An ocular insert to release antibiotic is being studied for use in the treatment of infectious bovine keratoconjunctivitis (IBK). of several systems investigated, the hydrogel copolymer formulation containing 90% methylmethacrylate - 10% hydroxyethyl methacrylate shows antibiotic (tylosin tartrate) release characteristics compatible with desired rates required throughout a 5-day period. Thin layer chromatography (TLC) is being used to characterize the amounts of tylosin tartrate released at different periods from two release device systems. Scanning electron microscopy (SEM) is being used to monitor surface smoothness, to insure adequate joining of device segments, and to identify the presence of microstructural defects.