Loading and Release of a Phospholipid From Contact Lenses

Purpose. Dry eye syndrome has been associated with the lack of phospholipids in the tear film, leading to disruption of the tear film and subsequent irritation. This study explores the feasibility of loading a phospholipid into contact lenses for controlled release to the eye. Methods. Silicone hydrogel contact lenses were loaded with 33 mu g of radio-labeled 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) from a solution of n-propanol. The loaded lenses were soaked at 35 degrees C in either water or artificial tear solution (ATF), and the elution of DMPC was quantified by scintillation counting. Results. About 33 mu g of DMPC was loaded into the lenses. An average of nearly 1 mu g of DMPC was eluted into ATF within the first 10 h. Elution was about five times faster in ATF than in water. The elution appears to be controlled by the diffusivity of DMPC in the contact lens and the properties of the elution solution. Conclusions. This type of lens technology may have the potential to deliver phospholipids to help address contact lens-related dryness through lipid layer stabilization. (Optom Vis Sci 2011; 88: 502-506)