title: Loading and release of a phospholipid from contact lenses.
abstract: OBJECTIVE
  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.
authors.affiliation: Chemical Engineering Department, Brigham Young University, Provo, UT, USA. pitt@byu.edu
authors.forename: William G
authors.initials: WG
authors.lastname: Pitt
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Jack
authors.forename: Yibei
authors.initials: Y
authors.lastname: Zhao
authors.forename: Jared L
authors.initials: JL
authors.lastname: Nelson
authors.forename: John D
authors.initials: JD
authors.lastname: Pruitt
mesh_terms: D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects*; D004134:Dimyristoylphosphatidylcholine / Q000008:administration & dosage; D016503:Drug Delivery Systems; D015352:Dry Eye Syndromes / Q000209:etiology* / Q000517:prevention & control*; D005240:Feasibility Studies; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D007202:Indicators and Reagents / Q000008:administration & dosage; D009883:Ophthalmic Solutions / Q000494:pharmacology; D010743:Phospholipids / Q000008:administration & dosage*; D012828:Silicones
chemical_list: D007202:Indicators and Reagents; D009883:Ophthalmic Solutions; D010743:Phospholipids; D012828:Silicones; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D004134:Dimyristoylphosphatidylcholine