A wide variety of ocular drug delivery systems have been developed and some are applied in currently marketed ophthalmic drug products but, although many are able to improve topical drug delivery into the anterior eye segment, they all display relatively low drug bioavailability. Topical delivery to the retina has been considered virtually impossible and currently there are no noninvasive topical drug delivery systems on the market for the posterior segment. Here preparation and testing of fast dissolving aqueous eye drop microsuspension that can deliver therapeutic drug concentrations to the retina will be described. Three sample drugs (i.e., dexamethasone, irbesartan and dorzolamide) will be used. Animal models will be used to describe the PK in rabbits and results of double-blind clinical studies in humans shown. Phase II studies of aqueous dexamethasone eye drop microsuspension in diabetic macular edema have recently been completed and Phase III studies are ongoing.
Learning Objectives:
Understanding of the relevant physiochemical and biological barriers to topical drug delivery to the eye.
Understanding of the route of drug permeation from the eye surface to the posterior segment of the eye.
Understanding of the physiochemical properties of fast-dissolving aqueous eye drop microsuspension and how it provides for sustained drug delivery to the posterior segment of the eye.
