some of which might ionize to carry a negative charge. Therefore, the
negative charge on the surface of cubosomes was mainly due to
the ionization of the carboxylic end group of oleic acid. Although
the zeta potential in this system was not high enough to provide
effective electric repulsion to avoid the aggregation of particles,
however, P407 acting as a steric stabilizer, would not only stabilize
the cubic phase dispersions efficiently but also preserve the inner
cubic structure of the particles