Liposomal Carriers and Cannabinoid Absorption

What Is a Liposome?

A liposome is a vesicle with a spherical shape. It has a membrane composed of a phospholipid layer. It plays a vital role in drug delivery or delivery of genetic materials into the cell. Liposomes can be composed of naturally derived phospholipids with mixed lipid chains (such as egg phosphatidylethanolamine) or of pure components like DOPE (dioleoylphosphatidylethanolamine). The lipid bilayer has the ability to fuse with other lipid bilayers (the cell membrane for instance), hence delivering the contents of the liposomes.

Why Liposomes Are So Great

Liposomal technology is an effective and innovative method of delivering nutrient through supplementation. Liposomes are made of phospholipids. These phospholipids are the major building blocks of cell membranes. Because of this, it is very easy for liposomes to bind with cell membranes to deliver drugs or nutrients to the intracellular environment. Because of this enhanced absorption and delivery, nutrients or drugs delivered at lower doses via liposomal forms possess equal or greater efficacy than the higher doses provided in forms that are not readily bioavailable. Basically, liposomes provide a carrier around the drug or nutrient that facilitates absorption of that nutrient or drug by the body. 

How Liposomes Work

A liposome consists of a core of aqueous solution surrounded by a hydrophobic membrane. Hydrophobic solutes that get dissolved in the core do not have the ability to pass through the bilayer. The bilayer associates with hydrophobic chemicals. Thus, a liposome can be loaded with hydrophilic or hydrophobic molecules. For the molecules to be delivered to the site of action, the lipid bilayer can fuse with the cell membrane or other bilayers, thus delivering the liposome contents. However, this is a non-spontaneous and complex event.

By preparing liposome in a drug or DNA solution (which normally would not be able to diffuse through the membrane), they can easily be delivered past the lipid bilayer and then distributed non-homogeneously.

Helping Cannabinoids Bypass the Stomach

Cannabidiol (CBD), tetrahydrocannabinol (THC), and other cannabinoids do not have a high bioavailability. CBD is poorly absorbed through the skin’s upper layers. The same applies when it is administered orally. Studies have shown that just five percent of CBD entering the stomach is absorbed, compared to 30 percent of absorption when the derivatives of cannabis are smoked or vaporized.

Almost all fat absorption occurs in the small intestines as the last phase of the digestion process. Cannabinoids have a high solubility in fats and oils, and cannabis extracts are taken in very small amounts, at times on empty bowels. A small amount of cannabinoid oil or any other cannabis preparation is absorbed via the mouth into the blood, but only ingestion of food can kick-start the digestive process, and the cannabinoid will likely be expelled out of the body without being absorbed.

Cannabinoids can be oxidized and degraded by various enzymes. When encapsulated in liposomes, degradation is limited. Liposomes enhance oral absorption of THC and cannabinoids, bypassing the degrading effects that digestive secretions have on cannabinoids, and having them transported through the intestinal membrane. A liposomal cannabinoid preparation also allows more precise and consistent dosing.

The Effect on Topical Cannabis Preparations

Patients who use topical cannabis preparations can benefit greatly from liposomal formulas. Animal studies focused on mice have shown that administration of cannabinoids in a liposomal form gave rise to a significant accumulation of the substance within the underlying muscles and the skin. This and other studies have shown that salves and skin creams containing cannabinoid liposomes permit the deep penetration of CBD into the epidermis.

Both oral and dermal preparations can include liposomes to achieve a more efficient way to consume cannabinoids because they enhance the delivery of high concentrations of CBD and other active ingredients. With this augmented bioavailability, the amount necessary for users to reach an optimal dose can be changed.

The Effect on the Pulmonary Administration of THC Liposomes

The effect of liposomal delivery of THC administered via the pulmonary route was studied using animals. The study was titled PHARMACOKINETICS OF LIPOSOMAL ẟ9 TETRAHYDROCANNABINOL. According to the researchers, pulmonary liposomal THC has some merits over smoking cannabis derivatives and oral THC. It is easy to administer, has no need for a functional bowel, it skips the hepatic first-pass effect, and the exposure to other chemicals that are present in the cannabis extracts of flowers.

Conclusion

Without a doubt, it is believed that the cannabis industry’s use of liposomal carriers will grow rapidly in the next 5 to 10 years. This is possible due to the many benefits that it confers including:

• Allowing for adjustment and incremental dosing.
• Cost-effectiveness by being able to consume a lower dose for a similar effect.
• Increased intracellular delivery.
• Microencapsulation which protects against the harsh environment of the gastrointestinal tract.
• High absorption and bioavailability compared with other forms of administration.

References

Sercombe, Lisa et al. Advances and Challenges of Liposome Assisted Drug Delivery. Front Pharmacol. 2015; 6: 286. Web. Accessed 20 October 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4664963/