- Tao Yi: College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
The objectives of the present work were, first, to develop a new solid self-microemulsifying drug delivery system (SMEDDS) for oral poorly water-soluble drugs such as nimodipine; and second, to evaluate its oral bioavailability in healthy rabbits. The liquid SMEDDS consisted of ethyl oleate, Labrasol, Cremophor RH 40 and nimodipine. The solid SMEDDS was prepared by spray-drying the liquid SMEDDS in a laboratory spray dryer, using dextran as solid carrier. The imaging of TEM and photo correlation spectroscopy revealed no difference in the droplet size of reconstituted microemulsion between both SMEDDS. Solid state characterization of the solid SMEDDS was performed by SEM, DSC, and X-ray powder diffraction. The same dose of nimodipine in the solid SMEDDS and in the liquid SMEDDS resulted in similar AUC and C(max) values, but the maximum absorption was retarded by the solid SMEDDS. AUC and C(max) after oral administration of the solid SMEDDS were 2.6- and 6.6-fold higher, respectively, compared with those of the conventional tablet. These results demonstrate that the solid SMEDDS may preserve an improved bioavailability with releasing microemulsion lipid droplets from the formulation in vivo. Thus, this solid self-microemulsifying system may provide a useful solid dosage form for oral poorly water-soluble drugs.