Techniques And Methods For Liposome Manufacturing

By Jody Leach


Liposomes are microscopic spheres made from the same material as the cell membranes in the human body. They have attracted a lot of attention due to their amazing properties. They can be used to carry drugs, nutrients and other agents to specific destinations in the body. There are various different preparation methods and techniques for liposome manufacturing and those used depend on on various factors.

When phosphlipids such as lecithin come into contact with water, an interesting effect occurs. The molecules consist of a head which loves water and two tails that repel it. This means that the heads all face one side and the tails the other. Another layer is formed with tails all facing the tails of the first later and the heads facing the other way. These layers form the membranes around and inside every cell of the human body.

It is possible to customize liposomes for different applications. These applications include delivering drugs to kill cancer cells, transferring DNA to make genetic modifications to cells or delivering cosmetic nutrients to the skin. Preparation method is affected by the application. For example, the concentration and toxicity of drugs used for treating cancer requires a particular preparation method.

Various lipids and mixtures can be used to make liposomes and some of these are of a higher quality than others. What they have in common is they do not go through the digestive tract and the encapsulated payload is not biologically active until it reaches the cells. It is how, when, where and why the rupture of the membrane occurs that the difference between them comes in.

Liposomes are usually synthesized by mixing and dissolving phospholipids in organic solvent. A clear lipid film is formed by removing the solvent. Hydration of this film eventually leads to formation of large vesicles which have several layers, much like the structure of an onion. Each bilayer is separated from the other by water. A form of energy is required to reduce their size. Sonication, agitation by sound waves, is one method used and extrusion is another.

Different methods are known to have certain weaknesses and strengths. Some allow for high load dosing and others offer much lower dose loading. Some of them offer more consistency and stability. The encapsulated content is affected more by some methods than others.

The type of manufacturing processes and equipment used both have an effect on the type of liposomes produced. Inconsistent sizes, high production costs and structural instability are just some of the challenges faced in production. Many advances are being made in this respect as research proceeds at a rapid pace. An exciting example is research into how to make liposomes that can target certain organs or diseased tissue.

Although conventional methods of manufacture are effective, research continues apace to make them more so. Much research is being conducted into ways in which liposomes can be created that have a strong chemical affinity for the cells of a particular organ or kind of tissue. They also need to have the ability to deliver payloads to the cells as efficiently as possible.




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