The properties of taurocholate-lecithin powder (SIF Powder) and the biorelevant media FeSSIF and FaSSIF prepared from the powder were investigated using various techniques. The powder is stable and shows no change in the physical or chemical characteristics for at least 12 months in the original container stored at 2-8 degC. FeSSIF and FaSSIF were stable with respect to hydrolysis for at least 48 h at 37 degC. Oxidation in FeSSIF was detected at a very low level and to an even lower extent in FaSSIF. FaSSIF comprises a complex mixture of colloidal aggregates including rod-like, spherical, disc-like mixed micelles and vesicles. Consistent particle size was achieved by equilibrating the medium at room temperature (RT) after preparation. In comparison, FeSSIF only comprises smaller mixed micelles and requires no equilibration. The dissolution rates of three poorly water-soluble model drugs tested in FaSSIF media differing in average particle size controlled at 30 nm and 50 nm were not statistically different. However, differences in the average particle size can affect visual clarity: FaSSIF is generally slightly opalescent above an average size of approximately 50 nm and appears clear below approximately 50 nm. Challenge tests showed that FaSSIF is more susceptible to microbial spoilage than FeSSIF. Reproducible FeSSIF and FaSSIF can be made conveniently from the powder by employing standard preparation methods at RT.