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them into particulate forms, but not all lipid phases can be dispersed into
particulate forms in excess water. A lipid that forms, for example, normal
micellar phases has suffi cient high water solubility to exist as surfactant mono-
mers upon dilution. The reversed “ water - in - oil ” self - assembled lipid aggre-
gates, on the other hand, can form stable dispersions in large excess of water
with the help of a suitable stabilizer (Kaasgaard and Drummond, 2006).
10.2.2
Formation of Nonlamellar Crystalline Particles
Analogous to liposomes, which are aqueous dispersion of lamellar phase,
cubosome (Barauskas et al., 2005b), hexosome (Barauskas et al., 2006a), and
sponge (Barauskas et al., 2006b) nonlamellar crystalline particles are disper-
sions of reversed bicontinuous cubic, reversed hexagonal, and L
3
phases,
respectively. Figure 10.2 shows cryo-TEM (transmission electron microscopy)
images of these dispersed LCNPs. Detailed reviews on the preparation tech-
niques and materials for nonlamellar liquid crystalline dispersion can be found
(Boyd et al., 2009; Kaasgaard and Drummond, 2006; Larsson, 1999; Sagalowicz
et al., 2006a,b; Yang et al., 2004). In brief, preparation of LCNP ranges from
(a)
(c)
(e)
(g)
100 m
100 m
100 m
100 m
(d)
(f)
(h)
(b)
50 m
20 m
50 m
10 m
Figure 10.2
Cryo-TEM images of different nonlamellar lipid LCNPs: reversed bicon-
tinuous cubic phase [(a)-(d)], sponge or L
3
phase [(e)-(f)], and reversed hexagonal
phase [(g)-(h)] particles. Fourier transforms of magnifi ed areas in panels (b), (d), (f),
and (h) show the structural periodicity of the different nanoparticles consistent with
the mesophase structures indicated above. [Reprinted with permission from Barauskas
et al. (2005a). Copyright 2005 by the American Chemical Society.]
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