RESUMO
PURPOSE: In order to treat inflammatory and proliferative disorders of the posterior segment of the eye, the authors evaluated the use of a biodegradable intrascleral implant for slow release of triamcinolone acetonide (TA). METHODS: The intrascleral implant (1 mm thick and 3 mm in diameter) was made of alginic acid and PLA (poly (D, L-lactide)) containing 4 mg of TA. In vitro release of TA was evaluated by HPLC. To evaluate in vivo release of TA, the implant was placed into a scleral pocket in 18 rabbit eyes and the concentrations of TA in the aqueous humor, vitreous, and retina-choroid-sclera were measured by HPLC at 1, 2, 4, 8, and 12 weeks after implantation. The toxicity and biocompatibility of the implant were evaluated by slit lamp examination, IOP, electroretinogram, and light microscopy. RESULTS: In vitro study demonstrated that the implant released TA in controlled manner for at least 8 months. The TA detected in the vitreous after 8 to 12 weeks and was not detected in retina-choroid-sclera at 8 weeks after implantation. The TA was not detected in aqueous humor. No significant toxicity to the retina was observed. CONCLUSIONS: These results suggest that the intrascleral implant of TA could be a promising system for the delivery of steroids to the posterior segment of eye in cases of inflammatory or proliferative disorders of posterior segment.