Researchers at Germany’s Fraunhofer Institute for Applied Polymer Research IAP are working with Israeli and German partners to develop long-wearing contact lenses that can release medicine. The active ingredient is encapsulated in liposomes and bound to the inside of the contact lenses. This enables it to remain in the eye for longer. Sugars are added to make the contact lens particularly comfortable to wear, report agenceis.
When eye diseases are treated topically often only about 5% of the drug has an effect on the eye tissue. The German-Israeli research team would therefore like to use contact lenses as a transport system for active substances in order to prolong the contact time of the drug with the tissue in the eye. This system could be used, for example, to relieve pain, improve wound healing and protect the cornea. However, there are a lot of requirements: the active ingredient must be released for as long as possible, the contact lens needs to have excellent lubricating properties and all components must be biologically inert.
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There is currently no such application system on the market that meets all of these requirements.The Israeli partner company EyeYon Medical has already developed drug-administering contact lenses that ensure longer residence times of the active substances. Nahum Ferera, CEO of EyeYon Medical, explains: “These contact lenses release the drug for approximately 20 minutes. When eye drops are used, only 4% of the active ingredient generally reaches its target. We would like to extend this length of time as well as the bioavailability.
According to some studies, up to 30% of all contact lens wearers complain that wearing contact lenses is generally uncomfortable. With the help of the Fraunhofer IAP and the other partners, we want to improve both parameters – the release time of the drug and wearing comfort.”
The goal of the German-Israeli research team is to coat the inside of the contact lens with liposomes that carry a drug and release it over time. The liposomes are produced at the Weizmann Institute of Science by a research group led by Prof. Jacob Klein and Dr. Ronit Goldberg.
The use of liposomes is not the only strategy for optimizing contact lenses. “Sugars play a key role in this project”, explains Dr. Ruben R. Rosencrantz, who heads up the project at the Fraunhofer IAP. “Sugars act as lubricants at different locations in our bodies. In the eye’s mucous layer, for example, they enable the eyelid to glide smoothly. In order to achieve precisely this effect with contact lenses, we at the Fraunhofer IAP have developed polymers with a high sugar content, so-called glycopolymers.