New technology could replace eye drops
Researchers at the Cullen Eye Institute at Baylor College of Medicine have developed nanowafer technology to delivery ocular drugs, an alternative to inefficient eye drops.
Dallas-Researchers at the Cullen Eye Institute at Baylor College of Medicine have developed nanowafer technology to delivery ocular drugs, an alternative to inefficient eye drops.
What is a nanowafer?
According to researchers, a nanowafer is a small, transparent circular disc that contains arrays of drug-loaded nanoreservoirs-essentially, a lens that is one-twentieth the thickness of a contact lens that will deliver a drug slowly and consistently before dissolving.
“It’s made out of a polymer that has an array of wells in it that vary in size from nanometer to micrometer,” says Steven Pflugfelder, MD, an author on the study, speaking exclusively to Optometry Times. “A drug can be placed in those wells. It’s a way of adjusting the release of the drug from this wafer on the surface of the eye.
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Similar to a contact lens, the nanowafer is placed on eye; however, it wouldn’t go on cornea.
“In the study it was placed on the cornea, but for dry eye, it would go on conjunctiva because it would blur vision,” says Dr. Pflugfelder.
Dr. Pflugfelder says how the length of time for the nanowafer to dissolve depends on the polymer of which it is made-some would take days, while others might last hours.
According to Dr. Pflugfelder, the device came about when a nanobiologist who had a background in developing similar wafer drug delivery systems thought it might be ideal for treating ocular conditions.
Next: The problem with drops
The problem with drops
Eye drops can be inefficient to administer, especially for elderly patients, but options are limited for dispensing ocular medicine. Eye drop users typically have low compliance rates, and the medication does not always successfully make it into the eye-or stay there.
“Drops have a short residence time, and they aren’t efficient in loading up tissue with drug,” says Dr. Pflugfelder.
But he says the nanowafer is much more efficient in drug delivery due to the wafer’s longer contact time, which results in a greater tissue uptake.
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“The wafer is perhaps 100 times more efficient in loading conjunctiva tissue with drug,” he says. “Then it would release back into tear film or provide therapeutic concentrations for 24 hours, let’s say. The release time would vary on if the drug is lipid soluble or water soluble, in which case the polymer that we choose to dissolve it in may vary so wafer remains stable. Theoretically, the wafer could be used for glaucoma drugs, fluoroquinolones, antibiotics or peptides.”
Punctal plugs and contact lenses are both being explored as potential alternatives to eye drops.
“There are definitely other competing drug delivery systems, like drug-eluting contact lenses," says Dr. Pflugfelder. "They seem to release the drug faster."
Next: Potential applications
Potential applications
According to Dr. Pflugfelder, the research team at Baylor is looking to apply this technology to a variety of ocular conditions from ocular trauma to dry eye.
“Development of a nanowafer drug delivery system that can be readily instilled on the ocular surface by the patient’s fingertip without any clinical procedure will be not only very convenient but also most desirable for treating eye injuries, infections, chronic dry eye, glaucoma, and other ocular inflammatory conditions,” the study’s authors write.
Optometry Times Editorial Advisory Board member Joseph P. Shovlin, OD, FAAO, is interested in learning more about additional applications. “I’d like to know if other drugs are conducive to that type of delivery system, including glaucoma and other anti-inflammatories and antimicrobials, anti-virals and anti-infectives. Fluoroquinolones have a higher molecular weight, so that may have an effect.”
According to researchers, the nanowafer could be rapidly translated into human trials because the polymers and drugs used in its development are already in clinical use.
Depending on cost and convenience to patients, nanowafer drug delivery might lead to better adherence and compliance, says Dr. Shovlin.
Next: Benefits on the battlefield
Benefits on the battlefield
The Baylor College of Medicine researchers have grants from the U.S. Department of Defense to study this technology’s potential for treating traumatic eye injuries suffered on the battlefield.
“That’s a big problem in the military with explosive devices that soldiers are exposed to-not only the explosion with the particles but chemicals that damage the pH of the eye,” says Dr. Pflugfelder. “In the field, medics could stabilize the eye for first 24 hours. Usually when soldiers have injuries like that, they often have neurological problems as well. The eye can be stabilized until the patient is transferred to hospital to take care of all the problems.”
