The role of blood-ocular barrier transporters in retinal drug disposition: an overview.
BACKGROUND
Delivery of drugs to the retina remains a major challenge which needs to be addressed urgently because retinal disorders are leading causes of visual impairment and significantly affect a patient's quality of life. Systemic drug administration is one possible route for treating retinal disorders; however, retinal transfer of drugs from the circulating blood is strictly regulated by two blood-ocular barrier systems, the blood-aqueous barrier and the blood-retinal barrier.


METHODS
This review summarizes the latest biological research regarding blood-ocular barrier drug transporters.


RESULTS
The blood-ocular barrier sites and their respective roles in aqueous humor dynamics and retinal homeostasis are briefly presented. The potential impact of ATP-binding cassette (ABC) and solute carrier (SLC) drug transporters, such as ABCB, ABCC, ABCG, SLC7, SLC16, SLC19, SLCO/SLC21A, SLC22A and SLC29 transporters, on the permeability of drugs across the blood-ocular barriers is then illustrated.


CONCLUSIONS
As more information becomes available regarding the blood-ocular barrier transporters, we may be able to design simpler and more effective routes for drug delivery to the retina and, consequently, improve the treatment of retinal diseases.
Tomi
Masatoshi
M
Department of Pharmaceutics, University of Toyama, Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama 930-0194, Japan.
Hosoya
Ken-ichi
K
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects; D018916:Blood-Aqueous Barrier / Q000378:metabolism*; D001813:Blood-Retinal Barrier / Q000378:metabolism*; D002460:Cell Line; D016503:Drug Delivery Systems; D005123:Eye; D006706:Homeostasis; D006801:Humans; D008658:Inactivation, Metabolic; D026901:Membrane Transport Proteins / Q000378:metabolism*; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D012164:Retinal Diseases / Q000188:drug therapy* / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D026901:Membrane Transport Proteins