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And the search goes on... for the perfect contact lens technology that will make an unhealthy ocular surface impervious to the presence of a big foreign object. Well, good luck with that, I guess.
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 μg of radio-labeled 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) from a solution of n-propanol. The loaded lenses were soaked at 35°C in either water or artificial tear solution (ATF), and the elution of DMPC was quantified by scintillation counting.
RESULTS.: About 33 μg of DMPC was loaded into the lenses. An average of nearly 1 μg 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.
METHODS.: Silicone hydrogel contact lenses were loaded with 33 μg of radio-labeled 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) from a solution of n-propanol. The loaded lenses were soaked at 35°C in either water or artificial tear solution (ATF), and the elution of DMPC was quantified by scintillation counting.
RESULTS.: About 33 μg of DMPC was loaded into the lenses. An average of nearly 1 μg 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.
Pitt WG, Jack DR, Zhao Y, Nelson JL, Pruitt JD.
*PhD †BS ‡MS Chemical Engineering Department, Brigham Young University, Provo, Utah (WGP, DRJ, YZ), and CIBA VISION Corporation, Global Research, Duluth, Georgia (JLN, JDP).