MDMA pretreatment versus 6.6 ± 1.1% after 1.5 mg/kg of MDMA (p = 0.0001). The metabolic ratio (MR) increased almost 60-fold from 0.018 ± 0.028 to 0.998 ± 0.932 after MDMA administration, with 100% of the subjects having a value greater than the antimode of 0.3 that signified the poor-metabolizer phenotype. Data analysis of results obtained in the present study compared with those from a previous study in male subjects showed significant differences in the dextromethorphan/DOR MR in the 0- to 8-hour (session 1) and 4- to 12-hour (session 2, post MDMA) collection periods (p = 0.032 and p = 0.01, respectively). CYP2D6 activity recovered after 10 days to 90% of baseline activity, with a recovery half-life of 36.6 ± 22.9 hours. Male subjects showed a shorter recovery half-life (27.6 ± 25.1 hours). The measurement of CYP3A4 activity indicated a non-significant increase in C(max) and AUC values of MM after drug intake, but urinary data reflected significant differences in dextromethorphan/MM MR in both sexes, although the difference was more pronounced in women. Dextromethorphan/MM MR increased almost 3-fold from baseline. DISCUSSION AND CONCLUSION: In women the pretreatment with MDMA resulted in a decrease in dextromethorphan clearance. CYP2D6 activity recovered after 10 days to 90% of baseline activity. Regarding CYP3A4 activity, there is an apparent decrease in its activity after MDMA use. In women, MDMA use has been associated with psychiatric symptoms and psychological problems that may require psychopharmacological treatment with antidepressant drugs, some of which are known CYP2D6 substrates. MDMA-induced mechanism-based inhibition of CYP2D6 is of relevance, and physicians should be advised to prescribe medications whose metabolic disposition is not regulated by CYP2D6.

Pharmacokinetic and safety profile of rupatadine when coadministered with azithromycin at steady-state levels: a randomized, open-label, two-way, crossover, Phase I study.

BACKGROUND: Rupatadine is an oral active antihistamine and platelet-activating factor antagonist indicated for the management of allergic rhinitis and chronic urticaria in Europe. OBJECTIVE: The purpose of this study was to describe the effect of the concomitant administration of azithromycin and rupatadine on the pharmacokinetics of rupatadine and its metabolites after repeated doses. METHODS: This was a multiple-dose, randomized, open-label, 2-way, crossover, Phase I study in which healthy male and female volunteers received rupatadine 10 mg once a day for 6 days either alone or with azithromycin 500 mg on day 2 and 250 mg from day 3 to day 6. Treatments were administered after a fasting period of 10 hours with 240 mL of water, and fasting conditions were kept until 3 hours postmedication. A washout period of at least 21 days between the 2 active periods was observed. Blood samples were collected and plasma concentrations of rupatadine and its metabolites desloratadine and 3-hydroxydesloratadine were determined by liquid chromatography tandem mass spectrometry. Tolerability was based on the recording of adverse events (AEs), physical examination, electrocardiograms, and laboratory screen controls at baseline and the final study visit. RESULTS: Twenty-four healthy volunteers (15 males, 9 females; mean [SD] age, 25.67 [5.58] years; weight, 65.96 [8.57] kg) completed the study. Except for maximum observed concentration during a dosing interval (Cmax,ss) of 3-hydroxydesloratadine, on average, there were no statistically significant differences in mean plasma concentrations in any of the main pharmacokinetic parameters of rupatadine, desloratadine, and 3-hydroxydesloratadine when administered in combination with azithromycin or alone. The Cmax,ss ratio was 111 (90% CI, 91-136) and area under the plasma concentration-time curve during a dosing interval (AUC0-tau) ratio had a value of 103 (90% CI, 91-117). The corresponding ratios for the rupatadine metabolites were 109 (90% CI, 100-120) for Cmax,ss and 103 (90% CI, 96-110) for AUC0-tau for desloratadine and 109 (90% CI, 103-115) for Cmax,ss and 104 (90% CI, 100-108) for AUC0-tau for 3-hydroxydesloratadine. Point estimates for Cmax,ss ratios using paired data were 111% for rupatadine, 109% for desloratadine, and 109% for 3-hydroxydesloratadine. The 90% CIs were included in the interval 80% to 125% for desloratadine and 3-hydroxydesloratadine, whereas 90% CI for rupatadine was shifted to the right of the interval used for comparing bioavailability of the drugs. A total of 5 subjects reported 9 AEs; 5 of these were thought to be related to the drug administration and all were categorized as mild or moderate. The reported AEs were somnolence (1/24 in the rupatadine group and 1/24 in the rupatadine plus azithromycin group), diarrhea (1/24 in the rupatadine plus azithromycin group), and gastric discomfort (2/24 in the rupatadine plus azithromycin group). Four AEs were considered not to be related (2 episodes of headache, 1 anemia, 1 cheilitis). All were resolved spontaneously. No serious AEs were reported. CONCLUSIONS: The results of this study in these healthy volunteers found no significant differences in pharmacokinetic parameters other than Cmax,ss of 3-hydroxydesloratadine between rupatadine 10 mg administered alone or with azithromycin 500 mg on day 2 and 250 mg from day 3 to day 6. The administration of rupatadine compared with rupatadine plus azithromycin met the regulatory definition of bioequivalence in terms of exposure and rate parameters; however, Cmax,ss of rupatadine was outside the conventional confidence interval.

Antihistaminic effects of rupatadine and PKPD modelling.

Rupatadine is a new oral antihistaminic agent used for the management of allergic inflammatory conditions, such as rhinitis and chronic urticaria. The aim of the present study was to develop a population pharmacokinetic/pharmacodynamic (PKPD) model for the description of the effect of rupatadine and one of its active metabolites, desloratadine, on the histamine-induced flare reaction and to predict the response to treatment after repeated administrations of rupatadine. Both rupatadine and desloratadine were characterized by two-compartmental kinetics. For both compounds, covariates sex and weight had a significant effect on several parameters. The pharmacodynamics were described by an indirect model for the inhibition of flare formation that accounted for the contribution of both rupatadine and desloratadine to the antihistaminic effect. The final PKPD model adequately described the original data. The simulated response after repeated once-daily administrations of 10 mg rupatadine showed a significant and maintained antihistaminic effect over time, between two consecutive dosing intervals.

Influence of food on the oral bioavailability of rupatadine tablets in healthy volunteers: a single-dose, randomized, open-label, two-way crossover study.

BACKGROUND: Rupatadine is an oral active antihistamine for the management of diseases with allergic inflammatory conditions, such as perennial and seasonal rhinitis and chronic idiopathic urticaria. Oral rupatadine has been approved for the treatment of allergic rhinitis and chronic urticaria in adults and adolescents in several European countries. OBJECTIVE: The purpose of this study was to describe the effect of the concomitant intake of food on the pharmacokinetic profile and bioavailability of a single dose of rupatadine. METHODS: This was a single-dose, randomized, open-label, 2-way crossover study in which healthy male and female volunteers received a single, 20-mg oral dose of rupatadine under fed and fasting conditions. Blood samples were collected and plasma concentrations of rupatadine and its active metabolites desloratadine and 3-hydroxydesloratadine were determined by liquid chromatography tandem mass spectrometry. Tolerability was based on the recording of adverse events (AEs), physical examinations, electrocardiograms, and laboratory tolerability tests immediately before each treatment period and at the final visit of the study. RESULTS: Twenty-four volunteers (12 males; mean [SD] age, 25.4 [5.3] years [range, 18-34 years]; mean [SD] weight, 71.2 [4.3] kg [range, 64-77 kg]; 12 females; mean [SD] age, 26.8 [6.5] years [range, 18-38 years]; mean [SD] weight, 58.4 [6.8] kg, [range 50-69 kg]) were enrolled and randomized with equal distribution of sex. A significant increase in AUC from drug administration to the final quantifiable sample (AUC(0-t)) and AUC from drug administration to infinity (AUC(0-infinity)) values of rupatadine was seen under fed conditions without affecting C(max). The ratios (90% CI) of the mean log-transformed AUC(0-t) and AUC(0-infinity) for rupatadine revealed a significant increase in AUC(0-t) (ratio 131%; 90% CI, 111%-154%) and AUC(0-infinity) (ratio 133%; 90% CI, 113%-156%), whereas C(max) remained unaltered (ratio 97%; 90% CI, 80%-116%). Plasma concentration-time profiles of desloratadine and 3-hydroxydesloratadine were similar with and without food, and no differences were seen for AUC(0-t), AUC(0-infinity), or C(max). Seven (28%) subjects reported > or =1 AE. All AEs were mild, resolved spontaneously, and did not affect the outcome of the study. CONCLUSIONS: The results of this study indicate that concomitant intake of food with a single 20-mg oral dose of rupatadine exhibits a significant increase in rupatadine bioavailability. Despite the absence of bioequivalence, the drug was well tolerated under fed and fasting conditions, and no major changes in severity and/or prevalence of AEs were reported.