Microemulsion:A Versatile Tool for Ocular Drug Delivery

Eye drops are the most acceptable dosage form by ocular route, which as has disadvantage of bioavailability. The anatomical and physiological constrains limited permeability of drug such as drug loss from the ocular surface by lachrymal drainage, blood-ocular barriers. A number of drug delivery system has been developed to improve the bioavailability and to prolong the residence time of drugs on the eye. Such as promising system for ocular drug delivery is a microemulsion. Microemulsions are clear, stable, isotropic mixtures of oil, water and surfactant, frequently in combination with a cosurfactant. This review gives an overview of the potential of microemulsions as delivery vehicles for eye. Both lipophilic and hydrophilic characteristics are present in microemulsions, so that the loaded drugs can diffuse passively as well get significantly partitioned in the variable lipophilic-hydrophilic corneal barrier.