The Interplay Between Liver First-Pass Effect and Lymphatic Absorption of Cannabidiol and Its Implications for Cannabidiol Oral Formulations

Penetratin and Mannose-Functionalized Cannabidiol Lipid Nanoparticles Encapsulating the BDNF Gene Reduce Amyloid-Induced Inflammation

Inflammation is emerging as a critical player in the disease progression of Alzheimer's disease (AD) by its interaction with amyloid beta plaques in a feed-forward loop. There is also a decline in the nourishment and enriching neurotrophic factor, brain-derived neurotrophic factor (BDNF), in the brain. Therefore, supplementing the brain with BDNF by gene delivery and delivering the anti-inflammatory agent, cannabidiol (CBD) in this case, to mitigate inflammation-induced disease cascade offers an attractive treatment strategy. To achieve the brain localization of CBD and pBDNF, lipid nanoparticles (LNPs) functionalized with mannose and penetratin were utilized. CBD and pBDNF were successfully encapsulated in the LNPs (more than 80%) with a size less than 180 nm, polydispersity index less than 0.25, and zeta potential of 23 mV. CBD was released from the formulation over a period of a week. The dual-functionalized LNPs demonstrated higher cellular uptake of CBD and expressed a significantly higher amount of BDNF (p-value <0.05) after transfection than their nonmodified counterparts in four brain cell lines, i.e., brain endothelial cells (b.END3), immortalized microglia cells (IMGs), primary astrocytes, and primary neurons. Similarly, the permeation of CBD through the dual-modified LNPs across the in vitro coculture blood-brain barrier model was significantly higher (p-value <0.05) compared to free CBD or nonfunctionalized nanoparticles. The LNPs demonstrated anti-inflammatory activity against lipopolysaccharides and human amyloid beta1-42 oligomer induction as they reduced the protein and mRNA expression of pro-inflammatory cytokines TNF-α (p < 0.05) and IL-1β (p < 0.05) in IMG cells. In summary, the penetratin and mannose-functionalized LNPs encapsulating CBD and pBDNF could serve as a promising therapy in AD, requiring further validation in animal models.

CBD and the 5-HT1A receptor: A medicinal and pharmacological review

Cannabidiol (CBD), a phytocannabinoid, has emerged as a promising candidate for addressing a wide array of symptoms. It has the ability to bind to multiple proteins and receptors, including 5-HT1AR, transient receptor potential vanilloid 1 (TRPV1), and cannabinoid receptors. However, CBD's pharmacodynamic interaction with 5-HT1AR and its medicinal outcomes are still debated. This review explores recent literature to elucidate these questions, highlighting the neurotherapeutic outcomes of this pharmacodynamic interaction and proposing a signaling pathway underlying the mechanism by which CBD desensitizes 5-HT1AR signaling. A comprehensive survey of the literature underscores CBD's multifaceted neurotherapeutic effects, which include antidepressant, anxiolytic, neuroprotective, antipsychotic, antiemetic, anti-allodynic, anti-epileptic, anti-degenerative, and addiction-treating properties, attributable in part to its interactions with 5-HT1AR. Furthermore, evidence suggests that the pharmacodynamic interaction between CBD and 5-HT1AR is contingent upon dosage. Moreover, we propose that CBD can induce desensitization of 5-HT1AR via both homologous and heterologous mechanisms. Homologous desensitization involves the recruitment of G protein-coupled receptor kinase 2 (GRK2) and β-arrestin, leading to receptor endocytosis. In contrast, heterologous desensitization is mediated by an elevated intracellular calcium level or activation of protein kinases, such as c-Jun N-terminal kinase (JNK), through the activity of other receptors.

Rapeseed oleosomes facilitate intestinal lymphatic delivery and oral bioavailability of cannabidiol

Due to high lipophilicity and extensive first-pass metabolic loss, cannabidiol (CBD) has low oral bioavailability. Co-administration of CBD and long-chain lipids facilitates the intestinal lymphatic delivery, resulting in higher systemic bioavailability, as well as high levels of the drug within the intestinal lymphatic system. However, despite previous attempts with various lipid-based formulations, the oral bioavailability of CBD is still limited. In this work, we have developed a novel formulation of CBD based on natural rapeseed oleosomes. In vivo studies in rats demonstrated that oral administration of CBD-loaded rapeseed oleosomes leads to substantially higher oral bioavailability and intestinal lymphatic targeting of CBD in comparison with rapeseed oil or artificial emulsion made of rapeseed oil and lecithin. In vitro mechanistic assessments, including in vitro lipolysis and peroxide value determination suggest that the lower oxidative state of the oil in oleosomes in comparison to crude oil or artificial emulsion is likely to be the main factor responsible for the superior performance of the CBD-loaded rapeseed oleosomes in vivo. Although further investigation will be needed, the data suggest that natural seeds-derived oleosomes can be used as a promising lipid-based drug delivery platform promoting the bioavailability and lymphatic delivery of lipophilic drugs.

LC-MS/MS-Based Concurrent Quantification of Cannabidiol and Melatonin in Mouse Plasma to Elucidate Complex PK Interactions

Objective: This study aimed to develop a quantitative analytical method for the simultaneous determination of cannabidiol (CBD) and melatonin (MT) in mouse plasma using the protein precipitation method coupled with LC-MS/MS. Additionally, this study sought to investigate the impact of CBD on the pharmacokinetics of MT in mice using this method. Methods: Mouse plasma samples were precipitated with acetonitrile and analyzed using a Kromasil 100-5-C8 (2.1 × 50 mm) column. Following a single administration, thirty male ICR mice were randomly assigned to five groups: MT 2 mg/kg intravenously (i.v.), MT 10 mg/kg orally (p.o.), MT + CBD (10 + 10) mg/kg p.o., MT + CBD (10 + 40) mg/kg p.o., and MT 10 mg/kg p.o. followed by CBD 2 mg/kg i.v. Pharmacokinetic parameters were calculated using a non-compartmental model and analyzed to investigate the interactions of CBD with MT. Results: The calibration curves for CBD and MT were linear over the range of 2 to 1000 ng/mL. Co-administration of a high dose of CBD (40 mg/kg) orally reduced the Cmax of MT (10 mg/kg) to 57% of the control, while the area under the curve from 0.5 to 8 h (AUC(0.5-8h)) was 2.85-fold that of the MT-only group. When CBD (2 mg/kg) was administered intravenously alongside MT orally, the AUC(0.5-8h) was 1.54 times that of MT given orally alone. The AUC of CBD was positively correlated with the AUC of the distribution and elimination phases of MT, while the Cmax of CBD negatively correlated with the Cmax of MT. Conclusions: The developed LC-MS/MS method is robust and suitable for pharmacokinetic studies involving CBD and MT. The in vivo effects of CBD on MT pharmacokinetics are complex. High oral doses of CBD inhibit both the intestinal absorption and metabolic clearance of MT, resulting in a more smooth PK profile.

Self-Nanoemulsifying Drug Delivery System of Morin: A New Approach for Combating Acute Alcohol Intoxication

Purpose

Acute alcohol intoxication (AAI) is a life-threatening medical condition resulting from excessive alcohol consumption. Our research revealed the potential of morin (MOR) in treating AAI. However, MOR's effectiveness against AAI was hindered by its poor solubility in water and low bioavailability. In this study, our aim was to develop a self-nanoemulsifying drug delivery system (SNEDDS) to enhance MOR's solubility and bioavailability, evaluate its anti-AAI effects, and investigate the underlying mechanism.

Methods

The composition of MOR-loaded self-nanoemulsifying drug delivery system (MOR-SNEDDS) was determined by constructing pseudo-ternary phase diagrams, and its formulation proportion was optimized using the Box-Behnken design. Following characterization of MOR-SNEDDS, we investigated its pharmacokinetics and biodistribution in healthy animals. Additionally, we assessed the anti-AAI effects and gastric mucosal protection of MOR-SNEDDS in an AAI mice model, exploring potential mechanisms.

Results

After breaking down into tiny droplets, the optimized mixture of MOR-SNEDDS showed small droplet size on average, even distribution, strong stability, and permeability. Pharmacokinetic studies indicated that MOR-SNEDDS, compared to a MOR suspension, increased the area under the plasma concentration-time curve (AUC0-t) by 10.43 times. Additionally, studies on how drugs move and are distributed in the body showed that MOR-SNEDDS had an advantage in passively targeting the liver. Moreover, in a mouse model for alcohol addiction, MOR not only decreased alcohol levels by boosting the activity of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) in the stomach and liver, which counteracted the loss of righting reflex (LORR), but also reduced alcohol-induced damage to the stomach lining by lowering malondialdehyde (MDA) levels and increasing superoxide dismutase (SOD) levels. Furthermore, MOR-SNEDDS notably amplified these effects.

Conclusion

MOR exhibits significant potential as a new medication for treating AAI, and utilizing MOR-SNEDDS with high oral bioavailability represents a promising new strategy in combating AAI.

Intestinal Lymphatic Biology, Drug Delivery, and Therapeutics: Current Status and Future Directions

Historically, the intestinal lymphatics were considered passive conduits for fluids, immune cells, dietary lipids, lipid soluble vitamins, and lipophilic drugs. Studies of intestinal lymphatic drug delivery in the late 20th century focused primarily on the drugs' physicochemical properties, especially high lipophilicity, that resulted in intestinal lymphatic transport. More recent discoveries have changed our traditional view by demonstrating that the lymphatics are active, plastic, and tissue-specific players in a range of biological and pathological processes, including within the intestine. These findings have, in turn, inspired exploration of lymph-specific therapies for a range of diseases, as well as the development of more sophisticated strategies to actively deliver drugs or vaccines to the intestinal lymph, including a range of nanotechnologies, lipid prodrugs, and lipid-conjugated materials that "hitchhike" onto lymphatic transport pathways. With the increasing development of novel therapeutics such as biologics, there has been interest in whether these therapeutics are absorbed and transported through intestinal lymph after oral administration. Here we review the current state of understanding of the anatomy and physiology of the gastrointestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. We summarize the current state-of-the-art approaches to deliver drugs and quantify their uptake into the intestinal lymphatic system. Finally, and excitingly, we discuss recent examples of significant pharmacokinetic and therapeutic benefits achieved via intestinal lymphatic drug delivery. We also propose approaches to advance the development and clinical application of intestinal lymphatic delivery strategies in the future. SIGNIFICANCE STATEMENT: This comprehensive review details the understanding of the anatomy and physiology of the intestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. It highlights current state-of-the-art approaches to deliver drugs to the intestinal lymphatics and the shift toward the use of these strategies to achieve pharmacokinetic and therapeutic benefits for patients.

CBD-Loaded Nanostructured Lipid Carriers: Optimization, Characterization, and Stability

Cannabidiol (CBD) has demonstrated its potential to enhance depression treatment through various biological pathways. However, the application potential of CBD is significantly impeded by its polymorphic nature, limited water solubility, and hepatic first-pass metabolism. To improve chemical stability and water solubility, nanostructured lipid carriers loaded with CBD (CBD-NLCs) were developed using a hot-melt emulsification method and optimized by response surface methodology (RSM). The process parameters were optimized using a four-factor and three-level Box-Behnken experimental design consisting of 29 experiments. The CBD-NLCs were formulated and characterized, demonstrating desirable properties, including a mean particle size of 54.33 nm, a PDI value of 0.118, a zeta potential of -29.7 mV, and an impressive encapsulation efficiency rate of 87.58%. The nanoparticles were found to possess an approximately spherical shape, as revealed by scanning and transmission electron microscopy. The stability studies have demonstrated that CBD-NLCs effectively mitigated the photodegradation of CBD and exhibited a stable behavior for 42 days when stored. The CBD-NLCs displayed a biphasic release profile characterized by an initial burst release (over 50% of CBD released within 20 min) followed by a subsequent gradual and sustained release, aligned with first-order kinetics and Fickian diffusion. These findings demonstrate the potential suitability of this formulation as a carrier for CBD in food fortification and pharmaceutical applications.

Infant formula as a solid lipid dose form for enhancement of the oral bioavailability of cannabidiol for paediatric patients

Cannabinoids can save paediatric patients from harmful psychological conditions caused by epilepsy. However, the limited aqueous solubility of the drug presents a limitation to oral absorption and bioavailability. Previous studies have shown the enhancement of oral bioavailability for poorly water-soluble drugs using milk or milk-based products like infant formula as a novel lipid-based formulation, due to digestion of the lipids to enhance drug solubility that is particularly well suited to infants and in low economy settings. Therefore, this study has investigated the in vitro solubilisation enhancement of cannabidiol (CBD) in milk-based products during digestion using synchrotron small angle X-ray scattering, followed by pharmacokinetic studies to determine the relative oral bioavailability. The in vitro results, coupled with in vivo data, demonstrate a two-fold increase in the oral bioavailability of CBD in bovine milk as well as infant formula. The results of this study indicate the potential for infant formula to be considered as a novel formulation approach for CBD. Further study is encouraged for more drugs with infant formula to strengthen the correlation between the solubilisation of drug and their oral bioavailability.

Enhancing cannabidiol bioaccessibility using ionic liquid as emulsifier to produce nanosystems: Characterization of structures, cytotoxicity assessment, and in vitro digestion

The emulsifying potential of a biocompatible ionic liquid (IL) to produce lipid-based nanosystems developed to enhance the bioaccessibility of cannabidiol (CBD) was investigated. The IL (cholinium oleate) was evaluated at concentrations of 1 % and 2 % to produce nanoemulsions (NE-IL) and nanostructured lipid carriers (NLC-IL) loaded with CBD. The IL concentration of 1 % demonstrated to be sufficient to produce both NE-IL and NLC-IL with excellent stability properties, entrapment efficiency superior to 99 %, and CBD retention rate of 100 % during the storage period evaluated (i.e. 28 days at 25 °C). The in vitro digestion evaluation demonstrated that the NLC-IL provided a higher stability to the CBD, while the NE-IL improved the CBD bioaccessibility, which was mainly related to the composition of the lipid matrices used to obtain each nanosystem. Finally, it was observed that the CBD cytotoxicity was reduced when the compound was entrapped into both nanosystems.

Development and characterization of nanostructured lipid carriers for cannabidiol delivery

This study evaluated the physicochemical characteristics of nanostructured lipid carriers (NLCs) as a potential vehicle for cannabidiol (CBD), a lipophilic molecule with great potential to promote health benefits. NLCs were produced using hemp seed oil and fully-hydrogenated soybean oil at different proportions. The emulsifiers evaluated were soybean lecithin (SL), Tween 80 (T80) and a mixture of SL:T80 (50:50). CBD was tested in the form of CBD-rich extract or isolate CBD, to verify if it affects the NLCs characteristics. Based on particle size and polydispersity, SL was considered the most suitable emulsifier to produce the NLCs. All lipid proportions evaluated had no remarkable effect on the physicochemical characteristics of NLCs, resulting in CBD-loaded NLCs with particle size below 250 nm, high CBD entrapment efficiency and CBD retention rate of 100% for 30 days, demonstrating that NLCs are a suitable vehicle for both CBD-rich extract or isolate CBD.

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.

Advances and Challenges in Modeling Cannabidiol Pharmacokinetics and Hepatotoxicity

Cannabidiol (CBD) is a pharmacologically active metabolite of cannabis that is US Food and Drug Administration approved to treat seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex in children aged 1 year and older. During clinical trials, CBD caused dose-dependent hepatocellular toxicity at therapeutic doses. The risk for toxicity was increased in patients taking valproate, another hepatotoxic antiepileptic drug, through an unknown mechanism. With the growing popularity of CBD in the consumer market, an improved understanding of the safety risks associated with CBD is needed to ensure public health. This review details current efforts to describe CBD pharmacokinetics and mechanisms of hepatotoxicity using both pharmacokinetic models and in vitro models of the liver. In addition, current evidence and knowledge gaps related to intracellular mechanisms of CBD-induced hepatotoxicity are described. The authors propose future directions that combine systems-based models with markers of CBD-induced hepatotoxicity to understand how CBD pharmacokinetics may influence the adverse effect profile and risk of liver injury for those taking CBD. SIGNIFICANCE STATEMENT: This review describes current pharmacokinetic modeling approaches to capture the metabolic clearance and safety profile of cannabidiol (CBD). CBD is an increasingly popular natural product and US Food and Drug Administration-approved antiepileptic drug known to cause clinically significant enzyme-mediated drug interactions and hepatotoxicity at therapeutic doses. CBD metabolism, pharmacokinetics, and putative mechanisms of CBD-induced liver injury are summarized from available preclinical data to inform future modeling efforts for understanding CBD toxicity.

Construction of An Oral Bioavailability Prediction Model Based on Machine Learning for Evaluating Molecular Modifications

OBJECTIVE

This study aims to explore the impact of ADME on the Oral Bioavailability (OB) of drugs and to construct a machine learning model for OB prediction. The model is then applied to predict the OB of modified berberine and atenolol molecules to obtain structures with higher OB.

METHODS

Initially, a drug OB database was established, and corresponding ADME characteristics were obtained. The relationship between ADME and OB was analyzed using machine learning, with Morgan fingerprints serving as molecular descriptors. Compounds from the database were input into Random Forest, XGBoost, CatBoost, and LightGBM machine learning models to train the OB 7prediction model and evaluate its performance. Subsequently, berberine and atenolol were modified using Chemdraw software with ten different substituents for mono-substitution, and chlorine atoms for a full range of double substitutions. The modified molecular structures were converted into the same format as the training set for OB prediction. The predicted OB values of the modified structures of berberine and atenolol were compared.

RESULTS

An OB database of 386 drugs was obtained. It was found that smaller molecular weight and a higher number of rotatable bonds (ten or less) could potentially lead to higher OB. The four machine learning models were evaluated using MSE, R2 score, MAE, and MFE as metrics, with Random Forest performing the best. The models' predictions for the test set were particularly accurate when OB ranged from 30% to 90%. After mono-substitution and double substitution of berberine and atenolol, the OB of both drugs was significantly improved.

CONCLUSIONS

This study found that some ADME properties of molecules do not have an absolute impact on OB. The database played a decisive role in the process of the machine learning OB prediction model, and the performance of the model was evaluated based on predictions within a range of strong generalization ability. In most cases, mono-substitution and double substitution were beneficial for enhancing the OB of berberine and atenolol. In summary, this study successfully constructed a machine learning regression prediction model that can accurately predict drug OB, which can guide drug design to achieve higher OB to some extent.

Fine-tuning the activation behaviors of ternary modular cabazitaxel prodrugs for efficient and on-target oral anti-cancer therapy

The disulfide bond plays a crucial role in the design of anti-tumor prodrugs due to its exceptional tumor-specific redox responsiveness. However, premature breaking of disulfide bonds is triggered by small amounts of reducing substances (e.g., ascorbic acid, glutathione, uric acid and tea polyphenols) in the systemic circulation. This may lead to toxicity, particularly in oral prodrugs that require more frequent and high-dose treatments. Fine-tuning the activation kinetics of these prodrugs is a promising prospect for more efficient on-target cancer therapies. In this study, disulfide, steric disulfide, and ester bonds were used to bridge cabazitaxel (CTX) to an intestinal lymph vessel-directed triglyceride (TG) module. Then, synthetic prodrugs were efficiently incorporated into self-nanoemulsifying drug delivery system (corn oil and Maisine CC were used as the oil phase and Cremophor EL as the surfactant). All three prodrugs had excellent gastric stability and intestinal permeability. The oral bioavailability of the disulfide bond-based prodrugs (CTX-(C)S-(C)S-TG and CTX-S-S-TG) was 11.5- and 19.1-fold higher than that of the CTX solution, respectively, demonstrating good oral delivery efficiency. However, the excessive reduction sensitivity of the disulfide bond resulted in lower plasma stability and safety of CTX-S-S-TG than that of CTX-(C)S-(C)S-TG. Moreover, introducing steric hindrance into disulfide bonds could also modulate drug release and cytotoxicity, significantly improving the anti-tumor activity even compared to that of intravenous CTX solution at half dosage while minimizing off-target adverse effects. Our findings provide insights into the design and fine-tuning of different disulfide bond-based linkers, which may help identify oral prodrugs with more potent therapeutic efficacy and safety for cancer therapy.

Synthesis, antimicrobial properties and in silico evaluation of coumarin derivatives mediated by 1,4-dibromobutane

In this study, monobrominated coumarins (5-6) and bis-coumarins (7-9) were synthesized from 3-carboxylic coumarin and 7-hydroxy-4-methyl coumarin using 1,4-dibromobutane as a binding agent, according to the synthesis procedures described in the literature. Amongst these coumarins, three are new compounds: monobrominated coumarin 5 and bis-coumarins 7 and 9. The structures of the synthesized coumarins were confirmed by FTIR, NMR and HRMS-ESI. In vitro antimicrobial evaluation of these coumarins against strains of twelve bacteria and four fungi revealed their bactericidal and fungicidal properties, with increased antibacterial activity for monocoumarins and improved antifungal activity for bis-coumarins. It was also found that the antibacterial activity was enhanced by the etheric bond, Br atom and alkyl chain and reduced by the ester bonds at position 3 of the pyrone ring or an additional coumarin unit, while the antifungal activity was reinforced by ester bonds and deactivated by the Br atom. For the first time, the in silico investigations of such coumarins were carried out and it was observed that they are less toxic, suitable for oral administration with good permeability through cell membrane, are able to circulate freely in the bloodstream and cross Blood-Brain-Barriers. Moreover, their molecular docking in DNA indicated stable coumarin-DNA complexes with good scores. The results of molecular dynamics simulations performed for 200 ns revealed the rigidity and stability of bis-coumarins (7-9) in the DNA binding pocket and predict that they are potent binders.Communicated by Ramaswamy H. Sarma.

Application of Oil-in-Water Cannabidiol Emulsion for the Treatment of Rheumatoid Arthritis

Introduction: Rheumatoid arthritis (RA) is a chronic autoimmune disease with unknown cause. It mainly affects joints and, without proper treatment, negatively impacts their movement, causes painful deformities, and reduces the patients' quality of life. Current treatment options consist of various types of disease-modifying antirheumatic drugs (DMARDs), however 20-30% of patients are partially resistant to them. Therefore, development of new drugs is necessary. Possible option are compounds exhibiting their action via endocannabinoid system, which plays an important role in pain and inflammation modulation. One such compound - cannabidiol (CBD) has already been shown to attenuate synovitis in animal model of RA in in vivo studies. However, it has low bioavailability due to its low water solubility and lipophilicity. This issue can be addressed by preparation of a lipid containing formulation targeting lymphatic system, another route of absorption in the body. Materials and Methods: CBD-containing emulsion was prepared by high-shear homogenization and its droplet size distribution was analysed by optical microscopy. The relative oral bioavailability compared to oil solution as well as total availability of CBD were assessed in a cross-over study in rats and absorption of CBD via lymphatic system was observed. The effect of CBD on the animal model of RA was determined. Results: Compared to oil solution, the emulsion exhibited higher absolute oral bioavailability. Significant lymphatic transport of CBD was observed in all formulations and the concentrations in lymph were calculated. The therapeutic effect of CBD on RA was confirmed as an improvement in clinical symptoms as well as morphological signs of disease activity were observed during the study. Conclusion: In this work, we prepared a simple stable emulsion formulation, determined the pharmacokinetic parameters of CBD and calculated its absolute bioavailability in rats. Moreover, we successfully tested the pharmaceutical application of such a formulation and demonstrated the positive effect of CBD in an animal model of RA.

Targeting the Endocannabinoid System Present in the Glioblastoma Tumour Microenvironment as a Potential Anti-Cancer Strategy

The highly aggressive and invasive glioblastoma (GBM) tumour is the most malignant lesion among adult-type diffuse gliomas, representing the most common primary brain tumour in the neuro-oncology practice of adults. With a poor overall prognosis and strong resistance to treatment, this nervous system tumour requires new innovative treatment. GBM is a polymorphic tumour consisting of an array of stromal cells and various malignant cells contributing to tumour initiation, progression, and treatment response. Cannabinoids possess anti-cancer potencies against glioma cell lines and in animal models. To improve existing treatment, cannabinoids as functionalised ligands on nanocarriers were investigated as potential anti-cancer agents. The GBM tumour microenvironment is a multifaceted system consisting of resident or recruited immune cells, extracellular matrix components, tissue-resident cells, and soluble factors. The immune microenvironment accounts for a substantial volume of GBM tumours. The barriers to the treatment of glioblastoma with cannabinoids, such as crossing the blood-brain barrier and psychoactive and off-target side effects, can be alleviated with the use of nanocarrier drug delivery systems and functionalised ligands for improved specificity and targeting of pharmacological receptors and anti-cancer signalling pathways. This review has shown the presence of endocannabinoid receptors in the tumour microenvironment, which can be used as a potential unique target for specific drug delivery. Existing cannabinoid agents, studied previously, show anti-cancer potencies via signalling pathways associated with the hallmarks of cancer. The results of the review can be used to provide guidance in the design of future drug therapy for glioblastoma tumours.

Nanocarriers for Cannabinoid Delivery: Enhancing Therapeutic Potential

Medical cannabis has potential therapeutic benefits in managing pain, anxiety, depression, and neurological and movement disorders. Phytocannabinoids derived from the cannabis plant are responsible for their pharmacological and therapeutic properties. However, the complexity of cannabis components, especially cannabinoids, poses a challenge to effective medicinal administration. Even with the increasing acceptance of cannabis-based medicines, achieving consistent bioavailability and targeted distribution remains difficult. Conventional administration methods are plagued by solubility and absorption problems requiring innovative solutions. After conducting a thorough review of research papers and patents, it has become evident that nanotechnology holds great promise as a solution. The comprehensive review of 36 research papers has yielded valuable insights, with 7 papers reporting enhanced bioavailability, while others have focused on improvements in release, solubility, and stability. Additionally, 19 patents have been analyzed, of which 7 specifically claim enhanced bioavailability, while the remaining patents describe various formulation methods. These patents outline effective techniques for encapsulating cannabis using nanocarriers, effectively addressing solubility and controlled release. Studies on the delivery of cannabis using nanocarriers focus on improving bioavailability, prolonging release, and targeting specific areas. This synthesis highlights the potential of nanotechnology to enhance cannabis therapies and pave the way for innovative interventions and precision medicine.

Cannabidiol - Help and hype in targeting mucosal diseases

Cannabidiol (CBD) is one of the most commonly utilised phytocannabinoids due to its non-psychoactive and multiple potential therapeutic properties and its non-selective pharmacology. Recent studies have demonstrated efficacy of CBD in some types of drug resistant epilepsies in combination with other therapies; comparative efficacy to other agents or placebo has been hoped for anxiety, chronic pain, and inflammatory disorders based on animal data. Although CBD products are generally treated as a restricted substance, these are being eased, partially in response to significant growth in CBD product usage and increased production but more due to emerging evidence about its safety and pharmacological properties. Currently, only one CBD product (Epidiolex®) has been approved by the Australian Therapeutic Goods Administration and US Food and Drug Administration. CBD has demonstrated promise in alleviating gut and lung diseases in vitro; however, its physicochemical properties pose a significant barrier to achieving pharmacological effects in in vivo and clinical trials. Improving CBD formulations and delivery methods using technologies including self-emulsifying emulsion, nano and micro particles could overcome these shortfalls and improve its efficacy. This review focuses on the therapeutic potential of CBD in gastrointestinal and lung diseases from the available in vitro, in vivo, and clinical research. We report on identified research gaps and obstacles in the development of CBD-based therapeutics, including novel delivery methods.

Poly(ethylene glycol)-b-poly(epsilon-caprolactone) nanoparticles as a platform for the improved oral delivery of cannabidiol

Cannabidiol (CBD), a non-psychoactive constituent of Cannabis, has proven neuroprotective, anti-inflammatory and antioxidant properties though his therapeutic use, especially by the oral route, is still challenged by the poor aqueous solubility that results in low oral bioavailability. In this work, we investigate the encapsulation of CBD within nanoparticles of a highly hydrophobic poly(ethylene glycol)-b-poly(epsilon-caprolactone) block copolymer produced by a simple and reproducible nanoprecipitation method. The encapsulation efficiency is ~ 100% and the CBD loading 11% w/w (high performance liquid chromatography). CBD-loaded nanoparticles show a monomodal size distribution with sizes of up to 100 nm (dynamic light scattering), a spherical morphology, and the absence of CBD crystals (high resolution-scanning electron microscopy and cryogenic-transmission electron microscopy) which is in line with a very efficient nanoencapsulation. Then, the CBD release profile from the nanoparticles is assessed under gastric- and intestine-like conditions. At pH 1.2, only 10% of the payload is released after 1 h. Conversely, at pH 6.8, a release of 80% is recorded after 2 h. Finally, the oral pharmacokinetics is investigated in rats and compared to a free CBD suspension. CBD-loaded nanoparticles lead to a statistically significant ~ 20-fold increase of the maximum drug concentration in plasma (Cmax) and a shortening of the time to the Cmax (tmax) from 4 to 0.3 h, indicating a more complete and faster absorption than in free form. Moreover, the area-under-the-curve (AUC), a measure of oral bioavailability, increased by 14 times. Overall results highlight the promise of this simple, reproducible, and scalable nanotechnology strategy to improve the oral performance of CBD with respect to common oily formulations and/or lipid-based drug delivery systems associated with systemic adverse effects.

Pharmacokinetics of Two Nanoemulsion Formulations of Δ8-Tetrahydrocannabinol in Rats

The use of Δ8-tetrahydrocannabinol (Δ8-THC) has increased in recent years. Given that the oral absorption of cannabinoids in oil formulations is typically slow and variable, nanoemulsions may be an improved delivery vehicle. Therefore, we characterized the pharmacokinetics (PK) in Sprague-Dawley rats following the administration of three different oral formulations containing 10 mg/kg Δ8-THC: a translucent liquid nanoemulsion, a reconstituted powder nanoemulsion, and a medium chain triglyceride (MCT) oil solution for comparison. Δ8-THC was also administered intravenously at 0.6 mg/kg. Plasma samples were quantified for Δ8-THC and two metabolites, 11-hydroxy-Δ8-THC (11-OH-Δ8-THC) and 11-carboxy-Δ8-THC (COOH-Δ8-THC). Non-compartmental PK parameters were calculated, and a PK model was developed based on pooled data. Despite a smaller median droplet size of the translucent liquid nanoemulsion (26.9 nm) compared to the reconstituted powder nanoemulsion (168 nm), the PK was similar for both. The median Tmax values of Δ8-THC for the nanoemulsions (0.667 and 1 h) were significantly shorter than the median Tmax of Δ8-THC in MCT oil (6 h). This resulted in an approximately 4-fold higher Δ8-THC exposure over the first 4 h for the nanoemulsions relative to the MCT oil solution. The active 11-OH-Δ8-THC metabolite followed a similar pattern to Δ8-THC. The non-compartmental bioavailability estimates of Δ8-THC for the nanoemulsions (11-16.5%) were lower than for the MCT oil solution (>21.5%). However, a model-based analysis indicated similar bioavailability for all three oral formulations. These results demonstrate favorable absorption properties of both nanoemulsions, despite the difference in droplet sizes, compared to an MCT oil formulation.

Pharmacokinetics and oral bioavailability of cannabidiol in horses after intravenous and oral administration with oil and micellar formulations

BACKGROUND

Intravenous pharmacokinetics and oral bioavailability of cannabidiol (CBD) with different formulations have not been investigated in horses and may represent a starting point for clinical studies.

OBJECTIVES

To describe pharmacokinetics after intravenous and oral administrations with oil and micellar formulations and simulate different treatments.

STUDY DESIGN

Single intravenous experiment and two-way randomised oral experiments, Latin-square design.

METHODS

Eight healthy horses received intravenous CBD at 1.00 mg/kg dose, oral CBD in sesame oil and in micellar formulation, both at 10.00 mg/kg. Concentrations were measured using LC-MS/MS and fitted by nonlinear mixed effect modelling. Parameters obtained were used to simulate single and multiple treatments at steady state.

RESULTS

Intravenous and oral concentrations were simultaneously fitted using a three-compartment model. Final estimates indicate that CBD has a volume of distribution of 36 L/kg associated with a systemic clearance of 1.46 L/h/kg and half-lives ranged between 24 and 34 h. Oral bioavailability was close to 14% for both oral administrations. Simulated dose regimen of CBD every 12 and 24 h predicted similar percentages to reach effective plasma concentration with both oral formulation at 10.00 mg/kg.

MAIN LIMITATIONS

A small horse population was used (8 horses per trial).

CONCLUSIONS AND CLINICAL IMPORTANCE

Oral bioavailability was low at the doses studied but fell within the range described for horse and other species. CBD had a high steady-state volume of distribution, a high clearance and long half-lives. No adverse reactions were detected at any dose or route. The micellar formulation showed a faster absorption and higher concentration peak, while the oil formulation presented lower levels, but more maintained over time. Simulations predicted that both could be useful in multiple oral dose treatments. These results indicated that CBD could be of interest, but further studies are needed to evaluate its clinical use in horses.

Development of a Novel In Vitro Model to Study Lymphatic Uptake of Drugs via Artificial Chylomicrons

The lymphatic system plays a crucial role in the absorption of lipophilic drugs, making it an important route for drug delivery. In this study, an in vitro model using Intralipid® was developed to investigate the lymphatic uptake of drugs. The model was validated using cannabidiol, halofantrine, quercetin, and rifampicin. Remarkably, the uptake of these drugs closely mirrored what would transpire in vivo. Furthermore, adding peanut oil to the model system significantly increased the lymphatic uptake of rifampicin, consistent with meals containing fat stimulating lymphatic drug uptake. Conversely, the inclusion of pluronic L-81 was observed to inhibit the lymphatic uptake of rifampicin in the model. This in vitro model emerges as a valuable tool for investigating and predicting drug uptake via the lymphatic system. It marks the first phase in developing a physiologically based predictive tool that can be refined further to enhance the precision of drug interaction predictions with chylomicrons and their subsequent transport via the lymphatic system. Moreover, it can be employed to explore innovative drug formulations and excipients that either enhance or hinder lymphatic drug uptake. The insights gained from this study have significant implications for advancing drug delivery through the lymphatic system.

Archaeosomes facilitate storage and oral delivery of cannabidiol

Cannabidiol (CBD) has received great scientific interest due to its numerous therapeutic applications. Degradation in the gastrointestinal (GI) tract, first-pass metabolism, and low water solubility restrain bioavailability of CBD to only 6% in current oral administration. Lipid-based nanocarriers are delivery systems that may enhance accessibility and solubility of hydrophobic payloads, such as CBD. Conventional lecithin-derived liposomes, however, have limitations regarding stability in the GI tract and long-term storage. Ether lipid-based archaeosomes may have the potential to overcome these problems due to chemical and structural uniqueness. In this study, we compared lecithin-derived liposomes with archaeosomes in their applicability as an oral delivery system of CBD. We evaluated drug load, storage stability, stability in a simulated GI tract, and in vitro particle uptake in Caco-2 cells. Loading capacity was 6-fold higher in archaeosomes than conventional liposomes while providing a stable formulation over six months after lyophilization. In a simulated GI tract, CBD recovery in archaeosomes was 57 ± 3% compared to only 34 ± 1% in conventional liposomes and particle uptake in Caco-2 cells was enhanced up to 6-fold. Our results demonstrate that archaeosomes present an interesting solution to tackle current issues of oral CBD formulations due to improved stability and endocytosis.

Real-World Evidence of Factors Affecting Cannabidiol Exposure in Children with Drug-Resistant Developmental and Epileptic Encephalopathies

The identification of factors that affect cannabidiol (CBD) systemic exposure may aid in optimizing treatment efficacy and safety in clinical practice. In this study, we aimed to correlate CBD plasma concentrations at a steady state to demographic, clinical, and pharmacological characteristics as well as seizure frequency after the administration of a purified CBD oil solution in a real-world setting of children with drug-resistant developmental and epileptic encephalopathies (DEEs). Patients receiving oral CBD pharmaceutical products at maintenance were enrolled. Venous blood samples were drawn before the CBD morning dose, 12 h apart from the last evening dose (C0 or CBD trough concentration). A linear mixed-effect analysis was implemented to assess the correlation between C0 and clinical, laboratory, pharmacological, and lifestyle factors. Fifteen females and seven males with a median age of 12.8 years (ranging between 4.7 and 17.2) were included. The median CBD dose was 8.8 mg/kg/day (ranging between 2.6 and 22.5), and the CBD C0 median (range) was 48.2 ng/mL (3.5-366.3). The multivariate model showed a 109.6% increase in CBD C0 in patients with concomitant levothyroxine (β = 0.74 ± 0.1649, p < 0.001), 56.8% with food (β = 0.45 ± 0.1550, p < 0.01), and 116.0% after intake of a ketogenic diet (β = 0.77 ± 0.3141, p < 0.05). All patients included were responders without evidence of an association between C0 and response status. In children with DEEs, systemic concentrations of CBD may be significantly increased when co-administered with levothyroxine, food, or a ketogenic diet.

Effects of Oral Cannabinoids on Systemic Inflammation and Viral Reservoir Markers in People with HIV on Antiretroviral Therapy: Results of the CTN PT028 Pilot Clinical Trial

Chronic HIV infection is characterized by persistent inflammation despite antiretroviral therapy (ART). Cannabinoids may help reduce systemic inflammation in people with HIV (PWH). To assess the effects of oral cannabinoids during HIV, ten PWH on ART were randomized (n = 5/group) to increasing doses of oral Δ9-tetrahydrocannabinol (THC): cannabidiol (CBD) combination (2.5:2.5-15:15 mg/day) capsules or CBD-only (200-800 mg/day) capsules for 12 weeks. Blood specimens were collected prospectively 7-21 days prior to treatment initiation and at weeks 0 to 14. Plasma cytokine levels were determined via Luminex and ELISA. Immune cell subsets were characterized by flow cytometry. HIV DNA/RNA were measured in circulating CD4 T-cells and sperm by ultra-sensitive qPCR. Results from both arms were combined for statistical analysis. Plasma levels of IFN-γ, IL-1β, sTNFRII, and REG-3α were significantly reduced at the end of treatment (p ˂ 0.05). A significant decrease in frequencies of PD1+ memory CD4 T-cells, CD73+ regulatory CD4 T-cells, and M-DC8+ intermediate monocytes was also observed (p ˂ 0.05), along with a transient decrease in CD28-CD57+ senescent CD4 and CD8 T-cells. Ki-67+ CD4 T-cells, CCR2+ non-classical monocytes, and myeloid dendritic cells increased over time (p ˂ 0.05). There were no significant changes in other inflammatory markers or HIV DNA/RNA levels. These findings can guide future large clinical trials investigating cannabinoid anti-inflammatory properties.

Challenges and considerations for treating PTSD with medicinal cannabis: the Australian clinician's perspective

INTRODUCTION

Preclinical and experimental research have provided promising evidence that medicinal cannabis may be efficacious in the treatment of posttraumatic stress disorder (PTSD). However, implementation of medicinal cannabis into routine clinical therapies may not be straightforward.

AREAS COVERED

In this review, we describe some of the clinical, practical, and safety challenges that must be addressed for cannabis-based treatment of PTSD to be feasible in a real-world setting. These issues are especially prevalent if medicinal cannabis is to be combined with trauma-focused psychotherapy.

EXPERT OPINION

Future consideration of the clinical and practical considerations of cannabis use in PTSD therapy will be essential to both the efficacy and safety of the treatment protocols that are being developed. These issues include dose timing and titration, potential for addiction, product formulation, windows of intervention, and route of administration. In particular, exposure therapy for PTSD involves recall of intense emotions, and the interaction between cannabis use and reliving of trauma memories must be explored in terms of patient safety and impact on therapeutic outcomes.

Differences in Plasma Cannabidiol Concentrations in Women and Men: A Randomized, Placebo-Controlled, Crossover Study

The potential therapeutic benefits of cannabidiol (CBD) require further study. Here, we report a triple-blind (participant, investigator, and outcome assessor) placebo-controlled crossover study in which 62 hypertensive volunteers were randomly assigned to receive the recently developed DehydraTECH2.0 CBD formulation or a placebo. This is the first study to have been conducted using the DehydraTECH2.0 CBD formulation over a 12-week study duration. The new formulation's long-term effects on CBD concentrations in plasma and urine, as well as its metabolites 7-hydroxy-CBD and 7-carboxy-CBD, were analyzed. The results of the plasma concentration ratio for CBD/7-OH-CBD in the third timepoint (after 5 weeks of use) were significantly higher than in the second timepoint (after 2.5 weeks of use; p = 0.043). In the same timepoints in the urine, a significantly higher concentration of 7-COOH-CBD was observed p < 0.001. Differences in CBD concentration were found between men and women. Plasma levels of CBD were still detectable 50 days after the last consumption of the CBD preparations. Significantly higher plasma CBD concentrations occurred in females compared to males, which was potentially related to greater adipose tissue. More research is needed to optimize CBD doses to consider the differential therapeutic benefits in men and women.

Physiologically based pharmacokinetic modeling and simulation of cannabinoids in human plasma and tissues

There has been an increased public interest in developing consumer products containing nonintoxicating cannabinoids, such as cannabidiol (CBD) and cannabigerol (CBG). At the present time, there is limited information available on the pharmacokinetics of cannabinoids in humans. Since pharmacokinetic profiles are important in understanding the pharmacological and toxicological effects at the target sites, physiologically based pharmacokinetic (PBPK) modeling was used to predict the plasma and tissue concentrations of 17 cannabinoids in humans. PBPK models were established using measured (in vitro) and predicted (in silico) physicochemical and pharmacokinetic properties, such as water solubility and effective human jejunal permeability. Initially, PBPK models were established for CBD and the model performance was evaluated using reported clinical data after intravenous and oral administration. PBPK models were then developed for 16 additional cannabinoids including CBG, and the plasma and tissue concentrations were predicted after 30 mg oral administration. The pharmacokinetic profiles of the 16 cannabinoids were similar to CBD, and the plasma concentration and time profiles of CBD agreed well with clinical data in the literature. Although low exposure was predicted in the plasma (maximum plasma concentrations < 15 nM), the predicted tissue concentrations, especially the liver (maximum liver concentrations 70-183 nM), were higher after oral administration of 30 mg cannabinoids. These predicted plasma and tissue concentrations could be used to guide further in vitro and in vivo testing.

Self-nanoemulsifying formulation for oral delivery of sildenafil: effect on physicochemical attributes and in vivo pharmacokinetics

Sildenafil (SLD) is employed for the management of erectile dysfunction and pulmonary arterial hypertension. It exhibits meagre water solubility and is available in the form of citrate salt hydrate to improve the solubility. However, it still exhibits moderate solubility, high first-pass metabolism, resulting in very less oral bioavailability. The present study demonstrates the preparation of self-nanoemulsifying drug delivery system for augmenting the oral bioavailability of SLD. Oleic acid and Capmul MCM C8 blend (oil phase), Cremophor^® RH40 (surfactant), and Labrafil^® M1944 CS (cosurfactant) were selected as main constituents for making liquid preconcentrate based on the solubility and emulsification study. The preconcentrate upon dilution and emulsification showed droplet size 52.03 ± 13.03 nm, PDI 0.143 ± 0.028, and % transmittance was 99.77 ± 1.86% with SLD load of 40 mg/g of formulation. The prepared formulation was further assessed for stability, in vitro release, Caco-2 cell uptake, and in vivo pharmacokinetic performance. SLD-SNEDDS formulation was found to be robust in terms of stability against several folds dilution in the gastrointestinal tract (GIT), freeze-thaw cycles, and had a storage stability of 3 months at 4 °C and 25 °C. SLD-SNEDDS showed ~4.7-fold and ~5-fold increase in time- and concentration-dependent cellular uptake as against SLD cultured with Caco-2 cells. In vivo pharmacokinetic study revealed ~5.8- and ~2.5-fold increase in AUC_0-∞ values in case of SLD-SNEDDS as against SLD suspension and SLD citrate solution, respectively.

Pharmacovigilance on cannabidiol as an antiepileptic agent

Introduction: Cannabidiol (CBD) is an active chemical contained in the plant Cannabis sativa. It is a resorcinol-based compound that crosses the blood-brain barrier without causing euphoric effects. CBD has a plethora of pharmacological effects of therapeutic interest. CBD has been authorized in the European Union as an anticonvulsant against serious infantile epileptic syndromes, but its safety profile is still not sufficiently described. Methods: With the goal of expanding information on the safety of CBD use as an antiepileptic agent beyond the most common side effects known through clinical studies, an analysis of serious case reports on suspected adverse reactions (SARs) to CBD licensed as an anti-epileptic drug found in the EudraVigilance database is reported in this article. EudraVigilance is a system purchased by the European Medicines Agency (EMA) for monitoring the safety of medicinal products marketed in Europe. Results: The most frequent serious SARs to CBD in EudraVigilance were epilepsy aggravation, hepatic disorders, lack of efficacy, and somnolence. Discussion: Based on our analysis, the following precautions should be adopted for appropriate monitoring of potential adverse effects, more attention towards possible CBD medical use as an antiepileptic: awareness of interactions with other drugs, epilepsy aggravation, and drug effectiveness.

Strategies for enhancing the oral bioavailability of cannabinoids

INTRODUCTION

Oral administration of cannabinoids is a convenient route of administration in many cases. To enhance the poor and variable bioavailability of cannabinoids, selected strategies utilizing proper delivery systems have been designed. Low solubility in the GI aqueous media is the first and most critical barrier. Thereafter, cannabinoids can reach the systemic blood circulation via the portal vein that is associated with significant hepatic first pass metabolism (FPM) or bypass it via lymphatic absorption.

AREAS COVERED

The solubility obstacle of cannabinoids is mainly addressed with lipid-based formulations such as self-nanoemulsifying drug delivery systems (SNEDDS). Certain lipids are used to overcome the solubility issue. Surfactants and other additives in the formulation have additional impact on several barriers, including dictating the degree of lymphatic bioavailability and hepatic FPM. Gastro-retentive formulation is also plausible.

EXPERT OPINION

Comparison of the role of the same SNEDDS formulation, cyclosporine vs. cannabinoids, when used to elevate the oral bioavailability of different compounds, is presented. It illustrates some similarities and major mechanistic differences obtained by the same SNEDDS. Thus, the different influence over the absorption pathway illuminates the importance of understanding the absorption mechanism and its barriers to properly select appropriate strategies to achieve enhanced oral bioavailability.

Cannabidiol and Cannabidiol Metabolites: Pharmacokinetics, Interaction with Food, and Influence on Liver Function

Cannabidiol (CBD) is widely available and marketed as having therapeutic properties. Over-the-counter CBD is unregulated, many of the therapeutic claims lack scientific support, and controversy exists as to the safety of CBD-liver interaction. The study aims were to compare the pharmacokinetics of commercial CBD and CBD metabolites following the ingestion of five different CBD formulations, determine the influence of CBD on food induced thermogenesis, determine the influence of food on CBD pharmacokinetics, and determine the influence of CBD on markers of liver function. Fourteen males (body mass index ≥ 25 kg/m²) were studied in a placebo-controlled, randomized, crossover design. On five occasions, different CBD formulations were ingested (one per visit). On two additional occasions, CBD or placebo was ingested following a meal. CBD servings were standardized to 30 mg. Considerable pharmacokinetic variability existed between formulations; this pharmacokinetic variability transferred to several of the metabolites. CBD did not influence food induced thermogenesis but did favorably modify early insulin and triglyceride responses. Food appreciably altered the pharmacokinetics of CBD. Finally, CBD did not evoke physiologically relevant changes in markers of liver function. Collectively, these data suggest that consumers should be aware of the appreciable pharmacokinetic differences between commercial CBD formulations, CBD is unlikely to influence the caloric cost of eating but may prove to be of some benefit to initial metabolic responses, consuming CBD with food alters the dynamics of CBD metabolism and increases systemic availability, and low-dose CBD probably does not represent a risk to normal liver function.

Cannabidiol (CBD) Dosing: Plasma Pharmacokinetics and Effects on Accumulation in Skeletal Muscle, Liver and Adipose Tissue

Oral cannabidiol (CBD) consumption is widespread in North America and Europe, as it has analgesic, neuroprotective and antitumor effects. Although oral CBD consumption in humans affords beneficial effects in epileptic and inflammatory states, its pharmacokinetics and subsequent uptake into tissue are largely unknown. This study investigated plasma pharmacokinetics and accumulation of CBD in gastrocnemius muscle, liver and adipose tissue in adult rats following oral gavage. CBD was fed relative to body mass at 0 (control), 30, 115, or 230 mg/Kg/day for 28 days; with 6 males and 6 females per dosing group. Pharmacokinetics were assessed on day 1 and day 28 in the group receiving CBD at 115 mg/Kg/day. The rise in tissue CBD was closely related to specific pharmacokinetic parameters, and adipose tissue levels were ~10 to ~100 fold greater than liver or muscle. Tissue CBD levels were moderately correlated between adipose and muscle, and adipose and liver, but were highly correlated for liver and muscle. CBD feeding resulted in several gender-specific effects, including changes in pharmacokinetics, relationships between pharmacokinetic parameters and tissue CBD and differences in tissue CBD levels. CBD accumulation in mammalian tissues has the potential to influence receptor binding and metabolism; therefore, the present findings may have relevance for developing oral dosing regimens.

Triglyceride-Mimetic Prodrugs of Buprenorphine Enhance Oral Bioavailability via Promotion of Lymphatic Transport

Buprenorphine (BUP) is a potent opioid analgesic that is widely used for severe pain management and opioid replacement therapy. The oral bioavailability of BUP, however, is significantly limited by first-pass metabolism. Previous studies have shown that triglyceride (TG) mimetic prodrugs of the steroid hormone testosterone circumvent first-pass metabolism by directing drug transport through the intestinal lymphatics, bypassing the liver. The current study expanded this prodrug strategy to BUP. Here different self-immolative (SI) linkers were evaluated to conjugate BUP to the 2 position of the TG backbone via the phenol group on BUP. The SI linkers were designed to promote drug release in plasma. Lipolysis of the prodrug in the intestinal tract was examined via incubation with simulated intestinal fluid (SIF), and potential for parent drug liberation in the systemic circulation was evaluated via incubation in rat plasma. Lymphatic transport and bioavailability studies were subsequently conducted in mesenteric lymph duct or carotid artery-cannulated rats, respectively. TG prodrug derivatives were efficiently transported into the lymphatics (up to 45% of the dose in anaesthetised rats, vs. less than 0.1% for BUP). Incorporation of the SI linkers facilitated BUP release from the prodrugs in the plasma and in concert with high lymphatic transport led to a marked enhancement in oral bioavailability (up to 22-fold) compared to BUP alone. These data suggest the potential to develop an orally bioavailable BUP product which may have advantages with respect to patient preference when compared to current sublingual, transdermal patch or parenteral formulations.

Development and pharmacokinetic evaluation of a self-nanoemulsifying drug delivery system for the oral delivery of cannabidiol

The number of lipophilic drug candidates in pharmaceutical discovery pipelines has increased in recent years. These drugs often possess physicochemical properties that result in poor oral bioavailability, and their clinical potential may be limited without adequate formulation strategies. Cannabidiol (CBD) is an excellent example of a highly lipophilic compound with poor oral bioavailability, due to low water solubility and extensive first-pass metabolism. An approach that may overcome these limitations is formulation of the drug in self-nanoemulsifying drug delivery systems (SNEDDS). Herein, CBD-SNEDDS formulations were prepared and evaluated in vitro. Promising formulations (F2, F4) were administered to healthy female Sprague-Dawley rats via oral gavage (20 mg/kg CBD). Resulting pharmacokinetic parameters of CBD were compared to those obtained following administration of CBD in two oil-based formulations: a medium-chain triglyceride oil vehicle (MCT-CBD), and a sesame oil-based formulation similar in composition to an FDA-approved formulation of CBD, Epidiolex® (SO-CBD). Compared to MCT-CBD, administration of the SNEDDS formulations led to more rapid absorption of CBD (median T_max values: 0.5 h (F2), 1 h (F4), 6 h (MCT-CBD)). Administration of F2 and F4 formulations also improved the systemic exposure to CBD by 2.2 and 2.8-fold compared to MCT-CBD; however, no improvement was found compared to SO-CBD.

Cannabinoid Formulations and Delivery Systems: Current and Future Options to Treat Pain

The field of Cannabis sativa L. research for medical purposes has been rapidly advancing in recent decades and a growing body of evidence suggests that phytocannabinoids are beneficial for a range of conditions. At the same time impressing development has been observed for formulations and delivery systems expanding the potential use of cannabinoids as an effective medical therapy. The objective of this review is to present the most recent results from pharmaceutical companies and research groups investigating methods to improve cannabinoid bioavailability and to clearly establish its therapeutic efficacy, dose ranges, safety and also improve the patient compliance. Particular focus is the application of cannabinoids in pain treatment, describing the principal cannabinoids employed, the most promising delivery systems for each administration routes and updating the clinical evaluations. To offer the reader a wider view, this review discusses the formulation starting from galenic preparation up to nanotechnology approaches, showing advantages, limits, requirements needed. Furthermore, the most recent clinical data and meta-analysis for cannabinoids used in different pain management are summarized, evaluating their real effectiveness, in order also to spare opioids and improve patients' quality of life. Promising evidence for pain treatments and for other important pathologies are also reviewed as likely future directions for cannabinoids formulations.

Current trends on cannabidiol delivery systems: where are we and where are we going?

INTRODUCTION

Cannabidiol (CBD), a phytocannabinoid from Cannabis sativa, has several therapeutic properties. However, its high lipophilicity, metabolization, and instability impair its bioavailability and translational use in clinical settings. Several advanced drug delivery systems (ADDSs) have been evaluated as CBD carriers to overcome these drawbacks. These systems can improve the CBD dissolution profile, protect it against metabolization, and produce a site-specific release, increasing its bioavailability and making CBD administration clinically effective.

AREAS COVERED

This review summarizes scientific reports on cannabidiol advanced delivery systems (CBD-ADSs) that have been (i) developed, and (ii) applied therapeutically; reports published in the main scientific databases until January 2020 were included. Studies without experimental data and/or published in languages other than English were excluded. Moreover, pharmaceutical technology tools in CBD therapeutic use have been discussed, emphasizing the clinical translation of CBD carrier use.

EXPERT OPINION

Studies reporting CBD-ADS use for medicinal applications were reviewed and revealed multifaceted systems that can overcome the physicochemical drawbacks of CBD and improve its biological activities. Therefore, researchers concluded that the developed CBD-ADS can be used as an alternative to traditional formulations because they show comparable or superior effectiveness in treatment protocols. Although several criteria remain to be met, our findings emphasize the potential of CBD-ADSs for translational therapeutics, particularly for neurological-disorders.

The role of new medical treatments for the management of developmental and epileptic encephalopathies: Novel concepts and results

Developmental and epileptic encephalopathies (DEEs) are among the most challenging of all epilepsies to manage, given the exceedingly frequent and often severe seizure types, pharmacoresistance to conventional antiseizure medications, and numerous comorbidities. During the past decade, efforts have focused on development of new treatment options for DEEs, with several recently approved in the United States or Europe, including cannabidiol as an orphan drug in Dravet and Lennox-Gastaut syndromes and everolimus as a possible antiepileptogenic and precision drug for tuberous sclerosis complex, with its impact on the mammalian target of rapamycin pathway. Furthermore, fenfluramine, an old drug, was repurposed as a novel therapy in the treatment of Dravet syndrome. The evolution of new insights into pathophysiological processes of various DEEs provides possibilities to investigate novel and repurposed drugs and to place them into the context of their role in future management of these patients. The purpose of this review is to provide an overview of these new medical treatment options for the DEEs and to discuss the clinical implications of these results for improved treatment.

Cannabidiol in the treatment of epilepsy: Current evidence and perspectives for further research

The therapeutic potential of cannabidiol (CBD) in seizure disorders has been known for many years, but it is only in the last decade that major progress has been made in characterizing its preclinical and clinical properties as an antiseizure medication. The mechanisms responsible for protection against seizures are not fully understood, but they are likely to be multifactorial and to include, among others, antagonism of G protein-coupled receptor, desensitization of transient receptor potential vanilloid type 1 channels, potentiation of adenosine-mediated signaling, and enhancement of GABAergic transmission. CBD has a low and highly variable oral bioavailability, and can be a victim and perpetrator of many drug-drug interactions. A pharmaceutical-grade formulation of purified CBD derived from Cannabis sativa has been evaluated in several randomized placebo-controlled adjunctive-therapy trials, which resulted in its regulatory approval for the treatment of seizures associated with Dravet syndrome, Lennox-Gastaut syndrome and tuberous sclerosis complex. Interpretation of results of these trials, however, has been complicated by the occurrence of an interaction with clobazam, which leads to a prominent increase in the plasma concentration of the active metabolite N-desmethylclobazam in CBD-treated patients. Despite impressive advances, significant gaps in knowledge still remain. Areas that require further investigation include the mechanisms underlying the antiseizure activity of CBD in different syndromes, its pharmacokinetic profile in infants and children, potential relationships between plasma drug concentration and clinical response, interactions with other co-administered medications, potential efficacy in other epilepsy syndromes, and magnitude of antiseizure effects independent from interactions with clobazam. This article is part of the special issue on 'Cannabinoids'.