Spray-drying of solid lipid nanoparticles (SLN™)

Aqueous dispersions of solid lipid nanoparticles (SLN(TM)) were converted by spray-drying into dry, reconstitutable powders which could be stored over a long period. After redispersion, the resulting granulates were still acceptable for i.v. administration with respect to the particle size distribution and toxicity. Therefore only physiologically acceptable excipients such as carbohydrates and alcohols (ethanol and methanol) were added to the SLN dispersions before spraying. The particle size was influenced by the applied spraying parameters and by the chemical nature of the lipid phase, the type of carbohydrate and the spraying, and the redispersion medium. An identical size distribution before and after the spraying process, followed by subsequent redispersion was achieved by: reducing the temperature by spraying alcoholic dispersions, reducing the lipid concentration while increasing the sugar concentration, and by redispersion in a poloxamer 188 solution. (C) 1998 Elsevier Science B.V. All rights reserved.