ABSTRACT:
The aim of this study is to formulate a novel ophthalmic nanosuspension (ONS), an alternative carrier system to traditional colloidal carriers for controlled release (CR) of Indomethacin (IM). In the present study, ONS is employed to avoid some of major disadvantages of colloidal carriers systems such as instability in cul de sac and short half life by increasing efficiency of drug encapsulation as well as by CR. A quassi-emulsion solvent evaporation method was used to prepare IM loaded Eudragit RS 100 ONS with the aim of improved ocular bioavailability and distribution. Five different formulations were prepared and evaluated for pH of ONS, particle size, entrapment efficiency, differential scanning calorimetry (DSC), in vitro release profile, in vivo release studies and stability studies. An average size range of 50 to 500 nm in diameter was obtained and encapsulation efficiency up to 96.0% was observed for all the formulations. Cumulative percent drug released for all formulations after 14 h was between 86.24 to 96.18% indicating effective CR property of ONS. The release profile revealed from best formulation followed Non-Fickian diffusion mechanism. In vivo studies showed that IM concentration in aqueous humor up to 6 h was 73.80, 45.19 and 41.71µg/ml. No appreciable difference was observed in the extent of degradation of product during 90 days in the nanosuspension, which were stored at various temperatures Overall, the study also revealed that ONS was capable of releasing the drug for a prolonged period of time and increased bioavailability.