A liposomal delivery system is an advanced method of transporting substances into the body. Liposomes are both efficient and effective transporters due to their ability to be recognised by both water and lipids in the body making them ideal for the delivery of such things as vitamins, medicines, skin-care products and dry eye sprays. For many medicines it is essential for quick and thorough absorption and use.
Taken internally, liposomes are able to avoid destruction from the harsh acid environment of the digestive system and are more easily taken - up via passive absorption through cell membranes. The mucos membranes of the mouth also allows for effective absorption, as does the porous epithelial tissue of the skin.
Liposomes are related to a family of lipid-based delivery. For example, emulsions, which require a blend of lipids and water for skin moisturizers. These products often use molecules, called surfactants, which enable the oil and water to blend. Lecithin is an example of an emulsifier.
Emulsions are sophisticated and can be used in many applications.
Liposomes escort nutrients in nano-sized vesicles which are made of a phospholipid bi-layer making them easily recognised and absorbed.
Liposomes are biocompatible with both hydrophobic (water repelling) and hydrophilic (water-loving) molecules.
The phospholipid bi-layer
The cells in the body are surrounded by a phospholipid membrane which is critical to the structure, functioning and protection of cells.
Phospholipids consist of a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail which line-up in two parallel layers - a phospholipid bilayer. This makes-up the cell membrane and is critical to the functioning of the cell. Phospholipids are members of a class of lipids (fat-like) substances containing a phosphate group and two fatty acids (long-chains of hydrogen and carbon molecules) which are attached to a glycerol unit).
Delivery systems for products
Before liposomes, other developments to help with the delivery of products or medicines included:
- Micelles - particles composed of surfactants with their lipophilic tails forming the core.
- Nanoemulsions - particles with an oil core surrounded by a monolayer of surfactants.
- Solid-lipid nanoparticles (SLPs) – particles with a solid lipid core.
- Nanostructured lipid carriers (NLCs) - particles with a core blend of solid and liquid lipids.
Liposomes use a different delivery system. Rather than the use of a surfactant to stabilize a drop of oil in water, phospholipids are arranged into spherical cell membrane-like lipid bilayers. Their heads which are water-loving (hydrophilic) point towards the aqueous component and their fatty tails arranged tucked towards each other which trap water and water-soluble compounds. At the same time both hydrophobic and hydrophilic compounds can be packaged into spheres in the core of the biolayer. This potentially protects against degradation from stomach acid and facilitates up-take in the gastrointestinal tract. The liposomes membranes interact with cell membranes offering enhanced cell uptake.
Why avoid the gastrointestinal tract?
Many drug molecules can rapidly degrade on coming into contact with the hostile environment of the gastrointestinal tract (GIT).
Ingredients of liposomes
Phospholipids can be isolated from lecithins obtained from assorted seed oils – such as soy, sunflower and canola; egg yolk and milk. Lecithin contains an important phospholipid called phosphatidyl choline (PC) which is considered a beneficial and therapeutic product, and has also been found to be very versatile for the formation of liposomes. Phospholipids are valuable in their own right – phosphatidyl choline is the main component of cell membranes and micellizing agent in bile.
Uses of liposomal delivery
Liposomes have many applications some of which include:
Injectable drugs use liposomes for transport of pharmaceuticals.
Oral absorption through the mucous membranes of the mouth and digestive system. The nano-sized liposomes and nano-emulsion structures are readily absorbed via passive absorption, avoiding stomach acid, for direct and efficient absorption, getting the best of vitamins and nutriceuticals.
Transdermal absorption. Ultra-flexible liposomes are often considered the best choice for transdermal absorption of some medications due to their high performance as transdermal penetration-enhancers and their good stability in suspension.
- Dry Eye – can be due to a deficiency of the lipid layer of the tear film. This film usually prevents evaporation by acting as a seal. Distributing liposomes as a spray over the eye can provide instant relief from dry eye and stabilizes the lipid layer - addressing the deficiency not just the symptoms.
- Skin moisturizing - using liposomal delivery offers an enhanced delivery of active ingredients into the skin.
Some products which are available in a liposomal delivery system include vitamin C, vitamin D, vitamin B12, glutathione, turmeric, dry eye spray, medications and facial moisturisers.
References
- Liposomes as Advanced Delivery Systems for Nutraceuticals https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818067/
- Lipid-based Nanocarriers as an Alternative for Oral Delivery of Poorly Water- Soluble Drugs: Peroral and Mucosal Routes https://pubmed.ncbi.nlm.nih.gov/22834821/
- Liposomal Delivery Systems: Design Optimization and Current Applications https://www.jstage.jst.go.jp/article/bpb/40/1/40_b16-00624/_html/-char/en
- https://study.com/academy/lesson/what-is-a-phospholipid-structure-functions-composition.html
- Liposome: classification, preparation, and applications https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3599573/#:~:text=A%20stealth%20liposome%20is%20a,PEG%20and%20colloidal%20in%20nature.
- Moisturizers: The Slippery Road https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4885180/
- https://www.tearsagain.com.au/blogs/news/the-benefits-of-liposomal-eye-sprays-for-dry-eyes-explanation-made-simple
- Liposomes can both enhance or reduce drugs penetration through the skin https://www.nature.com/articles/s41598-018-31693-y
HealthylifePharmacy
HealthylifePharmacy
