Abstract
Purpose :
Dexamethasone (DEX) is widely used for the treatment of severe macular diseases. However, it is difficult to deliver effective doses of DEX to the posterior eye segment for long periods. We have generated a simple insertion technique of intra-choroidal sustained DEX implant through posterior scleral approach. This procedure would be helpful to increase the DEX level in the posterior retina.
Methods :
An implant was prepared by dissolving poly(DL-lactide)(PLA) and DEX. In vitro release of DEX was measured at 1, 7, and 28 days by mass spectrometry. In vivo, 20G needle was shallowly stabbed the sclera of Japanese white rabbit and moved ahead in the choroid. After that, the implant in 20G needle, was inserted to the choroid at 2 disc diameter inferior to the optic disc by using an injector. After the implantation, the DEX level in the retina was determined at 1, 7, and 28 days by mass spectrometry. Possible adverse effects of the implant, were evaluated by ophthalmoscopy and light microscopy.
Results :
The implant showed an initial burst within 24 hours, and then the DEX was gradually released at least for 4 weeks in vitro. In vivo, the intra-choroidal implant at 24 hours effectively delivered the DEX into the posterior retina. After that, this implant released the DEX constantly at least for 4 weeks. DEX implant showed no retinal abnormalities except the implantation site in ophthalmoscopy and light microscopy.
Conclusions :
We have demonstrated a simple methodology of intra-choroidal sustained drug delivery system in posterior eye segment. This new drug delivery system may be possible to insert an implant near the optic disc-macular lesion, and useful in adjusting the most effective and minimum medication to individual patient.
This is a 2020 ARVO Annual Meeting abstract.