To investigate the uptake and release kinetics of the synthetic glucocorticoid anti-inflammatory drug dexamethasone into various conventional and silicone hydrogel contact lens materials.
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.
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 μg/lens and 102 ± 11 μg/lens, respectively, and galyfilcon took up the least amount of drug at 34 ± 6 μg/lens. The release of the drug from the lens materials was also statistically significant. The majority of the lenses released between 20 and 30 μg/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 μg/lens, whereas lotrafilcon A slowly released only 11 ± 0.2 μg/lens.
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.
From the Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada.
Funded by the Natural Science and Engineering Research Council (NSERC).
Address correspondence and reprint requests to Adrienne Boone, Ph.D., University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L3G1; e-mail: email@example.com
Accepted June 11, 2009.