Advancing the stimuli response of polymer-based drug delivery systems for ocular disease treatment

The development of efficient therapies for ocular diseases remains a significant challenge because of the static and dynamic barriers in the eye. A variety of pharmaceutical strategies have been explored to overcome these ocular physiological barriers and thereby improve therapeutic bioavailability in both anterior and posterior ocular tissues. This mini-review summarizes, analyzes, and discusses recent advances in the field of ophthalmic drug delivery systems (DDSs). Specifically, the focus is on design strategies using stimuli-responsive polymers and their applications for the treatment of prevalent ocular diseases such as dry eye, ocular infection, glaucoma, and age-related macular degeneration. The stimuli-responsive polymers are categorized according to their responses in various ocular environmental conditions (such as temperature, pH, and ions). Additionally, general strategies and methodologies for the construction of effective ophthalmic stimuli-responsive DDSs are investigated by exploiting key parameters such as the stimuli-response type, ocular biocompatibility, ocular biodegradability, drug encapsulation and release, as well as the modifiable structure of the polymers. Also discussed in this review are the interrelationships among the designed structures, properties, and functions of the stimuli-responsive DDSs and their pharmacological treatment efficacies. In summary, we believe that the recent progress in the field of stimuli-responsive DDSs constitutes a significant advance for the development of effective pharmacological treatments for eye disorders.