Objectives: 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 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.
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.