[Influence factors of the separation of steroids using oil-in-water microemulsion liquid chromatography].

The effect of the varying operating parameters on the separation of steroids was studied by oil-in-water microemulsion liquid chromatography (MELC). The parameters included the surfactant concentration, the type of oil phase, the nature of organic solvent additives, and the pore size of the stationary-phase. The optimized conditions for the separation of 6 steroids were as follows: a Venusil ASB C18 (T) column (5 microm, 30 nm, 250 mm x 4.6 mm) was used at 35 degrees C, the microemulsion mobile phase consisted of 30 g/L sodium dodecylsulfate (SDS), 0.8% (w/w) n-octane, 6.6% (w/w) n-butanol. The optimized method can be used for the separation, identification and simultaneous determination of steroids in bulk drugs and in pharmaceutical dose forms.