Mathematical model of drug release to the posterior segment of the eye after topical drug delivery

Drug delivery to the posterior segment of the eye is one of the most important topics in ophthalmology. There are several ways to do this. The purpose of this paper is to develop a mathematical model for assessing drug levels in the retina using the topical delivery that involves the corneal and non-corneal routes. The model includes systems of partial differential equations that are linked by interface boundary conditions. The permeability and consumption rate parameters simulate the presence of inner membranes and barriers with different values. The sensitivity study shows that tissue diffusion, tissue clearance rate, and membrane permeability play an important role in drug delivery to the target tissue. Numerical simulation is used to describe these events and compare the two methods. A weak problem formulation is introduced for the corneal route.