Ocular delivery of acetylsalicylic acid by repetitive Coulomb-controlled iontophoresis

To investigate the potential of transscleral coulomb-controlled iontophoresis (CCl) for repetitive delivery of acetylsalicylic acid (ASA) into the eye, a total of 50 rabbits was included in this study. Fourteen animals received serial CCl treatment. Fourteen animals underwent CCl with either ASA or balanced salt solution (BSS) for at least 6 days at 24- and 48-hour intervals. Eighteen animals received a single CCl application, while 18 animals were injected with 15 mg ASA/kg body weight intravenously. HPLC analysis was performed to determine the levels of salicylic acid (SA) in ocular tissues. Apart from clinical follow-up, 2 rabbits in the ASA and BSS groups were examined by electroretinography, and 2 animals were examined histologically. Though high concentrations of SA were measured, no alterations were observed clinically, histologically and electrophysiologically. Repetitive CCl demonstrated its potential as a topical drug delivery system for ASA into the eye. This transscleral delivery of ASA resulted in significant and sustained intraocular concentrations of SA without side effects. lontophoresis may be advantageous in clinical administration maintaining therapeutic levels of ASA while avoiding adverse effects associated with the systemic administration of nonsteroidal anti-inflammatory drugs.