title: Uptake and release of dexamethasone phosphate from silicone hydrogel and group I, II, and IV hydrogel contact lenses.
abstract: OBJECTIVE
  To investigate the uptake and release kinetics of the synthetic glucocorticoid anti-inflammatory drug dexamethasone into various conventional and silicone hydrogel contact lens materials.
  
  
  METHODS
  Three conventional and six silicone hydrogel lenses were used in this study. A 0.1% dexamethasone solution was formulated and used to dope the various contact lens materials. The uptake and release of the drug was measured using a UV-visible light spectrophotometer at various time points during a period of 24 hr for each phase.
  
  
  RESULTS
  Statistical analysis showed that all lenses took up a significant amount of dexamethasone. Alphafilcon A and lotrafilcon A showed the greatest uptake of dexamethasone, at 118 +/- 10 microg/lens and 102 +/- 11 microg/lens, respectively, and galyfilcon took up the least amount of drug at 34 +/- 6 microg/lens. The release of the drug from the lens materials was also statistically significant. The majority of the lenses released between 20 and 30 microg/lens, except for alphafilcon A and lotrafilcon A, which released a statistically different amount of drug when compared with the other lens materials. Alphafilcon A released 65 +/- 1.3 microg/lens, whereas lotrafilcon A slowly released only 11 +/- 0.2 microg/lens.
  
  
  CONCLUSIONS
  Although most of the lenses released enough drug to have anti-inflammatory action, none of the materials released drug for a long enough period of time to be clinically useful as a drug delivery device.
authors: Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada. anboone@uwaterloo.ca
authors: Adrienne
authors: A
authors: Boone
authors: Alex
authors: A
authors: Hui
authors: Lyndon
authors: L
authors: Jones
mesh_terms: D000893:Anti-Inflammatory Agents / Q000493:pharmacokinetics*; D003263:Contact Lenses, Hydrophilic / Q000145:classification*; D003907:Dexamethasone / Q000493:pharmacokinetics*; D016503:Drug Delivery Systems / Q000295:instrumentation* / Q000592:standards; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D012828:Silicones; D013053:Spectrophotometry / Q000379:methods; D013997:Time Factors
chemical_list: D000893:Anti-Inflammatory Agents; D012828:Silicones; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D003907:Dexamethasone