A rheological study on microemulsion gels of isopropyl myristate, polysorbate 80, glycerol, and water

Phase studies were carried out on systems composed of isopropyl myristate, polysorbate 80, glycerol, and water at different glycerol-to-water ratios. Stable microemulsion gel, regions were identified, and an influence of the glycerol-to-water ratio on the area of existence of microemulsion gels was obtained. An optimum glycerol-to-water mass ratio of 2:8 was found for the largest microemulsion gel region. The rheological study indicated a pseudoplastic behavior of microemulsion gels, which makes them suitable for easier spreading on the skin. The apparent: viscosity of the examined microemulsion gels decreases when the glycerol-to-water mass ratio increases. The maximum value of apparent viscosity was det ermined when the combined glycerol-water content was dose to 40% w/w.