Formulation and evaluation of brinzolamide encapsulated niosomal in-situ gel for sustained reduction of IOP in rabbits

Abstract

Glaucoma, the multifactorial disease of the eye, is characterized by many biological risk factors as well as genetic factors which lead to degeneration of optic nerves. The major factor which is associated with glaucoma is increase in intraocular pressure (IOP). Treatment for glaucoma should be such that to reduce the IOP either by decreasing the production of aqueous humor or by enhancing its drainage. Currently, the most commonly used approach is the use of conventional ophthalmic eye drops, which accounts for approximately more than 90% of the available marketed ophthalmic dosage forms. Brinzolamide, the carbonic anhydrase inhibitor, in the present study has been formulated as niosomes to provide a sustained action and compared with niosomal in-situ gel loading Brinzolamide. Brinzolamide loaded niosomes had vesicle size of 236.2 ± 3.1 nm and a high zeta potential of −46.2 ± 3.1 mV. A high Encapsulation efficiency of 79.99 ± 2.2% and a sustained release profile in vitro for 24 h. The Niosomal in-situ gel system showed good gelation capacity and adequate spreadability. In-vivo studies conducted on healthy New Zealand white rabbits showed maximum IOP reduction at 8 h and maintained IOP reduction effect till 24 h. The study showed a sustained release of Brinzolamide from the niosomal in-situ gel and a sustained reduction in IOP in rabbits for 24 h with a single administration.