Ultrasonic Cannabis Oil Nanoemulsions
- Cannabinoids such as THC, CBD etc. are lipophilic (= hydrophobic) and thereby hardly to disperse in water-based formulations.
- Ultrasonic homogenizers are powerful emulsifiers, so that they are widely used to produce stable nano-emulsions of cannabinoids in water or any aqueous phase.
- The ultrasonic production of cannabis oil-emulsions (o/w) is an easy and fast procedure, which convinces by optimum results.
Cannabis oil emulsions are produced to formulate cannabinoid suspensions for cannabis-, hemp-, THC- or CBD-based products such as tinctures, capsules, lotions, and e-cigarette vape cartridges. Cannabinoids are not soluble in water, but show a good solubility in non-polar solvents such as oils and fats. To overcome the immiscibility of cannabinoids in water, a suitable emulsification technique is required. Ultrasonic cavitation is well-known and well-established technique to produce fine-sized, stable emulsions (o/w, w/o, w/o/w, o/w/o micro- and nanoemulsions).
Oil: Vegetable oils such as olive or coconut oil assist the absorption of the active substances of cannabis into the digestive system. Cannabinoids such as CBD and THC can hardly be absorbed without oil or fat. To achieve an optimal absorption, cannabis extracts are mostly mixed into oil and then further processed into an emulsion.
Emulsifier: Lecithin, which is available in powder, granules and liquid form, is an emulsifier, which is approved for food and medical products. For cannabis oil emulsions, lecithin is one of the most common emulsifiers. Other emulsifiers, which give good effects are gum arabic or starch-based emulsifiers.
How to Prepare a Cannabis Emulsion with Sonication
In order to prepare stable CBD nano-emulsions, a mix of Polysorbate 80 and Lecithin works very well. There is no need to buy overpriced pre-mixes as both additives are easily available in food-grade.
- Polysorbate 80: also known/sold as Alkest TW 80, Scattics, Canarcel, Poegasorb 80, Montanox 80, Tween 80
- Lecitin: Lipoid is a manufacturer of high-quality lecithin.
For 2wt% CDB oil in water use: 2wt% CBD oil, 2wt% Polysorbate 80, 1wt% Lecithin, 95wt% water
For 5wt% CDB oil in water use: 5wt% CBD oil, 3.3wt% Polysorbate 80, 1.7wt% Lecithin, 90wt% water
Ultrasonic energy requirement: approx. 300 to 400Ws/g of sonication energy at amplitudes of 40 to 70 micron.
- Oil Mixture: For the preparation, the hash oil (e.g. BHO) is premixed with olive oil before preparing the emulsion. Therefore, approx. 10mL of hash oil is mixed into 40mL of olive oil.
- O/W-Emulsion: In order to prepare the cannabis oil emulsion, take a beaker with approx. 100mL of water. As emulsifier, approx. 10-15 grams of liquid soy lecithin are added. The water should have room-temperature. Place the water beaker in a water bath in order to control temperature during sonication. The sonotrode of the UP400St is immersed into the beaker with water. For sonication, 50% amplitude is setted. The hash oil/olive oil mix is slowly poured into the 100mL of room-temperature water while sonicating the water to form an emulsion. Even better results are obtained, when the oil is pipetted with an eyedropper directly beneath the sonotrode.
For larger scale setups the use of an InsertMPC48 is recommended to inject the CBD oil directly into the cavitational area.
Ultrasonic cavitation is well-known as a reliable method to prepare superior emulsions in the nano range. Emulsions with turbidities (microemulsions, approx. 150-100nm) become clear and transparent or even translucent when sonicated since the droplet size is minimized to diminutive droplets in the range of approx. 10nm. Thereby, emulsion stability is increased significantly, too. Ultrasonically produced emulsions are often self-stable without addition of an emulsifier or surfactant.
For cannabis oil, a nano emulsion has besides its stability the additional advantage that the cannabinoids are better absorbed and have a more profound effect. This means that the cannabis product can be lower dosed to get the same effects.
Ultrasonification is widely used to produce liposomes as pharmaceutical and cosmetic vesicles. Liposomes are lipid-based nanocarriers for active drug components, which improve the bioavailability and therapeutic effects of the active substances such as CBD or THC. Since cannabinoids are really delicate molecules, they are prone to degradation by oxidization as well as to degradation by different enzymes. When encapsulated in liposomes, the cannabinoids are prevented against degradation.
By sonication, cannabinoids can be effectively encapsulated into liposomes.
Click here to read more about liposomal encapsulation of active substances!
In order to produce long-term stable oil-in-water (o/w) nanoemulsions, it is necessary to use a suitable surfactant or to form liposomes to encapsulate the lipophilic bioactive compounds into a carrier oil. For cannabis oil, the carrier oil should have food quality and not interfere with appearance, taste, and stability of the final product. Coconut oil and olive oil are widely used as carrier oils for cannabinoids.
Carrier oils are a very important factor to create a physicochemically stable emulsion since they may help to prevent the emulsion against Ostwald ripening. The Ostwald ripening is the driving force which destabilizes an emulsion by droplet coarsening. Long chain triglyceride nanoemulsions are long-term stable against Ostwald ripening. Olive oil and coconut oil contain long chain triglycerides, so that both, olive and coconut oil are a preferred carrier oils.
Hielscher Ultrasonics is the leading supplier for powerful and reliable ultrasonic systems – from lab and bench-top devices to full industrial machines for the processing of large volumes under demanding conditions. Our ultrasonic devices are used for emulsification, homogenization and extraction in the food & beverage as well as in the pharmaceutical & cosmetic industry.
The table below gives you an indication of the approximate processing capacity of our ultrasonicators:
Facts Worth Knowing
Nanoemulsions, also known as miniemulsion or submicron emulsion, are emulsions with a droplet size between 20-500nm. A nanoemulsion is a thermodynamically stable isotropic system, which consists in two immiscible liquids (e.g. oil and water). One of the two immiscible liquids is dispersed very fine into the second phase in order to form a single phase. Emulsifiers, e.g. surfactants and co-surfactants are added to stabilize the emulsions by preventing the coalescence of the droplets. The main difference between an emulsion and a nanoemulsion is determined by the size and shape of particles/droplets dispersed in the continuous phase. Ostwald ripening is the major destabilization mechanism in nanoemulsions. Ostwald ripening is a diffusion degradation process, which means that an inhomogeneous structure such as an emulsion changes over time. The emulsion droplets increase over time as the smaller droplets dissolve and redeposit their material onto the larger droplets.
The oil type has major influence on the intensity and rate of Ostwald ripening. This means that the choice of a suitable oil can affect the emulsion stability significantly.
Nanoemulsions show an improved delivery of active ingredients (e.g. drugs).
About Butane Hash Oil (BHO)
Hash oil is produced by solvent extraction, e.g. ultrasonic extraction, ultrasonically-assisted supercritical C02 extraction etc. For the production of hash oil, preferably dry, decarboxylated plant material is used. As solvents for extraction the following liquids are frequently used: chloroform, dichloromethane, petroleum ether, naphtha, benzene, butane, methanol, ethanol, isopropanol, and olive oil. By the use of non-polar solvents such as benzene, chloroform and petroleum ether, the water-soluble constituents of marijuana or hashish cannot be extracted so that a more potent oil is obtained. Cannabis extracts that have been extracted with non-polar solvents are known to taste much better than extracts obtained with polar solvents. Extracts are often washed with alkali to improve the odor and taste.
Hash oil should be stored in an airtight container and protected from light. When exposed to air, warmth and light (especially when formulated without antioxidants), the oil loses its taste and psychoactivity due to aging.
There are at least identified 113 types of cannabinoids in cannabis. Cannabinoids are active phytochemical substances that are used for their psychoactive and/or medical effects. THC or tetrahydrocannabinol is the primary psychoactive compound in cannabis. CBD or cannabidiol is another important ingredient which is used for its therapeutic effects. Cannabinoids are lipophilic and potentially acid-labile compounds. Cannabinoids are insoluble in water, but they are very soluble in non-polar solvents (e.g. fat and oil). To improve the digestion of cannabinoids, the cannabis extracts is mostly mixed into carrier oils.