The ophthalmic rod: a new ophthalmic drug delivery system I

The ophthalmic rod (OR) is a new drug delivery system, intended as an alternative to conventional therapy in ophthalmology. The rod is made of a nontoxic plastic. It is dipped into a drug solution which after drying forms a thin homogeneous coating. The OR is then packed and sterilized by gamma radiation. The effects of radiation on the contents of the drugs were studied using IR, UV, and thin-layer chromatography (TLC). Sterility, dose variation, and simulated drug delivery in vitro were tested. Pure drugs were used; no preservatives were included. To deliver the drug, the tip of the rod is introduced into the conjunctival sac and rubbed against the palpebral conjunctiva of the lower lid. ORs with tropicamide, oxybuprocaine HCl, pilocarpine HCl, and fluorescein sodium were used. The behavior of the drugs administered by this system was compared with eyedrops. Results of trials with three drugs, i.e., tropicamide, oxybuprocaine HCl, and fluorescein sodium on ORs applied to the eyes of humans and those of the rabbit are discussed.