Potential evaluation of dendrimer and iontophoresis association for ocular drugs administration

Abstract

The main ocular diseases that require less invasive and more efficient treatments include macular degeneration, viral infections, uveitis and retinal degeneration. The great challenge is to develop adequate delivery systems for drugs, such as dexamethasone and ganciclovir, widely used in the treatment of these pathologies. These systems have to make that drug reaches the disease site in appropriate therapeutic concentrations, with minimal side effects, ease of application and at the same time prolong the time of drug action. Therefore, the development of strategies that enable effective topical application of those drugs would be of great value to the treatment of such diseases and patient comfort. The goal of this project is to prepare and characterize dendrimer containing lipophilic (dexamethasone) and hydrophilic drug (ganciclovir), separately, and study the ocular passive and iontophoretic absorption of these substances from dendrimer formulations developed in in vitro and in vivo. It is known that dendrimer can prolong the residence time of drugs in the eye. Nanoparticulated dendrimeric systems are, however, large in size and may have difficult to cross the membranes of the eye, the cornea and sclera, to achieve the posterior segment. The application of iontophoresis on these systems should facilitate the penetration of drugs and even of dendrimer to internal segments of the eye. Thus, dendrimer-drugs complexes, from dendrimer with different functional groups, will be obtained and characterized, and the ability of these complexes to prolong the time residence of drug in the eye will be evaluated in vivo. The influence of iontophoresis in penetration of formulations containing the delivery systems developed (dendrimer-drug) will be evaluated, and the quantities of drugs present in different segments of the eye will be determined. Finally, iontophoretic mechanisms that affect the delivery and ocular penetration of hydro and lipophilic drugs, administered alone or encapsulated in dendrimer, will be studied in an attempt to propose effective formulations for topical administration aimed at the treatment of ocular pathologies.