Formulation and evaluation of ion activated In-Situ gelling ophthalmic solution containing brimonidine tartrate using 3² factorial design

The objective of the current work is to develop an ion activated in situ gel for treatment of Glaucoma with Brimonidine Tartrate. As conventional eye drops exhibit the demerits of poor bioavailability, naso-lachrymal drainage and rapid pre-corneal elimination, it was proposed that ion activated ophthalmic in situ gel formulation approach can be used to address these issues. The gels were formulated using 3² factorial design by cold method using sodium alginate as gelling agent in the concentration of 1%, 1.25% and 1.5 %. HPMC K4M and Carbobol 971 P were used as mucoadhesive agent to increase ocular residence. The evaluation of the prepared formulations was done for appearance, gel strength, mucoadhesion, viscosity, gelation, pH, drug content, sterility and in vitro diffusion. The ocular irritancy test was done by HET-CAM test as well as the results show that the prepared in situ gel formulation exhibit sustained drug release up to 6 hours with excellent mucoadhesion which can achieve the objective of better ocular bioavailability.