Evaluation of RGD peptide hydrogel in the posterior segment of the rabbit eye.

The aim of this study was to evaluate the biocompatibility and biodegradability of RGD peptide hydrogel in the posterior segment of the eye as a biomaterial potentially useful for sustained drug delivery systems. RGD peptide hydrogel was injected into the vitreous cavity and suprachoroidal space of rabbit eyes. Clinical follow-up and histological observation were performed up to four weeks. The biodegradability was also evaluated by the lifetime of the hydrogel which was defined by ophthalmoscopic observation or ultrasonography. The results showed that RGD peptide hydrogel was well tolerated in the vitreous cavity and suprachoroidal space, and disappeared from the injection sites progressively. As for suprachoroidal injection, the hydrogel was clearly identified by ultrasound echography and was confirmed innoxious to the retinal vessels by fluorescein angiography. Histological observations showed that the structures of retina, choroid and other tissues around the injection site remained normal after the injection. The lifetime of the hydrogel was 25.7 ± 2.65 days and 14.3 ± 3.3 days in the vitreous cavity and suprachoroidal space, respectively. The results obtained demonstrated that RGD peptide hydrogel, which showed excellent biocompatibility and favorable biodegradability in the posterior segment of rabbit eyes, appears to be a promising biomaterial to deliver drugs focally to the choroid and the retina.