LIPOSOMAL ENCAPSULATION TECHNOLOGY

WHAT IS A LIPOSOME?

The name liposome is derived from two Greek words: 'Lipos' meaning fat and 'Soma' meaning body.

DEFINITION

An artificial microscopic vesicle consisting of an aqueous core enclosed in one or more phospholipid layers.

In other words a liposome is a tiny 'micro' sized bubble or sphere (vesicle) made from a phospholipid (in our case, phosphatidylcholine). This is the same material of which our cell membranes consist. These bubbles can be filled with substances such as Vitamin C, Glutathione or even drugs.

Liposomes have the ability to carry either water or fat-soluble payloads, which makes them an ideal delivery system.

FORMATION

Phospholipids are amphiphilic, they consist of a hydrophilic (water loving) head and hydrophobic (water hating) tail.

When phospholipids are placed in an aqueous solution, the hydrophobic tails face each other avoiding the water and forming a phospholipid bilayer while the hydrophilic heads form hydrogen bonds with the water molecules.

The lipid bilayer will form a closed sphere (liposome) to completely exclude water from the hydrophobic tail.

WHY LET (LIPOSOMAL ENCAPSULATION TECHNOLOGY)?

The liposomal delivery system has many advantages over regular oral ingestion.

BIOAVAILABILITY

When a regular capsule or pill is ingested it must first pass from the mouth through the digestive system to finally be absorbed in the small intestine.

During this process, digestives enzymes in the mouth and stomach, digestive acids, bile salts and various gut flora degrade the nutrients before they are finally metabolised by the liver and made available to the body.

This entire process slows and reduces the nutrients' bioavailability.

Liposomes are attractive encapsulation systems that provide enhanced stability of encapsulated materials against a range of environmental, enzymatic, and chemical stresses. These may include the presence of enzymes or reactive chemicals, and exposure to extreme pH, temperature, and ionic strength changes.

Liposomes have been widely used in the pharmaceutical and food industries because of their biocompatibility and biodegradability. Their absence of toxicity, small size, and ability to carry a wide variety of bioactive compounds, due to the amphiphilicity of the phospholipid encapsulating material, make them a popular delivery agent.

DELIVERY

Once the liposome has reached the small intestine it is absorbed by the enterocytes of the villi. Inside the enterocytes, the liposomes are incorporated into chylomicrons.

Together, they travel through the lymph system, bypassing the liver (portal circulation) into the subclavian vein.

INTRACELLULAR

Another major advantage of the liposomal delivery system is the way it delivers the nutrients on an intra-cellular level.
A liposome can do this in a number of ways:

ENDOCYTOSIS

Endocytosis is a process in which the liposome gains entry into a cell without actually passing through the cell membrane. The cell engulfs the liposome forming a membrane-bounded vesicle called an endosome.

ADSORPTION

The liposome wall adheres to that of the cell and releases its payload into the cell.

FUSION

The melding of the liposome membrane with the membrane of the cell, carrying the contents of the liposome into the cell.

LIPID EXCHANGE

The contents of the liposome and cell exchange their lipid contents.