Ethosomes are an innovative way to improve the delivery of skincare ingredients across the powerful skin barrier.
The word ethosome is a combination of the words ethanol and liposomes. When these two ingredients are combined, they make a carrier that excels at delivering topical ingredients past the surface of the skin. To understand why this technology is so important, we need to backtrack slightly and review how topicals interact with the skin.
How the skin barrier works against skincare ingredients
We usually refer to topical ingredients as cosmeceuticals. This word is yet another mash-up, a combination of cosmetics and pharmaceuticals. As the name suggests, cosmeceuticals are at the intersection of cosmetics (for beauty or decoration) and pharmaceuticals (for skin health).
Cosmeceuticals include actives that treat and prevent skin conditions such as acne, aging, hyperpigmentation, and hair loss. At the surface, these conditions can appear frivolous, but they can have a severe impact on self-esteem and even quality of life.
We also use transdermal drug delivery systems for serious health conditions, beyond those associated with aesthetics. These include treatment of viral or fungal infections, hormone therapy, arthritis, and many more. Transdermal application is a good choice for localized treatments, or where oral bioavailability is low.
In many cases, we already have effective cosmeceutical drugs and ingredients for combatting these conditions. However, the efficacy of those drugs might be limited by the skin barrier, which prevents the active ingredients from penetrating the skin surface.
To understand how that happens, let’s take a closer look at the skin. The skin evolved as a natural separation against the environment, so it’s a powerful barrier. That’s a good thing, but it sometimes works against us when we’re trying to deliver drugs through the surface of the skin. The outermost layer of the skin is called the stratum corneum, which is composed of a tight network keratin protein, designed to keep moisture in and bacteria out.
When chemists design cosmeceuticals, they need to come up with a way to make the drugs compatible with the composition of the stratum corneum. That way the drugs will be able to penetrate past the dermal surface.
There have been several technologies developed to help solve this issue, including methods like microneedling and liposomal nanoparticles. However, the existing technologies are not ideal for various reasons related to cost, efficacy, and consumer compliance.
What are ethosomes?
Ethosomes are a new delivery system that could improve skin penetration for topical ingredients. These systems are comprised of a high concentration of ethanol (20-45%) along with phospholipids. Ethosomes are uniquely able to carry actives through the surface of the skin. The combination of chemicals has a synergistic effect. In other words, the combination of the two ingredients is more effective than a hydroethanolic control or phospholipid control alone.
There are several different types and formulations of ethosomes, so the pathway may vary depending on which one is being used. Each active ingredient must be tested in different ethosomes in order to optimize the delivery. Ethosomes are effective carriers for drugs of many different chemistries, including hydrophilic, lipophilic, and high molecular weight molecules.
The role of ethanol in ethosomes
Ethanol is essential to the function of the ethosome in three major ways:
1. Ethanol initiates the skin penetration by interacting with the stratum corneum and changing the conformation. Ethanol upsets the lipid bilayer in the skin, and decreases skin lipid density. This allows the ethosome to penetrate into deeper layers of the skin. It is understood that the phospholipid component is retained at the surface of the skin while the active ingredients are able to gradually penetrate deeper.
2. Ethanol is also important to the ethosome because it decreases the size of the ethosome vesicle, making it easier to penetrate the skin. The higher the concentration of ethanol, the smaller the vesicle size. The opposite is true for phospholipid concentration.
3. Finally, ethanol increases the flexibility of the ethosome vesicle. When the ethosome is soft and malleable, it is able to transverse the lipid bilayer of the stratum corneum more easily.
How are ethosomes used?
Here are some examples of how ethosome delivery systems have been shown to improve bioavailability and efficacy of skin topicals.
Ethosomes have been studied for the enhanced delivery of minoxidil and finasteride, two drugs proven to enhance hair growth. Both of these drugs had improved bioavailability and efficacy when delivered in ethosomes. However, they are not yet available commercially since more research is needed to ascertain their safety.
Acne is a multi-factorial skin condition that occurs when hair follicles become clogged with dead skin, oil, and sweat. Anti-acne medications including bactericidal agents, benzoyl peroxide, and retinoids were more effective when delivered in ethosomes. Again, these are not yet commercially available as more research is needed.
Hyperpigmentation is a skin discoloration or darkening that occurs due to excess production of melanin, often as a result of inflammation (for example, due to acne) or sun exposure. Hydroquinone is an example of a drug that can treat hyperpigmentation by inhibiting the production of melanin. When delivered in ethosomes, hydroquinone has enhanced penetration that improves the efficacy. The same is true for other hyperpigmentation treatments such as Kojic acid and Vitamin C.
Ethosomes are a transdermal drug delivery vehicle comprised of phospholipids and 20-40% ethanol. The powerful skin barrier can prevent the absorption of drugs that are critical to the treatment of many conditions. Ethosomes offer an innovative and effective way to improve penetration of active compounds past the skin barrier. The presence of ethanol decreases the size of the ethosome vesicle, improves the vesicle flexibility, and allows for the disruption of the dense lipid bilayer of the skin – all of which contribute to improved penetration. Ethosomes represent an important discovery for the future of cosmeceuticals, or any drugs that can be effectively delivered transdermally.
Abu‐Huwaij, Rana, and Abdullah N. Zidan. “Unlocking the potential of cosmetic dermal delivery with ethosomes: A comprehensive review.” Journal of Cosmetic Dermatology (2023).
Nainwal, Nidhi, et al. “Transdermal applications of ethosomes–a detailed review.” Journal of liposome research 29.2 (2019): 103-113.
Verma, Poonam, and K. Pathak. “Therapeutic and cosmeceutical potential of ethosomes: An overview.” Journal of advanced pharmaceutical technology & research 1.3 (2010): 274.
Yang, Li et al. “Mechanism of transdermal permeation promotion of lipophilic drugs by ethosomes.” International journal of nanomedicine vol. 12 3357-3364. 26 Apr. 2017, doi:10.2147/IJN.S134708