Cell penetrating peptide constructs: A novel drug delivery to the eye

Purpose In neovascular age-related macular degeneration (AMD) blood vessels grow from the choroid under the retina causing macular damage and scarring. Anti-VEGF drugs such as, ranibizumab or aflibercept are administered by intravitreal injection to treat AMD related neovascularisation, We present a novel cell-penetrating peptide construct (CPPC) topical delivery system to deliver Ranibizumab to the retina using drops. Methods Peptides were produced using standard solid-phase peptide synthesis. They were analysed using mass spectrometry and purified using high-pressure liquid chromatography and used at a purity of >95%. CPPC were built around the drugs by vortexing for 10 seconds and incubating at room temperature. Drug delivery experiments were carried out ex-vivo in freshly enucleated porcine eyes. In vivo experiments were carried out in C57 mice. Mice had a three 100 μm laser burns to the choroid to model neo-vascularisation in AMD. They then received a single intravitreal injection of an anti-VEGF agent or CPPC/Ranibizumab applied topically to the conjunctival sac twice daily for the duration of the experiment. Choroidal neovascularisation was measured by immunohistochemistry. Results Ex vivo delivery to enucleated porcine eyes demonstrated that a single 60 μL drop could deliver 1.7 ± 0.4 μg/mL of ranibizumab to the vitreous cavity. Confocal images of immunohistochemistry on retinal wholemounts showed ranibizumab within the retina. In vivo experiments demonstrated both intravitreal injection and CPPC bound Ranibizumab reduced neovascularisation equally, compared to controls Conclusions CPPC can be used topically to deliver therapeutic levels of Ranibizumab to the posterior segment.