The eye is the most important sensory organ, which restricts most of the active substances
due to its static and dynamic barriers. The application of conventional eye drop is still popular,
but it was found to be less permeable to both anterior and posterior eye portions, requiring
more frequent administration. It seems to be a great challenge for the researcher to fabricate an ocular
formulation that crosses the barriers and achieves an optimal therapeutic concentration at the ocular
globe. Recent studies revealed that a nanostructured lipid carrier has great potential in ophthalmic
use and has become more popular due to its permeability in the eye cavity.
This review describes the nanostructured lipid carriers with respect to the mechanism of ocular
permeation, structural feature, manufacturing process, characterization, and its merits over other
nanocarriers. In recent years, newly nanostructured-based ocular formulations have been developed,
like surface-modified with various cationic compounds and their integration with different
polymeric systems, to enhance ocular bioavailability in both regions of the eye. Newly developed
nanostructured lipid carriers include surface modified cationic lipid, polymers, and thiolated compounds,
etc., that increases mucoadhesive property. Finally, nanostructured incorporated forms, in
situ gel, and hydrogel increase permeation in the posterior region of the eye.