Science for product makers: What is the relationship between emulsion droplets and the Blood Brain Barrier?

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As the applications of cannabis emulsion become more popular, a discussion has emerged surrounding this question: Do smaller droplets help cannabinoids pass the Blood Brain Barrier (BBB) more efficiently than larger droplets?

Based on a recent survey, the majority of people believe smaller droplet sizes help cannabinoids pass the BBB.

Therefore it may surprise you that, scientifically, those two items have no direct relationship. Let me explain.

My first post discussed how cannabinoids get absorbed in the small intestine when consuming cannabis emulsions. Let’s use THC as an example. The analogy goes like this: imagine a THC emulsion droplet as a bus and THC as the passengers. When it reaches the small intestine, the bus transfers passengers into a smaller vehicle called mixed micelle, which then gets absorbed in the small intestine.

As the THC gets transferred into mixed micelles, the emulsion droplets are disassembled: emulsifiers get displaced by bile salts and the carrier oil gets decomposed by enzymes. So in short, the job of the emulsion droplet is complete after this phase.

After THC is absorbed into the small intestine by mixed micelle, it will likely go through the lymphatic system or liver. Eventually the THC flows into the bloodstream, where it reaches every organ within the body, including the brain. At this point — long after the emulsion droplets have completed their job — the THC encounters the Blood Brain Barrier (BBB), the brain’s natural protector. The BBB only allows certain molecules — like THC — to pass through and blocks everything else (source). I will deliver a more detailed THC journey in a future post.

Fun fact: The highly selective permeability of the BBB poses a big challenge when developing effective medicine for Alzheimer’s and Parkinson’s diseases.

In conclusion: emulsion droplet size has no direct relationship in helping cannabinoids pass through the Blood Brain Barrier

To sum it up, emulsion droplets can speed up cannabinoids’ absorption in the small intestine through epithelial cells, making cannabinoids more available in the bloodstream. But it is totally up to the cannabinoid’s chemical structure to pass through the BBB. Because the emulsion droplet’s job is complete before the THC is even absorbed into the small intestine, small droplets do not help cannabinoids pass the BBB.

Dr. Harold Han — the “Happy Chemist” — combines his storied background in emulsion chemistry and science with curiosity and fascination in the rapidly growing cannabis industry. Developing nano and micro emulsions his entire career, Harold holds a Ph.D in Surface Chemistry from NYU and is the author of multiple patents in emulsion chemistry.

As the Chief Science Officer at Vertosa, Harold spearheads the company’s development of industry-leading and customized active ingredients for infused product makers, offering pre-suspended aqueous solutions to create incredibly homogenous and stable products while maximizing bioavailability, clarity, and taste.

To learn more about the science of cannabis, check out Harold’s Happy Chemist videos.