Confinement of Amorphous Lactose in Pores formed upon Co-Spray-Drying with Nanoparticles
(English)In: Journal of Pharmaceutical Sciences, ISSN 0022-3549, E-ISSN 1520-6017Article in journal (Other academic) Submitted
This study aims at investigating factors influencing humidity induced recrystallization of amorphous lactose, produced by co-spray-drying with particles of cellulose nanocrystals (CNC) or sodium montmorillonite (Na-MMT). In particular, the focus is on how the nanoparticle shape and surface properties influence the nano- to micrometer length scale nanofiller arrangement in the nanocomposites and how the arrangements influence the mechanisms involved in the inhibition of the amorphous to crystalline transition. The nanocomposites were produced by co-spray-drying. Solid-state transformations were analyzed at 60-94% relative humidity using X-ray powder diffraction, microcalorimetry, and light microscopy. The recrystallization rate constant for the lactose/CNC and lactose/Na-MMT nanocomposites was lowered at nanofiller contents higher than 60% and were stable for months at 80% nanofiller. The most likely explanation to these results is spontaneous formations of mesoporous particle networks that the lactose is confined within upon co-spray-drying at high filler content. Compartmentalization and rigidification of the amorphous lactose proved to be less important mechanisms involved in the stabilization of lactose in the nanocomposites.
IdentifiersURN: urn:nbn:se:uu:diva-300153OAI: oai:DiVA.org:uu-300153DiVA: diva2:950905