STERILIZATION AND FREEZE-DRYING OF DRUG-FREE AND DRUG-LOADED SOLID LIPID NANOPARTICLES

Solid lipid nanoparticles (SLN) have been prepared from three oil-in-w ater microemulsions, whose internal phase was constituted of different lipid matrices. The dispersion media were two aqueous solution of tre halose and Pluronic F68 at 2% besides distilled water. SLN were steril ized by autoclaving, were stable during sterilization and maintained a spherical shape and narrow size distribution as confirmed by TEM anal ysis. SLN dispersions in water did not present nanoparticles larger th an 1 mu m after storage at 4 degrees C for 1 year; they were freeze-dr ied after sterilization to b obtain dry products. Diazepam was used as model drug to incorporate into SLN, where it was shown by calorimetri c analysis to be in amorphous form. (C) 1997 Elsevier Science B.V.