Ocular pharmacokinetics

With the world’s population continuing to age into the 70s, 80s, and even early 100s, ophthalmic diseases, including glaucoma, age-related macular degeneration (AMD), ocular surface diseases, loss of vision, and even blindness, are on the rise. At the other end of the spectrum, young patients with inherited retinal diseases, for example, retinitis pigmentosa, are finding new hope in the form of gene therapy. In the research and development of these new therapies and modalities, ocular pharmacokinetics (PK) will play an increasing role, from drug discovery and candidate selection through dose selection for human proof-of-concept and full development, assessing efficacy and safety, including systemic exposure. An understanding of the principles and technologies for studying ocular PK is particularly important. This chapter summarizes ocular PK associated primarily with topical ocular and intravitreal routes of administration, briefly touching on other routes, for example, subconjunctival or subretinal, in the case of gene therapy. Various excellent reviews are available elsewhere (Agrahari et al., 2016; Gaudana et al., 2010; Del Amo et al., 2017; Urtti, 2006; Ghate and Edelhauser, 2006; Shen et al., 2018; Schoenwald, 2003).