Sublingual administration of Delta9-tetrahydrocannabinol/beta-cyclodextrin complex increases the bioavailability of Delta9-tetrahydrocannabinol in rabbits

Investigation of Cannabinoid Acid/Cyclodextrin Inclusion Complex for Improving Physicochemical and Biological Performance

This study aimed to investigate the enhancement of cannabinoid acid solubility and stability through the formation of a cannabinoid acid/cyclodextrin (CD) inclusion complex. Two cannabinoid acids, tetrahydro-cannabinolic acid (THCA) and cannabidiolic acid (CBDA), were selected as a model drug along with five types of CD: α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and methylated-β-cyclodextrin (M-β-CD). Phase solubility studies were conducted using various types of CD to determine the complex stoichiometry. The preparation methods of the CD inclusion complex were optimized by adjusting the loading pH solution and the drying processes (spray-drying, freeze-drying, spray-freeze-drying). The drying process of the cannabinoid acid/M-β-CD inclusion complex was further optimized through the spray-freeze-drying method. These CD complexes were characterized using solubility determination, differential scanning calorimetry (DSC), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and 1H NMR spectroscopy. DSC, XRD, and FE-SEM studies confirmed the non-crystalline state of the cannabinoid acid/CD inclusion complex. The permeation of THCA or CBDA from the M-β-CD spray-freeze-dried inclusion complex was highly improved compared to those of cannabis ethanolic extracts under simulated physiological conditions. The stability of the cannabinoid acid/M-β-CD inclusion complex was maintained for 7 days in a simulated physiological condition. Furthermore, the minimum inhibitory concentration of cannabinoid acid/M-β-CD inclusion complex had superior anti-cancer activity in MCF-7 breast cancer cell lines compared to cannabinoid acid alone. The improved physicochemical and biological performances indicated that these CD inclusion complexes could provide a promising option for loading lipophilic cannabinoids in cannabis-derived drug products.

Nanoformulations as a strategy to overcome the delivery limitations of cannabinoids

Medical cannabis has received significant interest in recent years due to its promising benefits in the management of pain, anxiety, depression and neurological and movement disorders. Specifically, the major phytocannabinoids derived from the cannabis plant such as (-) trans-Δ⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD), have been shown to be responsible for the pharmacological and therapeutic properties. Recently, these phytocannabinoids have also attracted special attention in cancer treatment due to their well-known palliative benefits in chemotherapy-induced nausea, vomiting, pain and loss of appetite along with their anticancer activities. Despite the enormous pharmacological benefits, the low aqueous solubility, high instability (susceptibility to extensive first pass metabolism) and poor systemic bioavailability restrict their utilization at clinical perspective. Therefore, drug delivery strategies based on nanotechnology are emerging to improve pharmacokinetic profile and bioavailability of cannabinoids as well as enhance their targeted delivery. Here, we critically review the nano-formulation systems engineered for overcoming the delivery limitations of native phytocannabinoids including polymeric and lipid-based nanoparticles (lipid nano capsules (LNCs), nanostructured lipid carriers (NLCs), nanoemulsions (NE) and self-emulsifying drug delivery systems (SEDDS)), ethosomes and cyclodextrins as well as their therapeutic applications.

Pharmacokinetics of Cannabis and Its Derivatives in Animals and Humans During Pregnancy and Breastfeeding

Cannabis is one of the most widely used illicit drugs during pregnancy and lactation. With the recent legalization of cannabis in many countries, health professionals are increasingly exposed to pregnant and breastfeeding women who are consuming cannabis on a regular basis as a solution for depression, anxiety, nausea, and pain. Cannabis consumption during pregnancy can induce negative birth outcomes such as reduced birth weight and increased risk of prematurity and admission to the neonatal intensive care unit. Yet, limited information is available regarding the pharmacokinetics of cannabis in the fetus and newborn exposed during pregnancy and lactation. Indeed, the official recommendations regarding the use of cannabis during these two critical development periods lack robust pharmacokinetics data and make it difficult for health professionals to guide their patients. Many clinical studies are currently evaluating the effects of cannabis on the brain development and base their groups mostly on questionnaires. These studies should be associated with pharmacokinetics studies to assess correlations between the infant brain development and the exposure to cannabis during pregnancy and breastfeeding. Our project aims to review the available data on the pharmacokinetics of cannabinoids in adults, neonates, and animals. If the available literature is abundant in adult humans and animals, there is still a lack of published data on the exposure of pregnant and lactating women and neonates. However, some of the published information causes concerns on the exposure and the potential effects of cannabis on fetuses and neonates. The safety of cannabis use for non-medical purpose during pregnancy and breastfeeding needs to be further characterized with proper pharmacokinetic studies in humans feasible in regions where cannabis has been legalized. Given the available data, significant transfer occurs to the fetus and the breastfed newborn with a theoretical risk of accumulation of products known to be biologically active.

Comparative Study of Dissolution for Cannabidiol in EU and US Hemp Oil Products by HPLC

For the first time, a simple and robust HPLC method has been developed for dissolution studies for cannabidiol (CBD) in hemp oil products. An isocratic elution of samples performed on SOLAS™ C18 150 mm x 4.6 mm, 5 μm column with a mobile phase consisting of 75:25 acetonitrile-water v/v, delivered at a flow rate 1.5 mL/minutes to variable wavelength detector using 214 nm. An in-house validated assay test was executed for calculating the purity of hemp oil products and also for considering the dissolution medium to be used. For dissolution studies, equivalent of 5 mg and/or 10 mg of the active was introduced into 500 mL of simulated gastric and intestinal fluids separately, and dissolution was performed at 50 rpm using paddles for 180 min. Dissolution profiles for hemp oil products purchased from the United States and Europe were compared. Additionally, dissolution testing was conducted to study the effect of percentage CBD release on increased agitation speed of 75 and 100 rpm and also, on extended dissolution runtime of 240 min.

Enhancing Efficacy, Performance, and Reliability of Cannabis Edibles: Insights from Lipid Bioavailability Studies

The legal sale of cannabis-enriched foods and beverages for medical or recreational purposes is increasing in many states and countries, especially in North America and Europe. These food-based cannabis delivery systems vary considerably in their compositions and structures, ranging from low-viscosity watery beverages to solid fatty chocolates. The rate and extent of release of the bioactive components in cannabis within the human gastrointestinal tract (GIT) affect their health and psychoactive effects. Studies with other types of hydrophobic bioactives, such as nutraceuticals and vitamins, have shown that food composition and structure have a major impact on their bioaccessibility, transformation, and absorption within the GIT, thereby influencing their bioavailability and bioactivity. This review outlines how insights on the bioavailability of other lipophilic bioactives can be used to facilitate the design of more efficacious and consistent cannabis-enriched products intended for oral consumption. In particular, the importance of food-matrix composition (such as fat type and level) and structural organization (such as fat domain dimensions) are discussed.

Isolation and Pharmacological Evaluation of Minor Cannabinoids from High-Potency Cannabis sativa

Seven new naturally occurring hydroxylated cannabinoids (1-7), along with the known cannabiripsol (8), have been isolated from the aerial parts of high-potency Cannabis sativa. The structures of the new compounds were determined by 1D and 2D NMR spectroscopic analysis, GC-MS, and HRESIMS as 8α-hydroxy-Δ(9)-tetrahydrocannabinol (1), 8β-hydroxy-Δ(9)-tetrahydrocannabinol (2), 10α-hydroxy-Δ(8)-tetrahydrocannabinol (3), 10β-hydroxy-Δ(8)-tetrahydrocannabinol (4), 10α-hydroxy-Δ(9,11)-hexahydrocannabinol (5), 9β,10β-epoxyhexahydrocannabinol (6), and 11-acetoxy-Δ(9)-tetrahydrocannabinolic acid A (7). The binding affinity of isolated compounds 1-8, Δ(9)-tetrahydrocannabinol, and Δ(8)-tetrahydrocannabinol toward CB1 and CB2 receptors as well as their behavioral effects in a mouse tetrad assay were studied. The results indicated that compound 3, with the highest affinity to the CB1 receptors, exerted the most potent cannabimimetic-like actions in the tetrad assay, while compound 4 showed partial cannabimimetic actions. Compound 2, on the other hand, displayed a dose-dependent hypolocomotive effect only.

Bioavailability of Δ⁹-tetrahydrocannabinol following intranasal administration of a mucoadhesive gel spray delivery system in conscious rabbits

BACKGROUND

The purpose of this study was to investigate the potential of the intranasal route for systemic delivery of solubilized Δ⁹-tetrahydrocannabinol (THC). A further aim was to investigate the effect of nasally administered chitosan-based nasal bioadhesive gel on THC bioavailability as a formulation strategy to decrease normal mucociliary drug clearance.

METHOD

The THC formulations were administered intranasally and compared to intravenous administration utilizing conscious rabbits.

RESULTS

After nasal administration, the THC nasal solution afforded a C(max) value of 20 ± 3 ng/mL at 20 minutes. Interestingly, the THC loaded in chitosan gel formulation followed almost the same profile at early time points and subsequently afforded a higher C(max) value of 31 ± 4 ng/mL (T(max) = 45 minutes). The absolute bioavailability of THC after nasal delivery was studied to compare plasma THC concentrations after nasal administration with those after intravenous injection. Absolute bioavailability values were 13.3 ± 7.8% and 15.4 ± 6.5% for the THC nasal solution and gel formulations, respectively.

CONCLUSION

The results of the present study suggest that intranasal administration of THC in solution or in a chitosan-based nasal gel formulation could be an attractive modality for delivery of THC systemically.

Pharmaceutical applications of cyclodextrins: effects on drug permeation through biological membranes

Objectives

Cyclodextrins are useful solubilizing excipients that have gained currency in the formulator's armamentarium based on their ability to temporarily camouflage undesirable physicochemical properties. In this context cyclodextrins can increase oral bioavailability, stabilize compounds to chemical and enzymatic degradation and can affect permeability through biological membranes under certain circumstances. This latter property is examined herein as a function of the published literature as well as work completed in our laboratories.

Key findings

Cyclodextrins can increase the uptake of drugs through biological barriers if the limiting barrier component is the unstirred water layer (UWL) that exists between the membrane and bulk water. This means that cyclodextrins are most useful when they interact with lipophiles in systems where such an UWL is present and contributes significantly to the barrier properties of the membrane. Furthermore, these principles are used to direct the optimal formulation of drugs in cyclodextrins. A second related critical success factor in the formulation of cyclodextrin-based drug product is an understanding of the kinetics and thermodynamics of complexation and the need to optimize the cyclodextrin amount and drug-to-cyclodextrin ratios. Drug formulations, especially those targeting compartments associated with limited dissolution (i.e. the eye, subcutaneous space, etc.), should be carefully designed such that the thermodynamic activity of the drug in the formulation is optimal meaning that there is sufficient cyclodextrin to solubilize the drug but not more than that. Increasing the cyclodextrin concentration decreases the formulation ‘push’ and may reduce the bioavailability of the system.

Conclusions

A mechanism-based understanding of cyclodextrin complexation is essential for the appropriate formulation of contemporary drug candidates.

Formulation of a novel tianeptine sodium orodispersible film

The present investigation was undertaken with the objective of formulating orodispersible film(s) of the antidepressant drug tianeptine sodium to enhance the convenience and compliance by the elderly and pediatric patients. The novel film former, lycoat NG73 (granular hydroxypropyl starch), along with different film-forming agents (hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and polyvinyl alcohol), in addition to three film modifiers; namely, maltodextrin, polyvinyl pyrrolidone K90 and lycoat RS780 (pregelatinized hydroxypropyl starch) were evaluated. Eight formulae were prepared by the solvent-casting method; and were evaluated for their in vitro dissolution characteristics, in vitro disintegration time, and their physico-mechanical properties. The promising orodispersible film based on lycoat NG73 (F1); showing the greatest drug dissolution, satisfactory in vitro disintegration time and physico-mechanical properties that are suitable for orodispersible films, was evaluated for its bioavailability compared with a reference marketed product (Stablon® tablets) in rabbits. Statistical analysis revealed no significant difference between the bioavailability parameters (C(max) (ng/ml), t(max) (h), AUC(0-t) (ng hml(-1)), and AUC(0-∞) (ng hml(-1))] of the test film (F1) and the reference product. The mean ratio values (test/reference) of C(max) (89.74%), AUC(0-t) (110.9%), and AUC(0-∞) (109.21%) indicated that the two formulae exhibited comparable plasma level-time profiles. These findings suggest that the fast orodispersible film containing tianeptine is likely to become one of choices for acute treatment of depression.

Formulation of ketotifen fumarate fast-melt granulation sublingual tablet

The purpose of this study was to prepare sublingual tablets, containing the antiasthmatic drug ketotifen fumarate which suffers an extensive first-pass effect, using the fast-melt granulation technique. The powder mixtures containing the drug were agglomerated using a blend of polyethylene glycol 400 and 6000 as meltable hydrophilic binders. Granular mannitol or granular mannitol/sucrose mixture were used as fillers. A mechanical mixer was used to prepare the granules at 40 degrees C. The method involved no water or organic solvents, which are used in conventional granulation, and hence no drying step was included, which saved time. Twelve formulations were prepared and characterized using official and non official tests. Three formulations showed the best results and were subjected to an ex vivo permeation study using excised chicken cheek pouches. The formulation F4I possessed the highest permeation coefficient due to the presence of the permeation enhancer (polyethylene glycol) in an amount which allowed maximum drug permeation, and was subjected to a pharmacokinetic study using rabbits as an animal model. The bioavailability of F4I was significantly higher than that of a commercially available dosage form (Zaditen solution-Novartis Pharma-Egypt) (p > 0.05). Thus, fast-melt granulation allowed for rapid tablet disintegration and an enhanced permeation of the drug through the sublingual mucosa, resulting in increased bioavailabililty.

Cyclodextrins and chitosan derivatives in sublingual delivery of low solubility peptides: A study using cyclosporin A, alpha-cyclodextrin and quaternary chitosan N-betainate

Systemic drug delivery through intraoral membranes may offer a promising administration route for lipophilic peptide drugs. The aim of the present study was to investigate the effect of alpha-cyclodextrin (alpha-CD) and a novel chitosan derivative, chitosan N-betainate (CH), on sublingual absorption of a hydrophobic model peptide cyclosporin A (CsA), and the effect of temperature on the complexation of CsA with alpha-CD. Complexation of CsA with alpha-CD was studied using the phase-solubility method. Sublingual absorption of CsA was studied by administration of solid CsA/alpha-CD complex (with and without CH solution), solid CsA/alpha-CD/CH formulation and solid plain CsA to rabbits. The solubility of CsA in aqueous alpha-CD solution (14%) increased with decreasing temperature; the solubility of CsA at room temperature, +5 and +1 degrees C was 1.2, 12 and 19mg/ml, respectively. The bioavailability of CsA after administration of plain CsA, solid CsA/alpha-CD and solid CsA/alpha-CD/CH (0.6+/-0.5, 1.4+/-0.7 and 1.7+/-0.8%, respectively; mean+/-S.D.) was further increased when solid CsA/alpha-CD was administered together with CH solution (3.2+/-2.2%). The present study shows that decreased temperature can be effectively utilized to produce CsA/alpha-CD complexes. It was also shown that alpha-CD and CH may be advantageous in sublingual delivery of lipophilic peptides, although the absolute bioavailability remains low.

Octylglucopyranoside and cyclodextrin in water. Self-aggregation and complex formation

At 25 degrees C ultrasonic attenuation spectra between 100 kHz and 400 MHz as well as sound velocities and densities of aqueous solutions of the surfactant n-octyl-beta-d-glucopyranoside and of the cage compound alpha-cyclodextrin have been measured. The liquid system reveals a critical association concentration (cac) exceeding the cmc of the surfactant almost by the cyclodextrin concentration and thus indicating a significant formation of cyclodextrin-surfactant inclusion complexes. The ultrasonic spectra display altogether four relaxation regions. The one with largest relaxation time (0.27 mus < or = tau(1) < or = 1.6 mus) exhibits a noticeable amplitude at surfactant concentrations larger than the cac only. It is assigned to the monomer exchange between the micelles and the suspending phase. A term with relaxation time tau(2) (33 ns < or = tau(2) < or = 135 ns) is characteristic for solutions containing both solutes. It is assumed to reflect the inclusion complex formation. Complexes with 1:1, 2:1, and 1:2 stoichiometry appear to exist. The terms at higher frequencies (4.8 ns < or = tau(3) < or = 9.8 ns; 0.8 ns <or = tau(4) < or = 2 ns) are due to fluctuations of the carbohydrate residues around the glucosidic bond angles and to the rotational isomerization of the exocyclic hydroxymethyl groups, respectively.

Cannabinoid ester constituents from high-potency Cannabis sativa

Eleven new cannabinoid esters, together with three known cannabinoid acids and Delta9-tetrahydrocannabinol ( Delta9-THC ), were isolated from a high-potency variety of Cannabis sativa. The structures were determined by extensive spectroscopic analyses to be beta-fenchyl Delta9-tetrahydrocannabinolate ( 1), epi-bornyl Delta9-tetrahydrocannabinolate ( 2), alpha-terpenyl Delta9-tetrahydrocannabinolate ( 3), 4-terpenyl Delta 9-tetrahydrocannabinolate ( 4), alpha-cadinyl Delta9-tetrahydrocannabinolate ( 5), gamma-eudesmyl Delta9-tetrahydrocannabinolate ( 6), gamma-eudesmyl cannabigerolate ( 7), 4-terpenyl cannabinolate ( 8), bornyl Delta9-tetrahydrocannabinolate ( 9), alpha-fenchyl Delta9-tetrahydrocannabinolate ( 10), alpha-cadinyl cannabigerolate ( 11), Delta9-tetrahydrocannabinol ( Delta9-THC ), Delta9-tetrahydrocannabinolic acid A ( Delta9-THCA ), cannabinolic acid A ( CBNA), and cannabigerolic acid ( CBGA). Compound 8 showed moderate antimicrobial activity against Candida albicans ATCC 90028 with an IC 50 value of 8.5 microg/mL. The isolated acids and the ester-containing fractions showed low affinity to the CB-1 receptor. [corrected]

Precipitation Complexation Method Produces Cannabidiol/β-Cyclodextrin Inclusion Complex Suitable for Sublingual Administration of Cannabidiol

In the present study, the precipitation complexation method was used to prepare a complex of cannabidiol (CBD) with beta-CD. The effect of beta-CD-complexation on the sublingual absorption of CBD was studied in rabbits. A solid CBD/beta-CD inclusion complex was prepared by precipitation and the effect of complex formation on the dissolution rate of CBD was studied. The absorption of CBD (a 250 microg/kg dose of CBD in all formulations) after sublingual administration of solid CBD/beta-CD complex and ethanolic CBD solution, and after oral administration of ethanolic CBD solution, was studied in vivo in rabbits. The dissolution rate of solid CBD/beta-CD complex in vitro was significantly (p<0.05) higher than that of plain CBD. The absorption of CBD (AUC0-300 min) decreased in the following order: sublingual ethanolic CBD solution (420+/-120 ngxmin/mL; mean+/-SD; n=4)>sublingual solid CBD/beta-CD complex (270+/-120 ngxmin/mL)>oral ethanolic CBD solution (concentrations in plasma below the quantitation limit). The results demonstrate that sublingual administration of a solid CBD/beta-CD complex enhances the absorption of CBD in rabbits when compared to oral administration of ethanolic CBD. Furthermore, the solid CBD/beta-CD complex may provide an alternative formulation for sublingual administration of CBD.