Long-acting drug delivery systems for ocular therapies

With an ever-increasing life expectancy in the modern day, chronic ocular diseases are becoming more common. At present, many of these have to be treated with repeated administrations of pharmacological agents, which bring issues ranging from a lack of compliance, due to difficulty in remembering to administer a dose, to more significant problems, such as endophthalmitis and retinal detachment, often associated with the multiple intravitreal injections required to treat some diseases of the posterior segment. In response to this, research into the development of long-acting ocular drug delivery systems has stepped up in recent years, with various types of sustained-release formulations being developed, which have positives and negatives, depending on the target site and the conditions being treated. This chapter aims to explain the increasing need for such systems and to highlight some of the key approaches being taken in the current research to produce them.