Liposomes have attracted much attention since they were first discovered. These artificially created, microscopic spheres have many properties that make them extremely useful. One of these is their bio-compatibility. They act in exactly the same way as the cellular membranes of the body. This means they can be used as a unique delivery system for nutrients, drugs and other agents to specific areas in an organism. There are a numbers of ways in which liposome manufacturing is achieved, all of which have advantages and disadvantages.
Phospholipids like lecithin is used as raw material. The phospholipid molecules have heads that love water. They also have two tails that are essential fatty acid chains repelled by water. When the phospholipids are put in a solution that is water-based, the heads end up side by side with the tails trailing behind. The fact that the tails repel water means that another layer lines up with the tails facing the tails of the first layer. This natural alignment results in two rows of tightly fitting molecules. These layers form membranes around and inside all cells.
Liposomes are used to deliver toxic drugs to target cancer cells. They are used for delivering nutrients deficient in the body or cosmetic nutrients to the skin. Many other medical applications are possible too such as in the field of genetics. Preparation methods depend on various factors such as the characteristics of the material to be carried, the consistency offered from batch to batch and scale of production.
All liposomes consist of a lipid bilayer encapsulating a payload of therapeutic molecules. They bypass the digestive tract, so the payload remains biologically inert until such stage as the cell membrane ruptures. The difference between liposomes comes in the way, how, when and where that occurs.
All the methods for preparation of liposomes have the same basic stages. Lipid vesicles are formed when thin lipid films are hydrated. The liquid bilayers become fluid, detach and self-close to form large vesicles. Once these large particles have formed, their size is reduced by energy input. This may be in the form of sonic energy called sonication or mechanical energy called extrusion.
So, the general elements consist of lipid preparation for hydration, hydration with agitation and then sizing of vesicles. Each different method used has certain advantages and disadvantages. Liquid hydration methods usually result in low dose loading. Sonication can affect the structure of an encapsulated drug.
Some of the problems associated with these processes are inconsistencies in size, structural instability and high costs. These problems are all receiving attention and solutions are being found. Cosmetology, for example, is benefiting from the production of tiny particles called nanosomes which are much, much smaller than normal liposomes and can therefore penetrate the skin more easily.
A great benefit involved in using liposomes is that they can be customized for different applications by varying the method of preparation, size, lipid content and surface charge. Many conventional techniques for preparing them and reducing their size are fairly simple to implement and equipment does not have to be too sophisticated. However, novel routes are being discovered for preparation due to motivation to scale-down for point-of-care applications or or to scale-up for industrial applications.
Phospholipids like lecithin is used as raw material. The phospholipid molecules have heads that love water. They also have two tails that are essential fatty acid chains repelled by water. When the phospholipids are put in a solution that is water-based, the heads end up side by side with the tails trailing behind. The fact that the tails repel water means that another layer lines up with the tails facing the tails of the first layer. This natural alignment results in two rows of tightly fitting molecules. These layers form membranes around and inside all cells.
Liposomes are used to deliver toxic drugs to target cancer cells. They are used for delivering nutrients deficient in the body or cosmetic nutrients to the skin. Many other medical applications are possible too such as in the field of genetics. Preparation methods depend on various factors such as the characteristics of the material to be carried, the consistency offered from batch to batch and scale of production.
All liposomes consist of a lipid bilayer encapsulating a payload of therapeutic molecules. They bypass the digestive tract, so the payload remains biologically inert until such stage as the cell membrane ruptures. The difference between liposomes comes in the way, how, when and where that occurs.
All the methods for preparation of liposomes have the same basic stages. Lipid vesicles are formed when thin lipid films are hydrated. The liquid bilayers become fluid, detach and self-close to form large vesicles. Once these large particles have formed, their size is reduced by energy input. This may be in the form of sonic energy called sonication or mechanical energy called extrusion.
So, the general elements consist of lipid preparation for hydration, hydration with agitation and then sizing of vesicles. Each different method used has certain advantages and disadvantages. Liquid hydration methods usually result in low dose loading. Sonication can affect the structure of an encapsulated drug.
Some of the problems associated with these processes are inconsistencies in size, structural instability and high costs. These problems are all receiving attention and solutions are being found. Cosmetology, for example, is benefiting from the production of tiny particles called nanosomes which are much, much smaller than normal liposomes and can therefore penetrate the skin more easily.
A great benefit involved in using liposomes is that they can be customized for different applications by varying the method of preparation, size, lipid content and surface charge. Many conventional techniques for preparing them and reducing their size are fairly simple to implement and equipment does not have to be too sophisticated. However, novel routes are being discovered for preparation due to motivation to scale-down for point-of-care applications or or to scale-up for industrial applications.
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