What are liposomes?
Liposomes are very small spherical vesicles formed by phospholipids, with a structure similar to that of cell membranes.
They are created spontaneously when lipids are dispersed in an aqueous medium. They can be of natural or synthetic origin.
Due to their configuration, liposomes allow the encapsulation of active ingredients for use as cosmetics, which provides greater protection for the active ingredients and allows them to penetrate deeper into the skin.
Liposomes have been used for more than half a century, when studies were initiated to use them to disperse lipophilic compounds. Later, cosmetic laboratories began to develop products encapsulated in liposomes.
Function of liposomes
The main functions of liposomes are to protect the active ingredients and transport them to deeper layers of the skin. In addition, being an encapsulation, liposomes allow the introduction of ingredients that cannot naturally penetrate the skin. They improve the bioavailability of certain compounds, thereby increasing their ability to reach their destination and be utilized by the body.
- Protection of the active ingredient: the properties of liposomes make it possible to maintain the stability of the active ingredient. They can also be used to protect these compounds from degradation or immune system attack, which can prolong their half-life and increase their effectiveness.
- Moisturizing: liposomes, by themselves, can increase skin hydration thanks to their hydrophilic composition.
- Transport of assets. The main function of liposomes is to transport these compounds through the body, either for distribution or for release at a specific site.
In addition, liposomes have the ability to fuse with cell membranes, which allows them to release their contents directly into cells. This makes them useful for the treatment of diseases affecting specific cells or tissues.
Types of liposomes
Depending on the active ingredient to be encapsulated, it is convenient to use different types of liposomes, which vary in size and lamellarity.
When liposomes are released in superficial layers, they are usually larger in size. While to be released at greater depths, they are smaller in size.
Within liposomes all types of actives can be encapsulated, even at the same time, as long as they are not larger than the liposomes themselves.
Depending on the structure and composition, we can find the following types of liposomes:
- Single liposomes: these are double-layered vesicles formed from a single lipid layer.
- Multilamellar liposomes: these are vesicles that have several lipid layers and can contain different types of lipids.
- Amphipathic liposomes: these are vesicles that have an amphipathic lipid layer, i.e. with a hydrophobic region and a hydrophilic region.
- Fusible liposomes are vesicles that have a high affinity for cell membranes and can fuse with them to release their contents.
- Disc-shaped liposomes: these are vesicles that have a flat, disciform structure.
- Nanotube liposomes: these are vesicles that have a tubular shape and can serve as vectors for drug delivery to specific cells.