Development, characterization and evaluation of ginger extract loaded microemulsion: In vitro and Ex vivo release studies.

Zingeber officinale (ginger) has been used for a long time in conventional medicine for the management of many diseases most important of which is inflammatory diseases. The aim of this study was formulation of topical microemulsion system to enhance the solubility, stability and release profile of ginger extract, as it is unstable in the presence of light, air, heat and long term storage. The solubility of ginger extract in different oils, surfactants, and cosurfactants was determined in order to find the optimal components for microemulsion. Isopropyl myristate (IPM) was selected as oil phase, tween 80 and PEG 400 were selected as surfactant and co-surfactant respectively based on highest solubility values. Pseudo-ternary phase diagram was constructed in order to find out the microemulsion region. The prepared microemulsions were evaluated for pH, viscosity, conductivity, refractive index, globular size, zeta potential, polydispersity index, ginger extract content, in-vitro and ex-vivo release profiles. The formulation GE1 showed best physicochemical properties with smallest globular size (19.75nm), highest release rate and flux value. It also showed significant (p<0.05) anti-inflammatory effect as compared to reference piroxicam drug solution. It is concluded that ginger extract can be used to develop stable microemulsion system with better skin permeation and promising antiinflammatory activity.