The first phase of this SBIR project focused on demonstrating the feasibility of a delivery vehicle for topically applied anti-infectives to achieve extended duration of pharmacologically active drug concentrations in the tear film, cornea, and conjunctiva. During this phase of the investigation, a tobramycin formulation (TobraSite) using InSite's proprietary insoluble polymer vehicle (DuraSiteTM) was developed that had similar bioavailability to a marketed tobramycin ointment product, TobrexR. The second phase of this SBIR project has two major objectives. One focuses on optimization of the formulation of ophthalmic use by addition of other components or manipulation of the physico-chemical parameters. The formulations that prove to be most beneficial in terms of product stability, safety, and efficacy will then be tested for safety in studies on animals. The second objective focuses on studies of the safety and efficacy of the primary formulation in humans.