A Novel Ophthalmic Pharmaceutical Nano emulsion: Methods of Preparations, Characterizations, and Applications

Ocular delivery drug is the major challenge faced by formulation scientists and pharmacologists because of the poor ophthalmic bioavailability. One of the most promising technologies is the Nanoemulsion drug delivery system. Nanoemulsions have the potential advantages in pharmaceutical industries because of the transparency at high droplet volume fraction, safe, patient compliant formulation which is being applied to enhance the solubility and higher rate of  bioavailability of lipophilic drugs, ease of manufacturing and permeation over conventional formulations that convert them to important drug delivery systems. As the drug is lipophilic in nature it can be easily soluble into the oil phase that is used in the formulation of the nanoemulsions and also reduced particle size to the nanometer range favors the formulation to achieve more surface area there by solubility of the lipophilic drug can be achieved. Nanoemulsions are submicron sized emulsion that is under extensive investigation as drug carriers for improving the delivery of therapeutic agents. These are clear, thermodynamically stable, isotropic liquid mixtures of oil, water, surfactant and co-surfactant. These are oil-in-water (o/w) type of emulsions with the average droplet size ranging from 5 - 200 nm and shows a narrow size distribution. Reduction in droplet size to nanoscale leads to change in physical properties such as optical transparency & unusual elastic behavior. Nanoemulsions have future widespread applications in different fields such as pharmaceutics, food technology, diagnostics drug therapies and biotechnologies. This review mainly discussed about the importance of ophthalmic nanoemulsions over other dosage forms, advantage and disadvantage various methods of preparation, characterization of nanoemulsions and applications.