title: Quantitation of cholesterol and phospholipid sorption on silicone hydrogel contact lenses.
abstract: The introduction of silicone hydrogel (SiHy) contact lenses to the consumer marketplace necessitates study of the susceptibility of these lenses to spontaneous deposition by hydrophobic lipid components of ocular tears. The use of radioisotopes to measure lipid sorption on SiHy contact lenses gives precise and accurate results but requires institutional infrastructure and compels efficient lipid removal from the lens. This study compares three methods of quantitating phospholipid and cholesterol sorption on SiHy lenses using radiolabeled cholesterol and phosphatidylcholine that were sorbed on lenses from an artificial tear fluid. A triple extraction technique using n-propanol gives the most reliable results. Comparison of sorption on SiHy lenses shows that balafilcon A and senofilcon A lenses sorb similar amounts, while lotrafilcon B lenses sorb comparatively less.
authors.affiliation: Chemical Engineering Department, Brigham Young University, Provo, Utah, 84602.
authors.forename: William G
authors.initials: WG
authors.lastname: Pitt
authors.forename: Krystian X
authors.initials: KX
authors.lastname: Perez
authors.forename: Ngai Keung
authors.initials: NK
authors.lastname: Tam
authors.forename: Erika
authors.initials: E
authors.lastname: Handly
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Chinn
authors.forename: Xiaojun Michael
authors.initials: XM
authors.lastname: Liu
authors.forename: Edmond Peter
authors.initials: EP
authors.lastname: Maziarz
mesh_terms: D000433:1-Propanol / Q000737:chemistry; D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry; D002784:Cholesterol / Q000737:chemistry*; D018639:Contact Lens Solutions; D003263:Contact Lenses, Hydrophilic; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D065346:Lubricant Eye Drops; D008422:Materials Testing; D010743:Phospholipids / Q000737:chemistry*; D015203:Reproducibility of Results; D012828:Silicones / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D018639:Contact Lens Solutions; D020100:Hydrogels; D008055:Lipids; D065346:Lubricant Eye Drops; D010743:Phospholipids; D012828:Silicones; C523195:balafilcon A; C524582:lotrafilcon B; D000433:1-Propanol; D002784:Cholesterol
keywords: cholesterol; lipid sorption; phospholipid; radioisotopes; silicone hydrogel contact lens