In March of this year, Industrial Sonomechanics (ISM) hosted a webinar, entitled "Water-Compatible Nanoemulsions: The Battle of Formulations", presented by ISM's President and Chief Scientific Officer, Dr. Alexey Peshkovsky. The video recording of this event has been posted on our YouTube channel.
The webinar generated over 100 questions, some of which were addressed by Alexey during the event. The answers to the remaining questions are provided below. If you have any additional questions, please do not hesitate to contact us or leave a comment below.
Webinar Questions & Answers:
1. What is the refractive index of the powder stabilizer?
The approximate average refractive index of NanoStabilizer®-LSO is 1.4 (it is a mixture of several ingredients).
2. How many different surfactants are typically utilized to prepare a stable emulsion?
Typically, a combination of at least two correctly selected surfactants produces better results than one surfactant at the same HLB value (which should match the required HLB value of the oil phase that is being nano-emulsified). Having said that, when translucency is not required and general stability is the only requirement, one surfactant may be enough (e.g., Q-Naturale).
3. Can nanoemulsions be used to solubilize hydrophobic substrates in certain enzymatic reactions to catalyze a reaction in a water-based environment?
Chemical reactions limited by mass transfer (e.g., when hydrophilic and hydrophobic substances react with each other) can typically be accelerated by increasing the reagents' contact surface area via nano-emulsification of one of them (e.g., oil) in the environment of the other (e.g., water with an enzyme). One example of this type of process is the ultrasound-assisted production of biodiesel: https://drive.google.com/file/d/0B3kibDwaHXrNR3JSY1M3aGlkTEk/view
4. Can you comment on fully transparent dispersions vs. nearly transparent Rayleigh scattering (bluish glow to the dosed water)?
Translucent and transparent dispersions comprise particles that are all smaller than approximately 1/4 of the smallest wavelength of visible light. Violet light has the shortest wavelength, at around 380 nm, so when all particles in a dispersion are smaller than 100 nm, light scattering is reduced and the formulation becomes translucent. Unless the particles are all much smaller than 100 nm, some residual scattering remains after dosing into the water, mainly involving blue and violet light (hence the bluish glow). When all particles are much smaller than 100 nm (in the range of 25 - 30 nm), the dispersion becomes transparent after dosing into water (scattering is negligible).
5. Does dissolved oxygen play a role in the chemical stability of cannabinoids dispersed in an oil-in-water emulsion?
In general, it is best practice to avoid the exposure of any cannabinoid-containing product to oxygen in order to avoid degradation. Fortunately, a secondary effect of ultrasonic processing is degassing, which leads to a significant reduction of oxygen content in finished nanoemulsions. Thus, CBD-loaded nanoemulsions prepared with our technology and stored in dark-glass containers remain stable in terms of their CBD content over the course of many months: https://blog.sonomechanics.com/blog/6-frequently-asked-questions-about-nanostabilizer
6. Can you use a THC distillate (liquid) with the NanoStabilizer®-LSO to make a water-soluble powder or do you have to start with an isolate? Besides the nano-powder, what else do you need to make a tablet? Other fillers?
THC distillate (as most other plant-derived oils) can be used with NanoStabilizer®-LSO to prepare a liquid nanoemulsion, which can then be dried to form a powder. NanoStabilizer®-LSO contains all the required ingredients to allow the formation of such solid nanoemulsions (water-soluble powders), so nothing needs to be added at this stage. The resulting powders can be pressed into tablets directly, but are typically diluted with neutral fillers first in order to adjust the dosing. For more information on NanoStabilizer®-LSO, please visit: https://blog.sonomechanics.com/blog/nanostabilizer-simplifies-producing-water-soluble-powder
7. What can you say about the Ostwald ripening of the nanoemulsions?
Ostwald ripening is one of the most common destabilization mechanisms for nanoemulsions. It is a process where small oil droplets experiencing high interfacial pressures dissolve into the continuous phase and re-deposit onto larger droplets where the interfacial pressure is lower. As this process continues, small droplets are eliminated and larger droplets grow at their expense. In oil-in-water nanoemulsions, Ostwald ripening can be prevented by proper selection and optimization of carrier oil and surfactant types and concentrations. NanoStabilizer®-LT and NanoStabilizer®-LSO have specially selected and optimized ingredients that prevent Ostwald ripening in finished nanoemulsions.
Download NanoStabilizer® Products Comparison Chart:
8. Regarding the packaging of nanoemulsions, you've mentioned glass would be ideal. For plastic containers, is there any particular type of liner that's needed or material the plastic should be made of to maximize the stability of the nanoemulsion?
While glass containers are preferred, most non-transparent plastic containers are also appropriate for storing concentrated nanoemulsions (after they have been sonicated and filtered but before they are diluted in a beverage). For diluted nanoemulsions (e.g., in a finished beverage product) that cannot be stored in glass containers, the contact material should be carefully selected to ensure that the oil content is not diminished. Please contact ISM for consulting on this phenomena and potential solutions.
9. Will a nano THC applied topically be a transdermal product. Nano THC in aloe vera gel? Will that be transdermal?
Cannabinoid-loaded nanoemulsions can be gelled and incorporated into water-compatible transdermal products. When cannabinoids are simply dissolved in an oil, however, the resulting products tend to only have topical action (local, with no transdermal delivery into the bloodstream).
10. Would a transdermal be more effective as a nano-formulation?
Yes, it would. See, for example:
11. Does stomach acid impact the integrity of the nanoparticles?
According to in vitro studies, stomach acid does not significantly alter the integrity of correctly prepared nanoparticles. Consequently, nanoparticles are able to reach the small intestine, diffuse through lumen and improve the efficiency of absorption of the incorporated bioactives by enterocyte cells.
12. Have you guys explored Psilocybin for nanoemulsion? Can it be a powder or sap-like oil, would either work for nanoemulsion?
Psilocybin is a relatively hydrophilic alkaloid compound that dissolves in water and, therefore, does not need to be nano-emulsified. Having said that, aqueous ultrasound-assisted extraction of psilocybin is a very efficient process when utilizing ISM high-amplitude ultrasonic equipment. For further information on cell disruption and aqueous ultrasound-assisted extraction of bioactives, please see:
13. Regarding absorption rate, do you find that absorption rates of nanoemulsions increase sublingually vs. going through the small intestine for nutrient uptake? Or do you find that the absorption rate is roughly equivalent regardless of the way they are consumed?
We have not performed rigorous studies to determine the differences in the sublingual vs. intestinal absorption efficiencies for nanoemulsions. However, anecdotally, the efficiencies appear to be similar. Sublingual administration often garners interest as a method of circumventing the first-pass effect. Note that digestive administration of nanoemulsions accompanied by triglycerides is also known to circumvent the first-pass effect as it promotes lymphatic delivery that avoids the hepatic route.
14. Is processing required to test the active concentration in the emulsion?
Bioactive concentration testing in nanoemulsions is typically performed with HPLC. For nearly any HPLC analysis, an extraction step is required prior to performing the analysis. If you will be outsourcing bioactive concentration testing, it is advised to inform the company that they will be analyzing an oil-in-water nanoemulsion so that the proper extractant and mobile phase can be selected.
15. For analysis of the powder, what mobile phase do you recommend with HPLC?
This depends on the binder. Typically methanol works well, as long as you are able to disperse the powder in it in a way that ensures complete extraction of the bioactives from the nanodroplets distributed throughout the binder. Sonication followed by filtration is recommended.
16. Why should someone not intake the nanoemulsion directly?
Nanoemulsions can be taken directly if desired, however, they tend to be quite bitter at high bioactive concentrations. Nano-emulsification increases the cumulative surface area of bioactive oils by orders of magnitude, which makes them much more available to your taste buds. Even when no bitterness is perceived in the original extract or isolate, increasing the contact surface area by such a large factor will likely bring it out.
17. Can I separate the oil from the emulsion?
Yes, the oil phase can be separated from a nanoemulsion. This is generally achieved by thermal or chemical means.
18. What are the best preservatives, anti-fungicides, anti-bacterials?
We do not specify any particular preservatives, antifungal or antibacterial components for nanoemulsions. Most common options can typically be used without issues.
19. Do the dark glass containers need to be opaque or the typical amber glass?
Amber glass is acceptable.
20. In the preparation of the powder, what is the usual carrier? How is it dried?
NanoStabilizer®-LSO contains everything needed, including the carrier and binder, so you can directly dry the finished nanoemulsion. Spray drying is the most commonly used drying method, however, other methods may also work well.
21. How is the extract made into a nanoparticle water-soluble powder?
Nanoemulsion in the powdered form can be made by using our ultrasonic equipment, NanoStabilizer®-LSO, and a drying solution.
22. Does the power and frequency of the ultrasonic equipment degrade the chemical components of the nanoemulsions?
Ultrasonic equipment, including its power and frequency, does not degrade the chemical components of nanoemulsions.
23. Does emulsion remain stable if it is diluted - for example, if 4% is diluted to 2%.
Nanoemulsions can be diluted with water to any lower concentration with no loss in stability.
24. Will a finished product be stable in an aluminum can? What is your experience with stability in aluminum cans? Do you have a suggestion for the best can liner?
Aluminum can packaging may or may not create an issue. This question was addressed during the webinar. Please see timestamp 0:52:58 of the following webinar recording:
25. What is the effect of pH on nanoemulsions? Besides pH, what other factors can affect stability?
The behavior of correctly prepared nanoemulsions is pH- and ionic strength-independent in a fairly wide range, covering most beverages. For further information, please see: https://blog.sonomechanics.com/blog/how-to-formulate-a-cannabis-extract-nanoemulsion-with-a-predictable-shelf-life
26. Any suggestion for the best carrier oils?
The highest bioavailability after oral administration is typically obtained with carrier oils composed of LCTs (olive oil, coconut oil, etc.). Please see the following article for more information: https://blog.sonomechanics.com/blog/the-role-of-carrier-oils-in-water-soluble-cbd-and-thc-formulations
27. Hello I'm based in France, 50 km from Paris, and searching for a solution to mix CBD + honey, what do you propose for this? Have you tested nanoemulsion from vegetal extract + CBD + honey and how were the results?
Honey is a water-based product so nanoemulsions can be readily mixed into it. CBD and other oil-compatible plant extracts, including propolis, can be nano-emulsified and added to the honey in a similar manner. The recommended NanoStabilizer® type for this purpose is NanoStabilizer®-LT.
28. What is the shelf life?
NanoStabilizer®-LT has the shelf life of 1 year and should be stored at 4 - 10 C. A correctly prepared translucent nanoemulsion will exhibit permanent kinetic stability against oil-phase separation. To maximize its shelf life, sterilize your nanoemulsion using a 220 nm-pore filter and store it in a dark-glass autoclaved container at 4 - 10 C.
29. Will the nanoemulsion reduce the taste and odor of hemp extract?
It will not. Nanoemulsions will retain the taste and odor of the active ingredient (hemp extract in this case). As discussed in the webinar, however, there are ways to manage the bitterness. Please see time stamp 0:40:25 of the webinar recording:
30. Are surfactants safe to consume?
All NanoStabilizer® (both LT and LSO) ingredients are food-grade and safe to consume.
31. What's the highest concentration of CBD isolate that can be nano-emulsified using the ISP-3000 and NanoStabilizer®? What is the maximum feasible concentration of CBD oil per ml for a nanoemulsion? What is the max concentration in powder and water base?
This question was addressed during the webinar. Please see timestamp 0:54:11of the webinar recording:
32. How does microfluidics compare to sonication to achieve a good nano-emulsified product? Do you have experience with microfluidization as a method for nano-emulsification? How does this process compare to ISM’s processing capability?
Our technology significantly outperforms microfluidization. The independent review paper referenced below includes a direct numerical comparison of our Barbell Horn®-based ultrasonic processing and microfluidization techniques applied to nano-emulsification. Please see page 46, especially the last paragraph before the Conclusions section:
33. If no surfactants are needed to achieve a nano-emulsified product, what is the purpose of buying Industrial Sonomechanics' NanoStabilizer®?
Surfactants and carrier oils are always required for producing high-quality nanoemulsions.
34. Could you be more specific about the bioavailability of MCT oil and why you do not suggest using it as a carrier oil? Why is MCT not as effective as long-chain triglycerides?
Here is a good reference on this subject: Qian C, Decker EA, Xiao H, McClements DJ, Nanoemulsion delivery systems: influence of carrier oil on ß-carotene bioaccessibility, Food Chem. 2012 Dec 1;135(3):1440-7. doi: 10.1016/j.foodchem.2012.06.047. Epub 2012 Jun 29.
35. At what temperature ranges do nanoemulsions break down and become standard emulsions?
This question was addressed during the webinar. Please see timestamp 0:50:27 of the webinar recording:
36. Which equipment is used to measure the droplet size?
Nanoemulsion droplet sizes can be measured by Dynamic Light Scattering (DLS). The following webinar talks about nanoemulsion analysis techniques:
37. What is the name of the test to know the diameter on the nanoemulsion final product?
Please see the answer to question 36.
38. Will nanoemulsion Hemp lose potency over time in a container (aluminum can, bottle)?
This question was addressed in one of our previous webinars. Please see time stamp 0:52:58 of this webinar recording:
39. When comparing ultrasonic processing to high-speed shearing, what are the benefits/disadvantages of one vs. the other? Can you elaborate on why your technology and ultrasonic processing are superior?
High-speed mixers do not provide sufficient shear intensity to produce translucent nanoemulsions, where all droplets are smaller than 100 nm. These devices are typically used to make emulsions with droplets in the micron range. This question was addressed in more detail during our last webinar. Please see time stamp 0:50:23 of the webinar recording:
40. With the BSP-1200 in use and the NanoStabilizer also in use, our largest issue remains to be bitterness. What is the most effective way to combat bitterness?
This question was addressed during the webinar. Please see timestamp 0:40:20 of the webinar recording:
41. What should be put on the ingredient line for the stabilizers? Do you have an idea how to declare this NanoStabilizer® on the European market on the label?
A specifications sheet (with a list of NanoStabilizer®-LT ingredients) and a certificate of analysis are always provided with purchase. These documents are usually sufficient for our customers' labeling purposes.
42. Regarding contract manufacturing, can you do this with THC or just CBD? Do you have contract manufacturing in other states other than Florida?
This question was addressed during the webinar. Please see timestamp 0:52:39 of the webinar recording:
48. Quillaja saponin vs. soy lecithin as emulsifier?