title: Kinetics of in vitro lactoferrin deposition on silicone hydrogel and FDA group II and group IV hydrogel contact lens materials.
abstract: The aim of this study was to compare the kinetics of lactoferrin deposition on silicone hydrogel (SH) and conventional FDA group II and group IV hydrogel contact lens materials. Seven lens materials, two conventional (etafilcon A, FDA group IV; omafilcon A, FDA group II) and five SH (lotrafilcon A, lotrafilcon B, balafilcon A, galyfilcon A and senofilcon A), were incubated in 1 ml (125)I-labeled lactoferrin solution for time periods ranging from 1 h to 28 days. At the end of specified incubation periods radioactive counts were determined on the lenses using an Automatic Gamma Counter. There was a gradual increase in lactoferrin deposition on all the lenses across all time points. At the end of 28 days the amount of lactoferrin/lens in microg was 11.3 +/- 1.9 for etafilcon A, 6.8 +/- 2.0 for omafilcon A, 2.1 +/- 0.9 for lotrafilcon A, 3.1 +/- 1.0 for lotrafilcon B, 11.8 +/- 2.9 for balafilcon A, 5.4 +/- 1.1 for galyfilcon A and 5.6 +/- 0.6 for senofilcon A. After 28 days, etafilcon A and balafilcon A deposited lactoferrin to the greatest degree (P < 0.05), but these were not different from each other (P = 0.48), while lotrafilcon A and B deposited the least (P < 0.05 vs. other lenses; P = 0.57 with each other). Galyfilcon A, senofilcon A and omafilcon A (P < 0.05 compared with other lenses; P > 0.05 with each other) deposited intermediate levels of lactoferrin. We concluded that radiochemical analysis is a sensitive and effective technique to determine the small quantities of lactoferrin deposited on SH lenses. The kinetics of lactoferrin deposition on contact lens materials depend on the chemical structure of the lens material.
authors.affiliation: Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Chow
authors.forename: Lakshman N
authors.initials: LN
authors.lastname: Subbaraman
authors.forename: Heather
authors.initials: H
authors.lastname: Sheardown
authors.forename: Lyndon
authors.initials: L
authors.lastname: Jones
mesh_terms: D003263:Contact Lenses, Hydrophilic; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry / Q000378:metabolism; D007781:Lactoferrin / Q000378:metabolism*; D012828:Silicones / Q000737:chemistry / Q000378:metabolism; D014481:United States; D014486:United States Food and Drug Administration
chemical_list: D012828:Silicones; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D007781:Lactoferrin