The last 10-20 years have seen the development and optimization of the technology of iontophoresis as a noninvasive method of drug delivery. Peptide and protein drugs (e.g., insulin and vasopressin) have been delivered iontophoretically without the pain and side effects associated with traditional subcutaneous injection (10,165,166). Iontophoresis also has the potential to revolutionize clinical diagnosis and monitoring procedures in that it offers an avenue for extracting information from the body without the need for invasive procedures (3,167,168). Iontophoresis is already used clinically in physical therapy clinics, and an allergy patch test is close to commercial reality (33,169).
Ocular iontophoresis is fast, painless, safe, and, in most cases, results in the delivery of a high concentration of the drug to a specific ocular site. Experimentally, iontophoresis has proven extremely useful as a reliable system for inducing reactivation of herpes simplex virus in various animal models of this ocular disease. Clinically, ocular iontophoresis is potentially a valuable adjunctive treatment for cytomegalovirus retinitis. In glaucoma studies, iontophoresis of fluorescein, adrenergic agents, and 5-fluorouracil has facilitated the study of aqueous humor dynamics, treatment of glaucoma, and the control of cellular proliferation of glaucoma surgery. Anesthetics and antibiotic/antifungal agents can be delivered transcorneally or transsclerally according to the site of infection. Ocular iontophoresis has
Table 3 Iontophoresis Equipment and Suppliers
2441 South 3850 West, Suite A Salt Lake city, UT 84120 (801) 975-1191 (800) 621-3347 Fax (801) 975-7366
Life-Tech, Inc. 4235 Greenbrier Drive Stafford, TX 77477 (713) 495-9411 (800) 231-9841 Fax (281) 492-6646
General Médical Company 1935 Armacost Avenue Los Angeles, CA 90025 (310) 820-5881 (800) 432-5362 Fax (310) 826-5778
Wescor, Inc. 459 South Main Street Logan, UT 84321 (435) 752-6011 (800) 453-2725 Fax (435) 752-4127
Fischer Co., Inc 517 Commercial Street Glendale, CA 91203 (818) 241-1178 (800) 525-3467 Fax (323) 245-2748
Phoresor II Auto model number PM900. This model provides an effective, safe, and easy to use system with a preset dose (40 mAmp-Mins) for iontophoretic drug application to the skin. This model is compact, easy to operate, fast to set-up, and portable. E-mail: [email protected],com Website: www.iomed.com
Iontophor-II model number 6111 PM/DX. This model provides a painless, safe, and effective method of delivering high concentrations of drug into a localized skin area. This unit is battery operated, compact, and portable. It is an excellent unit for maintaining constant current. This model has dual site treatment function that enables you to treat two sites simultaneously. E-mail: [email protected] Website: www.life-tech.com
Macroduct model 3700. This model is used for sweat stimulation (pilocarpine iontophoresis), collection and analysis (via a sweat analyzer). It is easy to operate and provides accurate and reliable sweat testing. E-mail: [email protected] Website: www.dataloggersinc.com
Fischer Galvanic Unit, Model MD-1a is a high-output iontophoretic device ideally suited for treatment of large areas (hyperhidrosis patients). It produces DC current in two ranges (0-10mAmp and 0-50mAmp). Available to physicians or by prescription only. E-mail: [email protected] com Website: www.rafischer. com
Table 3 Continued
Dagan Corporation 2855 Park Avenue Minneapolis, MN 55407 (612) 827-5959 Fax (612) 827-6535
MedTherm Corporation 2604 Newby Road Huntsville, AL 35805 (205) 837-2000
155 Schmitt Boulevard Farmingdale, NY 11735 (631) 249-1134 (800) 243-7446 Fax (631) 249-1242
MedTronic, Inc. 7000 Central Ave., NE Minneapolis, MN 55432 (612) 574-4000 (800) 525-5552 Fax (612) 785-6541
Dagan 6400 Advanced model. Micro-Iontophoresis current generator. Delivers precise drug delivery without batteries. Power is 100 to 115 volts AC. Current range is 0-1000 n/Amp.
Electro-Medicator Model A1 (Distributed by Pamir Electronics corp.: 603 N. Gordon Drive, Exton PA 19341; (610) 594-8537). This model is used for dental research and clinical practice. It is easy to operate and has AC charging or direct use of AC. E-mail: [email protected] Website: www.pamir.com
Desensitron II model number ID643DGC. This model is used for treating hypersensitive teeth by iontophoresis of fluoride ions. Current range is 0-0.5mAmp. E-mail: [email protected] Website: www.parkell.com
Model 9820. This iontophoretic device is part of complete system (Model 9800) for sweat analysis after pilocarpine iontophoresis. E-mail
also been used to introduce genes into the anterior and posterior segments of the rabbit eye (170).
There are several ongoing ocular iontophoresis studies that are particularly pertinent to this discussion and should be noted. Chapon et al. (171), using rabbits, have shown that transscleral iontophoresis delivered 15 times more of the anti-CMV agent ganciclovir to the retina and 6.5 times more to the choroid (6 h posttreatment 370 and 828 ng/mg, respectively) than topical administration. At 3 days posttreatment, retinal levels of ganciclovir remained significantly higher than those achieved by oral administration, intravenous injection, topical application, or intravitreal injection. Chauvaud et al. (172) presented initial findings of a Phase II clinical trial for transscleral iontophoresis of the anti-inflammatory corticosteroid SoluMedrol (hemisuccinate methylprednisolone). Transscleral iontophoresis of SoluMedrol was safe, well tolerated, and easily applicable to the treatment of severe ocular inflammation thereby reducing the systemic side effects of corticotherapy. Hayden et al. (173) studied transscleral iontophoresis of the anticancer drug carboplatin in transgenic mice with hereditary retinoblastoma. A dose-dependent inhibition of intraocular tumor formation was observed following repetitive iontophoretic treatment. These results suggest that transscleral iontophoresis of carboplatin may be useful, as well as advantageous, in the treatment of intraocular pediatric retino-blastoma. Ocular iontophoresis is not a panacea for all eye disorders, but it is a viable alternative delivery system for those substances that are not amenable to topical application and/or require repeated administration over an extended period of time.
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