Formulation Aspects Behind the Development of a Stable Biphasic Liquid Dosage Form with Special Reference to Microemulsion: A Review

A plethora of research and industrial processes used microemulsion system after its discovery by Jack H. Shulman. The microemulsionis defined as clear, stable, isotropic mixtures of oil, water, and surfactant, frequently in combination with a co-surfactant. They are solutions of oil, water,andamphiphile which are optically isotropic and thermodynamically stable. The aqueous phase present in the system contains salt(s) and other ingredients while the "oil" phase mainly forms a complex of different hydrocarbons and olefins. They do not require high shear conditions as compared to ordinary emulsions. Hence they are easy to prepare. Ultralow interfacial tension, large interfacial area, thermodynamic stability and the ability to solubilize immiscible liquids are some of its unique properties. They also show the ability to protect labile drug, control drug release, increase drug solubility, increase bioavailability and reduce patient variability. Hence, microemulsion has gained most significance in both basictypes of research as well as in industry. They have wide applications and uses such as in pharmaceuticals, cosmetics, cutting oils, biotechnology, food, agrochemicals, environmental detoxification, analytical applications, microporous media synthesis, etc. The microemulsion can be effectively used in dermal delivery because of its mechanism, hence can be used in pharmaceutical and cosmetics preparation. Microemulsion enhances the dermal absorption as they allow rapid penetration of active molecules due to the large surface area of the internal phase and their components reduce the barrier of stratum corneum. Thus, microemulsionisa promising vehicle for effective drug delivery. The current review article deals with information about the microemulsion. Also, the present study is performed for the motivation of the graduates towards publication and research. Hence, we have encouraged the graduates to prepare an informative article on the present subject.