The potential of iontophoresis in introducing methotrexate and carboplatin into the eye

Abstract

Abstract Purpose: Intraocular injections of methotrexate have been used recently in place of the systemic approach to treat intraocular lymphoma and, sometimes, intraocular inflammation. Subconjunctival/subtenon injections of carboplatin have been recently used lately in some centers to treat retinoblastoma. In the last few years we have investigated the potential of iontophoresis for introducing these two drugs into the eye. Methods: Cylindrical agar gels served as a model resembling the eye for examining the transport of carboplatin in‐vitro. In‐vivo iontophoretic studies of methotrexate and carboplatin were performed on eyes of healthy rabbits, and the levels of the drugs were measured in different parts of the eye. The iontophoretic device we have employed is a portable, easy‐to‐use (Tonopen‐like) system, operated by battery. The drugs were loaded into hydrogels of different sizes and shapes, and varying electrical currents were tested. Results: Iontophoresis increased significantly the levels of methotrexate in the various eye parts. In contrast, levels of carboplatin achieved by iontophoresis were not significantly different from our control mock iontophoresis. Conclusions: A short, low‐current, non‐invasive iontophoresis treatment using methotrexate‐loaded hydrogels has potential clinical value in treating ocular inflammatory diseases and intraocular lymphoma. In contrast, carboplatin has high passive diffusion properties from the hydrogel into the ocular tissue, and iontophoretic application has no obvious advantage over local injection or application.