| AU RESEARCH FOCUSED ON USING THE CONTACT LENS FOR DRUG DELIVERY Contact lenses — the small marvel long appreciated by the vision—impaired as being more worry-free than eyeglasses, may soon serve as a drug delivery mechanism designed to provide relief from eye irritations and diseases. Researchers in Auburn University’s Department of Chemical Engineering have developed a technology proven in laboratory testing to enable the contact lens to hold medication in concentrated, renewable doses and release the drug in a controlled, timed and targeted manner. The result may be a significant improvement over the use of drops and ointments, says the lead investigator, Mark Byrne, an AU assistant professor of chemical engineering. Since its inception, the hydrophilic (soft) contact lens has been considered to have potential as an effective medication delivery medium, Byrne says. The largest obstacle has been its limited capacity to hold and release medication in an effective and controlled manner - which has prevented any viable product showing up in the contact lens market. “We have overcome those problems by improving the structural properties within the polymer matrix of the gel that comprises the lens,” Byrne said. “A contact lens is mostly water. To clean and rehydrate it, one needs only to soak it in a saline-based cleaning solution. When the lens is made of the right materials, this same process enables it to be loaded with concentrated amounts of medication. Because it is easily placed directly on the eye, the contact lens can thus become a very effective medium for drug delivery.” Byrne explains that the key is in matching engineering technology with the science of biology. Although the AU technology uses materials no different from those found in commercially available contact lenses, Byrne says they have changed how those materials are incorporated into the lens, but not in a way that requires changes in the lens manufacturing process. “This technology has a fundamental link to biology,” Byrne said. “We’ve been able to match chemistry with the biology that comprises binding properties and other biological mechanisms in the human body. The result is a biometric polymer that binds with the desired medications and provides a controlled, timed release of these medications. We’ve not changed the material to a large extent. We've mostly changed the synthesis of the material.” Byrne says that 90 percent of the current eye treatment drugs available are either drops or ointments. Neither is as effective in targeting as is desired. “Typically, less than 7 percent of the applied drug is absorbed by the eye tissue,” Byrne said about ointments and drops. “Because of that poor absorption rate, the drug has to be applied in very high, multiple dosages to be effective.” Using the contact lens as the delivery mechanism, he says, enables the drug to be administered at lower doses and with greater absorption by the affected tissue, and with less impact on other untargeted tissues. Byrne began his research focused on using the contact lens as a delivery mechanism for antihistamine. “We found quickly-based on analysis of histamine action in the body - that the contact lens could be made effective for antihistamine delivery,” Byrne said. He and his team - comprised of doctoral candidate Siddarth Venkatesh and senior chemical engineering student Parker Sizemore - have now expanded their research to examining the contact lens as a delivery medium for anti-inflammatory drugs, antibiotics and other medications. Auburn has filed for patent protection on Byrne’s technology. |
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