Abstract
Purpose: :
Intravitreal needle injection is associated with risks of retinal detachment and endophthalmitis. Photokinetic drug delivery involves stimulation of optical sites of organic molecules causing reversible conformational changes and migration across tissue. The purpose of this study was to assess the feasibility of this technology to noninvasively deliver drugs into the eye.
Methods: :
In vitro
Results: :
Transscleral flux of methotrexate (84 µg/sq cm) was significantly higher (p<0.05) than passive controls (1.5 µg/sq cm) at 370nm/24 cps at 15’ of exposure. Further significant increases were observed at 30’ and 60’. Transscleral flux of insulin was examined over a 24 hour period. Light exposure at 450nm with a 24 cps pulse rate resulted in a 5-fold increase (26519 µU/sq cm) in flux across sclera (p<0.006) compared to control (3791 µU/sq cm). Hyaluronic acid permeation was tested at 405 nm/100 cps over a 24 hr period. A significant increase in transscleral flux was observed in the light-exposed group (13072 ng/sq cm) compared to controls (278 ng/sq cm, p<0.001). Scleral morphology was unchanged by light exposure.
Conclusions: :
Photokinetic technology is a novel platform to deliver molecules of a variety of molecular weights across intact sclera. Individual drug transcleral flux rates were highly wavelength and pulse rate dependent. This may be an alternative approach for posterior segment drug delivery which avoids the disadvantages of intravitreal needle injection.
Keywords: sclera • injection • retina