Transdermal patches can be used to slowly deliver a substance such as CBD oil to a person over an extended period of time. Modern patches are odourless, discrete, long-acting and convenient, allowing in some cases for an alternative to inhalation, oral or suppository use.
The concept behind transdermal patches isn’t new.
Medicated plasters were in use in China 4,000 or so years ago.¹ A piece of cloth or paper would be coated with a combination of an adhesive made with natural gum rubber or tar and the desired medication. This ancient form of medicated band-aid would then be applied to bare skin.
In order for a substance to be a candidate for being administered via a transdermal patch, it must be able to be absorbed through the skin. In the case of nitroglycerin or nicotine, skin contact is all that is necessary.² In the case of cannabis-derived applications such as CBD oil, a carrier solvent such as dimethylsulfoxide (DMSO) or a surfactant-lecithin organogel may be used to facilitate the transfer.
Motion sickness prevention patches have been around since the mid last century, and in 1973 a patent was filed for a transdermal patch that dispensed nitroglycerin for the treatment of coronary artery disease.³ In 1984 nicotine transdermal patches were developed specifically as an aid to quit smoking. Patches have been developed for hypertension, female hormone replacement therapy, pain relief, and testosterone.
In March of 1998, Lawrence L. Brooke et al. filed patent number US 6328992 B1 for a “Cannabinoid patch and method for cannabis transdermal delivery”.4 This patent described using a transdermal patch for cannabinoids such as CBD. One complication to production has been that transdermal patches have traditionally been required to have FDA approval and the FDA has been recalcitrant in approving not only CBD oil transdermal patches but many other potentially useful cannabis products.
In December of 2014, Mary’s Medicinals filed patent number US 9375417 B2 for “Transdermal cannabinoid formulations”.5
Today, there are several companies offering cannabis patches in a variety of formulations, with various doses and amounts of CBD, THC, and THCa.
Use of CBD oil and other cannabis transdermal patches.
Since the active ingredients are slowly absorbed over a long (8-12 hour isn’t uncommon) period, this method eliminates the intense rush associated with more traditional airborne methods. Depending on the specifics, it may take an hour or two for the effects to be felt. Descriptions of the experience compare it to a long acting cannabis infused edible.
Unlike nitroglycerin or nicotine, the active ingredients in cannabis have a very low toxicity, tending to make an over-consumption event less dire. As such multiple cannabis patches can be used in concert to regulate a particular desired dosage. Even so, exercising moderation as circumstances dictate is generally recommended.
- Nitroglycerin was discovered to be permeable to human skin by workers handling explosives developing headaches known as “nitroglycerin head”. Safety protocols were changed to allow explosives handlers to work headache free, which is probably for the best.
- Zaffaroni A. 1973. Bandage for controlled release of vasodilators. US Patent 3,742,951, Alza Corporation.
- Lawrence L. Brooke is perhaps best known for founding the hydroponic nutrient manufacturer General Hydroponics in 1976. The patent can be found at https://www.google.com/patents/US6328992
- The patent can be found at https://www.google.com/patents/US9375417?dq=TRANSDERMAL+CANNABINOID+FORMULATIONS
Featured Image courtesy of Andres Rodriguez