Effect of adding an amphiphilic solubilization improver, sucrose distearate, on the solubilization capacity of nonionic microemulsions

We have studied the effect of adding sucrose distearate (2C(18)SE) on the solubilization capacity of microemulsions formed in the water/C12EO6/n-decane system. Upon addition of 2C(18)SE to the binary water/C12EO6 system, a lamellar liquid crystal region developed. This suggests that the rigidity of the surfactant layer is strengthened. The solubilization of water and n-decane in the bicontinuous microemulsions increases about three times upon replacing 10% C12EO6 With 2C(18)SE; besides, the HLB temperature is not greatly affected by 2C(18)SE. On the other hand, sucrose monostearate (C18SE) does not have such a function. The effect of added 2C(18)SE On the solubilization capacity of the discrete droplet-type o/w or w/o microemulsions was also studied. The efficiency of the solubilization-improving effect is reduced when the system is far from the HLB temperature. (C) 2001 Academic Press.