Development of Triamcinolone Acetonide Nanocrystals for Ocular Administration.

Triamcinolone acetonide (TA) is a powerful anti-inflammatory drug used in the treatment of inflammatory ocular disorders; however, its poor aqueous solubility and ocular anatomical barriers hinder optimal treatment. The aim of this work was to obtain triamcinolone acetonide nanocrystals (TA-NC) to improve ocular corticosteroid therapy. Self-dispersible TA-NC were prepared by the bead milling technique followed by spray-drying, exhaustively characterized and then evaluated in vivo in an ocular model of endotoxin-induced uveitis (EIU). Self-dispersible TA-NC presented an average particle size of 257 ± 30 nm, a narrow size distribution and a zeta potential of -25 ± 3 mV, which remained unchanged for 120 days under storage conditions at 25 °C. In addition, SEM studies of the TA-NC showed uniform and spherical morphology, and FTIR and XRDP analyses indicated no apparent chemical and crystallinity changes. The subconjunctival administration of TA-NC in albino male white rabbits showed no clinical signs of ocular damage. In vivo studies proved that treatment with self-dispersible TA-NC alleviated the inflammatory response in the anterior chamber and iris in EUI rabbit eyes. Dispersible TA-NC are a promising approach to obtaining a novel nanometric TA formulation for ocular disorders.

Novel hybrid lipid nanocapsules loaded with a therapeutic monoclonal antibody - Bevacizumab - and Triamcinolone acetonide for combined therapy in neovascular ocular pathologies.

The aim of this study was to design and develop a novel hybrid formulation based on lipid nanocapsules containing bevacizumab (BVZ), an effective therapeutic antibody, on the surface and triamcinolone acetonide (TA) in the inner core (BVZ-TA-LNC) intended to improve ocular therapy. Hence, a phase inversion-insertion one step method was developed to drug loading and surface modification of lipid nanocapsules by post-insertion of a bifunctional polymer, followed by antibody coupling using "click" chemistry. The covalent bond and antibody capacity binding to its specific antigen were confirmed by thermal analysis and immunoassay, respectively. BVZ-TA-LNC presented nanometric size (102 nm), negative surface potential (-19 mV) and exhibiting 56% of TA in the lipid core. BVZ-TA-LNC tended to prevent the endothelial cell migration and significantly prevented the capillary formation induced by the vascular endothelium growth factor (VEGF). The novel hybrid system allowed the co-loading of two different therapeutic molecules and may be promising to improve the therapy of eye disorders that occur with inflammation and/or neovascularization.

Polysaccharide-Based Nanocarriers for Ocular Drug Delivery.

Obtaining successful ocular formulations able to support an efficient drug concentration at the target tissue for an appropriate period of time is an interesting challenge for modern pharmaceutical technology. In this sense, nanotechnology is one of the available strategies to obtain a drug carrier system that allows access to different compartments of the eye in order to deliver drugs to the desired site. Biodegradable polymers such as polysaccharides are promising biomaterials for the production of biocompatible and biodegradable nanocarriers (NCs). Different types of polysaccharide NCs are capable of improving the transport of drugs after ocular application and they can be either polysaccharide-matrix carriers or polysaccharide-coated carriers, depending on whether polysaccharide is used as a matrix or as a coating, respectively. This review focuses on recent advances achieved by polysaccharide-based NCs for the treatment of ocular disorders.