(448g) Molecularly Imprinted Extended-Wear Contact Lenses with Controlled Delivery of High Molecular Weight Comfort Molecules
AIChE Annual Meeting
Wednesday, October 19, 2011 - 10:40am to 11:00am
Up to 30 million contact lens wearers in the United States experience discomfort due to contact lens induced dry eye (CLIDE). Symptoms are typically treated through the application of eye drops containing macromolecular re-wetting agents, where a typical regime provides a cumulative mass delivery rate of 2.5 µg HPMC/day. Therapeutic soft contact lenses can alleviate CLIDE symptoms by slowly releasing comfort agent from the lens. We present the first extended wear silicone hydrogel contact lens engineered to controllably release of 120 KDa hydroxypropyl methylcellulose (HPMC) for extended periods. The lens was designed using lotrafilcon B, a commercial silicone hydrogel lens, and HPMC release rates were controlled by a molecular imprinting strategy. The release rate was tailored to deliver approximately 1,000 μg of HPMC over a period of up to 60 days in a constant manner at a rate of 16 μg/day under physiological flow rates. This rate is a 6 fold increase over the delivery from eye drops, and these lenses can release over the entire range of continuous wear, thereby maximizing comfort and convenience for the lens wearer. Release rates were significantly varied by controlling the imprinting effect. Adjusting the functional monomer to template ratio (M/T) to M/T values of 0, 0.2, 2.8, 3.4 corresponded to HPMC release durations of 10, 13, 23, and 53 days, respectively. These lenses had high optical quality and adequate mechanical properties for contact lens use. This work highlights the enormous potential of imprinting in the design and engineering of therapeutic contact lenses.