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t m c » p u l s e | a p r i l 2 0 1 5 32 Eyes on the Prize Reimagining the delivery system for eye medication, researchers at Baylor College of Medicine have developed a nanowafer technology that proves more effective than topical eye drops B y A l e x O r l a n d o Y our eye twitches subtly as the dis- penser approaches the periphery of your vision, despite your best inten- tions to look away. As your fingers pry your eyelids open, a makeshift vise that seems ill-equipped to the task at hand, your lids struggle to clamp shut in defense of the looming foreign object. After a few failed attempts, resulting in several drops dribbling down your cheek, the elusive liquid finally hits its target, resulting in several minutes of furious rubbing and blinking. But how effective is all this aggravation at treat- ing the underlying problem? Most people can relate to the frustrating reality of using topical eye drops. While they might seem like LEFT: Stephen C. Pflugfelder, M.D., and Ghanashyam Acharya, Ph.D., are leveraging their combined expertise to reinvent the way that eye medication is administered. RIGHT: The nanowafer drug delivery system—which allows for a slow, controlled release—consists of a small transparent disc containing arrays of drug-loaded nanoreservoirs, placed on the surface of the eye. I think this [technol- ogy] could be huge— it would enhance the effectiveness of the drug, improve compliance, and I think it will mark a major shift in the way that these drugs are induced. — STEPHEN C. PFLUGFELDER, M.D. Professor of Ophthalmology at Baylor College of Medicine a necessary annoyance in treating eye injuries and ailments, using eye drops multiple times per day can cause side effects such as irritation and toxicity from high concentrations, while poor patient compliance also poses problems. In response to these issues, researchers at Baylor College of Medicine have developed a nanowafer drug delivery system, where medication is slowly released from a nanowafer— a small transparent disc, containing arrays of drug-loaded nanoreservoirs, placed on the surface of the eye. 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. "One of our major discoveries has been that it looks like the short contact time of eye drops may not be sufficient for the medication to be effective," noted Stephen C. Pflugfelder, M.D., professor of ophthalmology at Baylor and an author on the paper. "Eye drops are very inefficient because they are diluted by the tears and then rapidly washed away from the eye, leaving very little time for the medication in the drop to be picked up or absorbed by the tis- sue. This technology is a whole different mechanism for achieving chronic, sus- tained levels—we're finding much higher penetration into the tissue." Ghanashyam Acharya, Ph.D., assistant professor of ophthalmology at Baylor and senior author of the paper, developed the wafer technology to be placed on the surface of the eye, where it slowly dissolves while maintaining a high concentration of the drug in the tear film and loads up the tissue to provide better efficacy. "Once you place the technology on the surface of the eye, slowly the drug will diffuse as tears come into contact with the wafer," he explained. "Over a period of time, the drug will continue to diffuse into the eye and