A method of making aggregate particles suitable for a powder aerosol composition that includes (a) forming a dispersion of nanoparticulate drug particles and/or nanoparticulate excipient particles in a non-aqueous liquid, wherein said drug particles and/or said excipient particles have a solubility of less than 10 mg/ml in said liquid dispersing media, wherein the nanoparticulate drug particles have a preselected crystalline form, and wherein, when the nanoparticles dispersed in said dispersion do not comprise excipient, the non-aqueous liquid has no suspension homogenizing surfactant dissolved therein (b) spray-drying the dispersion of nanoparticulate drug particles and/or nanoparticulate excipient particles to generate aggregate particles comprising nanoparticulate drug particles and/or nanoparticulate excipient particles, wherein the drug and/or excipient nanoparticles have maintained their preselected crystalline form, and wherein the aggregate particles have a mass median aerodynamic diameter of less than or equal to about 100 microns and wherein when the nanoparticles dispersed in said dispersion do not comprise excipient, the aggregate particles is substantially free of a homogenizing surfactant particles formed by such method and pharmaceutical compositions thereof.Linvention porte sur un procédé de fabrication dagrégats de particules, appropriés pour une composition de poudre pour aérosol, qui comprend (a) la formation dune dispersion de particules de médicament nanoparticulaire et/ou de particules dexcipient nanoparticulaire dans un liquide non aqueux, lesdites particules de médicament et/ou lesdites particules dexcipient ayant une solubilité inférieure à 10 mg/ml dans ledit milieu dispersant liquide, les particules de médicament nanoparticulaire ayant une forme cristalline prédéterminée et, lorsque les nanoparticules dispersées dans ladite dispersion ne comprennent pas dexcipient, le liquide non aqueux nayant pas de tensioactif dhomogénéisation de suspens
