Topical Ocular Delivery of TGF-β1 to the Back of the Eye: Implications in Age-Related Neurodegenerative Diseases

Dysregulation of the transforming growth factor-beta 1 (TGF-beta 1)/selected small mother against decapentaplegic (SMAD) pathway can be implicated in development of age-related macular degeneration (AMD), and the delivery of TGF-beta 1 could be beneficial for AMD. We developed a new ophthalmic formulation of TGF-beta 1 assessing the ocular pharmacokinetic profile of TGF-beta 1 in the rabbit eye. Small unilamellar vesicles (SUV) loaded with TGF-beta 1 were complemented with Annexin V and Ca2+, and the vitreous bioavailability of TGF-beta 1 was assessed after topical ocular administration by a commercial ELISA kit. We detected high levels of TGF-beta 1 (C-max 114.7 +/- 12.40 pg/mL) in the vitreous after 60 min (T-max) from the topical application of the liposomal suspension. Ocular tolerability was also assessed by a modified Draize's test. The new formulation was well tolerated. In conclusion, we demonstrated that the novel formulation was able to deliver remarkable levels of TGF-beta 1 into the back of the eye after topical administration. Indeed, this TGF-beta 1 delivery system may be useful in clinical practice to manage ophthalmic conditions such as age-related macular degeneration, skipping invasive intraocular injections.