Recent Developments in Lyotropic Liquid Crystals as Drug Delivery Vehicles - Self-Assembled Supramolecular Architectures: Lyotropic Liquid Crystals - page 247

Figure 8.22 Schematic illustration of the interactions between the components, rep-
resenting the second and third H II systems (water - glycerol - fi lled H II phases, in the
absence and presence of PC, respectively) at three temperatures: (a) 25°C, (b) 60°C,
(c) 70°C. For simplifi cation PC and tricaprylin are not shown in the image (Amar-Yuli
et al., 2011b ).

marked increase in the parallel and antiparallel - sheet bands (Fig. 8.21 ) were

detected in all systems, suggesting an initiation of insulin aggregation, with
noticeable variations between the hosting systems. The total

β

β sheets of

insulin in water increased from 25 to 37% at 70°C, and after 60 min treat-

ment further increased to 56%. Similar quantities of

∼

sheets were obtained
at 70°C when insulin was confi ned within the H II cylinders (39, 40, and 36%
in the water - , glycerol/water - H II phase, and glycerol/water-fi lled H II phase
containing PC, respectively). On the other hand, heat treatment of insulin for
60 min revealed the differences in system effi ciency in intermolecular

β

β - sheet

-sheet content was recorded in the
bulk solution, only a slight increase of 5% was observed when insulin was
incorporated in the water-fi lled H II channels. Moreover, when glycerol was
present in these narrow channels (in the second and third systems) insulin
retained its

growth. While an increase of ∼ 20% in β

-sheet content, although severe conditions (70°C for 60 min)
were applied. The addition of PC contributed to the stability of the secondary
structure of insulin.
Figure 8.22 illustrates the interactions between the components, represent-
ing the second and third H II systems. It should be stressed that in these new
systems, the dehydration process ended at 60°C, whereas further increase in
the temperature to 70°C caused the formation of stronger hydrogen bonds
between the GMO hydroxyls and water. Above 60°C, owing to the protein-
solvation effect, the water and glycerol molecules were probably excluded
from the protein surface and redistributed themselves in the vicinity of the
protein molecule with a preferential binding of the solvent components. The

β