Maltodextrins as drying auxiliary agent for the preparation of easily resuspendable nanoparticles

The drying of biodegradable polymeric nanoparticles (NP) is mandatory to improve their physical and chemical stability over time. Spray- or freeze-drying can induce irreversible aggregation of NP and therefore the use of drying auxiliary agents is required. The ability of four grades of maltodextrins differing in dextrose equivalent (DE) (i.e. DE2, DE6, DE12 and DE38) to protect PLGA NP from stresses was studied. High Mw maltodextrins (DE2) was not functional for obtaining an easily resuspendable dried product, since it needs a prolonged time to fully hydrate. Maltodextrins at intermediate DE showed a poor ability to protect NP from irreversible aggregation probably because too sensitive to environmental variation. DE38, which did not alter ζ-potential of NP, allowed to obtain an easily resuspendable nanosuspension independently of the drying process. The effectiveness of such material was attributed to the easiness of spray-dry a low viscous solution and to the ability of substitute the water molecules’ hydrogen bonds with NP during freeze-drying.