Model Liposomal Delivery System for Drugs and Vaccines
Since their discovery by Alec Bangham and colleagues in the
1960s, liposomes have been one of the most investigated forms
of Nano carriers.
They were first described as lamellae of swollen
or enlarged lipids that could act as a model membrane system.
Liposomes are spherically shaped amphiphilic lipid bilayers ranging
in size from 20 nm to 10 µm.
Their structure is strongly correlated with their unique ability
to physically entrap a variety of compounds, including proteins, nucleotides,
plasmids, macromolecules and ribonucleic acid/deoxyribonucleic acid.
Liposomes can increase drug uptake and reduce drug toxicity,
while prolonging biological half-life. Consequently,
liposomes can significantly increase the therapeutic index
of the drugs they deliver.
The inclusion of lipids allows liposomes to be biocompatible,
non-toxic, flexible, non-immunogenic and biodegradable.
The physicochemical properties of liposome vesicles depend on
the phospholipid used in the formulation, and can influence
the vesicle’s surface charge, size, permeability and stability.
Classical liposomes, better known as the first generation
of liposome vesicles, were developed to encapsulate compounds
for non-specific uptake through endocytosis, adsorption or lipid
exchange once administered in a host.
Adding cholesterol to the liposome membrane
can lead to reduced binding of sodium ions to the membrane.
This reduces the interaction between vesicles and serum opsonins,
and increases the circulation time of the
liposomes in the blood stream.
Vaccin Res Open J. 2020; 5(1): 10-16. doi: 10.17140/VROJ-5-117
