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This small transparent disc is placed on the surface of the eye and contains drug-loaded nanoreservoirs, delivering medicine more efficiently than eye drops.

While using eye drops to treat eye injuries may seem like a simple enough task, doing so multiple times per day can cause side effects such as irritation and toxicity from high drug concentrations, and poor patient compliance is also an issue. In response to this, researchers at Baylor College of Medicine have developed a nanowafer drug delivery system, in which there is a slow drug release from a nanowafer, or a small transparent disc placed on the surface of the eye that contains arrays of drug-loaded nanoreservoirs.

In their latest study published in ACS Nano, researchers found that in mice, the nanowafer drug delivery system was more effective in treating corneal neovascularization, which results in severe corneal clouding and blood vessel ingrowth, than a topical eye drop therapy.

“Eye drops are very inefficient because they are diluted out by the tears and then rapidly washed away from the eye so there’s very little time for the medication in the drop to be picked up or absorbed by the tissue, and as a consequence the concentration of it doesn’t achieve a high level,” said Dr. Stephen C. Pflugfelder, professor of ophthalmology at Baylor and an author on the paper.

Dr. Ghanashyam Acharya, assistant professor of ophthalmology at Baylor and senior author of the paper, developed the wafer technology that can be placed on the surface of the eye. It slowly dissolves and maintains a high concentration of the drug in the tear film and loads up the tissue to provide better efficacy.

Using an animal model, researchers sought to determine whether using the wafer technology would deliver medication more consistently to the eye when treating corneal neovascularization, which can be blinding.

“We found that the nanowafer was much more efficient compared to eye drop treatment. For example, once a day nanowafer treatment has almost twice the efficacy compared to delivering eye drops two times a day,” said Acharya.

“It’s very novel. In this study, not only did it demonstrate the efficacy in delivering these drugs that inhibit the corneal blood vessels but it also demonstrated the efficacy and feasibility of the wafer drug delivery system,” said Pflugfelder. “This would greatly revolutionize treatment of severe infections of the cornea that require treatment with eye drops every hour for 24 hours a day for days and weeks on end. It could deliver more antibiotic to the cornea and it could theoretically be done once a day.”

Researchers are now working on increasing the drug release from the nanowafer from once a day to one to two weeks. Also, because the technology does not require refrigeration, it would be very useful in treating eye infections and injuries in developing countries.

Others who took part in the study include Daniela C. Marcano, Crystal S. Shin, Xiaoyoung Yuan, Xia Hua and Lucas Isenhart of Baylor College of Medicine.  

This work was supported by a grant from the Department of Defense (Award No. 1W81XWH-13-1-0146).