The key point to grasp in considering the manufacture of liposomes is that
phospholipid membranes form spontaneously as a result of unfavourable interactions
between phospholipids and water. Thus the emphasis in making liposomes is not towards assembling the membranes (which happens on its own accord), but towards
getting the membranes to form vesicles of the right size and structure, and to entrap
drugs with high efficiency and in such a way chat they do not leak out of the liposome
once formed.
All methods of making liposomes involve three or four basic stages: drying down
of lipids from organic solvents, dispersion of the lipids in aqueous media, purification
of the resultant liposomes and analysis of the final product. The main difference
between the various methods of manufacture is in the way in which the membrane
components are dispersed in aqueous media, before being allowed to coalesce in the
form of bilayer sheets. The methods are classified according to three basic modes of
dispersion: physical dispersion, two-phase dispersion and detergent solubilization
