Ophthalmic dosage forms for drug delivery to posterior segment

Background Degenerative ocular diseases such as macular retinopathy and retinal disorders significantly affect vision loss and the quality of life. The prevalence of these ophthalmic diseases is increasing due to surges in the elderly population and diabetes mellitus. Ophthalmic drug delivery systems for intraocular drug delivery have been studied and developed for decades. Due to multiple barriers in the eye, including physiological and anatomic obstacles, many challenges remain for enhanced ocular drug delivery. Currently, only a few approaches are available to treat ocular diseases. Area covered This review investigated various barriers in the eye and the current ocular formulations such as intravitreal injections and intravitreal implants. In addition, different types of advanced ophthalmic drug delivery systems, including lens implants, microneedle arrays, micropumps, nano-formulations, sonophoresis, and transscleral iontophoresis, were briefly reviewed. Expert opinion Novel ophthalmic dosage forms for drug delivery to the posterior segment should be developed to achieve a safe therapeutic effect. If some achievements can be established in further studies, the paradigm of chronic ocular diseases can be shifted to home-based self-administration, thus improving the therapeutic efficacy and the patient’s quality of life.