cannetix Inc
Well-Known Member
Greetings RIU Community!
While reading through some journals today I stumbled across the following study pertaining to the absorption of drugs through the sublingual mucosa (the mucous membrane located under the tongue).
http://www.ijppsjournal.com/Vol3Suppl2/1092.pdf
It suggests;
"The absorption potential of the oral mucosa is influenced by the lipid solubility and therefore the permeability of the solution (osmosis); the ionization (pH); and the molecular weight of the substances. For example, absorption of some drugs via oral mucosa is shown to increase when carrier pH is lowering (more acidic) and decrease with a lowering of pH (more alkaline)"
Sublingual administration of Cannabis is generally achieved with a "tincture" that is held under the tongue, consisting of either Alcohol, Glycerol (Glycerine) or a Lipid (Fat/Oil). Due to the fact that none of these compounds, in their pure form, have a "Ph." - the question is this.
Can, by mixing, or in the case of oils, emulsifying the tincture with water of varying Ph. levels, can we effectively adjust the Ph. of the carrier and adjust the absorption rate of Δ9-THC and other "actives"?
My quest to answer this question leads me to this study submitted in AAPS PharmSciTech, the official, peer-reviewed journal of the American Association of Pharmaceutical Scientists. It suggests;
"As 95% of all drugs have ionizable groups, distribution coefficient (logD) that considers the extent of ionization, as well as intrinsic lipophilicity, may be a better descriptor that reflects the partitioning of a mixture of drug species as well as the actual drug lipophilicity at any given pH"
Due to the fact that Δ9-THC has no ionizable group, the lipophilicity of the solution at any given Ph may indeed be the major factor to absorption in this case. Δ9-THC is a highly lipophilic molecule on its own (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3570572/) but when dissolved in solution its lipophilicity is altered.
The high lipophilicity of Acids and low lipophilicity of bases suggests that the absorption of a tincture may be improved by raising Ph. of the carrier (making it more "alkaline" or "basic").
Again, because pure Ethanol, Glycerol, Lipids, etc. do not have a Ph. this would have to be achieved by mixing or emulsifying the solution with water that has an alkaline Ph.
However...
Due to the high lipophilicity of water, this may not be ideal for tinctures made with substances miscible with water including alcohol and glycerine. Instead, it may be possible to use an emulsification of an oil-based tincture with alkaline water to improve absorption through the sublingual mucosa.
According to the following link;
http://petrowiki.org/Stability_of_oil_emulsions
Alkaline (basic) solutions tend to form oil-in-water emulsions rather than the water-in-oil emulsions created by acidic solutions. The water component of the oil-in-water emulsion may itself act as a "carrier" for the oil, which is the carrier for Δ9-THC and other Cannabinoids. Furthermore, due to the low solubility of Δ9-THC in water vs. lipids Δ9-THC would remain highly concentrated within the emulsified oil. Due to the fact that water is miscible with Alcohol and Glycerol, dissolved Δ9-THC would be dispersed throughout the solution. An emulsion is not a solution and is not a homogenous mixture.
A side note about an Interesting "permeation enhancer" I came across during this research
The following link;
https://link.springer.com/article/10.1023/A:1015314314796?LI=true
States that;
"Transdermal delivery of highly lipophilic drugs can be realized by using the permeation enhancer combination propylene glycol-lauric acid" (The same study suggesting the best ratio for this mixture being 9 : 1)
Lauric acid is a major component of coconut oil, while propylene glycol is chemically very similar to vegetable glycerine or Glycerol. It is possible that the correct ratio of Glycerol : Coconut oil might provide the same permeability-enhancing effects to Cannabinoids dissolved in solution.