[Transcorneal and transscleral iontophoresis of the dexamethasone phosphate into the rabbit eye].
OBJECTIVE
To evaluate the efficiency of the dexamethasone phosphate penetration into the rabbit eye after transcorneal and transscleral iontophoresis using a drug loaded hydrogel assembled on a portable iontophoretic Mini Ion device.


METHODS
lontophoresis 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 electric current of 1 mAmp for 1, 2, and 4 min. In the control group, the dexamethasone was applied in drops into the conjunctival sac. Transconjunctival and transscleral iontophoresis were performed in the pars plana area, through the conjunctiva or directly on the sclera. Dexamethasone concentrations were assayed using HPLC method. To study the anatomical changes after iontophoresis application, histological examinations of corneas excised 5 minutes and 8 hours after the procedure were performed.


RESULTS
Dexamethasone levels in the rabbits' corneas after a single transcorneal iontophoresis were up to 38 times higher compared to those obtained after topical eye drops instillation. High drug concentrations were obtained in the retina and sclera 4 hours after transscleral iontophoresis as well. There were no statistically significant differences in the drug concentration after transscleral and tranconjunctival iontophoresis. Histological examination of the corneas after the iontophoresis showed only discrete reversible changes of the epithelium and the stroma.


CONCLUSIONS
A short, low-current, non-invasive iontophoretic treatment using the dexamethasone-loaded hydrogels has a potential clinical value in increasing the drug's penetration into the anterior and posterior segment of the eye.
Raiskup-Wolf
F
F
Ocná klinika, Fakultná nemocnica Univerzity Drázd'any, Nemecko. Frederik.Raiskup-Wolf@uniklinikum-dresden.de
Eljarrat-Binstock
E
E
Rehák
M
M
Domb
A
A
Frucht-Pery
J
J
D000818:Animals; D003315:Cornea / Q000378:metabolism; D003907:Dexamethasone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005123:Eye / Q000378:metabolism*; D007478:Iontophoresis; D011817:Rabbits; D012590:Sclera / Q000378:metabolism
C004180:dexamethasone 21-phosphate; D003907:Dexamethasone