A big hurdle for drugs that act on the brain is the blood-brain barrier (BBB), a fortress-like wall that guards your precious central nervous system against pathogens, toxins, and other larger molecules. It’s there to protect us, and it does a relatively good job, but it can also block out useful molecules, such as medicinal drugs.
However, scientists have found a potential new way to sneak drugs past this blood-brain barrier. The drug is attached to cannabidiol (CBD), a non-psychoactive compound in cannabis, which essentially acts as a Trojan horse.
The blood-brain barrier is a highly selective semipermeable layer of tightly linked cells that line capillaries in the brain to prevent certain cells, particles, and molecules from entering the brain and central nervous system. It was first discovered in the late 19th century when the German physician Paul Ehrlich injected a dye into the bloodstream of a mouse and noticed that all tissues became dyed except the brain and spinal cord.
Other research has used similar nanotechnology to get around the BBB, but CBD is a particularly desirable candidate as it’s non-toxic, with no known fatal overdose levels, and relatively well tolerated by most folks. As the results of this experiment show, it seems to be pretty effective at the job too.
Writing in the journal Molecular Pharmaceutics, pharmacologists from the Complutense University of Madrid believe their new CBD-based method could potentially be used to treat diseases that affect the central nervous system, such as Alzheimer’s disease and schizophrenia.
Bear in mind, this doesn’t mean you can simply take some CBD oil with other drugs and expect them to reach your brain. For this study, the researchers had to engineer specific CBD-nanocapsules.
The team attached CBD, which can easily nip through the blood-brain barrier, to the outside surfaces of lipid nanocapsules. These nanocapsules, in theory, could be loaded with medication, but the researchers packed them with a fluorescent molecule so they could track whether they made it into the brain. After injecting mice with the CBD-nanocapsules, the team was able to detect the fluorescent molecule in the animals’ brains, showing it had passed the barrier. They also tested out the method on human brain cells in a petri dish that mimics the blood-brain barrier, which also proved to be successful.
Importantly, the study authors argue that their CBD-based method “outperformed by six-fold” the leading method of drug delivery to the brain, known as G-Technology, that’s being trialed to treat diseases of the central nervous system.