OcuPhor™ – The Future of Ocular Drug Delivery
Satish Gupta, Rajendra Gurjar
Smriti College of Pharmaceutical Education, Indore
Abstract
Current methods for ocular delivery include topical administration (eye drops), subconjunctival injections, periocular injections, intravitreal injections, surgical implants, and systemic routes. However, all of these methods have limitations. Therapeutic levels of many drugs may be difficult to achieve in ocular tissues and systemic toxicities are of concern when the oral and intravenous routes of administration are used. Intravitreal injections, periocular injections, and sustained-release implants can be used to achieve therapeutic levels of drugs in ocular tissues, but invasive methods are inherently risky due to the potential for bleeding, infection, retinal detachment, and other local injuries. Eye drops are useful in treating conditions affecting either the exterior surface of the eye or tissues in the front of the eye, but cannot penetrate to the back of the eye for treatment of retinal diseases. To meet these needs a novel ocular iontophoresis system (OcuPhor TM) to deliver drugs safely and noninvasively to the back of the eye. OcuPhor TM Iontophoresis offers a non-invasive and reproducible means of delivering a model anionic drug to eye tissues, specifically to the retina/choroid
keyword:- OcuPhor, Iontophoresis , Ocular drug delivery
Introduction :
Age-related macular degeneration (AMD) and diabetic retinopathy (DR) are the major causes of blindness in the United States and Europe. Posterior uveitis and retinitis secondary to glaucoma also contribute considerably to loss of vision. These conditions affect tissues at the back of the eye, where drug treatment is difficult to administer.
Current methods for ocular delivery include topical administration (eye drops), subconjunctival injections, periocular injections, intravitreal injections, surgical implants, and systemic routes. However, all of these methods have limitations. Therapeutic levels of many drugs may be difficult to achieve in ocular tissues and systemic toxicities are of concern when the oral and intravenous routes of administration are used. Intravitreal injections, periocular injections, and sustained-release implants can be used to achieve therapeutic levels of drugs in ocular tissues, but invasive methods are inherently risky due to the potential for bleeding, infection, retinal detachment, and other local injuries. Eye drops are useful in treating conditions affecting either the exterior surface of the eye or tissues in the front of the eye, but cannot penetrate to the back of the eye for treatment of retinal diseases. To meet these needs a novel ocular iontophoresis system (OcuPhor TM) to deliver drugs safely and noninvasively to the back of the eye. OcuPhor TM Iontophoresis offers a non-invasive and reproducible means of delivering a model anionic drug to eye tissues, specifically to the retina/choroid
OCUPHORTM OCULAR DRUG DELIVERY TECHNOLOGY
Iontophoresis is an active method of drug delivery which uses a small electrical current to transport ionized drugs into and through body tissues. Early ocular iontophoresis devices designed for animal studies were inconvenient and not standardized (making it difficult to achieve reproducible results) and were impractical for human use. These early devices produced very high current densities, which damaged eye tissues. Iomed designed the OcuPhorTM ocular drug delivery system.
The OcuPhorTM system consists of
· drug applicator,
· dispersive electrode,
· an electronic iontophoresis dose controller.
The drug applicator is a small silicone shell that contains a patented silver-silver chloride ink conductive element; a hydrogel pad to absorb the drug formulation; and a small, flexible wire to connect the conductive element to the dose controller. The drug pad is hydrated with drug solution immediately prior to use, and the applicator is placed on the sclera of the eye under the lower eyelid (Figure 1).
Figure 1:- OcuPhorTM system
The eyelid holds the applicator in place during treatment, which usually takes less than 20 minutes.
Because iontophoretic drug delivery depends primarily on electrical current and dosing time, programming and setting the electronic controller can control drug dose and rate of administration.
Iomed's small, battery-powered controller delivers constant current and is designed to be placed conveniently away from the patient during a treatment session.
A dispersive pad is placed on the patient's skin and connected to the dose controller to provide a complete path for the electrical circuit.
An effective drug delivery system not only has to deliver therapeutic amounts of drug into target tissues, but also has to control the delivered dose and rate of dosing reproducibly.