Drug delivery to posterior segment of the eye: Conventional delivery strategies, their barriers, and restrictions

Abstract

Posterior eye segment diseases have been a crucial health ailment for years due to the anatomical structure of the human eye and the challenges to deliver drugs to certain tissues in the eye. This chapter discusses the parts of the posterior segment and its functions along with the possible barriers to conventional treatments. Topical and systematic drug delivery systems are traditional ways of treating most ocular diseases. However, these are not as effective due to low absorption, degradation of the therapeutic agents via enzymes, and toxicity due to higher drug doses to compensate for the low permeability. On the other hand, intravitreal, transscleral diffusion and iontophoresis along with ocular implants are novel techniques that increase the bioavailability as well as precision of the drug delivery.