title: Formation of organic nanoparticles from volatile microemulsions.
abstract: A method for preparation of nanoparticles of poorly water-soluble organic materials is presented. By this method, an oil-in-water microemulsion containing a volatile solvent with dissolved model material, propylparaben, undergoes solvent evaporation and conversion into nanoparticles by spray drying. The resulting powder can be easily dispersed in water to give a clear, stable dispersion of nanoparticles with a high loading of propylparaben. By filtration of this dispersion it was found that more than 95wt.% of the dispersed propylparaben is in particles of less than 450nm. X-ray diffraction revealed that propylparaben is present as nanocrystals of 40-70nm. After dispersion of the powder in water, formation of large crystals rapidly occurs. Addition of polyvinylpyrrolidone (PVP) prevented crystal growth during dispersion of the powder in water. The inhibition of propylparaben crystal growth by PVP was studied by molecular dynamic simulations that addressed the binding of PVP to the propylparaben crystal. A comparison was made between PVP and polyvinylalcohol, which did not display crystal inhibition properties.
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. katymargulis@yahoo.com
authors.forename: Katrin
authors.initials: K
authors.lastname: Margulis-Goshen
authors.forename: Hadas Donio
authors.initials: HD
authors.lastname: Netivi
authors.forename: Dan T
authors.initials: DT
authors.lastname: Major
authors.forename: Michael
authors.initials: M
authors.lastname: Gradzielski
authors.forename: Uri
authors.initials: U
authors.lastname: Raviv
authors.forename: Shlomo
authors.initials: S
authors.lastname: Magdassi