Preparation and Evaluation of Niosomes of Brimonidine Tartrate as Ocular Drug Delivery System

Nioosomes of brimonidine tartrate were prepared by film hydration method. The prepared vesicles were evaluated for photomicroscopic characteristics, entrapment efficiency, in vitro, ex- in vitro drug release, in vivo intra ocular pressure lowering activity. Methods employed for the preparation of vesicles were found to be simple and reproducible, produced vesicles of acceptable shape and size with unimodal frequency distribution pattern. The in vitro, ex-in vitro drug release studies showed that there was a slow and prolonged release of drug which followed zero order kinetics. The intra ocular pressure lowering activity of prepared formulations were determined and compared with pure drug solution. It was found that intra ocular pressure lowering action was sustained for longer period of time. Stability study data revealed that the formulations were found to be stable when stored at refrigerator temperature (2 °C to 8 °C) and at 25 °C with no change in shape and drug content. Results of the study indicated that it is possible to develop a safe and physiological effective topical niosomal formulation which is patient compliance.