Design and evaluation of SEDDS exhibiting high emulsifying properties

Within this study ten different self-emulsifying drug delivery systems (SEDDS) mainly containing Labrasol, Kolliphor EL, Cremophor RH40, Transcutol, dimethyl isosorbide, PEG 400 and various types of Capmul were evaluated for their potential mucosal use. These formulations were evaluated regarding the minimum extent of dilution needed to guarantee self-emulsification, emulsification time, stability in different body fluids including simulated saliva, vaginal and tear fluid, dynamic viscosity and cytotoxicity. Furthermore, log DSEDDS/Water was determined for cyclosporine used as model drug. Results showed that SEDDS have to be diluted to a final concentration of at least ≤ 40% to guarantee their self-emulsification. Emulsification time was in dependence of the type of formulation between 30 s and 30 min. The resulting oily droplets maintained their size over the entire observation period of 4 h. An up to 3.8-fold higher dynamic viscosity was observed for concentrated SEDDS (30% (v/v)) in comparison to diluted SEDDS (1% (v/v)). Log D SEDDS/Water for cyclosporine was in dependence on the type of formulation between 1.7 and 3.6. According to these results, SEDDS seem to be promising delivery systems for lipophilic drugs even on mucosal membranes where comparatively low quantities of body fluids are available for emulsification of the system.