Uptake and release of dexamethasone phosphate from silicone hydrogel and group I, II, and IV hydrogel contact lenses.

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 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.