Antinociceptive activity of Δ9-tetrahydrocannabinol non-ionic microemulsions

Deformable Vesicles with Edge Activators for the Transdermal Delivery of Non-Psychoactive Cannabinoids

BACKGROUND

Transdermal delivery of highly lipophilic molecules is challenging due to the strong barrier function of the skin. Vesicles with penetration enhancers are safe and efficient systems that could improve the transdermal delivery of non-psychoactive cannabinoids such as cannabidiol and desoxy-cannabidiol. In the last decades, research interest in desoxy-cannabidiol as a potent drug with anti-nociceptive properties has risen. Still, its scarce market availability poses a limit for both research and clinical applications. Therefore, it is necessary to improve the synthesis to produce sufficient amounts of desoxy-cannabidiol. Moreover, also the formulation aspects for this drug are challenging and require to be addressed to meet an efficient delivery to the patients.

OBJECTIVE

This work aimed to develop innovative phospholipid-based vesicles with propylene glycol (PG), oleic acid (OA), or limonene as edge activators, for the transdermal delivery of highly lipophilic drugs such as non-psychoactive cannabinoids. In particular, desoxy-cannabidiol was selected thanks to its anti-nociceptive activity, and its synthesis was improved enhancing the stereoselectivity of its synthon's production.

METHODS

Desoxy-cannabidiol was synthesized by Lewis acid-mediated condensation of p-mentha-2,8-dien- 1-ol and m-pentylphenol, improving the stereoselectivity of the first synthon's production. Transethosomes containing 20-50% w/w PG, 0.4-0.8% w/w OA, or 0.1-1% w/w limonene were optimized and loaded with cannabidiol or desoxy-cannabidiol (0.07-0.8% w/w, 0.6-7.0 mg/mL). Ex-vivo studies were performed to assess both the skin permeation and accumulation of the cannabinoids, as well as the penetration depth of fluorescein- loaded systems used as models.

RESULTS

An enantioselective bromination was added to the pathway, thus raising the production yield of pmentha- 2,8-dien-1-ol to 81% against 35%, and the overall yield of desoxy-cannabidiol synthesis from 12% to 48%. Optimized transethosomes containing 0.6 mg/mL cannabinoids were prepared with 1:10 PG:lipid weight ratio, 0.54 OA:lipid molar ratio, and 0.3 limonene:lipid molar ratio, showing good nanometric size (208 ± 20.8 nm - 321 ± 26.3 nm) and entrapment efficiency (> 80%). Ex-vivo tests showed both improved skin permeation rates of cannabinoids (up to 21.32 ± 4.27 μg/cm2 cannabidiol), and skin penetration (depth of fluorescein up to 240 μm, with PG).

CONCLUSION

Desoxy-cannabidiol was successfully produced at high yields, and formulated into transethosomes optimized for transdermal delivery. Loaded vesicles showed improved skin penetration of desoxy-cannabidiol, cannabidiol and a lipophilic probe. These results suggest the potential of these carriers for the transdermal delivery of highly lipophilic drugs.

Emulsion, hydrogel and emulgel systems and novel applications in cannabinoid delivery: a review

Emulsions, hydrogels and emulgels have attracted a high interest as tools for the delivery of poorly soluble hydrophobic nutraceuticals by enhancing their stability and bioavailability. This review provides an overview of these delivery systems, their unique qualities and their interactions with the human gastrointestinal system. The modulation of the various delivery systems to enhance the bioavailability and modify the release profile of bioactive encapsulates is highlighted. The application of the delivery systems in the delivery of cannabinoids is also discussed. With the recent increase of cannabis legalization across North America, there is much interest in developing cannabis edibles which can provide a consistent dose of cannabinoids per portion with a rapid time of onset. Indeed, the long time of onset of psychoactive effects and varied metabolic responses to these products result in a high risk of severe intoxication due to overconsumption. Sophisticated emulsion or hydrogel-based delivery systems are one potential tool to achieve this goal. To date, there is a lack of evidence linking specific classes of delivery systems with their pharmacokinetic profiles in humans. More research is needed to directly compare different classes of delivery systems for the gastrointestinal delivery of cannabinoids.

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.

Is 2-Hydroxypropyl-β-cyclodextrin a Suitable Carrier for Central Administration of Δ9 -Tetrahydrocannabinol? Preclinical Evidence

Preclinical Research Δ⁹ -Tetrahydrocannabinol (THC) is a hydrophobic compound that has a potent antinociceptive effect in animals after intrathecal (IT) or intracerebroventricular (ICV) administration. The lack of a suitable solvent precludes its IT administration in humans. 2-Hydroxypropyl-β-cyclodextrin (HPβCD) increases the water solubility of hydrophobic drugs and is approved for IT administration in humans. To investigate whether HPβCD might be a suitable carrier for ICV administration of THC in rats, two formulations containing THC complexed with HPβCD (30 and 135 μg of THC per animal) and vehicle were administered to Wistar rats. The antinociceptive effect (using the tail flick test), locomotor activity, and body temperature were evaluated. ICV injection of 135 μg of THC/HPβCD complex increased tail flick latency, reduced locomotor activity, and had a dual effect on body temperature. The 30 μg THC/HPβCD formulation only produced a hyperthermic effect. All animals appeared healthy, with no difference between the groups. These results were similar to those obtained in other preclinical studies in which THC was administered centrally using solvents that are unsuitable for IT administration in humans because of their toxicity. Our findings suggest that HPβCD may be a useful carrier for IT administration of THC in humans. Drug Dev Res 78 : 411-419, 2017. © 2017 Wiley Periodicals, Inc.