Innovative LC-MS/MS method for therapeutic drug monitoring of fenfluramine and cannabidiol in the plasma of pediatric patients with epilepsy.

We present a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying fenfluramine (FFA), its active metabolite norfenfluramine (norFFA), and Epidyolex®, a pure cannabidiol (CBD) oral solution in plasma. Recently approved by the EMA for the adjunctive treatment of refractory seizures in patients with Dravet and Lennox-Gastaut syndromes aged above 2 years, FFA and CBD still do not have established therapeutic blood ranges, and thus need careful drug monitoring to manage potential pharmacokinetic and pharmacodynamic interactions. Our method, validated by ICH guidelines M10, utilizes a rapid extraction protocol from 100 µL of human plasma and a reversed-phase C-18 HPLC column, with deuterated internal standards. The Thermofisher Quantiva triple-quadrupole MS coupled with an Ultimate 3000 UHPLC allowed multiple reaction monitoring detection, ensuring precise analyte quantification. The assay exhibited linear responses across a broad spectrum of concentrations: ranging from 1.64 to 1000 ng/mL for both FFA and CBD, and from 0.82 to 500 ng/mL for norFFA. The method proves accurate and reproducible, free from matrix effect. Additionally, FFA stability in plasma at 4 °C and -20 °C for up to 7 days bolsters its clinical applicability. Plasma concentrations detected in patients samples, expressed as mean ± standard deviation, were 0.36 ± 0.09 ng/mL for FFA, 19.67 ± 1.22 ng/mL for norFFA. This method stands as a robust tool for therapeutic drug monitoring (TDM) of FFA and CBD, offering significant utility in assessing drug-drug interactions in co-treated patients, thus contributing to optimized patient care in complex therapeutic scenarios.

Cannabinoid levels description in a cohort of patients with chronic and neuropathic pain treated with Cannabis decoction: A possible role of TDM.

The phytocomplex of Cannabis is made up of approximately 500 substances: terpeno-phenols metabolites, including Δ-9-tetrahydrocannabinol and cannabidiol, exhibit pharmacological activity. Medical Cannabis has several pharmacological potential applications, in particular in the management of chronic and neuropathic pain. In the literature, a few data are available concerning cannabis pharmacokinetics, efficacy and safety. Thus, aim of the present study was the evaluation of cannabinoid pharmacokinetics in a cohort of patients, with chronic and neuropathic pain, treated with inhaled medical cannabis and decoction, as a galenic preparation. In this study, 67 patients were enrolled. Dried flower tops with different THC and CBD concentrations were used: Bedrocan® medical cannabis with THC level standardized at 19% and with a CBD level below 1%, Bediol® medical cannabis with THC and CBD level standardized at similar concentration of 6.5% and 8%, respectively. Cannabis was administered as a decoction in 47 patients and inhaled in 11 patients. The blood withdrawn was obtained before the new dose administration at the steady state and metabolites plasma concentrations were measured with an UHPLC-MS/MS method. Statistically significant differences were found in cannabinoids plasma exposure between inhaled and oral administration of medical cannabis, between male and female and cigarette smokers. For the first time, differences in cannabinoid metabolites exposures between different galenic formulations were suggested in patients. Therapeutic drug monitoring could be useful to allow for dose adjustment, but further studies in larger cohorts of patients are required in order to confirm these data.

Evaluation of amorphous and lipid-based formulation strategies to increase the in vivo cannabidiol bioavailability in piglets.

Cannabidiol (CBD) suffers from poor oral bioavailability due to poor aqueous solubility and high metabolism, and is generally administered in liquid lipid vehicles. Solid-state formulations of CBD have been developed, but their ability to increase the oral bioavailability has not yet been proven in vivo. Various approaches are investigated to increase this bioavailability. This study aimed to demonstrate the enhancement of the oral bioavailability of oral solid dosage forms of amorphous CBD and lipid-based CBD formulation compared to crystalline CBD. Six piglets received the three formulations, in a cross-over design. CBD and 7 - COOH - CBD, a secondary metabolite used as an indicator of hepatic degradation, were analyzed in plasma. A 10.9-fold and 6.8-fold increase in oral bioavailability was observed for the amorphous and lipid formulations, respectively. However, the lipid-based formulation allowed reducing the inter-variability when administered to fasted animals. An entero-hepatic cycle was confirmed for amorphous formulations. Finally, this study showed that the expected protective effect of lipids against hepatic degradation of the lipid-based formulation did not occur, since the ratio CBD/metabolite was higher than that of the amorphous one.

Entry of cannabidiol into the fetal, postnatal and adult rat brain.

Cannabidiol is a major component of cannabis but without known psychoactive properties. A wide range of properties have been attributed to it, such as anti-inflammatory, analgesic, anti-cancer, anti-seizure and anxiolytic. However, being a fairly new compound in its purified form, little is known about cannabidiol brain entry, especially during development. Sprague Dawley rats at four developmental ages: embryonic day E19, postnatal day P4 and P12 and non-pregnant adult females were administered intraperitoneal cannabidiol at 10 mg/kg with [3H] labelled cannabidiol. To investigate the extent of placental transfer, the drug was injected intravenously into E19 pregnant dams. Levels of [3H]-cannabidiol in blood plasma, cerebrospinal fluid and brain were estimated by liquid scintillation counting. Plasma protein binding of cannabidiol was identified by polyacrylamide gel electrophoresis and its bound and unbound fractions measured by ultrafiltration. Using available RNA-sequencing datasets of E19 rat brain, choroid plexus and placenta, as well as P5 and adult brain and choroid plexus, expression of 13 main cannabidiol receptors was analysed. Results showed that cannabidiol rapidly entered both the developing and adult brains. Entry into CSF was more limited. Its transfer across the placenta was substantially restricted as only about 50% of maternal blood plasma cannabidiol concentration was detected in fetal plasma. Albumin was the main, but not exclusive, cannabidiol binding protein at all ages. Several transcripts for cannabidiol receptors were expressed in age- and tissue-specific manner indicating that cannabidiol may have different functional effects in the fetal compared to adult brain.

Effects of cannabidiol in cannabis flower: Implications for harm reduction.

Using a federally compatible, naturalistic at-home administration procedure, the present study examined the acute effects of three cannabis flower chemovars with different tetrahydrocannabinol (THC) to cannabidiol (CBD) ratios, in order to test whether chemovars with a higher CBD content produce different effects. Participants were randomly assigned to ad libitum administration of one of three chemovars (THC-dominant: 24% THC, 1% CBD; THC+CBD: 9% THC, 10% CBD; CBD-dominant: 1% THC, 23% CBD); 159 regular cannabis users (male = 94, female = 65) were assessed in a mobile pharmacology lab before, immediately after, and 1 h after ad libitum administration of their assigned chemovar. Plasma cannabinoids as well as positive (e.g., high, elation) and negative (e.g., paranoia and anxiety) subjective effects were assessed at each time points. Participants who used the CBD-dominant and THC + CBD chemovars had significantly less THC and more CBD in plasma samples compared to participants who used the THC-dominant chemovar. Further, the THC + CBD chemovar was associated with similar levels of positive subjective effects, but significantly less paranoia and anxiety, as compared to the THC-dominant chemovar. This is one of the first studies to examine the differential effects of various THC to CBD ratios using chemovars that are widely available in state-regulated markets. Individuals using a THC + CBD chemovar had significantly lower plasma THC concentrations and reported less paranoia and anxiety while also reporting similar positive mood effects as compared to individuals using THC only, which is intriguing from a harm reduction perspective. Further research is needed to clarify the harm reduction potential of CBD in cannabis products.

Pipette tip micro-solid phase extraction (octyl-functionalized hybrid silica monolith) and ultra-high-performance liquid chromatography-tandem mass spectrometry to determine cannabidiol and tetrahydrocannabinol in plasma samples.

This manuscript describes the development of an innovative method to determine cannabinoids (cannabidiol and tetrahydrocannabinol) in human plasma samples by pipette tip micro-solid phase extraction and liquid chromatography-mass spectrometry/mass spectromtery. An octyl-functionalized hybrid silica monolith, which had been synthesized and characterized, was used as a selective stationary phase. The octyl-functionalized hybrid silica monoliths presented high permeability and adequate mechanical strength. The micro-solid phase extraction variables (sample pH, draw-eject cycles, solvent for phase clean-up, and desorption conditions) were investigated to improve not only the selectivity but also the sorption capacity. The method was linear at concentrations ranging from the lower limit of quantification (10.00 ng/mL) to the upper limit of quantification (150.0 ng/mL). The lack of fit and homoscedasticity tests, as well as the determination coefficients (r2 greater than 0.995), certified that linearity was adequate. The precision assays presented coefficient of variation values lower than 15%, and the accuracy tests provided relative error values ranging from 3.2 to 14%. Neither significant carry-over nor matrix effects were detected. Therefore, the pipette tip micro-solid phase extraction/liquid chromatography-mass spectrometry/mass spectrometry method has demonstrated to be adequate to determine cannabidiol and tetrahydrocannabinol simultaneously in plasma samples for therapeutic drug monitoring of patients undergoing treatment with cannabinoids.

An Ultrafast Ultrahigh-Performance Liquid Chromatography Coupled With Tandem Mass Spectrometry Method for Cannabidiol Monitoring in Pediatric Refractory Epilepsy.

BACKGROUND: Cannabidiol (CBD) is a nonpsychoactive natural product that has been increasingly used as a promising new drug for the management of neurological conditions such as refractory epilepsy. Development of rapid and sensitive methods to quantitate CBD is essential to evaluate its pharmacokinetics in humans, particularly in children. The objective of this work was to develop and validate an ultrafast ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) method for CBD quantitation that is capable of detecting major CBD and tetrahydrocannabinol (THC) metabolites in the plasma of pediatric refractory epilepsy patients. METHODS: Eight-point CBD calibration curves were prepared using 60 µL of plasma from healthy volunteers. Samples were analyzed in a Shimadzu Nexera X2 UHPLC system, which was coupled to a Sciex QTRAP 6500 mass spectrometer. Chromatography was optimized in acetonitrile (ACN)/water with a 70%-90% gradient of ACN in 2 minutes. Multiple reaction monitoring transitions of major CBD and THC metabolites were optimized in patient plasma. RESULTS: The optimized UHPLC-MS/MS method was validated for the linear range (1-300 ng/mL) of CBD (r2 = 0.996). The limit of quantification and limit of detection were 0.26 and 0.86 ng/mL, respectively. Accuracy and precision met the acceptable validation limits. CBD recovery and matrix effects were 83.9 ± 13.9% and 117.4 ± 4.5%, respectively. The method was successfully applied to quantify CBD and detect the major CBD and THC metabolites in clinical samples. 7-COOH-CBD was the most intensely detected metabolite followed by glucuronide conjugates. CONCLUSIONS: A simple and sensitive method for rapidly monitoring CBD and identifying relevant metabolites was developed. Its applicability in samples from children treated for epilepsy was demonstrated, making it an excellent alternative for performing pharmacokinetic studies.

A validated method for the simultaneous quantification of cannabidiol, Δ9 -tetrahydrocannabinol, and their metabolites in human plasma and application to plasma samples from an oral cannabidiol open-label trial.

Cannabidiol (CBD) and Δ9 -tetrahydrocannabinol (THC) are the two best known and most extensively studied phytocannabinoids within Cannabis sativa. An increasing number of preclinical studies and clinical trials have been conducted with one or both compounds, often probing their therapeutic effects in conditions such as paediatric epilepsy, anxiety disorders or chronic pain. Accurate monitoring of THC and CBD and their metabolites is essential for tracking treatment adherence and pharmacokinetics. However, fully validated methods for the comprehensive analysis of major Phase I CBD metabolites are yet to be developed due to a historical lack of commercially available reference material. In the present study, we developed, optimised and validated a method for the simultaneous quantification of CBD, THC and their major Phase I metabolites 6-hydroxy-CBD (6-OH-CBD), 7-hydroxy-CBD (7-OH-CBD), 7-carboxy-CBD (7-COOH-CBD), 11-hydroxy-tetrahydrocannabinol (11-OH-THC) and 11-carboxy-tetrahydrocannabinol (11-COOH-THC) as per Food and Drug Administration (FDA) guidelines for bioanalytical method validation. The method is accurate, reproducible, sensitive and can be carried out in high-throughput 96-well formats, ideal for larger scale clinical trials. Deuterated internal standards for each analyte were crucial to account for variable matrix effects between plasma lots. The application of the method to plasma samples, taken from people who had been administered oral CBD as part of an open-label trial of CBD effects in anxiety disorders, demonstrated its immediate utility in ongoing and upcoming clinical trials. The method will prove useful for future studies involving CBD and/or THC and can likely accommodate the inclusion of additional metabolites as analytical reference materials become commercially available.

Cannabidiol Determination on Peripheral Capillary Blood Using a Microsampling Method and Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry with On-Line Sample Preparation.

The aim of this work is to evaluate volumetric absorptive microsampling (VAMS) from capillary blood as an alternative strategy for therapeutic drug monitoring (TDM) in patients treated with the newly available GW-purified form of cannabidiol (Epidiolex®). A fast ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) coupled to an online sample preparation system analysis was carried out on a Thermo Scientific Ultimate 3000 LC system coupled to a TSQ Quantiva triple quadrupole for the quantification of cannabidiol (CBD) and, in addition, delta-9-tetrahydrocannabinol (Δ9-THC). After validation using European Medicine Agency (EMA) guidelines the method was applied to samples obtained by finger prick of five pediatric patients treated with Epidiolex® and the results were compared to those obtained from venous blood and plasma. The method is linear in the range of 1-800 µg/L for both CBD and THC with intra- and inter-day precisions ranging from 5% to 14% and accuracies from -13% to +14% starting from 30 µL of sample. Stability in VAMS is ensured for up to 4 weeks at 25 °C thus allowing simple delivery. There was no difference (p = 0.69) between concentrations of CBD measured from VAMS sampled from capillary or venous blood (range: 52.19-330.14 or 72.15-383.45 µg/L) and those obtained from plasma (range: 64.3-374.09 µg/L) The VAMS-LC-MS/MS method represents a valid alternative strategy for therapeutic drug monitoring of patients treated with Epidiolex®.

Serum cannabidiol, tetrahydrocannabinol (THC), and their native acid derivatives after transdermal application of a low-THC Cannabis sativa extract in beagles.

Cannabinoids hold promise for treating health problems related to inflammation and chronic pain in dogs, in particular cannabidiol (CBD), and its native acid derivative cannabidiolic acid (CBDA). Information regarding systemic delivery of cannabinoids through transdermal routes is sparse. The purpose of this study was to determine pharmacokinetics of transdermal administration of a low-THC Cannabis sativa extract in healthy dogs. Six purpose-bred research beagles were treated with a transdermal CBD-CBDA-rich extract, and serum concentrations of CBD, CBDA, tetrahydrocannabinol (THC), and its acid derivative tetrahydrocannabinolic acid (THCA) were examined prior to and at the end of weeks 1 and 2. A 4 mg/kg dose of total cannabinoids twice daily resulted in appx 10 ng/ml of CBD, 21-32 ng/ml of CBDA, trace amounts of THCA, and unquantifiable amounts of THC in serum at the end of weeks 1 and 2 of treatment. Results showed that CBDA and THCA were absorbed better systemically than CBD or THC.

A Phase 2, Double-Blind, Placebo-Controlled Trial to Investigate Potential Drug-Drug Interactions Between Cannabidiol and Clobazam.

We investigated the effects of cannabidiol (CBD; 21-day maintenance dose) on the pharmacokinetics (PK) of clobazam (CLB) and monitored the safety of CBD (or placebo) plus CLB in 20 patients with uncontrolled epilepsy on stable doses of CLB. Blood samples collected until 24 hours postdose were evaluated by liquid chromatography tandem mass spectrometry. PK parameters of CLB and major metabolite N-desmethylclobazam (N-CLB), valproic acid, stiripentol, levetiracetam, topiramate, plant-derived highly purified CBD (Epidiolex in the United States; 100 mg/mL oral solution) and its major metabolites were derived using noncompartmental analysis. There was no evidence of a drug-drug interaction (DDI) between CBD and CLB: geometric mean ratio (GMR) of day 33:day 1 CLB was 1.0 (90%CI, 0.8-1.2) for Cmax and 1.1 (90%CI, 0.9-1.2) for AUCtau . There was a significant DDI between CBD and N-CLB: the GMR of day 33:day 1 N-CLB was 2.2 (90%CI, 1.4-3.5) for Cmax and 2.6 (90%CI, 2.0-3.6) for AUCtau . Placebo had no effect on CLB or N-CLB; CBD had no effect on levetiracetam. Data were insufficient regarding DDIs with other antiepileptic drugs. The safety profile of CBD (20 mg/kg/day) with CLB was acceptable; all but 1 adverse events (AEs) were mild or moderate. One serious AE (seizure cluster) led to CBD discontinuation. One patient withdrew after intolerable AEs. Although there was no evidence of a CBD and CLB DDI, there was a significant DDI between CBD and N-CLB. The safety profile of GW Pharmaceuticals' CBD formulation with CLB was consistent with other GW-sponsored trials.

The Effectiveness of Cannabis Flower for Immediate Relief from Symptoms of Depression.

Objective: Scientific research on how consumption of whole, natural Cannabis flower affects low mood and behavioral motivations more generally is largely nonexistent, and few studies to date have measured how common and commercially available Cannabis flower used in vivo may affect the experience of "depression" in real-time. Methods: We observed 1,819 people who completed 5,876 cannabis self-administration sessions using the ReleafApp™ between 06/07/2016 and 07/08/2019, with the goal of measuring real-time effects of consuming Cannabis flower for treating symptoms of depression. Results: On average, 95.8% of users experienced symptom relief following consumption with an average symptom intensity reduction of -3.76 points on a 0-10 visual analogue scale (SD = 2.64, d = 1.71, p <.001). Symptom relief did not differ by labeled plant phenotypes ("C. indica," "C. sativa," or "hybrid") or combustion method. Across cannabinoid levels, tetrahydrocannabinol (THC) levels were the strongest independent predictors of symptom relief, while cannabidiol (CBD) levels, instead, were generally unrelated to real-time changes in symptom intensity levels. Cannabis use was associated with some negative side effects that correspond to increased depression (e.g. feeling unmotivated) in up to 20% of users, as well as positive side effects that correspond to decreased depression (e.g. feeling happy, optimistic, peaceful, or relaxed) in up to 64% of users. Conclusions: The findings suggest that, at least in the short term, the vast majority of patients that use cannabis experience antidepressant effects, although the magnitude of the effect and extent of side effect experiences vary with chemotypic properties of the plant.

Cannabinoids in multiple sclerosis: A neurophysiological analysis.

OBJECTIVES: To investigate the action of cannabinoids on spasticity and pain in secondary progressive multiple sclerosis, by means of neurophysiological indexes. MATERIAL AND METHODS: We assessed 15 patients with progressive MS (11 females) using clinical scales for spasticity and pain, as well as neurophysiological variables (H/M ratio, cutaneous silent period or CSP). Testing occurred before (T0) and during (T1) a standard treatment with an oral spray containing delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Neurophysiological measures at T0 were compared with those of 14 healthy controls of similar age and sex (HC). We then compared the patient results at the two time points (T1 vs T0). RESULTS: At T0, neurophysiological variables did not differ significantly between patients and controls. At T1, spasticity and pain scores improved, as detected by the Modified Ashworth Scale or MAS (P = .001), 9-Hole Peg Test or 9HPT (P = .018), numeric rating scale for spasticity or NRS (P = .001), and visual analogue scale for pain or VAS (P = .005). At the same time, the CSP was significantly prolonged (P = .001). CONCLUSIONS: The THC-CBD spray improved spasticity and pain in secondary progressive MS patients. The spray prolonged CSP duration, which appears a promising tool for assessing and monitoring the analgesic effects of THC-CBD in MS.

Using the Absorption Cocktail Approach to Assess Differential Absorption Kinetics of Cannabidiol Administered in Lipid-Based Vehicles in Rats.

Lipid-based drug delivery systems have been vastly investigated as a pharmaceutical method to enhance oral absorption of lipophilic drugs. However, these vehicles not only affect drug bioavailability but may also have an impact on gastric emptying, drug disposition, lymphatic absorption and be affected by lipid digestion mechanisms. The work presented here compared the pharmacokinetic (PK) behavior of the non-intoxicating cannabinoid cannabidiol (CBD) in sesame oil vs. a self-nano emulsifying drug delivery system (SNEDDS). This investigation was conducted with a unique tool termed the "absorption cocktail approach". In this concept, selected molecules: metoprolol, THC, and ibuprofen, were coadministered with CBD in the SNEDDS and sesame oil. This method was used to shed light on the complex absorption process of poorly soluble drugs in vivo, specifically assessing the absorption kinetics of CBD. It was found that the concentration vs. time curve following CBD-sesame oil oral administration showed extended input of the drug with a delayed Tmax compared to CBD-SNEDDS. Using the "cocktail" approach, a unique finding was observed when the less lipophilic compounds (metoprolol and ibuprofen) exited the stomach much earlier than the lipophilic cannabinoids in sesame oil, proving differential absorption kinetics. Findings of the absorption cocktail approach reflected the physiological process of the GI, e.g., gastric retention, stomach content separation, lipid digestion, drug precipitation and more, demonstrating its utility. Nonetheless, the search for more compounds as suitable probes is underway.

Cannabidiol efficacy and clobazam status: A systematic review and meta-analysis.

OBJECTIVE: To evaluate the potential impact of concomitant clobazam (CLB) use on the efficacy of cannabidiol (CBD) treatment in patients with Dravet syndrome and Lennox-Gastaut syndrome using meta-analytical techniques. METHODS: We searched for randomized, placebo-controlled, single- or double-blinded trials. The proportion of patients who achieved ≥50% reduction from baseline in seizure frequency during the treatment period was assessed according to CLB status. Risk ratios (RRs) with 95% confidence intervals (CIs) were estimated. RESULTS: Four trials were included and enrolled 714 participants, 429 for the add-on CBD group and 285 for the add-on placebo group. Among CBD-treated patients, 240 (55.9%) were taking concomitant CLB (CLB-On) and 189 (44.1%) were not taking concomitant CLB (CLB-Off); in placebo-treated patients, 158 (55.4%) were CLB-On and 127 (44.6%) CLB-Off. The percentages of patients who had at least 50% reduction in seizure frequency during the treatment period were 29.1% in the CBD arm and 15.7% in the placebo group among CLB-Off patients (RR = 1.80, 95% CI = 1.12-2.90, P = .015). Among CBL-On patients, the ≥50% reduction in seizure frequency was found in 52.9% and 27.8% in the CBD and placebo groups, respectively (RR = 1.85, 95% CI = 1.40-2.44, P < .001). SIGNIFICANCE: CBD was associated with a higher rate of seizure response in comparison to placebo when added to the existing antiepileptic regimen both in patients taking and in those not taking concomitant CLB. The lack of randomization for CLB status and the limited sample size need to be considered in the interpretation of the findings.

Does cannabidiol have antiseizure activity independent of its interactions with clobazam? An appraisal of the evidence from randomized controlled trials.

Four pivotal randomized placebo-controlled trials have demonstrated that adjunctive therapy with cannabidiol (CBD) improves seizure control in patients with Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS). Between 47% and 68% of patients allocated to CBD treatment in these trials were receiving clobazam (CLB), which shows complex interactions with CBD resulting, in particular, in a 3.4- to 5-fold increase in plasma concentration of the active metabolite norclobazam. This raises concern as to the role played by these interactions in determining the reduction in seizure frequency in CBD-treated patients, and the question of whether CBD per se has clinically evident antiseizure effects. We appraised available evidence on the clinical consequences of the CBD-CLB interaction, focusing on subgroup analyses of seizure outcomes in patients on and off CLB comedication in the pivotal CBD trials, as provided by the European Medicines Agency Public Assessment Report. Evaluation of the results of individual trials clearly showed that improvement in seizure control over placebo was greater when CBD was added on to CLB than when it was added on to other medications. However, seizure control was also improved in patients off CLB, and despite the small sample size the difference vs placebo was statistically significant for the 10 mg/kg/d dose in one of the two LGS trials. Stronger evidence for an antiseizure effect of CBD independent of an interaction with CLB emerges from meta-analyses of seizure outcomes in the pooled population of LGS and DS patients not receiving CLB comedication. Although these results need to be interpreted taking into account methodological limitations, they provide the best clinical evidence to date that CBD exerts therapeutic effects in patients with epilepsy that are independent of its interaction with CLB. Greater antiseizure effects, and a greater burden of adverse effects, are observed when CBD is combined with CLB.

Clinically Significant Drug-Drug Interaction Between Methadone and Cannabidiol.

The use of cannabidiol products in pediatric patients is becoming more frequent because of the increased ease of accessibility. This case report illustrates the potential for cannabidiol to interact with stable medication regimens. A 13-year-old girl with metastatic cancer and chronic pain presented with increased sleepiness and fatigue. She had been started on 7.5 mg of methadone by mouth twice daily 4 months earlier. Unbeknownst to her physicians, her parents had commenced her on cannabidiol and subsequently increased the dose leading up to her presentation, thinking it would result in tumor shrinkage. The initial serum methadone level was 271 ng/mL, which decreased to 125 ng/mL 14 days after discontinuing cannabidiol. The reduced serum methadone level coincided with improved sleepiness and fatigue. Cannabidiol inhibits CYP3A4 and CYP2C19, both of which are involved in the metabolism of methadone. Pediatricians should be aware of this potential interaction and inquire if their patients are receiving cannabidiol.

The effect of piperine on oral absorption of cannabidiol following acute vs. chronic administration.

Piperine is an alkaloid naturally found in black pepper with a myriad of pharmacological attributes. Piperine's most far reaching indication is drug absorption enhancment, with supportive data regarding its ability to inhibit first pass effect mechanisms. However, alongside these findings, the role of piperine as an absorption enhancer is undermined with publications stating an apparent effect of a metabolic inducer. The aim of this work is to investigate the effect of repeated administration of piperine in a lipid-based formulation ,on oral absorption of cannabidiol (CBD), compared to acute piperine dosing. The effect of piperine on CBD absorption was determined pre-clinically in the freely moving rat model. Results of this work demonstrated that there was no significant difference in piperine's effect, when given chronically or in a single dose regimen. Both groups resulted in approximate 2.5-fold increase in oral bioavailability of CBD compared to control group without piperine.

Pharmacokinetics of Sativex® in Dogs: Towards a Potential Cannabinoid-Based Therapy for Canine Disorders.

The phytocannabinoid-based medicine Sativex® is currently marketed for the treatment of spasticity and pain in multiple sclerosis patients and is being investigated for other central and peripheral pathological conditions. It may also serve in Veterinary Medicine for the treatment of domestic animals, in particular for dogs affected by different pathologies, including human-like pathological conditions. With the purpose of assessing different dosing paradigms for using Sativex in Veterinary Medicine, we investigated its pharmacokinetics when administered to naïve dogs via sublingual delivery. In the single dose arm of the study, adult Beagle dogs were treated with 3 consecutive sprays of Sativex, and blood samples were collected at 12 intervals up to 24 h later. In the multiple dose arm of the study, Beagle dogs received 3 sprays daily for 14 days, and blood samples were collected for 24 h post final dose. Blood was used to obtain plasma samples and to determine the levels of cannabidiol (CBD), Δ9-tetrahydrocannabinol (Δ9-THC) and its metabolite 11-hydroxy-Δ9-THC. Maximal plasma concentrations of both Δ9-THC (Cmax = 18.5 ng/mL) and CBD (Cmax = 10.5 ng/mL) were achieved 2 h after administration in the single dose condition and at 1 h in the multiple dose treatment (Δ9-THC: Cmax = 24.5 ng/mL; CBD: Cmax = 15.2 ng/mL). 11hydroxy-Δ9-THC, which is mainly formed in the liver from Δ9-THC, was almost undetected, which is consistent with the use of sublingual delivery. A potential progressive accumulation of both CBD and Δ9-THC was detected following repeated exposure, with maximum plasma concentrations for both cannabinoids being achieved following multiple dose. Neurological status, body temperature, respiratory rate and some hemodynamic parameters were also recorded in both conditions, but in general, no changes were observed. In conclusion, this study demonstrates that single or multiple dose sublingual administration of Sativex to naïve dogs results in the expected pharmacokinetic profile, with maximal levels of phytocannabinoids detected at 1-2 h and suggested progressive accumulation after the multiple dose treatment.