Continuous drug delivery through the use of disposable contact lenses

This in vitro study examined the ability of the available disposable soft contact lenses to absorb various ocular therapeutic agents and release them. After a 2-h or 4-h presoaking time, we measured the amount of drug released into fresh saline baths for up to 3 h. Drug levels were determined spectrophotometrically at the peak ultraviolet (UV) absorption wavelength for each drug. Ciprofloxacin hydrochloride, prednisolone sodium phosphate, and cromolyn sodium were found to be released from the disposable contacts at a rate that provided higher concentrations of drug for a longer period of time than would be expected with drops. Depending on the lens used these drugs were released continuously for a period of up to 3 h. Disposable lenses soaked in pilocarpine hydrochloride or idoxuridine released drug for 30 min or less. These data indicate that disposable contact lenses could provide an acceptable means of drug delivery for some situations and overcome drawbacks associated with the use of nondisposable hydrogel lenses.