The potential ocular irritancy and/or damaging effects of
niosomal formulations F4, F6 and F12 were evaluated by
observing them for any redness, inflammation, or increased
tear production, upon application to the eyes of albino
rabbits. Each formulation was tested on three albino rabbits;
the experiment was performed by a single instillation (50 μl)
of the niosomal preparation under test into the conjunctival
sac of one eye, whilst the contralateral eye served as control.
Both eyes of the rabbits under test were examined for any
irritation signs, such as conjunctival: corneal edema and/or
hyperemia on the basis of direct visual observation using a slit
lamp, before treatment, and 1, 24 and 48 h after instillation
(31,32). The animal experiments were conducted in full
compliance with local, national, ethical and regulatory
principles for animal care and was approved by the Cairo
University Animal Care Committee