Formulation development and evaluation of loteprednol etabonate and tobramycin loaded ocular in-situ gel

The present study includes development of in-situ ophthalmic gel of Loteprednol etabonate and Tobramycin to be administered in the clu-de-sac of the eye using a combination of two polymers and optimization of the same. The pH triggered in-situ gel forming polymers selected for the study is Carbopol 940P. In the present work, Sodium alginate and Carbopol 940P were used as gelling agent that produced immediate gelation in presence of environmental stimuli like pH. Different formulations were prepared with varying concentrations of Sodium alginate and Carbopol 940P. These formulations were evaluated for the parameter like appearance, Viscosity, In-situ gelling capacity, In-vitro drug release study. A full factrorial design was applied to check the effect of varying concentrations of Sodium alginate (X1) and Carbopol 940P (X2) on the dependant variables i.e Viscosity (Y1) and time required to release 100% (Y2). The pH values of in-situ gel formulations were between 5.5-6.0. The release profile of formulations exhibited a sustained release upto 8 hrs. Isotonicity and Eye irritation study (HET-CAM) was carried out for the optimized batch. Formulation F5 was selected as optimized formulation with concentration of sodium alginate (1.2%w/v) and carbopol 940P (1.5%w/v) showing release upto 8hrs, viscosity (cps) and sol-gel transition time seconds. After stability study of optimized formulations it was found that there were no significant changes in the evaluation parameters. On the basis of these findings, the in-situ gel may be considered as feasible alternative to conventional eye drops.