With a number of therapeutic benefits but none of the legal restrictions of THC, CBD is quickly becoming a popular health supplement. Even parents are partaking.
Taken orally, CBD oil tinctures are the most common formulation on the market. Unfortunately, our bodies don’t metabolize CBD oil very well. Less than 20% of ingested CBD oil winds up in the bloodstream. However, researchers have found a new way to increase the speed and absorption of CBD.
CBD: A Very Popular Cannabinoid
Cannabidiol or CBD is one of the major cannabinoid compounds found in the cannabis plant. Unlike THC, the other major cannabinoid, CBD doesn’t cause intoxication.
But that doesn’t mean CDB is inactive. It interacts with a host of different cellular effectors, including the two primary cannabinoid receptors, CB1 and CB2. As a result, CBD can bring about a number of changes throughout the body. It can act as an anti-inflammatory and anti-convulsant, help people get a better night’s sleep, and has been shown to relieve pain.
As a testament to its efficacy, the US FDA approved Epidiolex, an oil preparation of CBD, for treating seizures caused by Lennox-Gastaut syndrome and Dravet syndrome in June 2018.
One Problem With Consuming Cannabidiol
CBD is a highly lipophilic molecule. This means that CBD prefers to mix with lipids or fats instead of water. That’s why CBD is usually offered in the form of an oil that patients and consumers can take orally.
Unfortunately, oral CBD (swallowed, vs. taken sublingually) has very low bioavailability. This means that only a small amount of ingested CBD will actually end up in the bloodstream and have an effect.
Taken this way, CBD bioavailability is less than 20%, with some estimates as low as 6%. There are several reasons for this, including low absorption. Additionally, CBD experiences the first pass effect. This occurs when enzymes in the gut and liver break down a drug before it can make it into the bloodstream.
That’s why researchers are eager to find better delivery methods for CBD.
Nanoemulsions: A New Drug Delivery Method
One promising method for improving CBD’s bioavailability is a nanoemulsion. Nanoemulsions are solutions that contain evenly distributed microscopic, insoluble particles within a mixture of water, oil and other substances that reduce surface tension and stabilize the mixture. Researchers have used nanoemulsions to increase the oral bioavailability of drugs with similar characteristics to CBD.
Can nanoemulsions also improve the bioavailability of CBD?
Scientists from the Showa University in Tokyo and the Mahidol University in Bangkok teamed up to answer this question. They published their results in the journal Medical Cannabis and Cannabinoids.
The researchers created an optimized nanoemulsion of CBD (CBD NE). The CBD NE contained:
- 99% pure CBD powder
- An oil phase consisting of vitamin E, ethanol, and Tween-20, a detergent frequently used to stabilize emulsions
- Distilled water
The researchers orally administered either CBD oil or the CBD NE to rats. They then collected blood samples over a period of 24 hours to examine CBD absorption.
CBD Nanoemulsion Increases Bioavailability
The CBD NE was very stable. The appearance and particle size of the mixture stayed the same even after six months of storage.
The rats absorbed the CBD NE much faster than the CBD oil. The CBD NE reached a maximal concentration in the blood after only 2 and a half hours compared to 8 hours for CBD oil.
From their data, the researchers calculated that the bioavailability of CBD oil was about 73% while the bioavailability of CBD NE was nearly 94%. Note that rats are able to metabolize CBD oil much better than humans (~73% bioavailability in rats vs 6-20% in humans). But an increase of 73% to 94% is still significant.
They also found that absorption of CBD oil relied on bile production while CBD NE did not. Bile production occurs in the liver and helps digest fats, including CBD oil. However, CBD NE absorption did not depend on bile production. CBD NE was most likely absorbed directly into the intestine without the help of bile, explaining its speedy absorption.
Although the study was short, the researchers didn’t report any major adverse side effects from the CBD NE.
From Rats to Humans
So what does this mean for humans?
While this study was performed in rats, the results are extremely promising. The researchers observed a significant increase in bioavailability using CBD formulated in a nanoemulsion.
The CBD NE that the researchers developed needs to be tested in humans in a clinical trial to see if it has a similar effect. It’s possible that the results could be even more striking in humans—we’re poor CBD metabolizers and have much more room for improvement.
Moreover, the CBD NE also increased the speed of CBD absorption. This could be very useful for patients seeking to treat pain and anxiety, two of the most common uses for CBD consumers.
This is the first study to create a nanoemulsion of CBD. This novel CBD formulation significantly increases the rate of absorption and the bioavailability of CBD in rats. Future studies should look at the effects of CBD nanoemulsions in humans.