Pharmaceutical Manufacturing Handbook: Production and

H 3 C
CH 3
N +
CH 3
O
O
O
O
–
P
O
O
O O
H 3 C
CH3 Dipalmitoyl phosphatidylcholine
(DPPC)
Bilayer
Self-assembly
NANOTECHNOLOGY FOR DRUG DELIVERY 1259
3D optimized structure of DPPC
Polar head group
Lipid chains
Vesicle
(liposome)
FIGURE 3 Structures of phospholipids and formation of liposomes.
lipids become “ free, ” bulk phospholipids must be dispersed throughout, forming a
thin fi lm, dissolution or emulsifi cation, wherein additional energy is sometimes
needed. Liposomes may have a size ranging from 10 nm to more than 10 μ m mainly
depending on composition and manufacturing approaches. A number of reports
about the preparation of liposomes can be found in the literature and a detailed
description of liposomes is in Chapter 7.1 of this handbook. In this section the