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Transcorneal and transscleral iontophoresis of dexamethasone phosphate using drug loaded hydrogel

Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
Journal of Controlled Release (Impact Factor: 7.26). 10/2005; 106(3):386-90. DOI: 10.1016/j.jconrel.2005.05.020
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ABSTRACT To evaluate dexamethasone penetration to the eye after a short transcorneal and transscleral iontophoresis using a drug loaded hydrogel assembled on a portable iontophoretic device.
Iontophoresis of dexamethasone phosphate was studied in healthy rabbits using drug loaded disposable HEMA hydrogel sponges and portable iontophoretic device. Corneal iontophoretic administration was performed with a current intensity of 1 mA for 1 and 4 min. Transconjunctival and transscleral iontophoresis were performed twice for 2 min at two near places in the pars-plana area, on the conjunctival membrane or directly on the sclera. Dexamethasone concentrations were assayed using HPLC.
Dexamethasone levels in the rabbit cornea after a single transcorneal iontophoresis for 1 min were up to 30 fold higher compared to those obtained after frequent eye drop instillation. Also, high drug concentrations were obtained in the retina and sclera 4 h after transscleral iontophoresis.
A short low current non-invasive iontophoretic treatment using dexamethasone-loaded hydrogels has potential clinical value in increasing drug penetration to the anterior and posterior segments of the eye.

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    • "Results from previous transscleral iontophoresis studies are generally consistent with this trend. For example, iontophoresis studies of dexamethasone phosphate, methylprednisolone, amikacin, cefazolin, ticarcillin, and gentamicin showed an increase in delivery into the eye when the electric current of iontophoresis was increased (Barza et al., 1986;Behar-Cohen et al., 2002;Vollmer et al., 2002;Eljarrat-Binstock et al., 2005). In a study of the effects of current density upon iontophoretic delivery of fluorescein into the posterior segment of the eye, electric current density was shown to significantly affect transscleral delivery when the current density was above 40 mA/cm 2 (Maurice, 1986). "
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