Disclosed is a method for producing a composition comprising nanoparticles of a therapeutically active compound, comprising the step of: dry milling a solid therapeutically active compound and a millable grinding compound in a mill comprising a plurality of milling bodies, for a time period sufficient to produce a solid dispersion comprising nanoparticles of the therapeutically active compound dispersed in an at least partially milled grinding compound. Also disclosed is a composition comprising the nanoparticle prepared by the method.