Microemulsion is prepared with appropriate water, oil, surfactant and cosurfactant and with special technics, whose particle size is between 10 and 100nm, whose appearance is transparent, whose different direction is parallel and whose thermodynamics is stability. As one kind of drug carrier, microemulsion has many advantages such as low viscosity, good stability, increasing incorporation of drugs that do not dissolve in water, improving stability and scatter of drugs, accelerating absorbabilit...