Sustained gentamicin release by presoaked medicated bandage contact lenses

Current therapeutic regimens for external ocular infections require instillation of antibiotics up to every quarter of an hour in concentrations higher than those commercially available. As an alternative to topically applied gentamicin eye drops, the possibility of sustained gentamicin release by bandage contact lenses was investigated. Ten hydrogel bandage contact lenses (61.4% HEMA and 38.6% water content) were soaked overnight in a 0.5% solution of sterile, unpreserved, commercially available gentamicin, and fitted thereafter on ten eyes of healthy adult volunteers. Gentamicin concentrations in the tear film were determined 10, 30, and 60 minutes, and 4, 8, 24, 48, 72, and 96 hours after fitting, using agar diffusion bioassay. Bactericidal concentrations (greater than 1.6 micrograms/ml) were found up to 3 days after contact lens fitting in all subjects. No toxic topical or systemic effects were seen.