The team from the University of Southern California has created a simple polymer device which is inserted under the conjunctiva and delivers a therapeutic to the affected area. In time the device could come to replace the intravitreal injections which patients suffering from glaucoma and related eye diseases currently have to be administered with.
Ellis Meng, researcher on the project, was keen to emphasise further refinements are in the pipeline. She said: "This prototype isn't optimally sized; it's our first go at proving the concept. We're now building a next-generation device." The one centimetre long prototype consists of a refillable reservoir sutured to the sclera which contains the therapeutic. Leading off this is a flexible tube which is inserted into the side of the eye and through which the drug is delivered.
Similar tubes are already used for draining excess fluid from the eyes of glaucoma patients. Pressing the reservoir dispenses the therapeutic in the current prototype but this system is due to be upgraded in future models, with the researchers planning on incorporating a simple electrolysis pump. This should ensure that accurate dosages are delivered.
When the reservoir is drained it can be refilled in situ. A syringe needle is used to refill the reservoir, which can be pierced repeatedly without developing a leak. Further improvements are planned for subsequent models, which are to be optimally sized with contoured corners. This is aimed at allaying concerns, raised in particular by ocular drug delivery expert Susan Barker, that patients may be able to feel the device.
Assuming further developments are a success commercialisation of the product would be a boon for those suffering from ocular diseases, who currently have limited drug delivery options. Current topical, systemic and intraocular suffer from limited efficacy due to physiological barriers and potential side effects. Consequently considerable effort has been put into the development of novel drug delivery devices.
Other research has focused on the use of microneedles to effectively deliver drugs to the back of the eye. In testing the device was inserted into the sclera and delivered 70 times more therapeutic than current techniques and without any negative side effects.
Considering the dearth of suitable drug delivery options currently available companies in the sector will be keen to get their products into the market, which is worth $6bn according biotech company QLT.