Characterization of the release of phospholipids from an extended-wear silicone hydrogel contact lens is performed to assess the possible use of these lenses for phospholipid delivery to alleviate dry eye symptoms and increase comfort to patients who prefer extended wear lenses.
Contact lenses were loaded with 200 μg of radiolabeled 1,2-dimyristoyl-sn-glycero-3-phosphatidyl choline (DMPC) from a solution of n-propanol. To simulate 30 days of daily use with overnight cleaning, these lenses were eluted for 16 hrs at 35°C into artificial tear fluid (ATF), and then eluted at room temperature (~22°C) for 8 hrs in 1 of 3 commercial contact lens cleaning systems. This was repeated for 30 days. The elution of DMPC into ATF showed a burst effect on the first day, followed by a fairly constant amount of elution through the remaining days. The type of cleaning system had a statistically significant effect on the elution rate during exposure to ATF. The rate of elution into cleaning solution showed no burst effect on the first day, and fairly constant elution thereafter, with one cleaner producing significantly more elution.
