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.
Formation of liposomes is not spontaneous. Lipid vesicles are formed when phospholipids like lecithin are placed in water. Each molecule has a water-loving head and two water-repelling tails. When these molecules are placed in a water-based solution, the heads line up side by side with the tails behind. The fact that the tails are repelled by water means that another layer lines up with the tails facing one another. These two rows form a protective membrane around the cell.
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.
The methods used in preparation may all be quite different but the basic stages remain the same. Thin lipid films are hydrated and this causes liquid bilayers to form. These large vesicles need to be reduced in size and energy output is required for this. Sonication is the use of sound waves and another mechanical method used is 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.
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.
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.
Formation of liposomes is not spontaneous. Lipid vesicles are formed when phospholipids like lecithin are placed in water. Each molecule has a water-loving head and two water-repelling tails. When these molecules are placed in a water-based solution, the heads line up side by side with the tails behind. The fact that the tails are repelled by water means that another layer lines up with the tails facing one another. These two rows form a protective membrane around the cell.
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.
The methods used in preparation may all be quite different but the basic stages remain the same. Thin lipid films are hydrated and this causes liquid bilayers to form. These large vesicles need to be reduced in size and energy output is required for this. Sonication is the use of sound waves and another mechanical method used is 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.
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.
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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