Determination of the rheological behavior of the
formulations
The rheological behavior of the formulations
was evaluated using the Power law given by the formula
cited above. Thus after measuring the rheological
behavior of the formulations, it was observed that
both formulations containing leaves and stems extracts
exhibit a Newtonian behavior, i.e., have an ideal viscous
behavior (Table 3).
It was shown that the relationship between
shear stress and the shear rate is linear. This means
that for a given temperature, the viscosity remained
constant during its measurement, regardless of time
and the shear employed (Corrêa et al., 2005).
Table 3. Parameters of rheological behavior of the
nanoemulsion formulations with hydroethanolic extracts
from stems and leafs of Vellozia squamata.
Nanoemulsion
Formulation with↓ Flow index Consistence
index (cP)
Apparent
viscosity (cP)
Stems extract 1.00 2.39 99.70
Leafs extract 1.00 2.39 99.70
cP: centi Poise.
Determination of droplets size
The particle size is an important parameter to
evaluate nanoemulsified systems due to the fact that
the particle size is the main factor responsible for the
permeation enhancing effect of active components
in the skin layers. In addition the particle size, it is
essential to know the polydispersity index, since
these factors together influence the stability of these
systems. The distribution of the particle size in the
nanoemulsion obtained with the hydroalcholic extracts
from V. squamata leaves and stems were measured for
seven days (Table 4). Both nanoemulsions presented
small droplet size and the microstructure have not
undergone significant changes over the seven days