ABSTRACT:
The novel carriers have been exploited through almost all the routes of administration. Many newer carriers are evolving with the advent of technology and the demand of targeted delivery like microemulsions. Microemulsions are clear, transparent, thermodynamically stable dispersions of oil and water, stabilized by an interfacial film of surfactant frequently in combination with a co-surfactant with a droplet size usually in the range of 20-200 nm. Microemulsions act as supersolvents of drug. They can solubilize hydrophilic and lipophilic drugs including drugs that are relatively insoluble in both aqueous and hydrophobic solvents. They have been used to improve the oral bioavailability of various poorly soluble drugs. Microemulsions as drug delivery tool show favourable properties like thermodynamic stability (long shelf-life), easy formation (zero interfacial tension and almost spontaneous formation), optical isotropy, ability to be sterilized by filtration, high surface area (high solubilization capacity) and very small droplet size. While microemulsions are used in several fields, this article focuses on the reported investigations for vaginal applications which exhibit minimal systemic absorption.