Nowadays, there is an increased interest in natural medicines. Cannabis (Cannabis sativa) has been used for various purposes for thousands of years – as an economic plant, for recreational and medical purposes. Natural cannabinoids are known for numerous effects, including positive therapeutic effects: they act as analgesics, antiemetics and they relieve problems and symptoms in neurological disorders and anorexia.
In the master's thesis we dealt with micellar solubilization of cannabinoids from industrial hemp. We were interested in the influence of various types of surfactants on the physical properties and stability of micellar solutions. The selected solutions were physically evaluated by photon correlation spectroscopy and we also observed changes in their appearance over a longer period of time. We used oil and alcoholic cannabinoid extracts and during the preparation of the solutions, we came to the conclusion that the most suitable one is alcoholic extract (CBD = 50 mg/g, THC < 1,9 mg/g).
With the experimental work, we found out that the selection of the organic cosolvent (ethanol, glycerol) has an effect on the average diameter of the micelles. The cannabinoid extract was successfully solubilized with Softigen® 767, and a combination of block copolymer (Lutrol® F 127) and anionic surfactant (Tween® 80). Clear solutions with a micelle size of 10 – 20 nm were formed. Solubilization was not successful using bile salts and other anionic surfactants (sodium laurly sulfate), opalescent solutions were formed. The same result was obtained with natural emulsifiers (lecithin, arabic gum, modified starch) and β-cyclodextrin. With these experiments, we came to the conclusion that Tween® 80 is crucial for the solubilization of the cannabinoid extract. At the end we tested a combination of synthetic (Tween® 80) and natural (arabic gum) surfactant. After changing the process and the recipe, a clear micellar solution was formed.
Based on results we have come to the conclusion, that the correct choice and combination of surfactants, and also optimization of the formulation is crucial for successful micellar solubilization of cannabinoids.
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