[Three conventional eye drops versus a single lyophilisate. A comparative bioavailability study]

The ocular bioavailability of a single application of a triple dose of sodium fluorescein to the human anterior segment of the eye was studied as a novel drug delivery device.

The lyophilisate contained a fluorescein dose of 204 microg corresponding to three conventional, preservative-free eye drops of 40 microl Fluorescein SE Thilo 0.17% (68microg each) (Alcon). A single lyophilisate was applied to one eye of 22 healthy volunteers (+1 min) and three conventional eye drops (+1, 16, 31 min) were applied to their fellow eye. In this randomized, open label study, fluorophotometry was performed (Fluorotron Master IItrade mark, Ocumetrics, Mountain View, California, USA) before and +15, 30, 45, 60, 120, 180, 240, 300, 360, 420 min after application. The fluorescein concentrations of the corneal stroma (C), mid-anterior chamber (AC) were analyzed by paired t-test.

Cornea and AC mean values (ng/ml) were significantly higher (p < 0.018, paired t-test) in the lyophilisate group up to 7 h after application, with the exception of +45 min. The mean fluorescein bioavailability from the lyophilisate was up to 11 times higher in the C and up to 8.7 times higher in the AC compared with the three preservative-free eye drops.

For the first time a triple dose was delivered to the human eye with a single lyophilisate application. Significantly better bioavailability was achieved in the C and AC for up to 7 h using this new device. The treatment of glaucoma, bacterial, viral, and fungal infections, as well as dry eye syndrome, for example, will be improved using lyophilisate.