Messy eye drops could soon become a thing of the past for glaucoma and dry-eye sufferers because researchers at the Children's Hospital in Boston, MA have developed contact lenses that gradually dispense medication to the eye at adjustable rates.
Although other researchers have developed drug-releasing contact lenses, none has been able to achieve a constant, steady release of substantial amounts of drug; typically, a burst of drug is delivered in the first few hours, followed by rapidly dwindling amounts that are too low to be therapeutic.
Daniel Kohane of Harvard Medical School and Joseph Ciolino of the Massachusetts Eye and Ear Infirmary and colleagues at the Department of Chemical Engineering at the Massachusetts Institute of Technology (MIT) have created a two-layer contact lens with an inner drug-bearing biodegradable polymer film known as PLGA, coated in a layer of a hydrogel called pHEMA. The US Food and Drug Administration has approved both PLGA and pHEMA for ocular use.
Kohane and colleagues tested the prototype lenses with an antibiotic called ciprofloxacin, which is often used in eye drops, for 30 days, the longest duration for which the FDA currently approves contact lenses. In some tests, the lenses continued releasing the drug for up to 100 days. The amounts dispensed were sufficient to kill pathogens in a laboratory assay.
The prototype lens is described in the July issue of the Journal of Investigative Ophthalmology and Visual Science.
The researchers have begun to test the lens in animals and plan to begin human testing as soon as possible.