Formulation and characterisation of in situ forming ocular depot implants for sustained protein delivery

Ranibizumab is a widely used anti-vascular endothelial growth factor (anti-VEGF) therapy for these conditions; however, its short intravitreal half-life necessitates monthly injections, which increase treatment burden, reduce patient compliance, and raise the risk of injection-related complications.

Therefore, there is a need for long-acting ocular drug delivery systems capable of providing sustained protein release while maintaining protein stability.This thesis investigated the development and characterisation of photocrosslinkable in situ forming ocular depot implants (ISFODIs) for long-term intravitreal delivery of ovalbumin (OVA), a model protein for ranibizumab. The ISFODIs consisted of PEGDA 700, PLGA, organic solvents, OVA and the photoinitiator Irgacure 819, combining solvent-induced phase inversion and photocrosslinking to form injectable depots following administration through a 27-gauge needle.Formulation optimisation demonstrated that phase inversion behaviour and photocrosslink density were critical determinants of depot performance.