A Sustained Release Formulation of Novel Quininib-Hyaluronic Acid microneedles inhibits Angiogenesis and Retinal Vascular Permeability in vivo

Abstract

Purpose : Pathologic neovascularisation and ocular permeability are hallmarks of proliferative Diabetic Retinopathy and Age-related Macular Degeneration. Current pharmacologic interventions targeting VEGF are effective in only a subset of patients and require multiple intraocular injections associated with iatrogenic infection. Thus, our goal is to develop novel drugs with sustained ocular-release, that are VEGF-independent, anti-angiogenic and reduce permeability. Here, sustained release of quininib from a novel quininib-hyaluronic acid microneedle formulation is determined in vitro, and the safety and efficacy evaluated in vivo.

Methods : Quininib-hyaluronic acid (HA) microneedles were formulated via a salt precipitation method from a quininib-HA solution and cross-linked with 4-arm-PEG-amine prior to freeze-drying. Microneedle conformation was characterised by scanning electron microscopy. The zeta potential (charge) of the microneedles was determined by electrophoretic light scattering. Quininib released in vitro from the microneedles was quantified by HPLC. Anti-angiogenic activity was assessed in a zebrafish hyaloid developmental angiogenesis assay. The potential to ameliorate retinal vascular permeability after one month was determined using a cysteinyl leukotriene induced rodent model of retinal vascular permeability optimised by our lab and assessed by an Evan’s Blue assay.

Results : The quininib-HA formulation generated hollow needle-shaped particles with a charge of -35.5 mV. The majority of particles were >1.0 µm in size with 30% of particles ranging between 0.5-1.0 µm. The incorporation of quininib into these microneedles was 98%. In vitro, 20% quininib was released over 4 months; in the presence of increasing concentrations of hyaluronidase a maximum of 60% quininib was released over 4 months. Quininib released from these microparticles significantly inhibited hyaloid vessel development in zebrafish larvae (n=30) compared to control (p=<0.0001) and significantly inhibited retinal vascular permeability in Brown Norway rats (n=7) one month after administration compared to neat quininib control (p=0.0071).

Conclusions : Quininib-HA microneedles allow for sustained release of Quininib; are safe in vivo and quininib released from these microneedles effectively inhibits angiogenesis and retinal vascular permeability in vivo.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.