title: Transscleral iontophoresis of cefazolin, ticarcillin, and gentamicin in the rabbit.
abstract: Corneal iontophoresis produces high concentrations of drugs in the anterior segment but not in the vitreous humor of the phakic eye, presumably because transport is impeded by the lens-iris barrier. We have used two modifications to produce high levels of commonly used antibiotics in the vitreous humor of the phakic rabbit eye: the device is placed over the pars plana, circumventing the lens-iris barrier; the contact area of the column of fluid is kept small (less than or equal to 1 mm diameter) so as to provide a high current density. Applying 2 mAmp for 10 minutes, we were able to achieve mean vitreal concentrations of cefazolin, ticarcillin, and gentamicin of 94-207 micrograms/ml in the normal rabbit eye. Drug penetration showed a correlation with strength of current (0.1-2 mAmp) and with duration of iontophoresis (1-10 minutes) but not with concentration of the drug solution. Transscleral iontophoresis is a promising noninvasive technique to achieve high vitreal levels of charged solutes.
mesh_terms: D000818:Animals; D002437:Cefazolin / Q000008:administration & dosage*; D004361:Drug Tolerance; D005839:Gentamicins / Q000008:administration & dosage*; D007478:Iontophoresis / Q000379:methods*; D009994:Osmolar Concentration; D010406:Penicillins / Q000008:administration & dosage*; D011817:Rabbits; D012590:Sclera; D013982:Ticarcillin / Q000008:administration & dosage*; D014822:Vitreous Body
chemical_list: D005839:Gentamicins; D010406:Penicillins; D013982:Ticarcillin; D002437:Cefazolin