Biocompatibility of an implantable ophthalmic drug delivery device

摘要

Diseases of the posterior eye present clinicians with a treatment challenge mainly due to the region's inaccessible location. Several drugs, including those available for the treatment of exudative age-related macular degeneration, are currently delivered by periodic injection into the eyeball. To avoid the risks and complications associated with this method, several implantable, timed release devices have been investigated to deliver these drugs directly to affected areas. Draper Laboratory and Massachusetts Eye and Ear Infirmary have proposed an implantable, fully programmable, mechanical device for long-term drug delivery to the eye wall. To investigate the biocompatibility of this solution, test devices containing gears or a ball bearing were designed to mimic elements of its moving parts, geometry and materials. Cell culture studies identified a polytetrafluoroethylene filter with 100m pores as a promising addition to seal devices from interaction with fibroblasts. Test devices with or without this membrane were implanted on the rabbit eye for 2 or 10 week periods. They were evaluated mechanically after implant, and surrounding tissues were inspected histologically. Gross observation revealed a significant amount of tissue formation around the devices, especially in the conjunctiva.