Copyright ©2013 Baishideng.
World J Pharmacol. Mar 9, 2013; 2(1): 18-34
Published online Mar 9, 2013. doi: 10.5497/wjp.v2.i1.18
Table 1 Route of administration dependent physiological barriers encountered in the diffusion path to the neural retina
Physiological barriersRoute of administration
Precorneal loss
Corneal ultrastructure
Corneal efflux proteins
Corneal tight junctions
Conjunctival efflux proteins
Conjunctival tight-junctions
Conjunctival vasculature
Aqueous humor outflow
Anterior chamber metabolism
Scleral vasculature
Choroidal vasculature
Bruch’s membrane
Outer BRB
RPE tight junctions
RPE efflux pumps
Inner BRB
Efflux proteins
Low concentration gradient
First pass effect
Absorption limitations
Metabolism in the GIT
Systemic metabolism