Scientists Working on More Efficient Way to Deliver CBD
A team of scientists is working on a new delivery method that would use tiny capsules for getting cannabidoil, or CBD, to the brain.
According to a study in mice, microcapsules containing cannabidiol can be combined with vesicles carrying a bile acid — an acid found in the gut — that boosts absorption. The combination was found to deliver CBD into the brain much more effectively than CBD capsules alone, or the therapy in liquid form.
“Our team was able to significantly improve the absorption and brain delivery of cannabidiol by administering it in a novel microcapsule form, in combination with a naturally occurring bile acid,” Ryusuke “Ryu” Takechi, PhD, the study’s senior author, said in a press release.
With this combined approach, which uses a bile acid called deoxycholic acid (DCA), the researchers were able to “improve the brain delivery of cannabidiol remarkably by 40 times,” Takechi said.
It also protected CBD “from oxidation and degradation by light, which helps extend product shelf-life,” he added.
These findings suggest that this new CBD delivery method could be used to treat multiple sclerosis (MS) and other neurological disorders such as Alzheimer’s disease, as well as traumatic brain injuries.
“Further research is needed to test whether this type of [therapy] delivery method could be successful in human studies, but our findings are very promising,” said Takechi, an associate professor at the Curtin Health Innovation Research Institute and the school of population health at Curtin University, in Australia.
The study, “Sodium alginate microencapsulation improves the short-term oral bioavailability of cannabidiol when administered with deoxycholic acid,” was published in the journal PLOS ONE.
CBD, the major non-psychoactive cannabinoid or active component in the cannabis plant, is suggested to have anti-inflammatory, antioxidant, neuroprotective, and immunomodulatory properties. As such, cannabidiol has gained increasing interest as a potential treatment for several neurological diseases, such as MS.
Notably, GW Pharmaceuticals’ CBD-containing nasal spray Sativex was found to reduce the pain and severity of involuntary muscle contractions (spasticity) in MS. It is approved in Europe and other regions as an add-on treatment for adults with moderate to severe, resistant MS spasticity.
However, CBD is highly sensitive to light and lipophilic — meaning it dissolves much more easily in fatty molecules or oils than in water-based solutions. Moreover, it is poorly absorbed by the gastrointestinal tract, resulting in low oral bioavailability in blood and tissues. Oral bioavailability is the extent to which a medication taken by mouth can be used by the body.
“Due to limitations in absorption, we aimed to design and test a new drug delivery method” for CBD, Takechi said.
Takechi and his team, along with colleagues at other universities in Australia, evaluated the efficacy of a new encapsulated form of CBD, as well as its combination with vesicles filled with an absorption-booster bile acid, in a study using healthy mice.
The study was funded by Zelira Therapeutics, an Australian pharmaceutical company focused on the development of cannabis-based products for a variety of medical conditions.
The new encapsulated form of CBD involves tiny vesicles made of a brown algae component, sodium alginate, that were previously shown to significantly increase the brain uptake and associated neuroprotective effects of another lipophilic therapy in mice.
Bile acids are carriers of fatty molecules and are produced to help break down and absorb dietary fats in the gut. One of these bile acids, DCA, was shown to improve the absorption of lipophilic therapies with low intestinal rates of dissolving. As such, DCA is being evaluated as a potential natural absorption-booster molecule for several therapies.
Mice received one of three oral regimens: a combination of CBD-filled vesicles and vesicles containing DCA, CBD-filled vesicles alone, or cannabidiol oil.
The results showed that mice given the combination approach had a 40% or greater increase in cannabidiol levels in the blood compared with those receiving CBD vesicles alone, or CBD oil.
The combination of CBD- and DCA-filled capsules also was associated with greater levels of cannabidiol in the brain of mice — 48% greater relative to CBD vesicles alone and 25% greater compared with CBD oil.
In addition, brain CBD levels peaked at 18 minutes after treatment, with a 300% increased availability compared with the other two regimens, which peaked at one hour after administration.
While none of these differences reached statistical significance, these early findings suggest that the combination approach “increased the short-term bioavailability of CBD in [blood] and brain,” the researchers wrote.
This may be due to a vesicle-associated protection of CBD “from oxidation, degradation by light, and acidic digestion within the stomach, enhancing the absorption through the [gastrointestinal] tract,” they added.
This helped improve the bioavailability of the CBD, the researchers found.
In addition, “we were able to show for the first time that a bile acid actually increased the uptake and retention of cannabidiol within the brain,” Takechi said, adding that bile acids “could be used to enhance the delivery of cannabidiol when taken orally, particularly when treating neurological disorders.”
Oludare Odumosu, PhD, Zelira’s CEO, said he was “delighted” by the outcome of the collaboration between Takechi and his team.
“The new encapsulation technology appears to significantly improve the efficiency with which cannabinoid-based [therapies] can be delivered into the brain,” Odumosu said. “This could lead to improvements in the effectiveness of cannabinoid therapies to treat neurological disorders while reducing cost and enhancing safety.”