We had the pleasure of learning from Dr. Anuj Chauhan, a professor from UF Chemical Engineering, at our general body meeting. Dr. Chauhan gave an engaging presentation on ophthalmic drug delivery using contact lenses. For more information, please see his abstract below. Thank you to all the members who attended!
(Picture from UF Chemical Engineering, http://www.che.ufl.edu/)
Ophthalmic drug delivery by contact lenses
Anuj Chauhan, Chemical Engineering,
University of Florida, Gainesville, FL 32611-6005, USA
Conventional ophthalmic drug by eye drops is very inefficient with a low bioavailability of 1-5%. We have shown through mathematical modeling that the corneal bioavailability can be increased to about 50% by using drug eluding contact lenses. Currently available commercial contact lenses are however not optimal for drug delivery due to the very short release duration of about an hour for most ophthalmic drugs. Our lab has focused on developing contact lenses that can deliver ophthalmic drugs for significantly longer durations compared to commercial lenses, but without sacrificing any of the critical optical, mechanical or transport properties. This talk will describe the following five approaches that we have developed for extended release of drugs from contact lenses, (i) Self assembled vesicles, (ii) Ionic surfactants, (iii) Polymeric nanoparticles chemically linked to the drugs, (iv) Diffusion barriers, and (v) New silicone hydrogel materials. Some of these approaches can be adapted to modify lenses after polymerization, so commercial contact lenses can be modified to increase the drug release duration. The release duration of drugs from the lenses depends on the physical properties, but in general we can increase the release duration by at least a factor of 100 compared to the commercial lenses. For some drugs, we have succeeded in increasing the drug release duration to as long as a few months. The drugs of interest include timolol, dorzolamide, latanoprost, cysteamine, dexamethasone, dexamethasone phosphate, cyclosporine, lidocaine, fluconazole, etc. In vitro results will be presented to show the drug release profiles and also to show that the designed lenses retain all critical properties necessary for extended wear including transparency, ion and oxygen permeability, modulus, water content, wettability, etc. Some of the approaches described above improve several other properties in addition to drug release profiles, including wettability, UV blocking, etc.