Drug delivery to the back of the eye following topical administration: an update on research and patenting activity.

Drug delivery to the back of the eye following topical administration remains an unmet need for the scientific community. Treatment of posterior segment diseases requires localized and long-term drug delivery to the retina, choroid, and Bruch's membrane. Until the last decade, there was limited evidence from large clinical trials that demonstrated the usefulness of pharmacotherapy compared to laser therapy or other vitreoretinal surgical techniques for the treatment of retinal diseases. This paradigm has shifted in recent years, with strong evidence demonstrating superior efficacy of ophthalmic drugs compared to previous gold standards. However, ophthalmologists are left with no options other than administering the therapeutics via implants and intravitreal injections, which are highly invasive and associated with patient non-compliance. A non-invasive topical therapy would enhance patient compliance and minimize the side-effects associated with intraocular implants and intravitreal injections. In an attempt to enhance patient compliance, the focus of research has shifted to the development of novel small molecule-based eye drop formulations. This review article discusses the relevant patents and summarizes the resurgence in the treatment of posterior segment eye diseases through topical drug administration.