By Yolanda Smith, BPharm
The scientific research about liposomes and how they can be applied for use has contributed to a breakthrough method for targeted drug delivery systems. Initially discovered in the 1960s, the research following this time has explained more about their properties and how they might be used. Today, they are indicated to help in the targeted administration for a number of highly toxic drugs, as a result of the research in this area.
The British hematologist, Alec Bangham, was the first to describe liposomes in scientific literature, when he used a negative stain to dry phospholipids when testing an electron microscope. He noted the resemblance to plasmalemma and was the first to capture evidence of the bilayer lipid membrane structure.
The practical use of liposome was launched into action after Bangham released a paper in 1965 with Jeff Watkins and Malcolm Standish outlining the properties of the liposomes.
As the research about liposomes has continued, more information has been discovered about their properties and potential for applied uses.
For example, research methods have enabled a mechanism for the liposomes to enter the body without detection by the reticuloendothelial system (RES) cells of the immune system. Cevc and Blume first put these specialized liposomes forward as a viable concept, and it was validated with the construction of the liposomes, containing PEG for longer circulatory life, with the assistance of Huang and Tochilin. The liposomes are now referred to as stealth liposomes.
The scientific research regarding the properties, functions and uses of liposomes is far from complete and there are further possibilities for their use in the future. For this reason, prospective research continues in the field of liposomes and their uses in medicine.
There is currently research investigations to determine the optimal quantity of PEG coating on the stealth liposome. PEG is known to increase circulatory lifespan, but it also hinders the ability of the liposome to bind to the target delivery site.
Additionally, most stealth liposomes are connected to a biological species ligand that has an effect on the expression and drug delivery. These ligands must be accessible to bind but the species can vary greatly, from monoclonal antibodies to specific antigens. The targeted delivery of liposomal drugs with the manipulation of ligand species is currently being investigated in scientific research. This would have notable benefits in further reducing toxicity of potentially hazardous medications.
Several questions about the optimal use of liposome in drug delivery remain, but as research continues there are likely to be more solutions to problems in the future.
Last Updated: Nov 2, 2015