TPGS-chitosan conjugated mucoadhesive micelles of brinzolamide for glaucoma therapy: In vitro and in vivo evaluation

Micelle is a promising avenue for ophthalmic drug development technology and an especially suitable choice for hydrophobic drugs. The aim of this investigation was to synthesize Brinzolamide (BRZ) loaded d-alpha-tocopherol polyethylene glycol succinate (TPGS) - Chitosan conjugated micelles (BTCM) prepared by solvent evaporation method and to investigate their intraocular pressure (IOP) reducing efficacy for the management of glaucoma. The formulated BTCM was evaluated with various parameters such as size, zeta potential, morphology, percentage drug entrapment efficiency, drug loading capacity, and mucoadhesion strength, in-vitro and ex-vivo release. In-vivo anti-glaucoma efficacy study was conducted by glucocorticoid-induced glaucoma rabbit eye model and evaluated with the Marketed formulation (MF). The optimized formula showed a micelle size of 74.32±1.46 nm, and suitable physicochemical properties and in-vitro release mechanism were observed in that biphasic erosion-diffusion pattern of BRZ releases up to 8 h. The Ex-vivo corneal penetration of BRZ from BTCM showed a higher permeability rate than MF. Additionally, BTCM showed sustained release of BRZ, better corneal tissue compatibility, and improved anti-glaucoma potential, as compared to MF. The results concluded that BTCM is the suitable option for anti-glaucoma therapy because of its capability to improve ocular mucoadhesion of loaded BRZ via the interaction with the mucous membrane of the corneal surface.