چکیده (انگلیسی):

Sink conditions are often violated when
using conventional release methods for dispersed
systems. A novel reverse dialysis bag method was
designed to overcome this problem. Model drug
transport rates from submicron emulsions obtained
using the conventional diffusion cell method and this
novel method were compared. In the side-by-side
diffusion cell method, emulsions were placed in the
donor chamber and surfactant/buffer solutions in the
receiver chamber. In the novel dialysis bag method,
emulsions were diluted infinitely in the donor phase
and surfactant/buffer solutions were placed in the
receiver phase (dialysis bags). Slow release rates and
linear release profiles were obtained using the sideby-
side diffusion cell method apparently due to
limited model drug solubility in the donor chamber
resulting in violation of sink conditions. Biphasic
release profiles were obtained using the dialysis bag
method apparently due to an initial rapid release of
free and micellar solubilized model drug from the
donor to the receiver chambers followed by slow
release from the oil droplets. Using both release
methods, an initial increase and latter decrease in
release rates were observed with increase in
surfactant concentration. The initial increase was
considered to be due to a decrease in the model drug
oil-in-water partition coefficients and the subsequent
decrease in release rates was due to micellar shape
change (spheres to rods) causing a decrease in
diffusion rates. Sink conditions were violated using
the side-by-side diffusion cell method but were
maintained in the dialysis bag method since
emulsions were diluted infinitely in the donor phase.