Recent overview of ocular patents.

Ocular drug therapy has always been considered as a major challenge in the field of drug delivery. The presence of blood ocular barriers and efflux pumps has imposed a great concern as well. Various vision threatening disorders require a long term therapy of drug molecules, especially for the diseases that affect the posterior segment. Pharmaceutical companies and other research institutes have adopted a multidisciplinary approach to meet the current challenges which is evidenced by the trends seen in the published and filed U.S. patents. Various strategies have been employed to achieve long term sustained and targeted delivery for both the anterior and the posterior segments of the ocular diseases. These strategies include formulating drugs into implant, micro or nanoparticulate systems and hydrogel-based systems. Transporter targeted approach has also allowed scientists to deliver drugs to both the segments of the eye. Recent developments such as delivery of drugs utilizing ultrasound, iontophoresis and microneedle based devices have been promising. Genebased therapeutics has opened a new avenue for vision threatening disorders. In all, the current developments in the entire field have been very exciting for finding out new strategies to treat vision threatening disorders.

Microdialysis assessment of drug delivery systems for vitreoretinal targets.

Posterior segment drug delivery challenges inherent in the treatment of many sight-threatening diseases have become increasingly apparent. Therapeutic interventions for ocular diseases such as neovascular retinopathies, inflammatory and/or infectious diseases may involve drug delivery to vitreoretinal targets. An important part of successful therapeutic strategies for such diseases involves verification that efficacious concentrations of the pharmacological agent are achieved within relevant intraocular regions. Microdialysis has been effectively employed for characterizing intraocular disposition in both anterior and posterior segments, providing important documentation of successful drug delivery to desired targets. Recent papers that showcase the maturation in the model development of microdialysis approaches for estimating posterior segment pharmacokinetics and further validation of the methodology are described in this review. Special problems examined include anterior and posterior ocular clearance mechanisms, intraocular metabolism and active transport of drugs.