Sustained release of antimicrobials in the middle ear using a biodegradable support.

The ototoxicity of a poly-L-lactic acid biodegradable support incorporating a therapeutically releasable amount of ampicillin was studied. This device has a shape that allows placement in the middle ear via a myringotomy incision. Once in the middle ear, it expands without mechanical interference and provides extended release of ampicillin. In vitro studies documented sustained release of ampicillin, and in vivo efficacy was demonstrated in otitis media induced in chinchillas and cats. Previous histopathologic studies showed a lack of inflammatory reaction from the device itself and documented its biodegradable characteristics. There was no evidence of ototoxicity on morphometry of the organ of Corti (hair cell counts) in chinchillas exposed to these devices for 3 weeks with and without ampicillin.