Intravitreal drug delivery

To achieve an ocular therapeutic effect, it is necessary that the desired drug is delivered to the target tissues in adequate concentrations and for an adequate duration of time. To reach the innermost tissues of the eye, such as the retina or the retinal pigment epithelium, such an objective can be rather challenging. Intrinsic anatomic and physiologic properties of the eye impose qualitative and quantitative limitations to the design of an efficient drug delivery system. The eye is a relatively isolated organ that receives a small share of the cardiac blood flow. It is essentially a fluid-filled cavity engulfed by avascular tissues, and it has multiple blood-ocular barriers. These factors complicate the dynamics of penetration and distribution of drugs inside the eye.